18 W High Power Factor LED Driver Evaluation Board User's Manual

NCL30088LED1GEVB
18 W High Power Factor
LED Driver Evaluation Board
User'sManual
Overview
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This manual covers the specification, theory of operation,
testing and construction of the NCL30088LED1GEVB
demonstration board. The NCL30088 board demonstrates a
18 W high PF buck boost LED driver in a typical T8 outline.
EVAL BOARD USER’S MANUAL
Table 1. SPECIFICATIONS
Key Features
Parameter
Value
Input voltage (Class 2 Input,
no ground)
100 − 277
V ac
Line Frequency
Power Factor (100% Load)
THD (Load > 30%)
Output Voltage Range
Output Current
Efficiency
Start Up Time
EMI (conducted)
Comment
As illustrated, the key features of this evaluation board
include:
• Wide Mains
• Low THD across Line and Load
• High Power Factor across Wide Line and Load
• Integrated Auto Recovery Fault Protection (can be
latched by Choice of Options)
♦ Over Temperature on Board (a PCB mounted NTC)
♦ Over Current
♦ Output and Vcc Over Voltage
50 Hz / 60 Hz
0.9
Min
20%
Max
90 − 180 V dc
100 mA dc
±2%
92%
Typical
< 500 msec
Typical
Class B
FCC/CISPR
Figure 1. Evaluation Board Picture (Top View)
© Semiconductor Components Industries, LLC, 2014
November, 2014 − Rev. 0
1
Publication Order Number:
EVBUM2285/D
NCL30088LED1GEVB
THEORY OF OPERATION
Power Stage
Auxiliary Winding
The power stage for the demo board is a non−isolated
buck−boost based. The controller has a built in control
algorithm that is specific to the flyback transfer function.
Specifically:
The auxiliary winding has 3 functions:
1. CrM timing
2. Vcc Power
3. Output voltage sense
Vout + Duty
(1*Duty)
Vin
CrM Timing
In the off time, the voltage on the transformer/inductor
forward biases Dout and D9. When the current in the
magnetic has reached zero, the voltage collapses to zero.
This voltage collapse triggers a comparator on the ZCD pin
to start a new switching cycle. The ZCD pin also counts rings
on the auxiliary winding for higher order valley operation.
A failure of the ZCD pin to reach a certain threshold also
indicates a shorted output condition.
This is applicable to flyback, buck−boost, and SEPIC
converters. The control is very similar to the control of the
NCL30080−83 with the addition of a power factor
correction control loop. The controller has a built in
hardware algorithm that relates the output current to a
reference on the primary side.
Iout +
Vref Nps
2 Rsense
Nps +
Npri
Nsec
Vcc Power
The auxiliary winding forward biases D9 to provide
power for the controller. This arrangement is called a
“bootstrap”. Initially the Cvcc, is charged through R4 and
R5. When the voltage on Cvcc reaches, the startup threshold,
the controller starts switching and providing power to the
output circuit and the Cvcc. Cvcc discharges as the
controller draws current. As the output voltage rises, the
auxiliary winding starts to provide all the power to the
controller. Ideally, this happens before Cvcc discharges to
the under voltage threshold where the controller stops
operating to allow Cvcc to recharge once again. The size of
the output capacitor will have a large effect on the rise of the
output voltage. Since the LED driver is a current source, the
rise of output voltage is directly dependent on the size of the
output capacitor.
There are tradeoffs in the selection of Cout and Cvcc. A
low output ripple will require a large Cout value. This
requires that Cvcc be large enough to support Vcc power to
the controller while Cout is charging up. A large value of
Cvcc requires that R4 and R5 be lower in value to allow a fast
enough startup time. Smaller values of R4 and R5 have
higher static power dissipation which lowers efficiency of
the driver.
Where Npri = Primary Turns and Nsec = Secondary Turns
We can now find Rsense for a given output current.
Rsense +
Vref Nps
2 Iout
Line Feedforward
The controller is designed to precisely regulate output
current but variation input line voltage do have an impact.
R3 sets the line feedforward and compensates for power
stage delay times by reducing the current threshold as the
line voltage increases. R3 is also used by the shorted pin
detection. At start up the controller puts out a current to
check for a shorted pin. If R3 is zero, the current sense
resistor is too low a value and the controller will not start
because it will detect a shorted pin. So R3 is required to make
the controller operate properly. In practice, R3 should be
greater than 250 W.
Voltage Sense
The voltage sense pin has several functions:
1. Basis for the reference of the PFC control loop
2. Line Range detection
Output Voltage Sense
The auxiliary winding voltage is proportional to the
output voltage by the turns ratio of the output winding and
the auxiliary winding. The controller has an overvoltage
limit on the Vcc pin at about 26 V minimum. Above that
threshold, the controller will stop operation and enter
overvoltage fault mode such as when an open LED string
occurs.
In cases where the output has a lot of ripple current and the
LED has high dynamic resistance, the peak output voltage
can be much higher than the average output voltage. The
auxiliary winding will charge the Cvcc to the peak of the
output voltage which may trigger the OVP sooner than
expected so in this case the peak voltage of the LED string
is critical.
The reference scaling is automatically controller inside
the controller. While the voltage on Vs is not critical for the
PFC loop control, it is important for the range detection.
Generally the voltage on Vs should be 3.5 V peak at the
highest input voltage of interest. The voltage on Vs
determines which valley the power stage will operate in. At
low line and maximum load, the power stage operates in the
first valley (standard CrM operation). At the higher line
range, the power stage moves to the second valley to lower
the switching frequency while retaining the advantage of
CrM soft switching.
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NCL30088LED1GEVB
SD Pin
2.5 V, the SD pin detects an OVP and shuts down the
controller. Typically, a zener to Vcc is used for this. In this
way, the designer can set the OVP to a lower value that the
OVP threshold built into the Vcc pin.
The SD pin is a multi−function protection input.
1. Thermal Foldback Protection
2. Programmable OVP
Thermal Protection
There is an internal current source from the SD pin.
Placing an NTC from the SD pin to ground will allow the
designer to choose the level of current foldback protection
from over temperature. Below 0.5 volts on SD, the controller
stops. Series or parallel resistors on the NTC and shape the
foldback curve. In the event that the pin is left open, there is
a soft voltage clamp at 1.35 V (nominal). Output current is
reduced when the voltage on the SD pin drops below 1 V.
Circuit Modifications
Output Current
The output current is set by the value of Rsense as shown
above. It’s possible to adjust the output current by changing
R7. Since the magnetic is designed for 18 W, it is possible
to increase the current while reducing the maximum LED
forward voltage within limits. Changes of current of ±10%
are within the existing EMI filter design and magnetic,
changes of more than 10% may require further adjustments
to the transformer or EMI filter.
Programmable OVP
While the SD pin has a current source for the OTP, it can
be overcome raising the voltage on the SD pin. At about
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NCL30088LED1GEVB
SCHEMATIC
+HVDC
R10
L3
+HVDC_iso
1.5mH
5.1k
AC_L
L2
F1
1
AC_N
L1
1
C4
D4
3.3mH
FUSE
AC1
+
AC2
−
C5
120nF 450V
120nF 450V
MB6S
3.3mH
R11
5.1k
Figure 2. Input Circuit
+HVDC_iso
1
LED−
R14
Rzcd
75k 1/2W
T1
D9
R15
BAS21DW5T1G
1 Meg
R5
Cout
18uF 200V
4.7
75k 1/2W
R1
+
620k
Dout
1
CVcc1
6.8uF
C12
R2
US1K−TP
U2
1n
1
10k
2
3
4
C11
1n
ZCD
Vcc
Vs
Drv
Comp
Gnd
SD
Cs
8
Q1
7
STU8N80K5
6
5
R3
NCL30088D
C10
620
1uF
Rtco
R16
+
56k
R4
t
10
100k Ohm NTC
Rsens
1.00
Figure 3. Main Schematic
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LED+
NCL30088LED1GEVB
BILL OF MATERIAL
Table 2. BILL OF MATERIAL*
Qty
Reference
Part
Manufacturer
Mfr_PN
PCB Footprint
Substitution
Allowed
1
Cvcc1
6.8 mF
TDK
C3216X7R1V685K160AC
1206
Yes
1
Cout
18 mF 200 V
Rubycon
200LLE18MEFC10X12.5
ALEL_10X12M5_V
ERT
Yes
2
C4, C5
120 nF 450 V
Panasonic
ECW−FD2W124KQ
CAP_BOX_12M6X
4M6_LS10
Yes
1
C10
1 mF
Taiyo Yuden
TMK105BJ105MV−F
402
Yes
2
C11, C12
1n
Kemet
C0402C102K3GACTU
402
Yes
1
Dout
US1K−TP
MCC
US1K−TP
SMA
Yes
1
D4
MB6S
MCC
MB6S
MB6S
Yes
1
D9
BAS21DW5T1G
ON Semiconductor
BAS21DW5T1G
SC−88A
No
1
F1
FUSE
Littelfuse
0263.500WRT1L
FUSE−HAIRPIN−L
S250
Yes
2
L1, L2
3.3 mH
Wurth
744772332
RAD_IND_LS5
Yes
1
L3
1.5 mH
Wurth
744772152
RAD_IND_LS5
Yes
1
Q1
STU8N80KS
ST
STU8N80K5
IPAK
Yes
1
Rtco
100 kW NTC
Epcos
B57331V2104J60
603
Yes
1
Rzcd
56k
Yaego
RC1206FR−0756KL
1206
Yes
1
R1
620k
Yaego
RC1206FR−07620KL
1206
Yes
1
R2
10k
Yaego
RC0402FR−0710KL
402
Yes
1
R3
620
Yaego
RC0402FR−07620RL
402
Yes
1
R5
4.7
Yaego
RC1206FR−074R7L
1206
Yes
2
R10, R11
5.1k
Yaego
RC1206FR−075K1L
1206
Yes
2
R14, R15
75k ½ W
Stackpole
RNCP1206FTD75K0
1206
Yes
1
R16
1 Meg
Yaego
RC1206JR−071ML
1206
Yes
1
T1
XFRM_LINEAR
Wurth
750314731
RM6_4P
Yes
6”
W1
Wire, Red, 24AWG
McMaster Carr
7587K922
UL1569
Yes
6”
W2
Wire, Blk, 24AWG
McMaster Carr
7587K921
UL1569
Yes
12”
W3, W4
Wire, Wht, 24AWG
McMaster Carr
7587K924
UL1569
Yes
*All Components to comply with RoHS 2002/95/EC
Construction Options
NCL30088B Revision 00
1
U2
NCL30088B
ON Semiconductor
NCL30088B
SO8
No
1
Rsens
1.13
Yaego
RC1206FR−071R13L
1206
Yes
1
R4
No Stuff
Yaego
RC0805JR−0710RL
805
Yes
NCL30088D Revision 01
1
U2
NCL30088D
ON Semiconductor
NCL30088D
SO8
No
1
Rsens
1
Yaego
RC1206FR−071RL
1206
Yes
1
R4
10
Yaego
RC0805JR−0710RL
805
Yes
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NCL30088LED1GEVB
GERBER VIEWS
Figure 4. Top Side PCB
Figure 5. Bottom Side PCB
Figure 6. PCB Outline
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NCL30088LED1GEVB
White Wires Here
Mark the appropriate Revision Here
Red Wire Here
1. Strip and tin lead wires to 6” ± 0.5” 4 Places.
Notch Here
Figure 7. Assembly Notes
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Black Wire Here
NCL30088LED1GEVB
CIRCUIT BOARD FABRICATION NOTES
11. Size tolerance of plated holes: ±0.003 in. :
non−plated holes ±0.002 in.
12. All holes shall be ±0.003 in. of their true position
U.D.S.
13. Construction to be SMOBC, using liquid photo
image (LPI) solder mask in accordance with
IPC−SM−B40C, Type B, Class 2, and be green in
color.
14. Solder mask mis-registration ±0.004 in. max.
15. Silkscreen shall be permanent non−conductive
white ink.
16. The fabrication process shall be UL approved and
the PCB shall have a flammability rating of
UL94V0 to be marked on the solder side in
silkscreen with date, manufactures approved logo,
and type designation.
17. Warp and twist of the PCB shall not exceed
0.0075 in. per in.
18. 100% electrical verification required.
19. Surface finish: electroless nickel immersion gold
(ENIG)
20. RoHS 2002/95/EC compliance required.
1. Fabricate per IPC−6011 and IPC6012. Inspect to
IPA−A−600 Class 2 or updated standard.
2. Printed Circuit Board is defined by files listed in
fileset.
3. Modification to copper within the PCB outline is
not allowed without permission, except where
noted otherwise. The manufacturer may make
adjustments to compensate for manufacturing
process, but the final PCB is required to reflect the
associated gerber file design ±0.001 in. for etched
features within the PCB outline.
4. Material in accordance with IPC−4101/21, FR4,
Tg 125°C min.
5. Layer to layer registration shall not exceed
±0.004 in.
6. External finished copper conductor thickness shall
be 0.0026 in. min. (ie 2oz)
7. Copper plating thickness for through holes shall be
0.0013 in. min. (ie 1oz)
8. All holes sizes are finished hole size.
9. Finished PCB thickness 0.031 in.
10. All un-dimensioned holes to be drilled using the
NC drill data.
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NCL30088LED1GEVB
BUCK BOOST INDUCTOR SPECIFICATION
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NCL30088LED1GEVB
ECA PICTURES
Figure 8. Top View
Figure 9. Bottom View
TEST PROCEDURE
• LED Load – 10 V – 30 V @ 1 A
Equipment Needed
• AC Source – 90 to 305 V ac 50/60 Hz Minimum 500 W
•
•
•
Test Connections
capability
AC Wattmeter – 300 W Minimum, True RMS Input
Voltage, Current, Power Factor, and THD 0.2%
accuracy or better
DC Voltmeter – 300 V dc minimum 0.1% accuracy or
better
DC Ammeter – 1 A dc minimum 0.1% accuracy or
better
AC Power
AC
Source
Wattmeter
1. Connect the LED Load to the red (+) and black (−)
leads through the ammeter shown in Figure 10.
CAUTION: Observe the correct polarity or the load may
be damaged.
2. Connect the AC power to the input of the AC
wattmeter shown in Figure 10. Connect the white
leads to the output of the AC wattmeter
3. Connect the DC voltmeter as shown in Figure 10.
UUT
DC Ammeter
DC Voltmeter
NOTE: Unless otherwise specified, all voltage measurements are taken at the terminals of the UUT.
Figure 10. Test Set Up
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LED Test
Load
NCL30088LED1GEVB
Functional Test Procedure
1. Set the LED Load for 26 V output.
2. Set the input power to 120 V 60 Hz.
CAUTION: Do not touch the ECA once it is energized
because there are hazardous voltages
present.
LINE AND LOAD REGULATION
Table 3. 120 V / MAX LOAD
Output Current
100 mA + 3 mA
Output Power
Power Factor
THD < 20%
Output Current
100 mA + 3 mA
Output Power
Power Factor
THD < 20%
90 V
135 V
180 V
Table 4. 230 V / MAX LOAD
90 V
135 V
180 V
Efficiency + Vout Iout
Pin
100%
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NCL30088LED1GEVB
TEST DATA
Figure 11. Power Factor over Line and Load
Figure 12. THD over Line and Load
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NCL30088LED1GEVB
Figure 13. Efficiency over Line and Load
Figure 14. Regulation over Line
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NCL30088LED1GEVB
Figure 15. Start Up with AC Applied 120 V Maximum Load
Figure 16. Start Up with AC Applied 230 V Maximum Load
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NCL30088LED1GEVB
Figure 17. Conducted EMI Pre−compliance QP Data 150 kHz − 1 MHz
Figure 18. Conducted EMI Pre−compliance Peak Data 150 kHz − 30 MHz
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NCL30088LED1GEVB
ON Semiconductor and the
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries.
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or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets
and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each
customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended,
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