Up to 180 W HV LCD TV Power Supply GreenPoint Reference Design

TND360/D
Rev. 0, February 2009
Up to 180 W High Voltage LCD TV
Power and Integrated Inverter Supply
12 February 2009
© 2009 ON Semiconductor
Disclaimer: ON Semiconductor is providing this reference design documentation
package “AS IS” and the recipient assumes all risk associated with the use
and/or commercialization of this design package. No licenses to ON
Semiconductor’s or any third party’s Intellectual Property is conveyed by the
transfer of this documentation. This reference design documentation package is
provided only to assist the customers in evaluation and feasibility assessment of
the reference design. It is expected that users may make further refinements to
meet specific performance goals.
2
Table of Contents
Overview..............................................................................................................4
LCD-TV Power Architecture and Evolution ......................................................5
Critical Design Objectives..................................................................................8
PFC Stage ............................................................................................................8
EMI filter ........................................................................................................9
Control Approach.........................................................................................11
Design Procedure ........................................................................................12
Test Results.................................................................................................16
Flyback Stage for Control, Signal & Audio Power .........................................18
NCP1351 variable OFF time PWM controller ..............................................18
ON Mode Operation.....................................................................................20
Cross Regulation Considerations ................................................................21
Flyback Waveforms .....................................................................................22
Standby Mode Considerations.....................................................................23
Higher Standby power capability solution ....................................................26
Configuring the Flyback for other output voltages........................................28
The secondary regulation and safety circuit ................................................32
Flyback safety tests .....................................................................................33
High Voltage Backlight Inverter.......................................................................39
Microsemi LX6503 backlight controller ........................................................40
Fixed frequency zero voltage switching Full Bridge .....................................42
Full Bridge Driver Circuit Description ...........................................................48
Full Bridge Zero Voltage Switching Waveforms...........................................50
High Voltage (HV) Transformer ...................................................................52
Basic Transformer Construction ..................................................................52
CCFL Drive and Current Balancing.............................................................53
Overall Efficiency Performance....................................................................58
Appendix ...........................................................................................................59
Board Photographs......................................................................................61
Schematics of SMPS1 .................................................................................62
Bill of Materials of the HV-LIPS board (SMPS1 Version).............................66
NCP1351 .....................................................................................................74
NCP1606/7 ..................................................................................................74
LX6503 ........................................................................................................74
Magnetics Suppliers ....................................................................................74
References on Energy Standards................................................................75
Schematics of Complete PCB with all Configuration Options ......................76
3
Overview
This reference document describes a built-and-tested, GreenPointTM solution for
and LCD-TV Integrated Power Supply (LIPS) that combines the main system
power with the backlight inverter. In this architecture the inverter is directly
powered from a high voltage rail (HV-LIPS) to improve the system power
conversion efficiency and simplify the overall architecture by eliminating a power
conversion stage. In this reference design, the inverter is configured to power 12
cold cathode fluorescent lamps (CCFL). All the circuitry is resident in on a single
PCB as might be found in a 32” LCD-TV. This reference design circuit consists
of a single-sided 175 mm x 330 mm printed circuit board designed to fit into the
chassis of a LCD-TV. The height is 25 mm.
Figure 1 illustrates the basic system architecture. As shown, ON Semiconductor
devices are combined with a next generation backlight controller from Microsemi
to provide a complete power solution. This design has been engineered to
achieve optimum performance compared to traditional LCD-TV power
architectures and at the same time simplify the overall bill of materials by
selecting a proprietary high efficiency fly-back controller topology that eliminated
the need for a dedicated standby power stage and still meets global standby
power requirements for television sets.
Figure 1: Overall System Block Diagram
4
LCD-TV Power Architecture and Evolution
One of the key differentiating factors of a flat TV over a classical TV is the
thickness of the cabinet - the thinner the better. This involves several
considerations:
•
•
•
•
The amount of power to be delivered is relatively large: the number of
watts per cm3 is much larger compared to the one in a CRT TV.
Because the TV will be used in the living room, audible noise can be a
problem, and the use of fans is limited.
Overall cost in the very competitive environment of the consumer
electronics world is critical
The panel, the power supply and the audio amplifiers are close to each
other; therefore the generation of EMI and susceptibility to EMC could
have an impact on picture and sound quality.
Mainstream (32”+) Flat TVs power supplies require the generation of several
voltage rails to power the various system blocks such as audio, backlighting, and
signal processing. The power supply does not generate all the voltages required
within the set, instead local linear and DC-DC converters on the signal
processing board are used to provide various low voltage rails. It is fairly
common for manufacturers to use a universal power supply that supports 90-265
Vac. This allows a single power supply design based on a specific TV size to be
used for a series of models for different regions simplifying logistics and reducing
development cost. If the LCD-TV is intended for global use and the power is
over 75 W, it is necessary to comply with IEC 61000-3-2, the EU standard for
harmonic reduction, so an active power factor control stage is used.
The largest single power consuming sub-system within the LCD-TV is the
backlight. The majority of LCD-TVs today use an array of CCFL lamps as the
backlight light source. These lamps are intended to be driven by a high AC
voltage and the current within the lamps is regulated to achieve even
backlighting. Historically the inverter was a separate module powered from a
nominal 24 V dc supply. An example of the classical 24 V dc architecture can be
found in earlier LCD-TV reference designs such as TND316/D. While this
approach simplified the design of the LCD-TV because the backlighting
requirements are tied to the LCD panel and one power supply design could be
used for panels from multiple vendors, the approach was inefficient and added
an extra power stage. For example, the AC input is boosted to 400 V dc in the
PFC stage and then transformed to 24 V dc with a flyback of resonant LLC half
bridge stage. The 24 V dc was then provided to the inverter module which
converted the low voltage DC voltage into a high voltage (> 1000 V ac) to drive
the lamps. This multi-stage conversion process results in significant losses and
increased system cost.
5
The HV-LIPS architecture employed in this reference design is intended to
improve the overall system efficiency by eliminating the 400 to 24 V dc
conversion stage and directly power the inverter from the high voltage PFC rail.
This requires the merging of the traditional power supply function within the LCDTV with the inverter in a seamless manner to optimize the overall system
solution. This has three primary benefits:
y
y
y
Increases overall system efficiency
Reduces active power consumption and heat generation which enhances
system reliability and reduces component stress
Reduces the overall number of parts to improve the overall bill of materials
cost
The other drivers for this architecture are increased consumer awareness on the
cost of energy and new regulatory considerations that are intended to address
overall power consumption of TVs and their impact on environment and the
energy infrastructure.
Historically, standby losses in consumer electronics were the primary concern of
governmental and power conservation agencies since these devices are always
connected to the AC main and always consuming some power, even in off mode.
As a result, there are numerous voluntary and regulatory standards around the
globe intended to reduce standby power. Some of the typical requirements are
listed below.
Region /
Country
China
Korea
Program name
Requirements for Televisions
CECP
Energy Saving
3W
3W
European Union
EU Eco-Label
European Union
EU Code of
Conduct
GEEA
Energy Star®
1 W or
9 W with an embedded set top box
(STB)
3 W with a STB
Europe
US
1W
1W
Table 1: Example Standby Requirements by Region
As the screen size of direct view flat TVs increases, so does the ON mode power
consumption. As a result, regulatory agencies have become concerned about
the cumulative impact on the power grid of ON state power as flat TVs gain
market share and consumers switch from CRT and projection TVs to large
display direct view technologies such as Plasma and LCD-TV. In the US, the
6
Environmental Protection Agency (EPA) started a process in 2006 to revise the
existing voluntary Energy Star standard for TVs to include active power
consumption requirements as part of its criteria for qualifying energy efficiency
TVs. This standard was revised and went into effect in November 2008 and now
incorporates maximum active power requirements as a function of screen size.
As part of the specification development process, existing TVs were evaluated to
the proposed standards and at the time, less than 30% of the TVs tested on the
market meet the active and standby test requirements. The active power limits in
the Version 3 Energy Star standard are listed in the table below. As illustrated,
there are a series of equations based on screen area and vertical resolution to
determine the active power limit. For example, a 42” High Definition TV can
consume no more than 208 W out of the box when tested against an
internationally approved audio/video test signal set which are meant to represent
a common viewing environment.
Screen Area
Maximum On Mode
Power Consumption
Maximum On Mode Power
Consumption
(A expressed in in2)
(A expressed in cm2)
Non-High Definition TVs (i.e. <= 480 Native Vertical Resolution)
PMax = 0.120 * A + 25
All Screen Areas
PMax = 0.01860 * A + 25
High Definition and Full High Definition TVs (i.e. > 480 Native Vertical Resolution)
A < 680 inch2 (< 4,387 cm2)
PMax = 0.200 * A + 32
PMax = 0.03100 * A + 32
680 inch2 <= A < 1045 inch2
(4,387 cm2 <= A < 6,742 cm2)
PMax = 0.240 * A + 27
PMax = 0.03720 * A + 27
A >= 1045 inch2 (>= 6,742 cm2)
PMax = 0.156 * A + 151
PMax = 0.02418 * A + 151
Table 2: Version 3 Energy Star Active Power Limits
Other countries have or are considering changes to their energy regulations to
drive the adoption of more power efficient TV products. For example, the Japan
Top Runner program takes a holistic approach which considers total energy
consumption (kWh/year) on an annual basis assuming 4.5 hours of active use
per day. This focuses the attention of TV manufacturers on methods to optimize
their system architectures for both active and standby power consumption.
Further details of the regional approaches to energy requirements for TVs can be
7
accessed by referring to appendix. Finally TV manufacturers are starting to
market the green aspects of their products to highlight and differentiate their
offerings and appeal to consumers who are concerned about the rising cost of
energy. While improvements in active power go beyond the power supply, and
include the display, backlight source, video and audio signal processing, and
control architectures, the HV-LIPS architecture in this reference design is
designed from the ground up to save power over the traditional architecture.
Moreover it is designed to reduce the total system cost at the complete bill of
materials level.
Critical Design Objectives
Input Voltage: Universal input 85-265 V ac, 47-63 Hz
System Supply
y
y
•
•
•
•
•
Active Power Factor Corrected, IEC61000-3-2 Compliant
Maximum steady state power 50 W, 60 W Peak
12 V / 4 A Peak
5 V / 2.5 A Peak
24 V - MOSFET gate drive bias
Flexibility to be modified to support other voltage/current configurations
Standby Pin< 400 mW with 50 mW load (5 V at 10 mA)
Inverter Supply
•
•
•
•
•
100 W Capable
Strike voltage > 1500 V ac, Operating Voltage >800 V ac
Fixed frequency inverter adjustable between 40-80 kHz
Digital and Analog dimming capable
Capable of synchronization to video clock source
PFC Stage
The heart of the High Voltage LIPS architecture is the active PFC front-end boost
stage. First, it allows the design to meet the harmonic content requirements of
IEC61000-3-2 which applies to power supplies with input power above 75 W.
Secondly, it provides a regulated 400 V dc high voltage rail for the inverter
section. The inverter utilizes the Microsemi LX6503 backlight control IC which is
configured in a fixed frequency resonant full bridge topology. The backlight
controller manages the power conversion process and provides all the necessary
control functions to regulate the current to an array of CCFL lamps including the
strike and dimming functions necessary for the LCD-TV.
Beyond powering the backlight, the PFC also provides power to an isolated
flyback switch mode power converter which generates all the necessary voltage
rails to power the digital and analog circuitry that perform the control, interface,
signal processing, and audio amplification functions within the LCD-TV. The
8
power required for this block can vary from 30 – 60 W depending on the set of
features and functions that the LCD-TV performances. To simplify and reduce
the overall complexity of the power conversion stage, a proprietary high
efficiency flyback controller (NCP1351) has been selected which eliminates the
need for a dedicated power standby power supply for most LCD-TV applications.
The NCP1351 was selected because it utilizes a quasi fixed ON time control
scheme which reduces the switching frequency of the flyback converter as the
load requirements are reduced. The two additional switches (placed on the
secondary) disconnect the main power loads to eliminate parasitic losses in
standby mode.
In summary, the architecture combines a front end power factor correction stage
with an optimized flyback stage which eliminates the need for a dedicated
standby power supply and a highly efficient, full featured inverter with current
balancing to drive the CCFL lamps which backlight the LCD-TV panel. All these
functions are integrated on a single PCB which includes the JIN-current
balancers to provide a complete power solution.
EMI filter
The input stage consists of a common mode filter (L5) combined with a
differential filter composed of L1 (150 µH) and filter capacitors C1 and C3 (2 x
470 nF) which have been added to filter the low frequency EMI due to the
discontinuous mode PFC. Varistor RV1 is used to suppress high energy pulses
and mains surges which may disturb overall operation. Resistors (R15-R20) have
been added to discharge C18 in a reasonable time when the mains power is
disconnected. This has a minor impact on standby consumption by increasing
the power by 59 mW at 230 V ac. A mains voltage is provided to the flyback
controller to allow it to start up directly from the line and avoid increased power
dissipation during standby.
9
2
BD1
+
1
GBU806
3
C1
0.47uF
450V
RV1
C5 Y 1nF
C9
L1
150uH
4
C3
0.47uF
450V
TVR10471KSY
C6 Y 1nF
X2 100nF
275V
L5
CFS24 - 2mH
RV5
eclat
RV4
eclat
C18
R15 150K
R16 150K
R17 150K
R20
150K
R19
AC Line - For PWM start
150K
1
150K
275V
1
R18
X2 1uF
2
J2
A
2
J1
A
F1
FUSE 4A 250V (Axial Lead)
L
FG
FG
N
CN1
4333-W05ST
Figure 2: AC Input Stage
10
Control Approach
The NCP1606B is a PFC controller designed to operate in variable frequency
critical conduction mode (CrM) which is the most appropriate solution for 150 W
(< 180 W):
•
•
•
The discontinuous operation mode does not require a hyper fast diode
with trr < 25 ns (with higher Vf) but allows the use of the latest diodes
developed by ON Semiconductor for discontinuous mode PFC circuits.
The new MUR550 has a Vf < 0.98V for 5A @ 150°C which provide an
improved efficiency for this 520 V diode which provide 20% of margin for
the 410 V PFC output.
In CrM, the next switching cycle is initiated when the boost inductor
current reaches zero. This control method means that the frequency
inherently varies with the line input voltage and the output load. For
detailed information on the operation of CrM Boost converter for PFC
applications, please refer to AND8123 at www.onsemi.com.
D1
L1
150uH
R4 27K
C3
0.47uF
450V
2
11
7
8
L2
1N5406(DO-201)
D2
MUR550APF(DO-201)
RT1
NTC 2R5
PFC_OUT
TF2815 - 150uH
R24
68
R2
1M3 1/4W
2
Q1
STP11NK50ZFPN
R5
68
8
ZCD
VCC
DRV
Ctrl
7
R25
470
6
CT
GND
FB
CS
C7
10nF 630V
3
1
R6
1M3 1/4W
1
+
C8
68uF 450V
+
BC856ALT1(SOT23)
C11 100nF
2
C12
3
Q2
390nF
R11
3
5
D3 MMSD4148
R8
68
2
IC1
NCP1606B
C10
68uF 450V
R9
10K
R10
1M3 1/4W
56K
1
4
R12
220
+
C13
47uF
C14
100nF
C16
1nF
R26
680
C19
220pF
R13
24K9
R14
0.10 2 W
ZD1
1N4733A
5.1V
PFC_GND
PFC_VCC
Figure 3: PFC Stage
Pin 1 (FB) senses the boost output voltage through the resistor divider formed by
R2, R6, R10 and R13. (The NCP1606B allows 4 time higher impedance than
NCP1606A for the same Over Voltage Protection: thus reducing parasitic
standby power consumption). This pin is the input of the error amplifier, whose
output is pin 2 (Ctrl). A combination of resistor R11 and capacitors C11 and C12
between those pins form a compensation network that sets the bandwidth of the
converter. For good power factor, this bandwidth is generally below 20 Hz.
Capacitor C16 is connected to pin 3 (Ct) to set the on time for a given control
voltage. The added resistor R25 in series with C16 provides an offset which allow
further reduction of Ton min to provide better stability during light load and high
11
mains input voltage. Additional resistors from the input voltage to Ct could
improve the power factor performance but in this application it is not necessary.
Moreover they would increase power consumption in standby mode.
CS (pin 4) provides cycle by cycle over current protection. This is accomplished
with an internal comparator which compares the voltage generated by the switch
current and Rsense (R14 through divider R12 and R26) to an internal reference.
The NCP1606B has a lower current sense threshold of 0.5 V (compare to 1.7 V
for the NCP1606A) to reduce Rsense power dissipation. The added capacitor
C19 filters any switching spikes which may impact the operation of the current
sense input. Zener ZD1 is added to protect R14 in case of short circuit of the
power switch Q1 and avoid damage to the controller with an open power
connection.
Pin 5 (ZCD) senses the demagnetization of the boost inductor. The next driver
switching cycle begins when the voltage at this pin rises above 2.1 V (typical)
and then drops below about 1.6 V (typical). A resistor (R4) from the zero current
detection (ZCD) winding limits the current into this pin. By pulling this pin to
ground, the driver pulses are disabled and the controller is placed in a low
current standby mode.
The NCP1606B features a powerful output driver (pin 7). This driver is capable
of switching the gates of large MOSFETs in an efficient manner but to reduce
EMI with a long PCB lead trace and high di/dt switching an added PNP transistor
Q2 has been added which is placed as close as possible to the power switch Q1.
Additionally, the driver incorporates both active and passive pull-down circuitry to
prevent the output from floating high when Vcc is off.
Pin 8 (Vcc) powers the controller. When Vcc is below its turn on level - Vcc(on),
typically 12 V dc - the current consumption of the part is limited to < 50 uA. Vcc
is directly supplied from the flyback converter through signal transistor Q108
controlled by the optocoupler PC101 which is OFF in Standby mode:
•
•
•
Both Vcc (Flyback and PFC) are compatible
The PFC is switching OFF so that the flyback is directly supply by the
mains voltage without boost operation in Standby mode
This approach improves further standby power performance thanks to the
two stage SMPS system
Design Procedure
The design of a CRM Boost PFC circuit has been discussed in several ON
Semiconductor application notes (see appendix). This section will briefly go
through the design procedure for a 400 V, 180 W converter based on the
NCP1606B PFC controller. A design tool, which gives these equations and
results, is available at www.onsemi.com.
12
Step 1: Define the boost parameters
Minimum AC Line Voltage
VacLL
Maximum AC Line Voltage
VacHL
Line Frequency
fLINE
Boost PFC Output Voltage
Vout
Maximum Output Voltage
Vout(max)
Boost Output Power
Pout
Minimum Frequency
f(min)
Estimated Efficiency
η
88
264
47-63
400
430
170
90
95
Vrms
Vrms
Hz
V dc
V dc
W
kHz
%
Step 2: Calculate the Boost inductor and peak currents
The inductor’s peak current is greatest at full load and low line. The value is
calculated with eq 1:
2 ⋅ 2 ⋅ Pout
= 5.8 A
(1)
Ipk (max) =
η ⋅ Vac LL
Now, the maximum boost inductor can be calculated:
2 ⋅ Vac LL ⋅ (
Vout
− Vac LL )
2
L≤
= 164μH
Vout ⋅ Vac LL ⋅ Ipk (max) ⋅ f (min)
2
(2)
A value of 150 µH was selected.
The fmin may be considered high but this allows the use a small / cost effective
PFC coil without major impact on both efficiency and EMI.
Step 3: Size the power components
The power components must be properly sized for the necessary current and
voltages which they will experience.
1. The Boost inductor, L
The inductor’s peak current is greatest at full load and low line. The value is
calculated with eq 1:
Icoil RMS =
2 ⋅ Pout
3 ⋅ Vac LL ⋅ η
= 2.35 A
(14)
An ER28 core was selected as it is a high volume commonly available product
with a total height < 23 mm. The 150 µH is build with 55 turns of 0.10 mm x 70,
is able to manage up to 7 A for L > 80% @ 100°C with limited power dissipation
thanks to the very good wire. The auxiliary winding for ZCD has 6 turns of 0.22
mm wire. The reference of the coil is JLC2832 and is available from Shenzhen
Jewel Electric.
13
2. The Boost Diode, DBOOST D2
Id MAX (rms ) =
Pout
4 2⋅ 2
= 1.2 A
⋅
⋅
π
3
η ⋅ Vac LL ⋅ Vout
(15)
The MUR550APF, axial type in DO-221 was selected as it has a much lower Vf
than standard ultra fast diodes and is specially designed for CrM / DCM PFC,
thus improving the boost stage efficiency without cost increase.
3. The MOSFET, Q1
I M (rms) =
4 ⎛ Pout ⎞
⎟
⋅⎜
3 ⎜⎝ η ⋅ VacLL ⎟⎠
2
⎡ ⎛ 8 ⋅ 2 ⋅ VacLL ⎞⎤
⎟⎥ = 2 A
⋅ ⎢1 − ⎜⎜
⎟
⎢⎣ ⎝ 3 ⋅ π ⋅ Vout ⎠⎥⎦
(16)
The MOSFET will see a maximum voltage equal to the Vout overvoltage level
(430 V dc for this example). If 90% derating is used for the MOSFET BVDSS, then
a 500 V FET is necessary to give adequate margin.
A STP11NK50ZFPN with 11 A capability and an RDSON < 0.52R @ 10 A was
selected to minimize power dissipation. This power MOSFET is housed in a TO220FP and is mounted on a heat-sink to improved power dissipation.
4. The sense resistor, RSENSE
RSENSE =
Vcs(lim it )
= 0.087 Ω
Ipeak
(17)
For the NCP1606B, Vcs(limit) = 0.5 V (typ)
To simplify design / procurement issues, a standard 0.1R with resistor divider
(R12 & R26) can be used to adjust the current limit to the desired threshold level.
PRsense = I M (rms) 2 ⋅ RSENSE = 0.4 W
(18)
5. The bulk capacitor, CBULK
32 ⋅ 2 ⋅ Pout 2
2
− (I LOAD (rms) ) = 1.13 A
Ic(rms) =
2
9 ⋅ π ⋅ Vac LL ⋅ Vout ⋅η
(19)
The bulk cap value was calculated to give acceptable ripple voltage while
avoiding triggering the output over voltage protection. To avoid expensive low
profile Snap-in types and stay below the 25 mm height maximum of this design,
two standard capacitors (C08/C10) are used in parallel and mounted flat on the
board to achieve the target ripple current while offering a cost effective solution.
14
The capacitors selected are KXG 68µF 450 V 18*20 or 18*25 mm 0.58 A rms
from Nippon Chemi-con.
Step 4: Supply Vcc to Bias the PFC
Generally, the most straightforward way to bias the PFC chip is with a resistor
connected between the AC input and Vcc (pin 8) to charge the Vcc cap. For the
LCD-TV application, there is a flyback converter that is always on even when the
TV is in standby. As a result, the PFC controller is supplied directly from the
auxiliary winding of the flyback converter thought and optocoupler which switches
OFF the PFC when the TV is powered down and enters standby mode.
Q108
BC846ALT1(SOT23)
1
3
R147 100
VCC1
R148
4K7
2
PFC_VCC
3
4
R153 10K
PC101B
SFH817A
R154
100K
PFC_GND
Figure 4: PFC Bias Control
When the TV set must be started, the microprocessor provides an ON signal
which drives the optocoupler PC101 on; so that the flyback Vcc is apply to the
PFC Vcc through Q108. When the Vcc voltage exceeds the Vcc(on) level (12 V
dc typical), the internal references and logic of the NCP1606 turn on. The
controller has an under-voltage lockout (UVLO) feature which keeps the part
active until Vcc drops below about 9 V dc. This hysteresis is large enough to
handle the flyback Vcc variation under normal load variation.
Step 5: Limit the Inrush Current
The sudden application of the mains to a PFC circuit can result in a large in-rush
current and voltage overshoot. To resize the power components to handle this
transient event is cost prohibitive. Furthermore, since the PFC is configured in a
boost topology, the controller cannot do anything to protect against this since the
voltage is applied through the inductor and rectifier to the output capacitor of the
boost converter. To address this, a rectifier D1 is added from the input voltage to
the output voltage bypassing the inductor and diverting the startup current to the
bulk capacitor. The bulk capacitor is then charged to the peak AC line voltage
without resonant overshoot and without excessive inductor current. After startup,
DBYPASS will be reverse biased and will not interfere with the boost converter.
Moreover, to further reduce the in-rush current which can be critical for the
mains fuse (limited I2xt), a 2.5R NTC (negative temperature coefficient)
15
thermistor (RT1) is placed in series with the mains connection (before the bridge)
to limit the in-rush current. The resistance value drops from a few ohms to a few
milliohms as the device is heated by the I2R power dissipation. Alternatively (as
used in our application), this NTC can be placed in series with the boost diode.
This improves the active efficiency as the resistor only sees the output current-instead of the input current (particularly interesting for low US mains supply).
However, in this configuration, NTC resistor may not be able to fully protect the
inductor and bulk capacitor against in-rush current during a brief interruption of
the mains, such as during line drop out and recovery.
Test Results
For figures 5-6, the signals illustrated in plots from top to bottom are as follows
•
•
•
•
STANDBY
+5 V
PFC VCC
PFC-OUT
5V/div
5 V/div
10 V/div
200 V/div
20 ms/div
1 ms/div (expanded scale)
Figure 5: Starting phase from Standby to ON
1 s/div
Figure 6: Switching OFF from ON to Standby
16
Mains current 0.5 A/div
F min 208 kHz (1 µs/div)
Vin = 110 V ac, Pout = 75 W
Fmax 295 kHz (1 µs/div)
Figure 7: Input AC Current, PFC Switch Frequency (Drain Voltage of Q1)
Mains current 0.5 A/div
Fmin 297 kHz (1 µs/div)
Vin = 230 V ac, Pout = 75 W
Fmax 450 kHz (1 µs/div)
Figure 8: Input AC Current, PFC Switch Frequency (Drain Voltage of Q1)
Mains current 1 A/div
Fmin 105 kHz (2 µs/div)
Vin = 110 V ac, Pout = 180 W
Fmax 158 kHz (2 µs/div)
Figure 9: Input AC Current, PFC Switch Frequency (Drain Voltage of Q1)
Mains current 1 A/div
Fmin 158 kHz (2 µs/div)
Vin = 230 V ac, Pout = 180 W
Fmax 562 kHz (0.5 µs/div)
Figure 10: Input AC Current, PFC Switch Frequency (Drain Voltage of Q1)
17
Flyback Stage for Control, Signal & Audio Power
With a dedicated dc-ac converter to supply the lamps, the flyback SMPS is used
to provide power to all the analog and digital blocks use for control, signal
processing and audio amplification. With a limited overall requested power (< 60
W), it is possible to consider a flyback with standby mode without the need of a
dedicated standby SMPS which improves the overall cost effectiveness of the
solution. To achieve such a feat requires a controller architecture that is
optimized for high efficiency at light load conditions.
NCP1351 variable OFF time PWM controller
The NCP1351 is a variable frequency controller implementing a fixed peak
current (quasi-fixed-Ton) together with a variable off time technique. It is tailored
for low power applications, mainly off line flyback power supplies below 80 W.
Based on a fixed peak current technique, the NCP1351B decreases its switching
frequency as the load becomes lighter. As a result, a power supply using this
solution naturally offers excellent no-load power consumption, while optimizing
the efficiency under other loading conditions. As the frequency decreases, the
peak current is gradually reduced to approximately 30% of the maximum peak
current to prevent transformer mechanical resonance. The risk of acoustic noise
is thus greatly diminished while achieving overall good standby power
performance.
18
R100
1M 1/4W
AC Line - For PWM start
R101
1M 1/4W
R102
1M 1/4W
T100
ER28L
1
PFC_OUT
R104
33K 2W
D101
MUR160
R108
0.47R 2W
PFC_GND
C100
10nF 250V
3
11
P
VCC1
4
R112
3K3
PC100B
SFH817A
3
R114
0
1
2
C112
470nF
R121
2K7
3
IC100
NCP1351B
FB
Vcc
CT
Timer
CS
Latch
D104
MMSD4148
R116 100
6
7
C114
100nF
D105
BAV21
C142
220uF/35 V
8
C113
100nF
R117 47
+
12
6
+
C116
10uF/35 V
+
C115
10uF/50 V
R118 10
5
ZD101
1N5929B 22V
P
4
C117
270pF
GND
Drv
5
C118
100pF
R125
1K
C119
100nF
9
10
P
D110
MMSD4148
C121
270pF
R129 100k
R130 150k
7
8
OPP CKT
C140
22pF
R134
27
D113
MMSD4148
Q106
STD3NK60ZT4
2
R170 1K
Q107
BC856ALT1(SOT23)
R136
47k
3
1
P
Figure 11: Primary side of the flyback converter
A 270 pF capacitor (C117) connected on pin 2 (Ct) defines the maximum
frequency without feedback information. An adjustable timer permanently
monitors the feedback activity and protects the supply in the presence of a short
circuit or overload. The feedback is completely independent of the coupling
between transformer windings. Once the timer elapses (capacitor C114 100 nF
connected on pin 8 “Latch” reaches 5 V dc), the NCP1351 stops switching and
tries to restart. On the NCP1351A, the protection is latched, and on the
NCP1351B it has auto-recovery which is optimum for LCD-TV applications.
The Latch fault input (pin 7) is available to provide additional protection functions
such as over-voltage protection (OVP) by sensing the primary auxiliary fly-back
voltage. A fault is detected when pin 7 exceeds 5 V dc. The OVP detect signal is
generated when the zener diode ZD101 starts to conduct current indicating the
OVP fault. Note that neither the NCP1351A & B will auto-restart when the fault is
removed due the latch function on pin 7 as a result the AC power must be
disconnected to reset the NCP1351.
19
The internal structure features an optimized arrangement which results in an
extremely low start-up current, a fundamental consideration when designing a
power supply to achieve low standby mode. The starting resistors R100-101-102
(3 x 1MR) are connected directly to the mains to limit power consumption in
standby. To reduce the starting time, the above starting resistors charge a small
10 µF capacitor (C115). Once the SMPS has started up, the voltage from the
auxiliary winding supplies the Vcc pin through diode D105. To avoid any startup
issues under light switching, a larger capacitor C142 is connected through the
isolation diode D104 to allow a smaller capacitor value to start the IC quickly.
The negative current sensing technique minimizes the impact of the switching
noise on the controller operation and allows the user to select the maximum peak
voltage across the current sense resistor R108. Its power dissipation can be
optimized and adjusted by R112. Lossless mains over-power-protection is
provided through a network of R130, C121, D110 and R129 which is connected
to the auxiliary flyback winding. Finally, the bulk input ripple ensures a natural
frequency dithering which smoothes the EMI signature.
To provide better noise immunity in the PCB layout, an additional RC network
R170 & C140 between DRV pin 5 and CS pin 3 provides leading edge blanking
(LEB) which avoids instability due to noise on CS. While this may not normally
be required with a negative current sense, in this case it improves performance
without shortening switching cycles. Due to the negative current sense, the LEB
is implemented with positive information from the DRV signal.
The feedback pin 1 (FB) operates based on a current signal that allows a direct
connection to the optocoupler. C112 and R121 are used to define the regulation
loop response time. Although the Driver pin 5 (DRV) is capable of driving directly
the Power MOSFET Q106, an additional PNP bipolar transistor Q107, placed
very close to the MOS, is used to switch OFF the MOSFET and avoid high di/dt
on long PCB tracks thus reducing EMI generation. As illustrated, the 8 pin SOIC
based NCP1351 provides all the basic SMPS control functions and give the user
the option to implement numerous protection features to ease the design of a
rugged and reliable low power switching power supply.
ON Mode Operation
Since the controller operates in quasi-fixed-Ton the switching frequency does
vary with load. For light loads, the flyback converter operates in discontinuous
mode (DCM). As the load increases the frequency increases until the controller
enters continuous conduction mode (CCM) which is optimal for highest
efficiency. The SMT (Switch Mode Transformer) has been designed to operate
in both DCM and CCM to maximize performance.
In CCM higher inductance is required which increases the number of turns in the
transformer, this mode provides better cross regulation due to the lower voltage
per turn which allows better adjustment of the multiple output voltages and
20
increase the coupling between all secondary windings and between primary to
secondary. This avoids a dead time which improves overall current form factor
and reduces overall peak current in the system (MOS, transformer, diodes and
capacitors). A possible drawback of approach is the recovery time of secondary
rectifier power diodes, but this issue does not exist here since all secondary
diodes use schottky technology in view of the output current required. The
primary / secondary turn’s ratio has been choosing allow the use of high volume
cost effective 600 V MOSFET. The transformer has a primary inductance of 2.5
mH which allows it to be in DCM for low power and enter CCM around 35 W
output. The primary current is around 1.6 A for 60 W.
Build on an EER28L, the transformer design consists of the following:
y
y
y
y
Primary has 2 x 55 turns
Auxiliary Vcc has 26 turns
5V secondary has 9 turns
12V secondary build on top of 5V has 9 turns
The reference of the transformer is BCK-28-1050 and is available from Shenzhen
Jewel Electric.
Cross Regulation Considerations
Achieving good cross regulation is a design challenge in LCD-TV applications as
the tolerances are tight, typically +/- 5% and the dynamic operation can vary
widely due to the high dynamic range of the audio amplification and the variety of
signal processing power load depending on the input video source. Below is the
typical output voltage and load range for the baseline reference design (SMPS1).
•
•
+5V from 0 to 2.5A
+12V from 0 to 4A
To improve the overall cross regulation performance, the +5V diode is connected
in the ground (GND) of the winding with +12 V on top of the 5 V winding. The
drawback of that is that both the +5V and +12V current go through both the 5 V
diode and winding (increasing power loses mainly in the +5V diode), the
advantage of this configuration is that the 12 V only sees 7 V of variation. An
additional advantage of this construction is that the reverse voltage of the 12 V
diode is limited by the same difference. Note the transformer was designed with
a low turns ratio thus reducing the effective current but increasing the reverse
voltage of the diode. In the reference design, a 100 V is used to ensure
adequate design margin and avoid the possibility of any reliability issues. This
also simplified procurement as the same T0-220 MBR20100CTG diode is used in
both outputs.
21
Flyback Waveforms
Drain voltage
200 V/div
Drain current
1 A/div
Figure 11: 25 kHz Operation (DCM)
PFC = 400 Vdc, 5 [email protected] 0.5 A and 12 V @ 0.5 A
Drain voltage
200 V/div
Drain current
1 A/div
Figure 12: 30 kHz Operation (CCM)
PFC = 400 Vdc, 5 [email protected] 1 A and 12 V @ 2 A
Drain voltage
200 V/div
Drain current
1 A/div
Figure 13: 43.8 kHz Operation (CCM)
PFC = 400 V dc, 5 [email protected] 2 A and 12 V @ 4 A
22
5 V diode D111, Vrr = 40 V Max
10 V/div 10 µs / div
12 V diode D107, Vrr = 52 V Max
Figure 14: 17 W load: 5 [email protected] 1 A and 12 V @ 1 A (DCM mode)
5 V diode D111, Vrr = 35 V Max
10 V/div 4 µs / div
12 V diode D107, Vrr = 50 V Max
Figure 15: 52 W output: 5 V @ 2 A and 12 V @ 3.5 A (CCM mode)
Standby Mode Considerations
The architectural approach used in the NCP1351 is optimized to achieve optimal
performance for light load efficiency. As a result, a dedicated standby flyback
converter is not required in this reference design. In standby mode, there is
limited power required to keep the microprocessor and control circuitry biased
when the LCD-TV is switched off. To achieve this low standby performance, it is
necessary to have additional switches on the secondary side to disconnect both
5 V dc (Q113) and 12 V dc (Q114) so that only the 5 V dc standby power rail
remains connected. Those two switches are supply with VS4 from a charge
pump (CC103, D100, ZD100 and C101) to avoid an additional winding on the
transformer T100.
This available higher voltage allows the use of NMOS switches instead of PMOS
switches for the high side switches power rails. Avoiding PMOS switches
reduces cost and solved additional safety issues in the event of an overload or
output short circuit since the PMOS switches could go out of saturation and enter
23
the linear region resulting in increased power dissipation and possible
overheating.
T100
ER28L
C103
10nF 250V
1
F100
0.47 1/2W
VS4
D100 BAV21
ZD100
1N5929B
15V
+ C101
10uF/50V
J103
A
J100
A
+
C106
1000uF/16V
R113 7.5K 1/4W
2
1
11
2
3
1
VS3
VS2
1
L101
1
2
+
3
C109
1000uF/16V
10uH
2
Q114
3
2
NTD3055-094T4G DPAK
+12V
R119 10K
+
C110
1000uF/16V
1
12
6
+
R120
20K
Vref
D107
MBR20100CTG (TO220)
5
Q103
BC846BDW SOT363
C143
4.7nF
R124
470
+12V
C111
330uF/16V
STB
D108
MMSD4148
R122
4K7
R127 2K2
J104
2
1
2
1
C122
1000uF/16V
+
L102
10uH
2
2
Q113
3
NTD14N03R DPAK
+5V
R131 10K
+
C123
1000uF/16V
1
7
8
+5V
VS1
3
+5VSB
+5VSB*
+
C138
330uF/16V
D111 MBR20100CTG (TO220)
9
10
1
+
C126
330uF/16V
Figure 16: Secondary side rectification of the Flyback converter
The charge pump voltage VS4 is always available (even in Standby mode).
There is no need for a switch to disconnect in Standby as the charge pump
provides a fixed amount of energy per cycle and thanks to the very low frequency
operation in Standby, the power is very limited, VS4 is very low and does not
have a appreciable impact on overall Standby power efficiency.
24
D124
0R
STB
+5VSB*
R158
2K2
R159
2K2
1
R157
1K
STANDBY
PC101A
SFH817A
D121
MMSD4148
2
R161
100K
Q111
BC846ALT1(SOT23)
6.3V
R163
4K7
Q112
BC846ALT1(SOT23)
R166
4K7
VS1-OVP
+5VSB*
ZD103
1N4733A 5V1 (DO-41)
R165 470
R167
470
R168
470
C137
10nF
Figure 17: Secondary side Standby / ON control of the Flyback
The system microprocessor generates an open collector “STANDBY” signal that
pulls R159 low when the system is in standby. When the STANDBY signal is
released, Q111 is switched on to drive optocoupler PC101 which allows the PFC
controller to be biased on (as explain in PFC part). The state of Q111 also
controls signal “STB” which goes up in Standby. The STB is applied to diode
D108 which provides a higher voltage than the regulated one on comparator
Q103 which drives down the gate of Q114 to switch OFF the +12 V. The ‘STB”
going down in ON mode, allowing the +12 V to be switch ON as a supply from
the charge pump VS4. The +5 V switch Q113, is directly drive by the +12 V.
Typical Standby performance
<
<
<
<
0.3 W
0.4 W
0.5 W
1W
(230 V ac)
(230 V ac)
(230 V ac)
(230 V ac)
/
/
/
/
0.2 W
0.3 W
0.4 W
0.9 W
(110 V ac)
(110 V ac)
(110 V ac)
(110 V ac)
no load
5 V dc @ 10 mA (50 mW)
5 V dc @ 20 mA (100 mW)
5 V dc @ 96 mA (480 mW)
Note that the standby performance is achieved without the need of a costly relay
to disconnect the rest of the supply where additional parasitic power losses occur.
This standby performance is below the levels required to achieve < 1 W standby
regulatory requirements. Note that further improvements could be achieved with
modifications of the clamping network. To protect the MOSFET and prevent the
voltage to be higher than the BVdss, the existing RC network (R104 & C100)
could be replaced by a 200 V TVS to clamp the overshoot. This will reduce the
25
standby power, as there is no power loss in the clamping network under no-load /
light load conditions. If ultra low standby is required then a dedicated flyback
could be added which would increase the overall system cost.
90 V ac
50 mW output
3.76 kHz
90 V ac
500 mW output
12.5 kHz
230 V ac 50 mW output
2.9 kHz
230 V ac 500 mW output
9.35 kHz
Figure 18: Flyback switching waveforms under different load conditions
Higher Standby power capability solution
In standby, the SMPS is operating in the audio range. As a result depending on
the transformer construction and mechanical design there is the possibility of
some audible noise. The most sensitive range for most people is in the 7 – 13
kHz range. This specific design has been implementation for a nominal standby
load of 50-75 mW so that the frequency in standby is < 5 kHz. If the required
standby power is higher, the converter may work in the critical audible range. To
avoid this issue, we can change the current limit in standby mode to reduce the
energy transferred by cycle so that frequency increases above the sensitive
range (>15 kHz) to provide the overall requested power. This increased switching
frequency does have a minor negative impact on efficiency in standby. The
section describes how the standby current and frequency can be adapted to
avoid the most critical 7 – 13 kHz range in standby.
26
R100
1M 1/4W
AC Line - For PWM start
R101
1M 1/4W
R102
1M 1/4W
T100
ER28L
1
PFC_OUT
R104
33K 2W
D101
MUR160
R108
1R 2W
PFC_GND
C100
10nF 250V
3
11
P
VCC1
4
R112
2K2
PC100B
SFH817A
3
R114
0
1
2
C112
470nF
R121
2K7
3
IC100
NCP1351B
FB
Vcc
CT
Timer
CS
Latch
D104
MMSD4148
R116 100
6
7
D105
BAV21
C142
220uF/35 V
8
C113
100nF
R117 47
C114
100nF
+
12
6
+
C116
10uF/35 V
+
C115
10uF/50 V
R118 10
5
ZD101
1N5929B 22V
P
4
C117
270pF
GND
Drv
5
C118
100pF
R125
1K
C119
100nF
9
10
P
D110
MMSD4148
C121
270pF
R129 100k
R130 150k
7
8
OPP CKT
C140
R134
27
22pF
D113
MMSD4148
Q106
STD3NK60ZT4
2
R170 1K
1
Q107
BC856ALT1(SOT23)
R136
47k
3
R169
33K
P
Q108
BC846ALT1(SOT23)
1
3
R147 100
VCC1
R148
4K7
2
PFC_VCC
3
R153 10K
4
PC101B
SFH817A
R154
100K
PFC_GND
Figure 19: Modifications of the Flyback to increase standby frequency
The Rsense resistor R108 is increased from 0.47R to 1R which provides more
voltage information and reduces the current (typically 1/2) in standby mode. To
maintain the same operating current in ON mode, a positive current from R139 is
generated when PFC_VCC is on which will compensate for the larger negative
voltage developed by the larger sense resistance R108: The variation of this
voltage between both ON and standby mode allows easy configuration. The
changes were minor as R112 was reduced from 3K3 to 2K2 and R139 (33 K)
was added. This provides up to 60 W power capability in ON mode with the same
27
current limit. The standby operating frequency is now 16.6 kHz with 160 mA in
the Flyback Power MOS which is an increase from the 7 kHz in the original
solution. This changes was implemented and tested and the results were
excellent despite a small impact on efficiency (+ 50 mW on mains input compare
to previous lower frequency mode).
200 V/div, 200 mA/div,
Figure 20:
10 µs/div
200 V/div, 200 mA/div
Switching Waveforms with 400 mW output, Pin = 1 W
Vin = 230 Vac, Fsw = 16.6 kHz
100 V/div, 200 mA/div,
Figure 21:
1 µs/div
10 µs/div
Switching Waveforms with 400 mW output, Pin = 810 mW
Vin = 110 V ac, Fsw = 27 kHz
Configuring the Flyback for other output voltages
The required voltage rails and currents needed for the LCD-TV signal processing,
audio and standby power are driven by the system architecture. As a result the
reference design incorporates sufficient flexibility to support multiple output
configurations with simple bill of material changes. The NCP1351B flyback
28
design includes flexibility to support up to 4 unique voltage rails. The standard
configuration (SMPS1) that the reference design uses has a 5 V dc and 12 V dc
output as well as a 24 V dc Driver rail. The table lists numerous alternate
configurations that can be realized to support different power schemes including
a variety of different audio amplifier output rails range from 12 to 24 V dc.
The below table provides most of the possible solutions. In all cases, the overall
power must be limited to < 60 W and < 4 A for both VS1 and VS2 and < 1.5A for
the VS3 output. The current on V Dr is limited to approximately 5 mA according
to the charge pump components used.
SMPS1 SMPS2 SMPS3 SMPS4 SMPS5 SMPS6 SMPS7 SMPS8 SMPS9
V Dr
VS3
24V
36V
26V
24V
36V
24V ON 14V ON 12V ON 24V ON
24V
28V
15V ON
24V
36V
24V ON
VS2 12V ON 12V ON 12V ON 5V ON 12V ON 12V ON 12V ON
5V
5V
5V
5V
3V3
3V3 Standby Standby 12V
12V
5V
VS1 ON +
ON +
ON +
ON +
ON +
LDO
LDO
ON +
ON +
from Standby Standby
Standby Standby Standby Standby Standby from
12V
12V
Table 3: Standard and alternative voltage configurations
29
T100
ER28L
C103
10nF 250V
1
F100
0.47 1/2W
C105
1nF 500V
10uH
2
2
Q100
3
C108
1nF 500V
2
VS2
C109
1000uF/16V
L101
1
10uH
2
2
3
D102
MMSD4148
R110
NA
Q102
Q114
NTP18N06G(TO220)
NTD3055-094T4G DPAK
+12V
R119 10K
+
C110
1000uF/16V
+
R120
20K
C111
330uF/16V
Vref
Q103
BC846BDW SOT363
D107
MBR20100CTG (TO220)
R124
D108
MMSD4148
R122
4K7
470
J104
1
2
1
1
+
+
C123
1000uF/16V
L102
1
F101
1
NA
+
C138
330uF/16V
Q104 NTP18N06G(TO220)
Q113 NTD14N03R DPAK
3
10uH
2
2
R131 10K
+
C124
1000uF/16V
1
0.47 1/2W
+5V
+5V
+
C126
330uF/16V
R132
NA
Vref
R128
100 1/2W
Q105
BC846BDW SOT363
R135 NA
STB
R133
NA
1
C125
100nF
D112
MMSD4148
IC102
LM7805C
IN
GND
C120
1nF 500V
+5VSB*
J102
NA
OUT
3
7
8
C122
1000uF/16V
+5VSB
J105
2
VS1
1
2
2
D111 MBR20100CTG (TO220)
3
2
R127 2K2
J101
NA
+12V
STB
C143
4.7nF
R126 NA
9
10
+24V
R113 7.5K 1/4W
3
5
C104
220uF/50V
STB
C144
4.7nF
R111 NA
C106
1000uF/16V
+
1
+
R107
NA
1
6
R106
NA
1
1
Q101
BC846BDW SOT363
J100
NA
+
D106 MUR420
12
+14V or +24V
NTD14N03R DPAK
Vref
2
1
J103
NA
R115
100 1/2W
L100
1
VS3
D103 MUR420
11
+ C101
10uF/50V
2
3
+30V
R103 NA
ZD100
1N5929B
15V
R109
100 1/2W
F102
0.47 1/2W
VS4
D100 BAV21
2
+5VSB
C139
100nF
Figure 22:
Schematic illustrating range of flexibility in configuring the
secondary side rectification of the flyback converter
SMPS 1 to 5 are similar designs with 2 or 3 output voltages with the added Driver
output rail to drive all NMOS switches. If VS1 has only one switch Q104 for the
standby, both VS2 and VS3 support a linear regulator (function explained below)
on top of the discrete switch used for the standby. The third output VS3 is of
particular interest when a higher voltage rail is required to power a dedicated
audio amplifier. The VS4 has a limited current capability (charge pump solution)
but if necessary, the voltage can be push up to 35 V to allow 30 V for tuner
through the resistive drop on fuse F102.
To be able to manage the strong load variation due to the wide audio amplifier
dynamic behavior, the 12 V dc (VS2 of SMPS1) has been designed as a simple
discrete regulator to avoid possible cross regulation issues: an additional discrete
comparator forces the switch to operate in linear mode (not full saturated) when
30
the load becomes so small that the voltage can rise up toward the upper
regulation limit. As a result of the transformer design and this discrete circuitry,
the 12 V dc output of the SMPS configuration offers excellent load and cross
regulation.
R113 7.5K 1/4W
VS4
VS2
L101
1
+
2
2
Q114
3
NTP18N06G(TO220)
+12V
R119 10K
+
C110
1000uF/16V
1
C109
1000uF/16V
10uH
+
R120
20K
C111
330uF/16V
Vref
Q103
BC846BDW SOT363
C143
4.7nF
R124
470
+12V
STB
R122
4K7
D108
MMSD4148
Figure 23: +12 V Discrete switch and linear regulator
The dual transistor Q103 is use as an amplifier to compare information from the
+12 V output to the Vref from the TL431 (IC101). This allows regulation on the
+12V rail and forces the MOSFET to stay full saturated as much as possible
under any condition. The MOSFET is housed in a DPAK so it has good power
handling given the maximum current of the output rail. Finally an additional
integrated linear regulator IC102 has been planned for SMPS6/7 to allow a
simple low current standby supply from the VS1 (adjustable from 5 to 12 V). A
modification of the regulation point (R161) in standby (see Figure 24) can reduce
the VS1 supply voltage lower to reduce power dissipation across IC102 and
improve standby efficiency.
VS1 / 5 Von
VS2 / 12 Von
VS4 / P 230 V~
I 12 Von
0.1
0.5
1
1.5
2
3
4
ON with 0.32A on 5VStby
I 5 Von
0.1
5.23 / 5.23
12.63 / 12.43
26.09 / 6.799
5.27 / 5.27
12.54 / 12.4
26.02 / 12.27
5.28 / 5.28
12.52 / 12.36
26.06 / 20
5.29 / 5.29
12.52 / 12.33
26.14 / 27.57
5.29 / 5.29
12.51 / 12.27
26.18 / 35
5.27 / 5.27
12.46 / 12.13
26.36 / 49.65
5.29 / 5.29
12.49 / 12.03
26.67 / 65.64
0.5
5.23 / 5.23
12.65 / 12.42
25.91 / 6.8
5.27 / 5.27
12.55 / 12.39
25.85 / 12.35
5.28 / 5.28
12.53 / 12.36
25.95 / 20.13
5.29 / 5.29
12.53 / 12.32
26.03 / 27.73
5.29 / 5.28
12.5 / 12.26
26.13 / 35.03
5.27 / 5.27
12.46 / 12.12
26.2 / 49.88
5.29 / 5.29
12.48 / 12.02
26.64 / 66.19
1
5.18 / 5.07
12.85 / 12.44
25.93 / 12.3
5.25 / 5.14
12.68 / 12.42
25.89 / 18.77
5.27 / 5.16
12.63 / 12.4
25.91 / 26.59
5.27 / 5.17
12.6 / 12.36
26.01 / 33.88
5.26 / 5.16
12.56 / 12.3
26.05 / 41.17
5.28 / 5.17
12.57 / 12.21
26.26 / 56.73
5.3 / 5.19
12.6 / 12.12
26.61 / 72.69
1.5
5.17 / 5
12.92 / 12.45
25.89 / 16.33
5.24 / 5.07
12.74 / 12.43
25.84 / 22.66
5.27 / 5.09
12.68 / 12.41
25.86 / 30.21
5.26 / 5.09
12.62 / 12.37
25.94 / 37.49
5.26 / 5.09
12.61 / 12.33
25.96 / 45
5.28 / 5.11
12.61 / 12.25
26.13 / 60.34
5.3 / 5.12
12.64 / 12.15
26.72 / 77.07
2
5.13 / 4.91
13 / 12.47
26.2 / 19
5.24 / 5.01
12.78 / 12.45
26.06 / 25.7
5.26 / 5.04
12.71 / 12.43
26.08 / 33.18
5.25 / 5.03
12.64 / 12.38
26.05 / 40.43
5.26 / 5.04
12.64 / 12.35
26.05 / 48.08
5.28 / 5.06
12.66 / 12.28
26.27 / 63.79
5.29 / 5.06
12.65 / 12.16
26.83 / 80.5
2.5
5.12 / 5.07
13.13 / 12.33
26.93 / 23.25
5.23 / 4.96
12.84 / 12.31
26.69 / 28.73
5.26 / 4.99
12.76 / 12.29
26.63 / 36.23
5.24 / 4.96
12.68 / 12.26
26.6 / 44.37
5.26 / 4.97
12.69 / 12.25
26.6 / 51.55
5.29 / 5.01
12.72 / 12.24
26.69 / 67.45
5.28 / 4.99
12.67 / 12.11
27.11 / 83.81
Table 4: +5V and +12V Output Performance over Load
31
The secondary regulation and safety circuit
VS1
R137
220
+5VSB*
1
VS2
PC100A
SFH817A
2
R138
1K
R142
16K2
R144
6K19
C130
470nF
R149 0
3
Vref
1
2
IC101
TL431ACLPRPG 1%(TO92)
R172 4K7
R164
100K
R155
2K49
D124
0R
STB
+5VSB*
R158
2K2
R159
2K2
1
R157
1K
STANDBY
PC101A
SFH817A
D121
MMSD4148
2
R161
100K
Q111
BC846ALT1(SOT23)
Q112
BC846ALT1(SOT23)
R166
4K7
6.3V
R163
4K7
VS1-OVP
+5VSB*
ZD103
1N4733A 5V1 (DO-41)
R165 470
R167
470
R168
470
C137
10nF
Figure 24: +12V Secondary regulation and safety circuitry
The regulation loop is controlled by a TL431 (IC101) and optocoupler PC100.
To reduce consumption as much as possible in standby, the regulation circuit is
supply by VS1 (5 V). Note the PCB has been designed with flexibility to allow
regulation from any of the output voltages. In the standard configuration, SMPS1,
both 5 V and 12 V are regulated with resistor dividers adjusted to have 2/3 on 5 V
and 1/3 on 12 V. To compensate for voltage drops due to output filters and
cables, the regulation point (reference pin 1 of IC101) is modified with resistor
32
R161. This has no impact during standby but during ON mode, R161 is in
parallel with R155 to increase all output voltages.
The secondary safety circuit provides Over Voltage Protection in the event of an
open regulation loop. If the +5 V Standby output exceeds 6.3 V (nom) (5.1
(ZD103) + 1.2 (Vbe of Q102 following the resistor divider), the overall control
circuit recognized the fault and forces the supply into STANDBY thus
disconnecting the load, avoiding damage to the signal processing and reducing
the power which helps to further increase the voltage to easily detect the issue
on the primary and switch OFF the NCP1351 with the OVP and Latch protection
(ZD101). To provide full design flexibility, OVP on each output voltage has been
planned on the PCB with extra zener diodes (ZD104 on VS2 and ZD105 on
VS3).
The high performance of the transformer (CCM) combined with the NMOS
switches, does not affect the series impedance during an output short circuit
providing rugged short circuit protection. The primary Over Power Limitation time
will be controlled by the timer and the converter will stay OFF until the next restart (for the auto-recovery NCP1351B).
Flyback safety tests
The following plots illustrate operation under unusual fault conditions that the
power supply must handle during safety testing that are meant to simulate a
possible failure in the field.
A) + 12 V Output short circuit
Figure 25 illustrates the switching behavior when a short is created on the 12 V
output. The top waveform on the right is the 12 V output and it is being loaded
from 1-8A (scale 5A/div). The next waveform is the drain voltage of Flyback
MOSFET Q106 (scale 500 V/div). The bottom two waveforms are the 5 V
Standby (5 V/div) and the drain current of Flyback MOSFET Q106 (1A/div). The
plot to the left is a longer time frame and it clearly shows that the 45 ms fault
timer being activated to disable operation. The third plot on the bottom shows an
expanding view of the drain voltage and drain current of Q106 showing the
current is limited in a cycle by cycle basis.
33
10 ms/div
10 µs /div
10 µs /div
Figure 25: + 12 V Output short circuit behavior
B) + 5 V Output short circuit
Figure 26 illustrates the switching behavior when a short is created on the 5 V
output. The top waveform on the right is the 5 V output and it is being loaded
from 1-8A (scale 5A/div). The next waveform is the drain voltage of Flyback
MOSFET Q106 (scale 500 V/div). The bottom waveform is the drain current of
Flyback MOSFET Q106 (1A/div). The plot to the left is a longer time frame and it
clearly shows that the 45 ms fault timer being activated to disable operation. In
this plot the bottom waveform is the 12 V out and it clearly shows the output
decaying after the timer is activated. The plot on the bottom shows an expanding
view of the drain voltage and drain current of Q106 showing the current is limited
in a cycle by cycle basis.
34
10 ms/div
20 µs/div
10 µs /div
Figure 26: + 5 V Output short circuit behavior
C) PFC behaviors with + 12 V or + 5 V Output short circuit
Figure 27 illustrates the switching behavior of the PFC when either the 12 V or 5
V rail is shorted. The top waveform on the right is the 12 V output and it is being
loaded from 1-8A (scale 5A/div). The next waveform is the drain voltage of
Flyback MOSFET Q106 (scale 500 V/div). The bottom waveforms consist of the
drain voltage of the PFC MOSFET Q1 (500 V/div) and the gated Vcc bias to the
PFC stage that is controlled from the 5 V Standby output. The plot to the left is a
longer timeframe view and shows the power supply trying to restart from Standby.
As illustrated, after the first fault event is detected, the PFC is never restarted as
the PFC Vcc will not rise up to the Vcc start level thanks to the coupling of the
transformer.
35
1 s/div
10 ms/div
Figure 27: PFC behavior with + 12 V or + 5 V Output short circuit
D) Over Voltage Protection Operation
The following test illustrates how the system protection operates if the regulation
fails open. The first section illustrates the protection operation in the event that
the fault occurs after the power supply has starting (in ON mode) and operating
under normal conditions. When the regulation loop is opened in ON mode, the
output voltages rise up. After 1.5 ms, the 5 V Standby reaches 7 V (typ) and the
secondary Over Voltage Protection switches the system into Standby to protect
the overall signal processing and the audio amplifier and speed up the primary
OVP:
This effect of this is demonstrated in Figure 28a and 28b.
•
•
•
•
Both the 12 V and 5 V output start falling
Both VS1 and VS2 rise as the load is removed
The Vcc of the PFC decays after the “ON/OFF” optocoupler switches OFF
After an ~ 2 ms, the primary Over Voltage Protection is activated and the
NCP1351 controller immediately switches OFF the Power MOS
For figures 28a, the signals illustrated in the plots (top to bottom) are as follows:
y
y
y
y
VS2 (+12 V before switch Q114)
+12 V
+5 V
VS1 (+5 V before switch Q113)
– 10 V/div
– 10 V/div
– 5 V/div
– 5 V/div
36
100 ms/div
2 ms/div (expanded scale)
Figure 28a: Output voltage behavior for OVP event (Open regulation loop)
For figures 28b, the signals illustrated in the plots (top to bottom) are as follows:
y
y
y
y
100 ms/div
VS2 (+12 V before switch Q114)
Vcc PFC
Vcc Flyback
Drain of Flyback MOSFET(Q106)
– 10 V/div
– 10 V/div
– 5 V/div
– 500 V/div
2 ms/div (expanded scale)
Figure 28b: Output voltage of Vcc for OVP event (Open regulation loop)
The other case occurs if the feedback loop is open at startup. In this scenario
both output voltages will rise up. After ~ 7 ms (reference is now the starting
point), the 5 V Standby reaches 7 V dc (typ) and the secondary Over Voltage
Protection switches the system into Standby:
•
Both 12 V and 5 V output are going down (additional delay for the 5 V
“supply” a longer time by the 12 V),
37
•
•
•
Both VS1 and VS2 go up as the output power has been reduced
The Vcc of the PFC is not going up as the “ON/OFF” optocoupler has
been switched OFF before the PFC has been able to turn on normally
After an additional ~ 4 ms, the primary Over Voltage Protection is
activated and the NCP1351 controller immediately switches OFF the
Power MOS
Note, as seen in Figure 29, the time is longer than for the “ON” mode test above.
This is due to the time required to charge the primary Vcc capacitors. As a result,
the secondary rectified voltage reach a higher level before the system stops (Up
to 19 V dc for VS2 and 9 V dc for VS1).
2 ms/div
Figure 29a: PFC behavior for OVP event (Same signals as Fig 28a)
2 ms/div
Figure 29b: PFC behavior for OVP event (Same signals as Fig 28b)
Regardless of the source of the over voltage protection fault, when this is
detected the NCP1351 enters a latched state. To exit this fault, the primary AC
38
power has to be removed resulting in a “mains reset”. This provides a very
robust safety mechanism.
High Voltage Backlight Inverter
The high voltage inverter can be implemented using a half or full bridge topology.
The decision on the topology is based on several considerations. With a half
bridge topology, if it is operating in a fixed frequency - highly desirable in LCD-TV
applications to avoid interference between the backlight and video signal - hard
switching of the MOSFET devices is inevitable which causes excessive loss in
the MOSFETs and generates severe EMI that must be dealt with to comply with
regulatory requirements.
PFC output
1
2
4
5
11
10
9
8
6
7
PFC_GND
Figure 30: Example of Half Bridge Inverter Power Stage
In addition to the high switching losses of the power MOSFETs, 4 additional
ultrafast diodes have to be incorporated to eliminate possible switching oscillation
and avoid the risk of cross conduction due to the large stored magnetic energy
and poor reverse recovery behavior of the MOSFET body diodes. To avoid
these disadvantages a full bridge topology is employed for the backlight inverter
power stage. This offers numerous advantages compared to the half bridge:
•
•
•
•
•
•
•
•
Zero Voltage Switching with fixed operating frequency
Reduced EMI and power losses
Reduced MOSFET switching stress and heat dissipation
Improved lamp current form factor (much closer to sinusoidal waveform)
No need for additional power diodes across the bridge
Half the current in the MOSFETs and transformer
Easier to implement primary side Over Current Protection
Similar cost thanks to the elimination of the fast recovery diodes and
reduced heat sinking.
Moreover because the controller is operating at a fixed frequency, it is possible to
synchronize the switching frequency to the video frequency and avoid any
possibility of the backlight subsystem interference interacting with the video
image.
39
Microsemi LX6503 backlight controller
The LX6503 is a high performance CCFL controller intended for LCD-TV and
other multi-lamp LCD display systems. It is particularly optimized to be a cost
effective solution for the High Voltage Inverter architecture. The controller
provides a pair of push-pull PWM drive signals with sufficient capacity to drive a
push-pull, half bridge or full bridge CCFL inverter with the addition of simple
external circuit. An on-chip regulator supplies both the operating voltage for the
output gate drive and bias to the internal control circuitry. This allows direct
connection of the controller to the system supply - up to 27 V without an external
regulator. In addition the controller offers a versatile synchronization capability
that allows the user to synchronize both the frequency and phase of the lamp
current to an external signal coming from the video processor (or other controller).
The lamp current regulation circuit comprises a simple and robust control loop
design with excellent regulation accuracy and dynamic response at transient
conditions. Furthermore a soft-start feature provides more reliable lamp strike
and allows effective control of the possible inverter start-up surge current and
lamp current/voltage overshoot. Lamp dimming operation is also well architected
to facilitate convenient and flexible digital or analog dimming control with
synchronization capability. In addition, reliable fault detection and protection
functions are facilitated including open lamp protection, over voltage, short circuit
and over current protection. Programmable strike and protection timing and fault
indication are also incorporated to provide robust operation. The device is
housed in a wide body SOIC-16 surface mount package.
+12V
C307
F301
0.47 1/2W
47uF
+
Output Drive A
C308 1uF
C311 4.7uF
vdd
R332
75K
R333
750K
R334
750K
IC300
LX6503-IDW
C312 220pF
C315
C318
Output Drive B
1
1uF
2
3
10nF
4
R343 10K
R344 10K
6
A_DIM
7
R348 4K7
AOUT
C_T
GND
BOUT
BRT_D
SS/FLT
BRT_A
COMP
ENABLE
8
ENABLE
VDD
C_R
C_B
5
PWM_DIM
VIN
ISNS
SYNC
VSNS
16
15
14
13
Current regulation information
12
R345 10K
11
10
Open Lamps Protection
9
R351 2K
GND Current information
C319
SYNC_IN
D313
100nF
C321
R355
R356
C322
R353
100pF
20K
10K
1nF
10K
C323
R357
100K
2.2nF
C324
R358
R359
C325
47pF
18K
22K
10nF
3
C326
R354
R360
C327
10nF
2K
33K
690pF
D314
VSNS1
BAT54SWT1
D315
2
2
1
2
BAV70LT1
R361
220
R362
220
Over Voltage Protection
3
1
1
R363
R364
22K
22K
3
VSNS2
CN306
4324-2S
1
LAMP
2 1
2 RTN
BAT54SWT1
Figure 31: LX6503 Schematic and Control Signals
40
A typical application circuit is illustrated in Figure 31. A built in regulator is
connected to pin 1 (VIN) to step down the input voltage to the internal operating
voltage VDD (pin 16). The VIN of the device can range from 6 to 27 V dc. In this
application, the VIN is directly supply from the +12 V dc through fuse resistor
F301 to protect the system in the event of a short circuit. C307 and C308 provide
low impedance filtering. VDD supplies both output gate drivers and the internal
control circuitry. The nominal operating voltage of VDD is 5.25 +/- 0.25V. Internal
UVLO function is provided to protect the system from under voltage operation.
An external low ESR capacitor C311 with lowest possible trace impedance to
VDD and GND pin provides good noise decoupling for the internal circuitry. The
main operating signals are described as following:
y
The operating frequency of the inverter is defined by the RC components
connected to the C-R (pin 2). A saw tooth oscillating waveform with 2.5 V
peak and 0.5 V valley is generated at this pin by the internal oscillator.
y
The lamp strike time and fault timing are programmable based on the
components connected to C_T (pin 3). A 5 µA charging current source is
connected to this pin internally from VDD.
y
Digital dimming can be controlled directly by a PWM signal applied on the
BRT_D (pin 5). Alternatively, a DC control signal ranging from 0.5 - 2.5 V can
also set the dimming duty from 0 to 100% with the frequency defined by the
capacitor on C_B (pin 4).
y
In addition, brightness can also be controlled by an analog dimming input on
BRT_A (pin 6). A DC voltage from 0.5 - 1.5 V sets the lamp current from zero
to maximum.
y
ENABLE (pin 7) controls the on/off operation of the inverter. The voltage
range from 2 - 4 V also sets the strike frequency of the inverter.
y
SYNC (pin 8) allows frequency synchronization with another backlight
controller in the system or to the video scanning clock signal to eliminate
possible frequency related interference.
y
VSNS (pin 9) is voltage sense input for voltage regulation and over voltage
protection.
y
ISNS (pin 10) is current sense input for lamp current regulation and open
lamp, over current detection.
y
COMP (pin 11) is the output of the error amplifier. The error amplifier is a
voltage controlled current source (GM) type which can normally provide
robust regulation control with simple compensation.
41
y
SS/FLT (pin 12) serves the function of soft start, strike frequency ramp and
low pass filter function for the synchronization control. During strike mode the
ramp signal of this pin controls the soft start of the inverter and the strike
frequency sweeping. When synchronization is operating in run mode, the
capacitor at this pin provides a low pass filter function for the synchronization
loop.
y
AOUT (pin 15) and BOUT (pin 13) are the gate driver outputs with source and
sink current capability of 0.6 A.
Fixed frequency zero voltage switching Full Bridge
VIN
QAH
AOH
AOL
QBH
BOH
BOL
A
B
QAL
AOL
QBL
AOH
BOL
BOH
T0
T1 T2T3 T4
T5 T6T7 T8
Figure 32: Operating Waveform of Full Bridge
T1~T2
T0~T1
VIN
VIN
AOH
BOH
A
AOH
A
B
BOL
BOH
AOL
B
BOL
AOL
(a)
(b)
42
T2~T3
A
AOH
AOL
(e)
T7~T8
T6~T7
VIN
VIN
VIN
AOL
BOL
(d)
T5~T6
AOH
BOH
A
(f)
AOL
AOH
BOH
BOL
BOH
B
A
B
A
B
BOL
B
BOL
(c)
AOH
BOH
A
B
AOL
BOL
AOH
BOH
A
B
AOL
VIN
VIN
BOH
AOH
T4~T5
T3~T4
VIN
AOL
(g)
BOL
(h)
Figure 33: Operating State Of Full Bridge
Figure 32 shows a full bridge circuit and the gate drive waveform on the 4
MOSFETs derived from the LX6503 controller. One important feature should be
noted is that the drive signals of high side and low side power switches of the
same bridge arm, i.e. AOH, AOL or BOH, BOL, are complementary to each other
by neglecting the dead time. With such a feature the stored magnetic energy in
the transformer primary winding can be used to push the switching node to the
opposite DC rail when a device is turned off, which essentially creates a zero
voltage condition across the counterpart device to be turned on next. If the stored
magnetic energy is large enough to sustain such condition till the end of the dead
time when the counterpart device is turned on, a zero voltage switching operation
will be successfully obtained. The detailed operation is described as follows:
Starting from the period from T0 to T1 as indicated in Figure 32, drive signals
BOH and AOL turns the diagonal devices QBH and QAL on and the transformer
primary winding current flows in the direction as indicated in Figure 33a. At T1
QBH is turned off by BOH and the magnetic energy stored in the leakage
inductance and transformer magnetization charges up the body capacitance of
43
QBH and discharges the body capacitance of QBL, and eventually pushes the
switching node B below the ground level. Once this transition is complete the
body diode of QBL becomes forward biased to clamp node B near ground level
and the current start circulating between QAL and the body diode of QBL as
indicated in Figure 33b. During this period the decay of the circulating current is
minimal because the rate of decay is inversely proportional to the voltage across
the transformer winding which is mainly the body diode forward drop.
It should be noted that it is not granted that the potential of switching node B can
always be pushed below ground level. If the stored magnetic energy is not large
enough to fully charge/discharge the body capacitance of QBH and QBL,
switching node B cannot be pushed below ground level and it will start oscillating
and eventually settle at the mid point level of the DC input. It should also be
noted that the time for the switching node B to swing to ground level is
dependent on the value of the MOSFET body capacitance, the transformer
leakage inductance, and the amplitude of the current at T1 instant. Higher current
level and LC value will result in a shorter swing time.
After the dead time T2-T1, QBL is turned on by BOL and the primary current
continues to circulate through QAL and QBL if it is not yet extinguished, as
shown in Figure 28c. Such condition remains through out the period between T2
and T3 during which the voltage across the transformer primary winding is nearly
zero. At the moment of T3, QAL is turned off by AOL and the circulating current
starts to charge the body capacitance of QAL and discharge the body
capacitance of QAH. If the remaining energy is sufficient to complete the charge
/discharge it will eventually push the switching node A above the positive DC rail
VIN and force the body diode of QAH to conduct. Node A will then be clamped at
near VIN level and the circulating current will continue to flow through the new
path of QAH body diode, DC input source, and QBL. Here it should be
particularly noted that during this period from T3 to T4 the decay of the circulation
current is much faster because the voltage across the transformer primary
winding has to rise to slightly higher than the DC input voltage in order to
maintain the continuous inductive current flow. If the remaining magnetic energy
is large enough to maintain the forward bias of QAH body diode and keep the
continuous current circulation till AOH goes high, a successful soft switching is
obtained to turn on QAH at zero voltage condition. If the remaining magnetic
energy is not large enough, however, it may enter the situation that the
circulation current extinguishes before full charge/discharge of the MOSFET
body capacitance and the switching node A will not be able to swing up to VIN
level, or after node A swings above VIN the circulation current extinguishes
before AOH comes on and the potential of node A swings back down. Under
either circumstance a zero voltage condition across QAH cannot be obtained to
realize a soft switching operation.
The above situation is more likely at light load under narrow PWM duty cycle,
and low transformer leakage inductance conditions, which generally results in
44
less stored magnetic energy. Another important factor to successful soft
switching is the dead time setting. If the dead time is too long, the inductive
circulation current cannot hold its continuity before AOH comes on and hence
decay to zero before QAH is turned on. As such the dead time should have an
upper limit. On the other hand, when a power switch is turned off, like QBH at T1
and QAL at T3, it takes a certain time for the switching node potential to swing to
the opposite DC rail. The swing time could have a wide range with different
designs depending on the values of the transformer primary leakage inductance,
the MOSFET body capacitance, and transformer primary current level etc.
Theoretically the switching node potential swing is part of the resonance cycle at
the switching transition. The frequency of the resonance is determined by the
transformer primary leakage inductance, the MOSFET body capacitance and
other minor parasitic parameters, and the theoretical free resonance peak
voltage (Here the free resonance peak means the peak voltage value at the ¼
resonance cycle point if there is no clamping to the DC rail by the MOSFET body
diode) which is determined by the L, C, R parameters of the resonance tank and
the transformer primary current level. Higher resonance frequency and higher
free resonance peak voltage will result in shorter time for the switching node to
swing to the opposite DC rail and vise versa. From this point the dead time also
needs to be long enough to allow full swing of the switching node potential under
a wide range of operating conditions. If the dead time is too short it may enter the
situation that the power MOS is turned on before its VDS is pushed to zero by the
switching node swing and thus soft switching cannot be realized. Taking account
of the above points, a reasonable dead time range for practical CCFL inverter
applications lies in the range of about 130 to 400 ns.
In actual application designs as indicated above under specific light load
conditions, zero voltage switching might not occur. Under such circumstances,
measures have to be taken in the design to ensure successful soft switching
operation. One approach is to increase the transformer magnetizing current or
the primary leakage inductance. This will increase the stored magnetic energy to
maintain the continuity of the inductive current during dead time. Another
approach is to increase or decrease the effective dead time of the power
switches externally to get the desired switching control timing according to the
particular inverter power circuit parameters.
At T4, QAH is turned on by AOH. If the current flowing in the direction as shown
in Figure 33d has not decayed to zero at this moment, it will keep flowing until it
decays to zero and then reverse the direction as shown in Figure 33e. The
following events evolve as shown in Figure 33f,g,h and so on continues the
switching operation of the next commutation process that essentially repeats the
same transitions as described above.
A typical set of actual waveforms of AOL, BOL, AOH and BOH from the
reference design is shown in figures 34-38.
45
Yellow-AOL; Blue-BOL; Purple-AOH; Green-BOH
Figure 34: Gate Drive output waveforms
Figure 35: Dead time between AOL (yellow) and AOH (purple): 280 ns
46
Figure 36: Dead time between AOL (yellow) and AOH (purple): 280 ns
Figure 37: Dead time between BOL (blue) and BOH (green): 280 ns
47
Figure 38: Dead time between BOL (blue) and BOH (green): 280 ns
Full Bridge Driver Circuit Description
In a HV-LIPS configuration, the power MOSFETs for the full bridge are located
on the primary side and the inverter controller is located on the secondary side
across the isolation boundary. The output drive signals employ a push-pull signal
format to drive two isolation transformers for the full bridge. The isolation
transformer provides two isolation functions: the safety isolation between the
primary and secondary, and isolation between the high side and low side
MOSFET. Therefore the output signals from the drive transformer can be
coupled to the power MOSFETs without the need of level shift function. The
remaining function for soft switching full bridge drive is the dead time insertion.
Figure 39 illustrates the drive circuit of one arm of the full bridge that incorporates
the dead time function.
48
F3000.47R 1W
PFC_OUT
D301
BAV21
2
R303 2K21
3
4
D303
C328
1uF
450V
3
2
C300
1
470 nF
M300
NTGD4167C
R304
56
Q300
6
BAT54SWT1
1
T303
2
4
R310
5
R308 422
BCK-13-021T
10K
9
HV Transformer
10
6
7
STD3NK50ZT4 (DPAK)
R318
1K5
Q302
C304
Q304
NTA4153N
1uF
D306
BAV21
R322
R320
C316
10K
1nF
100K
PFC_GND
Output Drive B
Output Drive A
Figure 39: Full Bridge Zero Voltage Switching Driver Circuit
Since winding 6-7 and 9-10 of T303 have the same phase, MOSFET Q302 is
switched ON after the positive going edge from winding 6-7 with a delay time
controlled by R318 and C316 together with the gate capacitance of Q302. In the
meanwhile, the NMOS (bottom) of driver M300 is switched ON immediately by
the positive going edge from winding 9-10 and thus turning OFF MOSFET Q300
quickly. During this time, C300 is also charged to replenish energy for the drive
circuit of Q300.
When the voltage of both windings drops to zero, the NMOS driver Q304 comes
on to quickly turn off MOSFET Q302: this is done without delay as the discharge
loop is a low impedance path. Simultaneously, the NMOS of driver M300 is
switched OFF (without delay) while the PMOS of M300 is switched ON with a
delay defined by R303 and the input capacitor of its gate.
In such an operating manner the switching OFF of the Power MOSFETs Q300
and Q302 is fast and without any deliberate delay while the switching ON of
Q300 and Q302 always has delay. The result is a controlled dead time which
prevents shoot through and facilitate zero voltage switching operation of the
power switches. With zero voltage switching of the full bridge operation, there is
no reverse recovery process for the body diode. Therefore ultra fast Power
MOSFETs or external fast recovery diodes are not required. Another advantage
of full bridge is that the current of the power MOSFETs and transformer primary
winding is half of the half bridge. In the reference design, STD3NK500ZT4 500
MOSFETS are used which are rated at 3 A with an RDSON of less than 3.3R at
49
2.3 A. In a half bridge design MOSFETs of RDSON of 1.65R would have to be
used to obtain similar conduction loss. Moreover, due to the low switching losses
in this implementation, surface mount DPAK packaging can be used without
additional heat sinks.
Full Bridge Zero Voltage Switching Waveforms
For figures 40-43, the top waveform is the current in the primary of the
transformer (1 A/div) and the bottom two waveforms are the voltage on bout
sides of the HV Transformer (500 V/div).
1 ms/div
Figure 40: 285 Hz Burst
20 µs/div
Figure 41: Burst mode soft-start
50
4 µs/div
Figure 42: Standard Inverter Drive Cycle (52 kHz)
20 µs/div
Figure 43: Burst mode soft-stop
51
High Voltage (HV) Transformer
The HV transformer provides two voltages in the opposite phase (+ and -) to
supply the lamps. With such outputs the voltages to the lamps is interleaved in a
way that the adjacent lamps are always connected to opposite voltages. Such
wiring arrangement will result in the smallest and localized HV electric field and
thus minimizes the interference to the LCD panel. In addition, such a
configuration can also drive U-shape lamps which will further reduce the overall
backlight system cost. In fact, dual phase voltage is the most common approach
on the market, and this transformer design offers very competitive cost compared
with two transformers or multi-transformer approach.
The high voltage transformer is designed to work in the frequency range of about
40 kHz to 80 kHz with a primary inductance of around 1.8 mH. It is build on a
UP34 core and is capable of providing up to 120 W output, which is more than
the power requirement of most 32” applications (about 95 W). So it would also be
able to drive a 37” without any problem and possibly up to 42” in future while the
efficiency of the CCFL backlight systems continually improve and the power
consumption reduce further.
The turn ratio has been optimized to get the required voltage / power for the
lamps with the target duty cycle. In actual applications, the inverter will operate
at higher duty cycle with smaller turns ratio which normally results in better lamp
current waveform and better inverter efficiency. But with the reduced headroom
of the output voltage there would a chance that the maximum output voltage is
not enough to ignite the lamps during strike operation. On the other hand, larger
turns ration provides more strike headroom but the inverter efficiency and lamp
current form factor will suffer. In this reference design a balancer network has
been employed to balance the lamp current. The balancer network has an
intrinsic mechanism to help lamp strike. In this sense it allows to use smaller
turns ratio for the transformer to get better inverter efficiency and the lamp
current waveform.
Basic Transformer Construction
• The turn ratio is 3.76 with 125 turns for the primary and 470 for each
secondary with a primary inductance of 1.8 mH
• For reduced losses, the primary wire is a 0.10 mm x 16 while the
secondary wire is single 0.15 mm
• To avoid isolation issues which could impact reliability, the secondary is
split with a multi-slot bobbin construction with care to avoid crossing wires
• The leakage inductance from the secondary is 19.2 mH for each
secondary winding with the primary shorted
The reference of the transformer is PIT 125050-3551 GP and is available from
Taipei Multipower Products (TMP) in Taiwan.
52
C306
100 nF
1
2
T309
11
10
9
8
4
5
6
7
PIT125050-3551 GP
C309
C310
5pF
5pF
C329
C330
R366 R337
R338
120
120
150
3
120
1
R365
2
5pF
R367
R368
R339
R340
120
120
150
120
D311
BAV70LT1
5pF
VSNS2
C313
5.6nF
VSNS1
C314
5.6nF
R345 10K
Figure 44: Schematic for both current and voltage sensing
The current and voltage sensing from the transformer is illustrated in Fig. 39. The
resistor banks of R355, R366, R337, R338 and R367, R368, R339, R340 at the
secondary winding return terminals convert the transformer current to voltage
signals. It essentially forms a full wave rectification circuit in combination with
D311 to obtain the current sense information of both positive and negative cycles.
The transformer output voltage is sensed by the two capacitor divider strings
connected to the two HV output terminals. The voltage sense signal from VSNS1
and VSNS2 are fed to the VSNS pin of the controller after rectification. This
information is used for voltage regulation as well as over voltage protection.
CCFL Drive and Current Balancing
The specific characteristics of CCFL lamps require special techniques to drive
them. The two most important functions required for successful CCFL operation
are the lamps strike and lamp current balancing because of the following:
•
The CCFL lamp requires a high voltage, normally about 1.5 to 2 times of
its normal operating voltage to make the initial gas breakdown inside the
lamp to start the normal operating cycle. This process is called strike (or
kick off, ignition etc.). Further, because the lamp operating voltage is much
lower than strike voltage, in multi-lamp parallel operation the voltage could
be clamped by the first striked lamps and the remaining lamps may not be
able to strike successfully.
y
Due to the very low dynamic impedance characteristics of CCFL, the
lamps will enter a “run away” situation, i.e. the current is concentrated to
one or a few lamps with lower operating voltage and the other lamps have
no current, when the lamps are put in parallel directly.
53
For to above reasons, lamp strike and current balancing have to be considered
carefully in order to get a reliable operation of the backlight system. The Jin
Balancer solution employed in this reference design can provide excellent lamp
current balancing function and in the meanwhile guarantees reliable lamp strike
in combination with the frequency sweeping strike technique. The Jin Balancer
technique is based on the electro-magnetic coupling mechanism of the balancing
transformer network that generates additional correction voltage to the lamps to
equalize the lamp current. The basic configuration of the balancer network is
shown in Figure 45. The serial loop of the balancer secondary windings
equalizes the primary side current and provides coupling mechanism between
the lamp circuits. With such coupling mechanism if a lamp is not stricken, the
energy from the stricken lamps will be automatically coupled to the balancer
primary winding of the un-stricken lamp circuit to increase the voltage across the
lamp and help it to strike. As can be seen from Figure 45 the wiring configuration
of the balancer network is uniform regardless the number of lamps. In addition,
one type of balancer transformer can fit with almost all the lamp sizes. These
features make the Jin balancer solution very flexible in CCFL inverter
applications. Apart from the balancing function, the signal from the secondary
winding loop can also be used to detect open lamp condition. When a lamp is
open, the voltages in the primary and secondary winding of the corresponding
balancer rise sharply, because of the significant increase of the magnetic flux in
the balancer core due to the disappearance of the primary current. With such an
indicator, open lamp detection can be easily accomplished by monitoring the
voltage signal from the balancer secondary. Because the primary and secondary
winding of the balancer are electrically isolated, the detection function can be
easily implemented with low voltage, low cost components in all types of lamp
configuration regardless whether the balancers are placed at low voltage or high
voltage side of the lamp, or whether the lamps are driven from single side or
differentially. Another advantage of this solution is that the lamp current
balancing is largely governed by the balancer turns ratio but not the absolute
value of the winding inductance. Therefore the solution is insensitive to
manufacturing tolerances such as differences in core assembly, or parameter
changes during operation such as inductance change with temperature etc.
54
Figure 45: JIN balance Approach
As illustrated in figure 45, each balancer transformer has 2 windings:
•
•
a “primary” winding connected in series with the lamp and
a “secondary” winding connected in series with all other secondary
windings as a closed loop.
The general requirements for the current balancing transformer are listed below.
In this specific 32” HV-LIPS application a single PCB is used to house the whole
power circuitry including power supply, inverter, and balancer network. As such
the balancer transformers uses a through-hole configuration to fit the assembly
process. If the design is to be scaled up to a larger panel size, the balancer
board might be separated from the main power board. In that case the balancer
transformers would be configured in an alternative surface mount packaging.
•
•
•
•
•
•
•
•
Core EFD1215
Primary: 39 µH +- 30%
Secondary (high voltage in series with the lamp): 625 mH +/-30%
Turns ratio: 1/125
Isolation: winding to core > 1.5 kV, winding to winding > 2.5 kV
Size: 20.9 x 13.3 x 7.8 mm
Through hole
The reference of the balancer transformer is PBT-07087-1322 GP from
TMP Taiwan
The below schematic illustrates how the balancer and sensing circuitry are
configured to drive four lamps. The resistor divider network from the balancer
secondary winding provides the monitor information for open lamp detection.
The analog signals from the divider network are OR’ed by the diode D302 and
55
D305 and fed to the controller to monitor the lamp status during both the strike
and run operations.
T300
PBT-07087-1322G
1
7
High Voltage
LAMP1
CN300
4
R300
4k7
D302
R306
3k3
R307
3k3
2
1
2
T301
PBT-07087-1322G
1
7
R302
4k7
1
3
6
LAMP2
4
6
SM02B-BHSS-1-TB
T302
PBT-07087-1322G
1
7
BAV70LT1
LAMP3
Open Lamps information
CN301
4
R312
4k7
D305
1
3
1
2
2
6
T305
PBT-07087-1322G
1
7
R313
4k7
R316
3k3
R317
3k3
1
2
1
2
LAMP4
4
6
SM02B-BHSS-1-TB
BAV70LT1
High Voltage 180° phase
Figure 46: Configuration of Balancer and Open Lamp Monitor
A classic approach for a 32” backlight subsystem is described below.
•
•
•
•
12 single lamps
All lamps are connected together to a common ground
The current sense for the system in on the ground wire
All lamps are driven “in phase” from a single output high voltage
transformer
The GreenPoint design has been developed to take advantage of the evolution of
lamp configurations and improve the overall system performance and flexibility.
•
•
•
Provide 2 interleaved + and – phase output to minimize the field
interference to the panel, since adjacent lamps are driven with opposite
phase voltage and the high voltage field is largely localized.
Provide 2 interleaved + and – phase output to allow for U shape lamp
applications with a virtual ground on the other side of the screen
Employ current sensing for overall lamp current regulation on the high
voltage transformer side instead of the “ground” side of the lamp.
Figure 47 illustrates a U shape lamp solution that cuts the number of current
balancers in half. Moreover it is important to see that this approach could be use
for 2 straight lamps connected together in an equivalent U lamp like arrangement
56
(pseudo U-Shape). This only requires minor panel configuration changes to
change the lamp connection on the other side of the panel.
T307
PBT-07087-1322G
1
7
High Voltage
U shape LAMP1
CN302
4
R301
4k7
D303
1
3
2
1
2
1
2
R303
4k7
SM02B-BHSS-1-TB
R308
3k3
R309
3k3
BAV70LT1
Open Lamps information
6
1
T303
PBT-07087-1322G
7
U shape LAMP2
CN303
4
6
1
2
1
2
High Voltage 180° phase
SM02B-BHSS-1-TB
Figure 47: HV-LIPS current balancing for U shape lamps
57
Overall Efficiency Performance
The focus of the reference design was to provide excellent parametric
performance coupled with a high efficiency architecture that operated all the
power conversion stages in a low loss manner. Some typical performance data
is described in the following table where the flyback and PFC stage were loaded
at various test load conditions. The inverter efficiency has been estimated
because precise output power measurement directly on the high voltage lamps is
difficult and not accurate enough. The PFC efficiency is > 95% over full range of
line input at typical load condition and the peak efficiency of the flyback converter
under a typical load configuration of 37 W is 78%. This is quite good considering
that there are some additional losses in both 5 V and 12 V output based on the
cross regulation technique that was used to assure tight regulation accuracy for
the 5V and 12 V rails. The efficiency of the inverter is optimized thanks to the full
bridge zero voltage switching topology that minimizes the switching losses. A
testimony of this is the fact that the full bridge MOSFETs uses surface mount
DPAK device and does not require any additional heat sinking.
FLYBACK
Output V x I
12,25 x 0,3
4,97 x 1,8
12.20 x 2
4.94 x 2.5
11.94 x 4
4.95 x 2.5
PFC
INVERTER
Pout
Pin
η
Pin
Pout
12.6
17
74%
100.8
117.8
36.8
46.9
78%
100.8
147.7
60.1
78.2
77%
100.8
179
Complete board
Pin
η
Total η *
230V => 120.7
98%
89%
110V => 123
96%
87%
230V => 150.8
98%
87%
110V => 154.3
96%
85%
230V => 182.6
98%
85%
110V => 188
95%
82%
*
Total η = (P out Flyback + 94% Pin inverter) / Pin PFC
Inverter η is estimated to be 94% (Ouput power on lamps is very difficult to mesure).
Summary
This complete GreenPoint reference design supports the emerging High Voltage
LIPS architecture which powers the inverter directly from the PFC stage thus
eliminating a complete power stage. Moreover due to the high efficiency
proprietary architecture of the NCP1351 flyback controller, the need and expense
associated with a dedicated standby supply is eliminated thus further simplify the
solution. The architecture illustrated in this reference design has a high degree
of flexibility to support a variety of voltage/current configurations with minor
changes to the schematic and components used. Finally thanks to the use of an
advanced backlighting controller with a zero voltage switching full bridge
topology, the inverter power can be easily scaled up to support a variety of LCDTV sizes up to 42”.
Authors: Jean-Paul Louvel and Bernie Weir
Special appreciation to Dr. Xiao Ping Jin at Microsemi for his contributing to this
document and strong support during the development of this reference design.
58
Appendix
The appendix consists of the following sections:
y
y
y
y
y
y
Photographs of complete board
Schematics of SMPS1
Bill of Material of SMPS1
Supporting Device Literature that is available
Relevant Global Energy conservation standards
Schematics of complete design supporting alternative power
configurations
59
Bottom View of SMPS1
60
Top View of SMPS1
Schematics of SMPS1
The following four pages contain the schematics for the SMPS1 implementation (see Table 3) of the GreenPoint HV-LIPS
design.
61
5
4
3
2
1
1N5406(DO-201)
2
D1
BD1
GBU806
L1
150uH
RT1
D2
4
3
D
RV1
7
8
L2
D
TF2815 - 150uH
R24
68
TVR10471KSY
Q1
STP11NK50ZFPN
R5
68
C6 Y 1nF
IC1
NCP1606B
C9
PFC_OUT
27K
C3
0.47uF
450V
X2 100nF
275V
D3 MMSD4148
ZCD
DRV
7
8
VCC
Ctrl
2
Q2
C12
L5
CFS24 - 2mH
3
RV5
eclat
RV4
eclat
R25
470
6
CT
GND
FB
1
CS
4
390nF
R11
+
R6
1M3 1/4W
C8
68uF 450V
1
+
BC856ALT1(SOT23)
C11 100nF
C
C7
10nF 630V
1
R8
68
5
R2
1M3 1/4W
3
C5 Y 1nF
R4
NTC 2R5
MUR550APF(DO-201)
2
C1
0.47uF
450V
11
2
-
Schematic of Greenpoint Reference Board (SMPS1 Configuration)
2
3
+
1
C10
68uF 450V
R9
10K
R10
1M3 1/4W
56K
C
R12
220
+
C18
X2 1uF
275V
C13
47uF
C14
100nF
R26
680
C19
220pF
R13
24K9
R14
0.10 2 W
C16
1nF
ZD1
1N4733A
5.1V
PFC_GND
R15 150K
R16 150K
R17 150K
PFC_VCC
R20
150K
R19
AC Line - For PWM start
150K
1
150K
1
R18
2
J2
A
B
2
J1
A
B
F1
FUSE 4A 250V (Axial Lead)
L
FG
FG
N
CN1
4333-W05ST
A
A
ON
Model Name
Size
Engineer
Subject
5
4
Schematic for HV-LIPS Greenpoint Reference Board (SMPS1)
3
2
ON SEMICONDUCTOR TWN S.E.C.
ON-MICRO-LIPS-32"
B
Dale Tittensor
EMI/ PFC
PCB
Revision
Date
Reviewer
Sheet
1
Pilot 3
2009.02.12
Jean-Paul Louvel
1 of 4
5
4
R100
1M 1/4W
R101
1M 1/4W
3
R102
1M 1/4W
2
T100
ER28L
AC Line - For PWM start
C103
10nF 250V
F100
0.47 1/2W
VS4
D100 BAV21
1
PFC_OUT
R104
33K 2W
C100
10nF 250V
ZD100
1N5929B
15V
+ C101
10uF/50V
Schematic of Greenpoint Reference Board (SMPS1 Configuration)
1
3
11
P
1
VCC1
1
FB
D104
MMSD4148
R116 100
Vcc
R117 47
VS2
D105
BAV21
R118 10
12
6
1
+
CT
Timer
3
CS
Latch
2
Q114
3
2
NTD3055-094T4G DPAK
+12V
+
C114
100nF
C115
10uF/50 V
7
R120
20K
+12V
C111
330uF/16V
Vref
C116
10uF/35 V
+
+
R119 10K
C110
1000uF/16V
+
C142
220uF/35 V
8
C113
100nF
R121
2K7
10uH
+
C109
1000uF/16V
3
2
L101
1
2
6
1
3
2
4
IC100
NCP1351B
R114
0
R113 7.5K 1/4W
C106
1000uF/16V
R112
3K3
PC100B
SFH817A
D
J100
A
+
J103
A
2
PFC_GND
VS3
D101
MUR160
R108
0.47R 2W
D
C112
470nF
1
D107
MBR20100CTG (TO220)
5
Q103
BC846BDW SOT363
STB
C143
4.7nF
ZD101
1N5929B 22V
R124
D108
MMSD4148
R122
4K7
470
P
4
C117
270pF
GND
Drv
5
R127 2K2
R125
1K
C119
100nF
J104
C118
100pF
2
1
D111 MBR20100CTG (TO220)
P
+5V
9
10
R129 100k
3
R130 150k
7
8
R134
27
22pF
D113
MMSD4148
R169
NI
10uH
2
2
C122
1000uF/16V
+
2
+
NTD14N03R DPAK
+5V
R131 10K
C123
1000uF/16V
1
Q113
3
+
C
C126
330uF/16V
Q106
STD3NK60ZT4
C127
Y 1nF
2
C140
L102
1
OPP CKT
R170 1K
VS1
C121
270pF
1
D110
MMSD4148
C
+5VSB
+5VSB*
+
C138
330uF/16V
Q107
BC856ALT1(SOT23)
R136
47k
3
1
R137
220
VS2
+5VSB*
1
P
PC100A
SFH817A
PFC_VCC
R138
1K
R142
16K2
R144
6K19
2
R147 100
VCC1
C130
470nF
R149 0
B
R148
4K7
2
B
Q108
BC846ALT1(SOT23)
1
3
4
Vref
3
3
R153 10K
IC101
TL431ACLPRPG 1%(TO92)
R172 4K7
1
R164
100K
2
PC101B
SFH817A
R154
100K
R155
2K49
D124
PFC_GND
0R
STB
+5VSB*
R158
2K2
R159
2K2
1
R157
1K
STANDBY
PC101A
SFH817A
R161
100K
6.3V
D121
MMSD4148
VS1-OVP
R163
4K7
2
A
A
+5VSB*
ZD103
1N4733A 5V1 (DO-41)
Q111
BC846ALT1(SOT23)
R165 470
Q112
BC846ALT1(SOT23)
Schematic for HV-LIPS Greenpoint Reference Board (SMPS1)
R166
4K7
R167
470
R168
470
C137
10nF
ON
Model Name
Size
Engineer
Subject
5
4
3
2
ON SEMICONDUCTOR TWN S.E.C.
ON-MICRO-LIPS-32"
B
Dale Tittensor
SMPS PCB
Revision
Date
Reviewer
Sheet
1
Pilot 3
2009.02.12
Jean-Paul Louvel
2 of 4
5
4
3
2
1
Schematic of Greenpoint Reference Board (SMPS1 Configuration)
D
D
CN311
4324-11S
1
2
3
4
5
6
7
8
9
10
11
+30V
+12V
+12V
+12V
+5V
+5V
+5V
C
C
CN309
4324-10S
10
9
8
7
6
5
4
3
2
1
+5VSB
+5VSB
STB
PWM_DIM
A_DIM
ENABLE
SYNC_IN
SYNC_OUT
B
B
A
A
ON
Model Name
Size
Engineer
Subject
5
4
Schematic for HV-LIPS Greenpoint Reference Board (SMPS1)
3
2
ON SEMICONDUCTOR TWN S.E.C.
ON-MICRO-LIPS-32"
B
Dale Tittensor
CONNECTORS PCB
Revision
Date
Reviewer
Sheet
1
Pilot 3
2009.02.12
Jean-Paul Louvel
4 of 4
10
9
8
7
6
5
4
3
2
1
F3000.47R 1W
PFC_OUT
H
D301
T300
PBT-07087-1322G
1
7
D300
H
CN300
Schematic of Greenpoint Reference Board (SMPS1 Configuration)
BAV21
M300
NTGD4167C
2
R303 2K21
BAV21
3
R304
56
4
2
C300
1
470 nF
Q300
2
C301
1
470 nF
2
STD3NK50ZT4 (DPAK)
T304
2
10
6
R312
4k7
D305
7
STD3NK50ZT4 (DPAK)
STD3NK50ZT4 (DPAK)
1K5
6
Q302
R316
3k3
R317
3k3
2
Q303
R319 1K5
T305
PBT-07087-1322G
1
7
R313
4k7
1
3
R318
SM02B-BHSS-1-TB
CN301
4
4
7
LAMP1
LAMP2
6
9
10
6
4
1
2
T302
PBT-07087-1322G
1
7
10K
9
1
2
R311
5
R309 422
BCK-13-021T
10K
2
4
BAV70LT1
1
R310
5
R308 422
BCK-13-021T
R306
3k3
R307
3k3
3
6
BAT54SWT1
1
T303
Q301
6
T301
PBT-07087-1322G
1
7
R302
4k7
1
3
STD3NK50ZT4 (DPAK)
6
BAT54SWT1
R300
4k7
D302
D304
3
G
4
R305
56
4
D303
C328
1uF
450V
2
R301 2K21
3
M301
NTGD4167C
4
BAV70LT1
1
1
2
1
2
LAMP3
LAMP4
G
SM02B-BHSS-1-TB
6
T306
PBT-07087-1322G
7
C305
C304
Q304
NTA4153N
1uF
F
1uF
R320
C316
10K
1nF
Q305
NTA4153N
CN302
R321
C317
10K
1nF
4
6
R323
D306
BAV21
R322
D307
BAV21
100K
100K
R324
4k7
D308
R326
3k3
R327
3k3
1
PFC_GND
T307
PBT-07087-1322G
1
7
R325
4k7
3
2
4
1
2
1
2
LAMP5
LAMP6
F
SM02B-BHSS-1-TB
6
T308
PBT-07087-1322G
1
7
BAV70LT1
CN303
4
+12V
E
C307
C306
100 nF
F301
0.47 1/2W
47uF
1
2
T309
R328
4k7
D309
11
10
R329
4k7
R330
3k3
R331
3k3
1
3
+
9
8
C308 1uF
2
4
5
4
BAV70LT1
6
7
C311 4.7uF
1
vdd
R333
750K
1uF
2
3
C318
10nF
4
VDD
C_R
AOUT
C_T
GND
C_B
R343 10K
5
5pF
5pF
C329
C330
5pF
5pF
BOUT
BRT_D
SS/FLT
BRT_A
COMP
15
R365
R366 R337
R338
14
120
120
150
120
R344 10K
6
A_DIM
7
ENABLE
R348 4K7
8
ENABLE
ISNS
SYNC
VSNS
R367
R368
R339
R340
120
120
150
120
VSNS2
C313
5.6nF
12
R335
4k7
D310
VSNS1
1
R346
4k7
9
D312
C320
100pF
D313
C
2
BAV70LT1
2
R357
R355
R356
C322
R353
20K
10K
1nF
10K
C323
C324
R358
R359
C325
C326
R354
R360
C327
47pF
18K
22K
10nF
10nF
2K
33K
690pF
100K
2.2nF
D314
VSNS1
B
2
1
1
3
R363
R364
22K
22K
CN306
4324-2S
1
1
2
2
VSNS2
BAT54SWT1
R347
4k7
4
1
2
LAMP11
LAMP12
SM02B-BHSS-1-TB
C
6
B
ON
ON SEMICONDUCTOR TWN S.E.C.
Model Name
Size
Engineer
Subject
8
1
2
LAMP
RTN
A
9
6
BAV70LT1
Note:
1. Input Voltage 400V.
2. Output 100W to 200W.
3. ENABLE active above 1.5V.
4. Analog dimming input (A_DIM) 1 to 4VDC, or equivalent PWM signal.
5. PWM dimming input (PWM_DIM) 1 to 4VDC, Controls duty cycle from 0 TO 100%,
Above 4V goes into continuous operation.
6. T2 and T3 about EE15 size, 25:38+38.
7. T1 about 108:360
10
T313
PBT-07087-1322G
7
R362
220
3
BAT54SWT1
LAMP9
LAMP10
R361
220
D315
2
1
2
SM02B-BHSS-1-TB
6
T314
PBT-07087-1322G
1
7
R350
3k3
R352
3k3
1
3
1
3
100pF
1
2
CN305
4
R349
1K
R351 2K
C321
4
BAV70LT1
C314
5.6nF
6
D
R341
3k3
R342
3k3
1
3
R345 10K
10
100nF
E
T311
PBT-07087-1322G
7
D311
BAV70LT1
C319
LAMP7
LAMP8
SM02B-BHSS-1-TB
11
SYNC_IN
1
2
6
T312
PBT-07087-1322G
1
7
R336
4k7
2
13
1
2
CN304
16
3
PWM_DIM
VIN
1
1
C315
C310
4
IC300
LX6503-IDW
C312 220pF
D
C309
R334
750K
2
R332
75K
PIT125050-3551 GP
6
T310
PBT-07087-1322G
1
7
7
Schematic for HV-LIPS Greenpoint Reference Board (SMPS1)
6
5
4
3
2
ON-MICRO-LIPS-32"
B
Dale Tittensor
INVERTER PCB
Revision
Date
Reviewer
Sheet
Pilot 3
2009.02.12
Jean-Paul Louvel
3 of 4
1
A
Bill of Materials of the HV-LIPS board (SMPS1 Version)
Designator
Package /
Dimensions
Component Type
Value
Rating
BD01
Bridge Rectifier
8A-600V
8A-600V
BD01A
Screw
BD01B
Heat-sink
C001,C003
CFS
470 nF
450V
Radial 15mm
MES474K450VDC
C005,C006
Y Cap
1 nF
400V / 4KV
Radial 10mm
5SE102MT402A97E
Joey Electronics
SUCCESS
C007
Ceramic Cap
10 nF
630V
Radial 5mm
10nF 1KV
SUCCESS
450V
Radial 7.5mm D18x20mm
Horizontal insertion:H <
20mm
C008,C010
Electrolytic 105°C
Reference
Supplier
GBU806
Taiwan Semiconductor
M3*8
70 mm
68 uF
YUAN FENG Industrial Co,LTD.
Nippon Chemi Con
EKXG451ELL680MM25S
HQX104K275I04SANYAY
Shanghai Ultra Tech (UTX)
EKMG500ELL470MF11D
Nippon Chemi Con
HQX105K275N04SANYAY
Shanghai Ultra Tech (UTX)
C009
X2 Cap
100 nF
275V
Radial 15mm
C011
Ceramic Chip Cap
100 nF
10V
805
C012
Ceramic Chip Cap
390 nF
10V
805
C013
Electrolytic 105°C
47 uF
25V
Radial 5mm D8mm
C014
Ceramic Chip Cap
100 nF
16V
805
C016
Ceramic Chip Cap
1 nF
10V
805
C018
CPMX-X2
1 uF
275V
Radial 22.5mm
C019
Ceramic Chip Cap
220 pF
10V
805
C100
Ceramic Cap
10 nF
250V
Radial 5mm
10nF 250V
C101
Electrolytic 105°C
10 uF
25V
Radial 5mm
EKY-500ELL100ME11D
C103
Ceramic Cap
10 nF
250V
Radial 5mm
10nF 250V
C106,C109,C110
Electrolytic 105°C Low Z
1000 uF
16V
Radial 5mm D8mm
EKY-160ELL102MH20D
Nippon Chemi Con
C111
Electrolytic 105°C Low Z
330 uF
16V
Radial 5mm D8mm
EKY-160ELL331MHB5D
Nippon Chemi Con
C112
Ceramic Chip Cap
470 nF
10V
805
C113,C114
Ceramic Chip Cap
100 nF
16V
805
C115,C116
Electrolytic 105°C
10 uF
35V
Radial 5mm D5
EKY-500ELL100ME11D
Nippon Chemi Con
C117
Ceramic Chip Cap
270 pF
10V
805
Nippon Chemi Con
C118,C119
Ceramic Chip Cap
100 pF
10V
805
C121
Ceramic Chip Cap
270 pF
25V
805
C122,C123
Electrolytic 105°C Low Z
1000 uF
16V
Radial 5mm D8mm
EKY-160ELL102MH20D
Nippon Chemi Con
C126
Electrolytic 105°C Low Z
330 uF
16V
Radial 5mm D8mm
EKY-160ELL331MHB5D
Nippon Chemi Con
66
C127
CCS-Y1
1 nF
400V / 4KV
Radial 10mm
5SE102MT402A97E
SUCCESS
C130
Ceramic Chip Cap
470 nF
10V
805
C137
Ceramic Chip Cap
10 nF
10V
805
C138
Electrolytic 105°C Low Z
330 uF
16V
Radial 5mm D8mm
KY 16VB330 8*12
Nippon Chemi Con
C140
Ceramic Chip Cap
22 pF
10V
805
C142
Electrolytic 105°C
220 uF
35V
Radial 5mm D8mm
C143
Ceramic Chip Cap
4.7 nF
25V
805
EKY-350ELL221MH15D
Nippon Chemi Con
C300,C301
Ceramic Chip Cap
470 nF
16V
805
C304,C305
Ceramic Chip Cap
1 uF
10V
805
C306
CFS
100 nF
450V
C307
Electrolytic 105°C
47 uF
16V
Radial 15mm
MES104K450VDC
Radial 5mm D5
EKMG500ELL470MF11D
Joey Electronics
Nippon Chemi Con
C308
Ceramic Chip Cap
1 uF
16V
805
C309,C310
Ceramic Cap
5 pF
2 kV
Radial 5mm
C311
Ceramic Chip Cap
4u7
10V
805
8NPO5R0D302A76E
SUCCESS
C312
Ceramic Chip Cap
220 pF
10V
805
C313,C314
Ceramic Chip Cap
5n6
16V
805
C315
Ceramic Chip Cap
1 uF
10V
805
C316,C317
Ceramic Chip Cap
1 nF
16V
805
C318
Ceramic Chip Cap
10 nF
10V
805
C319
Ceramic Chip Cap
100 nF
10V
805
C320,C321
Ceramic Chip Cap
100 pF
10V
805
C322
Ceramic Chip Cap
1 nF
10V
805
C323
Ceramic Chip Cap
2n2
10V
805
C324
Ceramic Chip Cap
47 pF
10V
805
C325,C326
Ceramic Chip Cap
10 nF
10V
805
C327
Ceramic Chip Cap
680 pF
10V
805
C328
CFS
1 uF
450V
Radial 15mm
MES105K450VDC
C329,C330
Ceramic Cap
5 pF
2 kV
8NPO5R0D302A76E
Joey Electronics
SUCCESS
CN001
Connector
4333-W05ST
5A 250V
Radial 5mm
Radial 15mm with 2 ext.
pins
4333-W05ST
LEAMAX Enterprise
CN300-CN305
HV Lamp Connector
SM02B-BHSS-1TB
2pins
Radial 12.5mm
01040023028
SUNDA
CN306
Signal connector
4324-2S
Straight
2pins
Radial 2.5mm
4324-2S
LEAMAX Enterprise
67
CN309
Signal connector
4324-10S
CN311
Signal connector
4324-11S
D001
Diode
1N5406
D002
Diode
D003
D100
Straight
10pins
Straight
11pins
Radial 2.5mm
4324-10S
LEAMAX Enterprise
Radial 2.5mm
4324-11S
LEAMAX Enterprise
3A-600V
DO-201
TOP Manual Axial 22.5mm
10mm High Preformed
1N5406
ON Semiconductor
MUR550APF
5A-520V
DO-201
TOP Manual Axial 22.5mm
10mm High Preformed.
MUR550APF
ON Semiconductor
Diode
MMSD4148
0.2A-100V
SOD-123
MMSD4148
ON Semiconductor
Diode
BAV21
0.2A 250V
DO-35 Axial 12.5mm
BAV21
PANJIT
D101
Diode Ultra Fast
MUR160
1A 600V
DO-41 Axial 12.5mm
MUR160
ON Semiconductor
D104
Diode
MMSD4148
0.2A 100V
SOD-123
MMSD4148
ON Semiconductor
D105
Diode
BAV21
0.2A 250V
DO-35 Axial 12.5mm
BAV21
PANJIT
D107
Diode, Dual Schottky
MBR20100CTG
20A 100V
TO-220AB
MBR20100CTG
ON Semiconductor
D107A
Screw
M3*8
D107B
Heat-sink
40mm
D107C
Insulator
SLTO-220
JUNHO
YUAN FENG Industrial Co,,LTD.
D108,D110
Diode
MMSD4148
0.2A 100V
SOD-123
MMSD4148
ON Semiconductor
D111
Diode, Dual Schottky
MBR20100CTG
20A 100V
TO-220AB
MBR20100CTG
ON Semiconductor
D111A
Screw
M3*8
D111B
Heat-sink
40mm
D111C
Insulator
SLTO-220
JUNHO
D113,D121
Diode
MMSD4148
MMSD4148
ON Semiconductor
D124
Carbon Chip Resistor
0R
D300,D301
Diode
BAV21
0.2A 250V
DO-35 Axial 12.5mm
BAV21
PANJIT
D302
Dual Signal Diode
BAV70LT1
0.2A 75V
SOT-23
BAV70LT1
ON Semiconductor
D122
0.2A 100V
SOD-123
YUAN FENG Industrial Co,,LTD.
0R / Jumper
1206
D303,D304
Dual Schottky diode
BAT54SWT1
0.2A 30V
SOT323
BAT54SWT1
ON Semiconductor
D305
Dual Signal Diode
BAV70LT1
0.2A 75V
SOT-23
BAV70LT1
ON Semiconductor
D306,D307
Diode
BAV21
0.2A 250V
DO-35 Axial 12.5mm
BAV21
PANJIT
D308-D313
Dual Signal Diode
BAV70LT1
0.2A 75V
SOT-23
BAV70LT1
ON Semiconductor
D314,D315
Dual Schottky diode
BAT54SWT1
0.2A 30V
SOT323
BAT54SWT1
ON Semiconductor
68
F001
Fuse
4A
250V
Axial 5x20mm
UBM-A004
F100
LV Fuse resistance
0.47R 1/2W
250V
Radial 5mm D10
FKN 050 J R47 FK
CONQUER
Synton-Tech Corporation.
F300
HV Fuse resistance
0.47R 1W
450V
Radial 5mm D10
FRN 100S J R47 FK
Synton-Tech Corporation.
F301
LV Fuse resistance
0.47R 1/2W
250V
Radial 5mm D10
FKN 050 J R47 FK
Synton-Tech Corporation.
IC001
PFC Controller
NCP1606B
SOIC-8
NCP1606B
ON Semiconductor
IC100
QFTon Controller
NCP1351B
SOIC-8
NCP1351B
ON Semiconductor
IC101
Voltage Ref.
TL431ACLPRPG
TO-92
TL431ACLPRPG
ON Semiconductor
IC300
Inverter Controller
LX6503-IDW
SOIC-16
LX6503-IDW
Microsemi
J001
Jumper
Axial 12.5mm
J002
Jumper
Axial 12.5mm
J100
Jumper
Axial 12.5mm
J103
Jumper
Axial 12.5mm
J104
Jumper
L001
Diff. Mode Filter
130uH
TOP Manual
JLC2030
Shenzhen Jewel Electric.
L002
PFC Coil
TF2815 - 150uH
TOP Manual
JLC2832
Shenzhen Jewel Electric.
L005
Common Mode Filter
CFS24 - 2mH
2.5A
TOP Manual
JLB24103
Shenzhen Jewel Electric.
L101,L102
Inductance filter
10uH
5A
Radial 5mm
JLC0895
M300.M301
Dual N+P MOS Driver
NTGD4167C
2A 30V
TSOP-6
NTGD4167C
Shenzhen Jewel Electric.
ON Semiconductor
PC100,PC101
Opto-coupler
SFH817A
DIP-4
SFH817A
SHARP
Q001
Power MOS
STP11NK50ZFP
11A 500V
TO220FP
STP11NK50ZFP
STMicroelectronics
Q001A
Screw
M3*8
Q001B
Heat-sink
70mm
Q002
PNP transistor
BC856ALT1
SOT-23
BC856ALT1
ON Semiconductor
Q103
Dual NPN
BC846BDW
SOT-363
BC846BDW
ON Semiconductor
Q106
Power MOS
STD3NK60ZT4
DPAK
STD3NK60ZT4
STMicroelectronics
Q107
PNP
BC856ALT1
SOT-23
BC856ALT1
ON Semiconductor
Q108,Q111,Q112
NPN
BC846ALT1
SOT-23
BC846ALT1
ON Semiconductor
1%
Axial 12.5mm
4A 600V
YUAN FENG Industrial Co,,LTD.
Q113
NMOS
NTD14N03R
14A 30V
DPAK
NTD14N03R
ON Semiconductor
Q114
NMOS
NTD3055-094T4G
12A 60V
DPAK
NTD3055-094T4G
ON Semiconductor
Q300-Q303
Power MOS
STD3NK50ZT4
3A 500V
DPAK
STD3NK50ZT4
STMicroelectronics
NTA4153N-SC75
ON Semiconductor
Q304,Q305
Signal NMOS
NTA4153N-SC75
1A 20V
SC75
R002
Carbon Film Resistor
1M3 1%
1/4W
Axial 12.5mm
69
R004
Carbon Chip Resistor
27K
805
R005
Carbon Chip Resistor
68
R006
Carbon Film Resistor
1M3 1%
R008
Carbon Chip Resistor
68
R009
Carbon Chip Resistor
10K
R010
Carbon Film Resistor
1M3 1%
R011
Carbon Chip Resistor
56K
805
R012
Carbon Chip Resistor
220
805
R013
Carbon Chip Resistor
24K9 1%
R014
Wirewound Resistor
0.10 5%
R015-R020
Carbon Film Resistor
150K
805
R024
Carbon Chip Resistor
68
805
R025
Carbon Chip Resistor
470
805
R026
Carbon Chip Resistor
680
805
R100,R101,R102
Carbon Film Resistor
1M
1/4W
Axial 12.5mm
R104
Metal Film Resistor
33K 5%
2W
TOP Manual Axial 22.5mm
10mm High Preformed.
R108
Wirewound Resistor
0.47R 5%
2W
TOP Manual Axial 22.5mm
R112
Carbon Chip Resistor
3K3
R113
Carbon Film Resistor
7K5
1/4W
Axial 12.5mm
R114
Carbon Chip Resistor
0R
805
R116
Carbon Chip Resistor
100
805
R117
Carbon Chip Resistor
47
805
R118
Carbon Chip Resistor
10
805
R119
Carbon Chip Resistor
10K
805
R120
Carbon Chip Resistor
20K
805
R121
Carbon Chip Resistor
2K7
805
R122
Carbon Chip Resistor
4K7
805
R124
Carbon Chip Resistor
470
805
R125
Carbon Chip Resistor
1K
805
R127
Carbon Film Resistor
2K2
R129
Carbon Chip Resistor
100K
805
1/4W
Axial 12.5mm
805
805
1/4W
Axial 12.5mm
805
2W
TOP Manual Axial 22.5mm
805
1/4W
Axial 12.5mm
805
70
R130
Carbon Chip Resistor
150K
805
R131
Carbon Chip Resistor
10K
R134
Carbon Film Resistor
27
R136
Carbon Chip Resistor
47K
805
R137
Carbon Chip Resistor
220
805
R138
Carbon Chip Resistor
1K
805
R142
Carbon Chip Resistor
16K2 1%
805
R144
Carbon Chip Resistor
6K19 1%
805
R147
Carbon Chip Resistor
100
805
R148
Carbon Chip Resistor
4K7
805
R149
Carbon Chip Resistor
0R
805
R153
Carbon Chip Resistor
10K
R154
Carbon Film Resistor
100K
R155
Carbon Chip Resistor
2K49 1%
805
R157
Carbon Chip Resistor
1K
805
R158,R159
Carbon Chip Resistor
2K2
805
R161
Carbon Chip Resistor
100K
805
R163
Carbon Chip Resistor
4K7
805
R164
Carbon Chip Resistor
100K
805
R165
Carbon Chip Resistor
470
805
R166
Carbon Chip Resistor
4K7
805
R167,R168
Carbon Chip Resistor
470
805
R170
Carbon Chip Resistor
1K
805
R172,R300
Carbon Chip Resistor
4K7
805
R301
Carbon Chip Resistor
2k21 1%
805
R302
Carbon Chip Resistor
4K7
805
R303
Carbon Chip Resistor
2k21 1%
805
R304,R305
Carbon Chip Resistor
56
805
R306,R307
Carbon Chip Resistor
3K3
805
R308,R309
Carbon Chip Resistor
422
805
R310,R311
Carbon Chip Resistor
10K
805
R312,R313
Carbon Chip Resistor
4K7
805
805
1/4W
Axial 12.5mm
805
1/4W
Axial 12.5mm
71
R316,R317
Carbon Chip Resistor
3K3
805
R318,R319
Carbon Chip Resistor
1K5
805
R320,R321
Carbon Chip Resistor
10K
805
R322,R323
Carbon Chip Resistor
100K
805
R324,R325
Carbon Chip Resistor
4K7
805
R326,R327
Carbon Chip Resistor
3K3
805
R328,R329
Carbon Chip Resistor
4K7
805
R330,R331
Carbon Chip Resistor
3K3
805
R332
Carbon Chip Resistor
75K
805
R333,R334
Carbon Chip Resistor
750K
805
R335,R336
Carbon Chip Resistor
4K7
805
R337
Carbon Chip Resistor
120
805
R338,R339
Carbon Chip Resistor
150
805
R340
Carbon Chip Resistor
120
805
R341,R342
Carbon Chip Resistor
3K3
805
R343-R345
Carbon Chip Resistor
10K
805
R346-R348
Carbon Chip Resistor
4K7
805
R349
Carbon Chip Resistor
1K0
805
R350
Carbon Chip Resistor
3K3
805
R351
Carbon Chip Resistor
2K0
805
R352
Carbon Chip Resistor
3K3
805
R353
Carbon Chip Resistor
10K
805
R354
Carbon Chip Resistor
2K0
805
R355
Carbon Chip Resistor
20K
805
R356
Carbon Chip Resistor
10K
805
R357
Carbon Chip Resistor
100K
805
R358
Carbon Chip Resistor
18K
805
R359
Carbon Chip Resistor
22K
805
R360
Carbon Chip Resistor
33K
R361,R362
Carbon Film Resistor
220
805
1/4W
Axial 12.5mm
R363,R364
Carbon Chip Resistor
22K
805
R365-R368
Carbon Chip Resistor
120
805
72
RT001
Thermistor
2R5 3W
TOP Manual Rad 7.5mm
RV001
Varistor
TVR10471KSY
TOP Manual Rad 7.5mm
TVR10471KSY
Thinking Electronic
T100
Switch Mode Transformer
Flyback EER28L
TOP Manual
BCK-28-1050
Shenzhen Jewel Electric.
T300-T302,T305T308, T310-T314
Current Balance
Transformer
PBT-07087-1322G
TOP Manual
PBT-07087-1322G
Taipei Multipower Products
(TMP)
T303,T304
Drive Transformer
TOP Manual
BCK-13-021TC
T309
Inverter. HV Transformer
TOP Manual
PIT125050-3551 AG
ZD001
Diode, Zener
BCK-13-021TC
PIT125050-3551
AG
1N4733A
5.1V 5%
DO-41 Axial 12.5mm
1N4733A
Shenzhen Jewel Electric.
Taipei Multipower Products
(TMP)
ON Semiconductor
ZD100
Diode, Zener
1N5929B
15V 5%
DO-41 Axial 12.5mm
1N5929B
ON Semiconductor
ZD101
Diode, Zener
1N4746A
22V 5%
DO-41 Axial 12.5mm
1N4746A
ON Semiconductor
ZD103
Diode, Zener
1N4733A
5.1V 5%
DO-41 Axial 12.5mm
1N4733A
ON Semiconductor
Notes:
Resistor tolerances are +/- 5% unless noted otherwise
Capacitor tolerances are +/- 10% unless noted otherwise
Electrolytic capacitor tolerances are +/- 20% unless noted otherwise
470V
SCK 15 2R5 8 M S Y
Thinking Electronic
73
NCP1351
• Datasheet
• AND8288 NCP1351 Evaluation Board Documentation
• Modeling the NCP1351
NCP1606/7
• NCP1606 Data Sheet
• NCP1607 Data Sheet
• AND8123 Power Factor Correction Operating in Critical Conduction Mode
• AND8353 Implementing Cost Effective & Robust Power Factor Correction with NCP1607
• AND8154 Universal Adapter Power Supply with Active PFC
• AND8016 Design of Power Factor Correction Circuits
• PFC Handbook
LX6503
• Data Sheet
• Backlight Design for large LCD-TV Screens Article
Magnetics Suppliers
• TMP – HV Inverter Transformer and Balancers
• Jewel – Flyback Transformer and PFC Inductor
74
References on Energy Standards
CSC (China)
• http://www.cecp.org.cn
EU Eco-label (Europe)
http://ec.europa.eu/environment/ecolabel/product/pg_television_en.htm
EU Code of Conduct (Europe)
• http://www.eup-network.de/product-groups/
Group for Energy Efficient Appliances (Europe)
• http://www.efficient-appliances.org/Criteria.htm
Top Runner (Japan)
• http://www.eccj.or.jp/top_runner/index.html
• http://www.eccj.or.jp/top_runner/e_0710.html
Energy Saving Label (Korea)
• http://www.kemco.or.kr/
Energy Star
• http://www.energystar.gov/
• http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=TV
• http://www.energystar.gov/index.cfm?c=tv_vcr.pr_crit_tv_vcr
Standby Considerations
• http://standby.lbl.gov
75
Schematics of Complete PCB with all Configuration Options
The following four pages contain the schematics for the complete PCB with all possible options (see Table 3) of the
GreenPoint HV-LIPS design for details on the alternate configurations.
76
5
4
3
2
1
1N5406(DO-201)
2
D1
BD1
GBU806
L1
150uH
RT1
D2
4
7
6
8
7
L2
L3
R3
100K
RV1
C5 Y 1nF
R22
100K
X2 100nF
275V
Q1
STP11NK50ZFPN
R5
68
R7
100K
IC1
NCP1606B
C9
D
TF2815 - 150uH
PQ3252 - 150uH
R24
68
TVR10471KSY
C6 Y 1nF
PFC_OUT
27K
5
ZCD
D3 MMSD4148
Q2
7
R21
100K
L5
L4
CFS24 - 2mH
CFS28 - 5mH
Ctrl
2
C12
3
RV5
eclat
C
VCC
CT
R23
100K
RV4
eclat
R25
470
6
GND
FB
1
CS
4
C8
68uF 450V
390nF
R11
+
1
R9
10K
+
R6
1M3 1/4W
1
BC856ALT1(SOT23)
C11 100nF
8
C7
10nF 630V
1
R8
68
DRV
R2
1M3 1/4W
2
R4
C10
68uF 450V
3
R1
100K
C4
1uF
450V
2
3
C3
0.47uF
450V
NTC 2R5
MUR550APF(DO-201)
3
-
D
C2
1uF
450V
11
9
2
C1
0.47uF
450V
2
3
+
1
Q3
STD5NK52ZD
56K
R10
1M3 1/4W
C
R12
220
+
X2 1uF
275V
C18
C13
47uF
C14
100nF
C15
NA
R26
680
C19
220pF
R13
24K9
C17
NA
R14
0.10 2 W
C16
1nF
ZD1
1N4733A
5.1V
PFC_GND
R15 150K
R16 150K
R17 150K
PFC_VCC
R18
150K
R20
150K
R19
AC Line - For PWM start
150K
1
B
1
B
2
RV2
eclat
J2
NA
2
J1
NA
L6
RV3
eclat
CHOKE (EMI Choke)
C20 X2 100nF
275V
F1
FUSE 4A 250V (Axial Lead)
A
A
L
5
FG
FG
N
CN1
ON
4333-W05ST
Model Name
Size
Engineer
Subject
4
Schematic of Complete PCB with alternative configurations
3
2
ON SEMICONDUCTOR TWN S.E.C.
ON-MICRO-LIPS-32"
B
Dale Tittensor
EMI/ PFC
PCB
Revision
Date
Reviewer
Sheet
1
PCB 3
2009.02.12
Jean-Paul Louvel
1 of 4
5
4
R100
1M 1/4W
R101
1M 1/4W
3
R102
1M 1/4W
2
T100
ER28L
AC Line - For PWM start
C103
10nF 250V
F102
0.47 1/2W
VS4
D100 BAV21
1
PFC_OUT
+30V
R103 NA
C100
10nF 250V
ZD100
1N5929B
15V
R109
100 1/2W
IC100
NCP1351B
D105
BAV21
CT
Timer
CS
Latch
1
VS2
L101
1
12
+
Drv
NTP18N06G(TO220)
NTD3055-094T4G DPAK
3
+12V
+
C114
100nF
C115
10uF/50 V
7
C116
10uF/35 V
+
ZD101
1N5929B 22V
5
Q103
BC846BDW SOT363
R124
470
J104
+5VSB
2
R129 100k
R130 150k
7
8
OPP CKT
R134
27
22pF
D113
MMSD4148
R169
NI
10uH
2
+
+
C123
1000uF/16V
1
2
C124
1000uF/16V
C
+5V
+
R131 10K
C126
330uF/16V
R132
NA
Vref
C120
1nF 500V
R128
100 1/2W
STB
R133
NA
D112
MMSD4148
R135 NA
C127
Y 1nF
Q107
BC856ALT1(SOT23)
IC102
LM7805C
R136
47k
1
3
1
+
+5VSB*
+5V
Q104 NTP18N06G(TO220)
Q113 NTD14N03R DPAK
3
Q105
BC846BDW SOT363
Q106
STD3NK60ZT4
2
C140
2
C122
1000uF/16V
0.47 1/2W
J102
NA
1
L102
1
3
+
C138
330uF/16V
NA
F101
1
J105
VS1
C121
270pF
1
R127 2K2
D111 MBR20100CTG (TO220)
9
10
D110
MMSD4148
D108
MMSD4148
R122
4K7
2
P
+12V
STB
C143
4.7nF
J101
NA
C
C111
330uF/16V
R126 NA
R125
1K
C119
100nF
R120
20K
Vref
3
D107
MBR20100CTG (TO220)
5
+
R119 10K
C110
1000uF/16V
C118
100pF
R170 1K
2
+
C109
1000uF/16V
2
C117
270pF
GND
2
1
4
Q102
Q114
10uH
+
C142
220uF/35 V
8
2
P
R123
NA
NA
R113 7.5K 1/4W
2
3
C106
1000uF/16V
6
C113
100nF
R121
2K7
D
D102
MMSD4148
R110
R111 NA
D106 MUR420
R118 10
+24V
STB
C144
4.7nF
2
C108
1nF 500V
1
2
Q101
BC846BDW SOT363
C125
100nF
R137
220
VS2
P
2
OUT
+5VSB
C139
100nF
+5VSB*
C141 470nF
1
R171 1K
IN
GND
Vcc
R117 47
C104
220uF/50V
3
FB
D104
MMSD4148
R116 100
6
+
R107
NA
1
1
NTD14N03R DPAK
3
1
R114
0
3
1
R112
3K3
2
2
4
VCC1
Q100
2
R106
NA
J100
NA
+
J103
NA
R115
100 1/2W
10uH
+14V or +24V
Vref
11
P
PC100B
SFH817A
L100
1
VS3
D103 MUR420
3
D
C107
NA
C105
1nF 500V
D101
MUR160
R108
0.47R 2W
PFC_GND
+ C101
10uF/50V
1
R104
33K 2W
C112
470nF
F100
0.47 1/2W
1
PC100A
SFH817A
B
Q108
BC846ALT1(SOT23)
1
3
PFC_VCC
2
R147 100
VS3
R138
1K
VCC1
C130
470nF
R149 0
R140
NA
R142
16K2
R143
NA
R144
6K19
R141
NA
B
C132
2
R148
4K7
C133
C131
NA
C134
NA
NA
NA
4
Vref
3
3
R145
NA
R153 10K
IC101
TL431ACLPRPG 1%(TO92)
R172 4K7
D124 MMSD4148
1
2
PC101B
SFH817A
R154
100K
STB
R155
2K49
D122 MMSD4148
+
R173
100K
PFC_GND
R164
100K
D125 MMSD4148
C128
470uF/6.3V
+5VSB*
R158
2K2
1
R157
1K
6.3V
R160
1K
R159
2K2
R161
100K
STANDBY
PC101A
SFH817A
2
A
VS2
VS2-OVP
ZD104
1N4733A 13V (DO-41)
27V
R163
4K7
D121
MMSD4148
+5VSB*
VS1-OVP
ZD103
1N4733A 5V1 (DO-41)
13V
D123
MMSD4148
A
VS3
VS3-OVP
ZD105
1N4733A 27V (DO-41)
Q111
BC846ALT1(SOT23)
R165 470
Q112
BC846ALT1(SOT23)
Schematic of Complete PCB with alternative configurations
R166
4K7
R167
470
R168
470
C137
10nF
ON
Model Name
Size
Engineer
Subject
5
4
3
2
ON SEMICONDUCTOR TWN S.E.C.
ON-MICRO-LIPS-32"
B
Dale Tittensor
SMPS PCB
Revision
Date
Reviewer
Sheet
1
PCB 3
2009.02.12
Jean-Paul Louvel
2 of 4
5
4
3
2
1
CN310
4324-4S
4 4
3 3
2 2
1 1
+24V
+24V
D
D
CN311
4324-11S
1
2
3
4
5
6
7
8
9
10
11
+30V
+12V
+12V
+12V
+5V
+5V
+5V
C
C
CN309
4324-10S
10
9
8
7
6
5
4
3
2
1
+5VSB
+5VSB
STB
PWM_DIM
A_DIM
ENABLE
SYNC_IN
SYNC_OUT
B
B
A
A
ON
Model Name
Size
Engineer
Subject
5
4
Schematic of Complete PCB with alternative configurations
3
2
ON SEMICONDUCTOR TWN S.E.C.
ON-MICRO-LIPS-32"
B
Dale Tittensor
CONNECTORS PCB
Revision
Date
Reviewer
Sheet
1
PCB 3
2009.02.12
Jean-Paul Louvel
4 of 4
10
9
8
7
6
5
4
3
2
1
F3000.47R 1W
PFC_OUT
H
D301
T300
PBT-07087-1322G
1
7
D300
H
CN300
3
C301
1
470 nF
6
T303
T315
T316
BCK-13-021T
PRT-203030-1622 GP
TF-1613-1
7
2
4
9
C302
5
10
1
6
NA
9
4
2
7
R314
3
2
STD3NK50ZT4 (DPAK)
1
R310
5
R308 422
T304
T317
T318
10K
BCK-13-021T
PRT-203030-1622 GP
TF-1613-1
7
2
4
9
C303
5
10
1
6
NA
9
4
2
7
R315
1K5
4
R312
4k7
D305
R313
4k7
R316
3k3
R317
3k3
1
3
STD3NK50ZT4 (DPAK)
NA
R318
Q302
2
6
CN301
10K
STD3NK50ZT4 (DPAK)
NA
SM02B-BHSS-1-TB
J301
NA
R311
5
R309 422
2
Q303
R319 1K5
LAMP1
LAMP2
T302
PBT-07087-1322G
1
7
BAV70LT1
6
BAT54SWT1
1
G
Q301
T301
PBT-07087-1322G
1
7
J302
NA
4
1
2
1
2
3
STD3NK50ZT4 (DPAK)
470 nF
1
BAT54SWT1
R306
3k3
R307
3k3
1
2
6
T305
PBT-07087-1322G
1
7
J304
NA
4
BAV70LT1
1
1
2
2
Q300
C300
R302
4k7
1
1
2
R300
4k7
D302
D304
2
C328
1uF
450V
R305
56
4
D303
C331
1uF
450V
2
3
R304
56
4
6
1
2
LAMP3
LAMP4
G
SM02B-BHSS-1-TB
J303
NA
1
BAV21
R301 2K21
3
4
1
2
R303 2K21
M301
NTGD4167C
2
BAV21
M300
NTGD4167C
6
T306
PBT-07087-1322G
7
C305
C304
Q304
NTA4153N
1uF
F
1uF
R320
C316
10K
1nF
Q305
NTA4153N
CN302
R321
C317
10K
1nF
4
6
1
2
R324
4k7
D308
R325
4k7
R326
3k3
R327
3k3
1
PFC_GND
3
2
T307
PBT-07087-1322G
1
7
J306
NA
4
1
2
LAMP5
LAMP6
F
SM02B-BHSS-1-TB
J305
NA
1
100K
100K
1
D307
BAV21
2
R322
2
R323
D306
BAV21
6
T308
PBT-07087-1322G
1
7
BAV70LT1
CN303
R330
3k3
R331
3k3
1
3
+
9
8
C308 1uF
2
4
5
J308
NA
4
BAV70LT1
6
7
C311 4.7uF
1
vdd
C334
5pF
5pF
5pF
5pF
C333
C329
C330
C335
5pF
5pF
5pF
5pF
4
C_T
GND
C_B
5
BOUT
SS/FLT
BRT_A
COMP
C317
R365
R366 R337
R338
14
NC
120
120
150
120
R344 10K
6
A_DIM
7
ENABLE
R348 4K7
8
ENABLE
ISNS
SYNC
VSNS
C316
R367
R368
R339
R340
NC
120
120
150
120
VSNS2
C313
5.6nF
12
VSNS1
R346
4k7
9
D312
C320
100pF
D313
C
2
BAV70LT1
2
R357
R356
C322
R353
20K
10K
1nF
10K
C323
C324
R358
R359
C325
C326
R354
R360
C327
47pF
18K
22K
10nF
10nF
2K
33K
680pF
100K
2.2nF
D314
VSNS1
B
2
1
1
3
R363
R364
22K
22K
CN306
4324-2S
1
1
2
2
VSNS2
BAT54SWT1
LAMP11
LAMP12
C
6
B
ON
ON SEMICONDUCTOR TWN S.E.C.
Model Name
Size
Engineer
Subject
8
1
2
SM02B-BHSS-1-TB
J311
NA
LAMP
RTN
A
9
J312
NA
4
1
2
BAV70LT1
Note:
1. Input Voltage 400V.
2. Output 100W to 200W.
3. ENABLE active above 1.5V.
4. Analog dimming input (A_DIM) 1 to 4VDC, or equivalent PWM signal.
5. PWM dimming input (PWM_DIM) 1 to 4VDC, Controls duty cycle from 0 TO 100%,
Above 4V goes into continuous operation.
6. T2 and T3 about EE15 size, 25:38+38.
7. T1 about 108:360
10
6
T314
PBT-07087-1322G
1
7
R362
220
3
BAT54SWT1
D
6
R361
220
D315
2
R347
4k7
R350
3k3
R352
3k3
1
3
1
3
LAMP9
LAMP10
CN305
4
R349
1K
100nF
1
2
SM02B-BHSS-1-TB
J309
NA
T313
PBT-07087-1322G
1
7
BAV70LT1
C314
5.6nF
R345 10K
10
C319
R355
J310
NA
4
1
2
D311
BAV70LT1
R351 2K
100pF
T312
PBT-07087-1322G
1
7
1
R341
3k3
R342
3k3
1
3
6
11
SYNC_IN
C321
R336
4k7
2
13
3
BRT_D
D310
16
15
R335
4k7
2
AOUT
E
T311
PBT-07087-1322G
7
2
10nF
R343 10K
PWM_DIM
VDD
C_R
SM02B-BHSS-1-TB
J307
NA
6
CN304
1
3
VIN
1
1uF
2
C318
C310
4
IC300
LX6503-IDW
1
C315
C309
R334
750K
C312 220pF
D
C332
2
R333
750K
2
R332
75K
PIT125050-3551 GP
LAMP7
LAMP8
1
D309
11
10
2
T309
1
2
1
1
2
1
F301
0.47 1/2W
47uF
R329
4k7
1
2
1
C307
R328
4k7
6
T310
PBT-07087-1322G
1
7
2
E
C306
100 nF
2
4
+12V
7
Schematic of Complete PCB with alternative configurations
6
5
4
3
2
ON-MICRO-LIPS-32"
B
Dale Tittensor
INVERTER PCB
Revision
Date
Reviewer
Sheet
PCB 3
2009.02.12
Jean-Paul Louvel
3 of 4
1
A