INFINEON ICE2QS02G

Datasheet Version 2.0, 13 June 2008
ICE2QS02G
Quasi-Resonant PWM
Controller
Power Management & Supply
N e v e r
s t o p
t h i n k i n g .
13 June 2008
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Edition 13 June 2008
Published by
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ICE2QS02G
Quasi-Resonant PWM Controller
Product Highlights
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ICE2QS02G
Quasi-resonant operation for higher efficiency and better EMI
Digital frequency reduction for higher average efficiency
Optimized for applications with auxiliary converter
Various protection features with Latch Mode and Auto-restart Mode
Adjustable blanking time for Over Load Protection and adjustable
restart time
Pb-free lead plating; RoHS compliant
PG-DSO-8
Features
Description
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ICE2QS02G is a second generation quasi-resonant
PWM controller optimized for off-line power supply
applications such as LCD TV, audio and printers, where
an auxiliary power supply for the IC is provided. The
digital frequency reduction with decreasing load enables
a quasi-resonant operation till very low load. As a result,
the system efficiency is significantly improved compared
to a free running quasi resonant converter implemented
with maximum switching frequency limitation only.
In addition, numerous protection functions have been
implemented in the IC to protect the system and
customize the IC for the chosen application. All of these
make the ICE2QS02G an outstanding product for real
quasi-resonant flyback converter in the market.
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Quasi-resonant operation
Load dependent digital frequency reduction
Built-in digital soft-start
Cycle-by-cycle peak current limitation with built-in
leading edge blanking time
VCC undervoltage protection
Mains undervoltage protection with adjustable
hysteresis
Foldback Point Correction with digitalized sensing
and control circuits
Over Load Protection with adjustable blanking time
Adjustable restart time after Over Load Protection
Adjustable output overvoltage protection with Latch
mode
Short-winding protection with Latch mode
Maximum on time limitation
Maximum switching period limitation
Typical Application
Mains
Input Voltage
C bus
Wp
Snubber
R VINS1
R ZC2
Ws
R ZC1
R VINS2
Lf
DO
VO
Cf
CO
C ZC
Wa
Auxiliary Supply
R BL
BL
VINS
VCC
ZC
C PS
C BL
R b1
Vcc Power Management
Zero Crossing Detection
GND
FB
Type
ICE2QS02G
Version 2.0
GATE
Global Protection Block
Digital Process Block
C FB
C DS
Gate
Driver
Current Mode Control
control unit
R b2
Optocoupler
Current
Limitation
ICE2QS02G
CS
R CS
TL431
R ovs1
R c1
C c1
C c2
R ovs2
Package
PG-DSO-8-8
3
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Table of Contents
Page
1
Pin Configuration and Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.1
Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.2
Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.3
Pin Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2
Representative Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
3
3.1
3.2
3.3
3.3.1
3.3.1.1
3.3.1.2
3.3.1.3
3.3.1.4
3.3.2
3.4
3.4.1
3.5
Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Startup Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
PWM Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Digital Frequency Reduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Up/down counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Zero crossing (ZC counter). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Ring suppression time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Switch on determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Switch Off Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Current Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Foldback Point Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Protection Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4
4.1
4.2
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.7
4.3.8
4.3.9
Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Supply Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Internal Voltage Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
PWM Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Current Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Soft Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Foldback Point Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Digital Zero Crossing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Gate Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
5
Outline Dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Version 2.0
4
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Pin Configuration and Functionality
1
Pin Configuration and Functionality
1.1
Pin Configuration
the transformer is detected when the ZC voltage falls
below VZCCT(100mV). Second, after the MOSFET is
turned off, an output overvoltage fault will be assumed
if VZC is higher than VZCOVP (4.5V). Finally, during the
MOSFET on time, a current depending on the main
input voltage flows out of this pin. Information on this
current is then used to adjust the maximum current
limit. More details on this function are provided in
Section 3.4.
Pin
Symbol
Function
1
BL
Blanking Time
2
ZC
Zero Crossing
3
FB
Feedback
4
CS
Primary Current Sensing
5
VINS
Input Voltage Sensing
6
GATE
Gate Driver Output
7
VCC
Controller Supply Voltage
8
GND
Controller Ground
1.2
Package
BL
1
8
GND
ZC
2
7
VCC
FB
3
6
GATE
CS
4
5
VINS
Figure 1
1.3
FB (Feedback)
Usually, an external capacitor is connected to this pin
to smooth the feedback voltage. Internally, this pin is
connected to the PWM signal generator for switch-off
determination (together with the current sensing
signal), and to the digital signal processing for the
frequency reduction with decreasing load during
normal operation. Additionally, the openloop/overload
protection is implemented by monitoring the voltage at
this pin.
CS (Current Sensing)
This pin is connected to the shunt resistor for the
primary current sensing, externally, and the PWM
signal generator for switch-off determination (together
with the feedback voltage), internally. Moreover, shortwinding protection is realised by monitoring the Vcs
voltage during on-time of the main power switch.
VINS (Input Voltage Sensing)
The voltage at this pin is used for Mains Undervoltage
Protection. The protection is triggered, once VVINS
drops below 1.25V. For a stable operation, a hysteresis
operation is ensured using an internal current source
(See Section 3.5). When the VVINS exceeds the
hysteresis point, the system resumes its operation with
a soft-start.
Pin configuration PG-DSO-8-8 (top view)
Gate(Gate drive output)
The GATE pin is the output of the internal driver stage,
which has a rise time of 100ns and a fall time of 25ns
when driving a 2.2nF capacitive load.
Pin Functionality
BL (Adjustable Blanking Time)
By connecting a capacitor and a resistor in parallel
between this pin and the ground, the blanking time for
can be fully adjusted, as well as the restart time. This
allows the system to face a sudden power surge for a
short period of time without triggering the overload
protection. Once the protection triggered, the IC will
restart using the internal soft-start circuit, after a period
of time fixed by the external resistance and capacitor.
VCC (Power supply)
The VCC pin is the positive supply of the IC and should
be connected to an external auxiliary supply.
GND (Ground)
This is the common ground of the controller.
ZC (Zero Crossing)
Three functions are incorporated at the ZC pin. First,
during MOSFET off time, the full demagnetization of
Version 2.0
5
13 June 2008
Figure 2
Version 2.0
Vdd
IBL
IVINSHys
6
FB
VREF RFB
11V
2pF
&
G5
VREF
Internal
Bias
Level
Adjustment
C7
C6
C5
Clock
Soft start control
12V
Undervoltage lockout
VFBOLP
25kΩ
&
G3
1
G2
C4
C3
C2
S
G4
R Q
VBLH
VBLL
C1
S
G1
R Q
VVINSTH
Voltage
reference
VPWM
q
PWM
Comparator
1
G7
1
G6
TPerMax
&
G10
Counter
control
GPWM
PWM OP
C12
S
G8
R Q
1
G9
Q
tCSSW
Leading Edge
Blanking time
tLEB
C10
2pF
C11
&
G12
VZCCT
D2
VCSSW
Gate
drive
VZCRS
VZCOVP
C8
48ms
clock
C9
Foldback point
correction
TOnMax
R
G11
S
Ring suppression
tZCOVP
ZC counter
Comparator
Up/down counter
10kΩ
Izc Vdd
D1
ZC
GND
CS
GATE
2
BL
VINS
VCC
Quasi-Resonant PWM Controller
ICE2QS02G
Representative Block Diagram
Representative Block Diagram
Representative block diagram
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Funtional Description
3
Funtional Description
switch-on and switch-off time points are each
determined by the digital circuit and the analog circuit,
respectively. As input information for the switch-on
determination, the zero-crossing input signal and the
value of the up/down counter are needed, while the
feedback signal VFB and the current sensing signal VCS
are necessary for the switch-off determination. Details
about the full operation of the PWM controller in normal
operation are illustrated in the following paragraphs.
All values which are used in the functional description
are typical values. For calculating the worst cases the
min/max values which can be found in section 4
Electrical Characteristics have to be considered.
3.1
General
ICE2QS02G is a second generation quasi-resonant
controller IC developed by Infineon Technologies. Its
application is mainly focused on power systems with
external standby power control, such as in LCD TV or
printer applications. Hence, the required IC VCC
voltage for the IC is here drawn from an auxiliary power
supply.
The digital frequency reduction system implemented in
this IC allows highly efficient power converter
throughout all the load range. This IC possesses also
numerous adjustable protection features, in order to
protect the system and customize the IC for the target
applications.
3.2
3.3.1
Digital Frequency Reduction
As mentioned above, the digital signal processing
circuit consists of an up/down counter, a ZC counter
and a comparator. These three parts are key to
implement digital frequency reduction with decreasing
load. In addition, a ringing suppression time controller
is implemented to avoid mistriggering by the high
frequency oscillation, when the output voltage is very
low under conditions such as soft start or output short
circuit . Functionality of these parts is described as in
the following.
3.3.1.1
Up/down counter
The up/down counter stores the number of the zero
crossing to be ignored before the main power switch is
switched on after demagnetisation of the transformer.
This value is fixed according to the feedback voltage,
VFB, which contains information about the output
power. Indeed, in a typical peak current mode control,
a high output power results in a high feedback voltage,
and a low output power leads to a low regulation
voltage. Hence, according to VFB, the value in the up/
down counter is changed to vary the power MOSFET
off-time according to the output power. In the following,
the variation of the up/down counter value according to
the feedback voltage is explained.
The feedback voltage VFB is internally compared with
three threshold voltages VFBZL, VFBZR1 and VFBZH, at
each clock period of 48ms. The up/down counter
counts then upward, keep unchanged or count
downward, as shown in Table 1.
Startup Phase
At the time ton, the IC begins to operate with a softstart.By this soft-start the switching stresses for the
switch, diode and transformer are minimised. The softstart implemented in ICE2QS02G is a digital timebased function. The preset soft-start time is 16ms with
4 steps. The internal reference for the feedback voltage
begins at 1.8V and with an increment of 0.55V for each
following step. During soft start, the Over Load
Protection function is disabled.
Vsst (V)
4.00
3.45
2.9
Table 1
2.35
1.8
ton
4
8
12
16
vFB
up/down counter
action
Always lower than VFBZL
Count upwards till
7
Time(ms)
Figure 3
Soft-start control voltage versus time
3.3
PWM Control
The PWM controller during normal operation consists
of a digital signal processing circuit including an up/
down counter, a zero-crossing counter (ZC counter)
and a comparator, and an analog circuit including a
current measurement unit and a comparator. The
Version 2.0
Operation of the up/down counter
Once higher than VFBZL, but
always lower than VFBZH
Stop counting, no
value changing
Once higher than VFBZH, but
always lower than VFBZR1
Count downwards
till 1
Once higher than VFBZR1
7
Set up/down
counter to 1
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Funtional Description
In the ICE2QS02G, the number of zero crossing is
limited to 7. Therefore, the counter varies between 1
and 7, and any attempt beyond this range is ignored.
When VFB exceeds VFBZR1 voltage, the up/down
counter is initialised to 1, in order to allow the system to
react rapidly to a sudden load increase. The up/down
counter value is also intialised to 1 at the start-up, to
ensure an efficient maximum load start up. Figure 4
shows some examples on how up/down counter is
changed according to the feedback voltage over time.
The use of two different thresholds VRL and VRH to
count upward or downward is to prevent frequency
jittereing when the feedback voltage is close to the
threshold point. However, for a stable operation, these
two thresholds must not be affected by the foldback
current limitation (see Section 3.4.1), which limits the
VCS voltage. Hence, to prevent such situation, the
threshold voltages, VFBZL and VFBZH, are changed
internally depending on the line voltage levels.
clock
to 0 every time after the GATE output is changed to
high.
The voltage vZC is also used for the output overvoltage
protection. Once the voltage at this pin is higher than
the threshold VZCOVP (4.5V) during off-time of the main
switch, the IC is latched off after a fixed blanking time
(tZCOVP).
To achieve the switch-on at minimum value of drainsource voltage, the voltage from the auxiliary winding is
fed to a time delay network (the RC network consists of
Rzc1, Rzc2 and Czc as shown in typical application circuit)
before it is applied to the zero-crossing detector
through the ZC pin. The needed time delay to the main
oscillation signal ∆t should be approximately one fourth
of the oscillation period (by transformer primary
inductor and drain-source capacitor) minus the
propagation delay from thedetected zero-crossing to
the switch-on of the main switch tdelay, theoretically:
T osc
∆t = ------------ – t delay
4
T=48ms
[1]
This time delay should be matched by adjusting the
time constant of the RC network which is calculated as:
t
VFB
R zc1 ⋅ R zc2
τ td = C zc ⋅ --------------------------------R zc1 + R zc2
VFBZR1
[2]
VFBZH
VFBZL
n
n+1
n+2
n+2
n+2
n+2
n+1
n
n-1
Up/down
counter
Case 1
4
5
6
6
6
6
5
4
3 1
Case 2
2
3
4
4
4
4
3
2
1 1
Case 3
7
7
7
7
7
7
6
5
4 1
Figure 4
3.3.1.3
Ringing suppression time
After MOSFET is turned on, there will be some
oscillation on VDS, which will also appear on the voltage
on ZC pin. To avoid that the MOSFET is turned on
mistriggerred by such oscillations, a ringing
suppression timer is implemented. The time is
dependent on the voltage vZC. When the voltage vZC is
lower than the threshold VZCRS, a longer preset time
applies, while a shorter time is set when the voltage vZC
is higher than the threshold.
t
1
Up/down counter operation
3.3.1.2
Zero crossing (ZC counter)
In the system, the voltage from the auxiliary winding is
applied to the zero-crossing pin through a RC network,
which provides a time delay to the voltage from the
auxiliary winding. Internally, this pin is connected to a
clamping network, a zero-crossing detector, an output
overvoltage detector and a ringing suppression time
controller.
During on-state of the power switch a negative voltage
applies to the ZC pin. Through the internal clamping
network, the voltage at the pin is clamped to around 0.2V.
The ZC counter has a minimum value of 0 and
maximum value of 7. After MOSFET is turned off, every
time when the falling voltage ramp of on ZC pin crosses
the VZCCT (100mV) threshold, a zero crossing is
detected and ZC counter will increase by 1. It is reset
Version 2.0
3.3.1.4
Switch on determination
After the gate drive goes to low, it can not be changed
to high during ring suppression time.
After ring suppression time, the gate drive can be
turned on when the ZC counter value is higher or equal
to up/down counter value.
However, it is also possible that the oscillation between
primary inductor and drain-source capacitor attenuates
very fast and IC can not detect enough zero crossings
and ZC counter value will not be high enough to turn on
the gate drive. In this case, a maximum switching
period (TPerMax) is implemented. After the specified
period since last time Gate is turned on, the gate drive
will be turned on again regardless of the counter values
and VZC. This function can effectively prevent the
8
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Funtional Description
3.3.2
Switch Off Determination
In the converter system, the primary current is sensed
by an external shunt resistor, which is connected
between low-side terminal of the main power switch
and the common ground. The sensed voltage across
the shunt resistor vCS is applied to an internal current
measurement unit, and its output voltage V1 is
compared with the regulation voltage VFB. Once the
voltage V1 exceeds the voltage VFB, the output flip-flop
is reset. As a result, the main power switch is switched
off. The relationship between the V1 and the vCS is
described by:
Current Limitation
There is a cycle by cycle current limitation realized by
the current limit comparator to provide an overcurrent
detection. The source current of the MOSFET is
sensed via a sense resistor RCS. By means of RCS the
source current is transformed to a sense voltage VCS
which is fed into the pin CS. If the voltage VCS exceeds
an internal voltage limit, adjusted according to the
Mains voltage, the comparator immediately turns off
the gate drive.
To prevent the Current Limitation process from
distortions caused by leading edge spikes, a Leading
Edge Blanking time (tLEB) is integrated in the current
sensing path.
A further comparator is implemented to detect
dangerous current levels (VCSSW) which could occur if
one or more transformer windings are shorted or if the
secondary diode is shorted. To avoid an accidental
latch off, a spike blanking time of tCSSW is integrated in
the output path of the comparator .
3.4.1
Foldback Point Correction
When the main bus voltage increases, the switch on
time becomes shorter and therefore the operating
frequency is also increased. As a result, for a constant
primary current limit, the maximum possible output
power is increased, which the converter may have not
been designed to support.
To avoid such a situation, the internal foldback point
correction circuit varies the VCS voltage limit according
to the bus voltage. This means the VCS will be
decreased when the bus voltage increases. To keep a
Version 2.0
0.9
0.8
0.7
0.6
80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
Vin(V)
[3]
In addition, there is a maximum on time, tOnMax,
limitation implemented in the IC. Once the gate drive
has been in high state longer than the maximum on
time, it will be turned off to prevent the switching
frequency from going too low because of long on time.
3.4
1
9
Figure 5
Variation of the VCS limit voltage according
to the IZC current
According to the typical application circuit, when
MOSFET is turned on, a negative voltage proportional
to bus voltage will be coupled to auxiliary winding.
Inside ICE2QS02G, an internal circuit will clamp the
voltage on ZC pin to nearly 0V. As a result, the current
flowing out from ZC pin can be calculated as
V BUS N a
I ZC = -----------------------R ZC1 N P
[4]
When this current is higher than IZC_1, the amount of
current exceeding this threshold is used to generate an
offset to decrease the maximum limit on VCS. Since the
ideal curve shown in Figure 5 is a nonlinear one, a
digital block in ICE2QS02G is implemented to get a
better control of maximum output power. Additional
advantage to use digital circuit is the production
tolerance is smaller compared to analog solutions. The
typical maximum limit on VCS versus the ZC current is
shown in Figure 6.
1
0.9
Vcs-max(V)
V 1 = 3.3 ⋅ V C S + 0.7
constant maximum input power of the converter, the
required maximum VCS versus various input bus
voltage can be calculated, which is shown in Figure 5.
Vcs-max(V)
switching frequency from going lower than 20kHz,
otherwise which will cause audible noise in most cases.
0.8
0.7
0.6
300
500
700
900
1100
1300
1500
1700
1900
2100
Iz c(uA)
Figure 6
VCS-max versus IZC
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Funtional Description
3.5
Protection Functions
The blanking time for Over Load Protection can be
calculated using equation [5].
ICE2QS02G provides various protection functions. The
following table summarizes these protection functions.
Table 2
V BLH 
T OLP = – R BL C BL ln  1 – ----------------I BL R BL
Protection features
VCC Undervoltage
Latch off
Overload/Openloop
Protection
Auto restart
Main undervoltage
Protection
Block Gate
recover with soft start
Output Overvoltage
Latch off
Short Winding
Latch off
[5]
The restart time for Over Load Protection can be
calculated using equation [6].
V BLL 
T RESTART = – R BL C BL ln  ------------ V BLH
[6]
During the switch off time, the voltage at the zerocrossing pin, ZC, is monitored for output overvoltage
detection. If this voltage is higher than the preset
threshold VZCOVP, the IC enters latch-off mode.
If the voltage at the current sensing pin is higher than
the preset threshold VCSSW of 1.68V during the on-time
of the power switch, the IC is latched off. This
consitutes a short winding protection.
Finally, this IC has an adjustable main undervoltage
detection system. Given the resistances RVINS1 and
RVINS2 connected to the VINS pin, the main turn off
voltage is given by equation [7].
During normal operation, the VCC voltage is
continuously monitored. In case of a VCC
undervoltage, the IC is reset and the main power switch
is kept off.
The Overload and Open Loop Protection contains an
adjustable blanking time and variable restart time.
Such an adjustable buffer time is indeed, useful, for
applications that usually work in low output power, but
require
a
short
duration
of
high
output
poweroccasionally. Here, when the regulation voltage,
VFB exceeds the threshold voltage of VFBOLP, an
internal current source of IBL starts charging the
external capacitor CBL. This current source turns off
only when the capacitor voltage, VBL reaches VBLH or
when VFB decreases below VFBH. Once VBL exceeds
VBLH, the overload/openloop protection is triggered by
turning off the GATE signal, and pulling high the
feedback voltage. From this time, CBL slowly
discharges through the external resistance RBL. When
VBL drops below VBLL, the IC restarts its operation
beginning with soft-start. The charging time and the
discharging time of the capacitor CBL, fix respectively
the openloop/overload protection blanking time and the
restart time of the IC. One example about how this
protection works is shown in Figure 7.
R VINS1 + R VINS2
V BUSOFF = V VINSTH ⋅ ---------------------------------------R VINS2
[7]
For system stability, a hysteresis is implemented in the
main undervoltage protection using an internal current
source IVINS, so that the main turn on voltage is given
by equation [8].
V BUSON = V BUSOFF + I VINSHys ⋅ R VINS1
[8]
Everytime IC recovers from a mains undervoltage
protection, IC will begin with a soft start.
VGATE
t
VBL
3.9V
0.5V
t
VFB
4.5V
tOLP
Figure 7
Version 2.0
trestart
tss
tOLP
trestart
tss
t
Over Load Protection and timers
10
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Electrical Characteristics
4
Electrical Characteristics
Note:
All voltages are measured with respect to ground (Pin 8). The voltage levels are valid if other ratings are
not violated.
4.1
Note:
Absolute Maximum Ratings
Absolute maximum ratings are defined as ratings, which when being exceeded may lead to destruction
of the integrated circuit. For the same reason make sure, that any capacitor that will be connected to pin 7
(VCC) is discharged before assembling the application circuit.
Parameter
Symbol
Limit Values
min.
max.
Unit
Remarks
VCC Supply Voltage
VVCC
-0.3
27
V
VINS Voltage
VVINS
-0.3
5.0
V
BL Voltage
VBL
-0.3
5.0
V
FB Voltage
VFB
-0.3
5.0
V
ZC Voltage
VZC
-0.3
5.0
V
CS Voltage
VCS
-0.3
5.0
V
GATE Voltage
VGATE
-0.3
10.0
V
Junction Temperature
Tj
-40
125
°C
Storage Temperature
TS
-55
150
°C
Thermal Resistance
Junction-Ambient
RthJA(DSO)
-
185
K/W
PG-DSO-8
ESD Capability
VESD
-
2
kV
Human body model1)
1)
According to EIA/JESD22-A114-B (discharging a 100pF capacitor through a 1.5kΩ series resistor)
4.2
Note:
Operating Range
Within the operating range the IC operates as described in the functional description.
Parameter
Symbol
Limit Values
min.
Unit
max.
VCC Supply Voltage
VVCC
VVCCUVP 25
V
Junction Temperature
TjCon
-25
°C
Version 2.0
11
Remarks
125
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Electrical Characteristics
4.3
4.3.1
Note:
Characteristics
Supply Section
The electrical characteristics involve the spread of values guaranteed within the specified supply voltage
and junction temperature range TJ from – 25 oC to 125oC. Typical values represent the median values,
which are related to 25°C. If not otherwise stated, a supply voltage of VCC = 18 V is assumed.
Parameter
Symbol
Limit Values
min.
typ.
max.
Unit
Test Condition
Start-Up Current
IVCCstart
-
300
-
µA
VVCC = 11V
Supply Current in normal
operation
IVCCop
-
1.5
-
mA
Output low
IFB = 0
Supply Current during Latch-off
mode
IVCCLO
-
300
-
µA
IFB = 0
VCC Turn-On Threshold
VVCCon
11.3
12.0
12.7
V
VCC Turn-Off Threshold
VVCCoff
-
11.0
-
V
VCC Turn-On/Off Hysteresis
VVCChys
0.6
1
1.4
V
4.3.2
Internal Voltage Reference
Parameter
Internal Reference Voltage
Version 2.0
Symbol
VREF
Limit Values
min.
typ.
max.
4.90
5.00
5.10
12
Unit
Test Condition
V
Measured at pin FB
IFB=0
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Electrical Characteristics
4.3.3
PWM Section
Parameter
Symbol
Limit Values
min.
typ.
max.
Regulation Pull-Up Resistor
RFB
13
20
30
PWM-OP Gain
GPWM
3.15
3.3
3.47
Offset for Voltage Ramp
VPWM
0.6
0.7
0.85
4.3.4
Unit
kΩ
V
Current Limit
Parameter
Symbol
Limit Values
min.
typ.
max.
Unit
Peak cuurent limitation in
normal operation
VCSTH
0.94
1.02
1.10
V
Leading Edge Blanking
tLEB
180
280
450
ns
4.3.5
Test Condition
Soft Start
Parameter
Symbol
Soft-Start time
soft-start time step
tSS
1)
Limit Values
min.
typ.
max.
11.8
16
-
tSSS
4
Unit
Test Condition
ms
ms
Internal regulation voltage at
first step 1)
VSS1
-
1.8
-
V
Internal regulation voltage step
at soft start 1)
VSSS
-
0.55
-
V
4.3.6
Test Condition
Foldback Point Correction
Parameter
Symbol
Limit Values
min.
typ.
max.
Unit
Test Condition
FBC start point
VCS_FBC_S
-
1.02
-
V
IZC=0.5mA
CS threshold minimum
VCS_FBC_MIN
-
0.65
-
V
IZC=1.8mA
Version 2.0
13
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Electrical Characteristics
4.3.7
Digital Zero Crossing
Parameter
Symbol
Limit Values
Unit
min.
typ.
max.
Zero crossing threshold voltage VZCCT
50
100
170
mV
Maximum current out from zero
crossing pin1)
IZCMAX
2.5
-
-
mA
Threshold to set Up/Down
Counter to one
VFBZR1
3.78
3.9
4
V
Threshold for downward
counting at low line
VFBZHL
3.10
3.2
3.32
V
Threshold for upward counting
at low line
VFBZLL
2.38
2.5
2.62
V
Threshold for downward
counting at high line
VFBZHH
2.55
2.7
2.90
V
Threshold for upward counting
at highline
VFBZLH
2.18
2.3
2.42
V
ZC current for IC switches
threshold to high line
IZCHL
-
1.3
-
mA
ZC current for IC switches
threshold to low line
IZCLL
-
0.8
-
mA
Counter time1)
tCOUNT
1)
48
Test Condition
ms
The parameter is not subjected to production test - verified by design/characterization
4.3.8
Protection
Parameter
Symbol
Limit Values
min.
typ.
max.
Unit
Overload or Open Loop
Detection threshold for OLP
protection at FB pin
VFBOLP
4.4
4.5
4.6
V
Charging current at BL pin
IBL
12
20
28
µA
Threshold for adjustable
overload blanking time
VBLH
3.80
3.9
4.01
V
Threshold for adjustable restart
time
VBLL
0.4
0.5
0.6
V
Output Overvoltage Detection
threshold at the ZC pin
VZCOVP
4.4
4.5
4.6
V
Blanking time for output
overvoltage protection1)
tZCOVP
-
100
-
µs
Threshold for short winding
protection
VCSSW
1.63
1.68
1.78
V
Blanking time for short winding
protection
tCSSW
-
190
-
ns
Version 2.0
14
Test Condition
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Electrical Characteristics
Main Undervoltage Protection
threshold
VVINSTH
-
1.25
-
V
Main Undervoltage Protection
hysteresis current source
IVINSHys
8.8
15
20
µA
Minimum ringing suppression
time
tZCRS1
1.87
2.8
3.5
µs
VZC > VZCT2
Maximum ringing suppression
time
tZCRS2
18
25
32
µs
VZC < VZCT2
Ringing suppression threshold
VZCRS
-
0.7
-
V
Maximum gate on time
tOnMax
25
30.0
35.1
µs
Maximum switching period
tPerMax
42
50.0
57
µs
1)
VFB>4.3V, VCS=0
The parameter is not subjected to production test - verified by design/characterization
4.3.9
Gate Driver
Parameter
Symbol
Limit Values
min.
typ.
max.
Unit
Test Condition
Output voltage at logic low
VGATElow
-
-
1.0
V
IOUT = 20mA;
VVCC=18V
Output voltage at logic high
VGATEhigh
9.0
10.0
-
V
IOUT = -20mA;
VVCC=18V
Output voltage active shut down VGATEasd
-
-
1.0
V
V
VVCC = 7V
IOUT = 20mA
Rise Time
trise
-
70
-
ns
COUT = 2.2nF; VGATE 2V
... 8V
Fall Time
tfall
-
30
-
ns
COUT = 2.2nF; VGATE 8V
... 2V
Version 2.0
15
13 June 2008
Quasi-Resonant PWM Controller
ICE2QS02G
Outline Dimension
5
Outline Dimension
PG-DSO-8
( Plastic Dual Small Outline)
Figure 8
PG-DSO-8-8
*Dimensions in mm
Version 2.0
16
13 June 2008
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