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Datasheet,Version 2.0, December 4, 2009
ICE2QS03
Quasi-Resonant Controller PWM
Power Management & Supply
Never
stop
thinking.
ICE2QS03 Revision History: Previous Version: Page
December 4, 2009 None Subjects (major changes since last revision)
Datasheet
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Edition December 4, 2009 Published by Infineon Technologies AG 81726 Munchen, Germany
(c) Infineon Technologies AG 12/4/09.
All Rights Reserved. Attention please! The information given in this data sheet shall in no event be regarded as a guarantee of conditions or characteristics ("Beschaffenheitsgarantie"). With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered.
ICE2QS03 Quasi-Resonant PWM Controller
Product Highlight
* Active burst mode for low standby power * Digital frequency reduction for better overall system efficiency * Integrated power cell for IC self-power supply
Features
* * * * * * * * * * * Quasiresonant operation till very low load Active burst mode operation at light/no load for low standby input power (< 100mW) Digital frequency reduction with decreasing load Power cell for VCC pre-charging with constant current Built-in digital soft-start Foldback correction and cycle-by-cycle peak current limitation Auto restart mode for VCC Overvoltage protection Auto restart mode for VCC Undervoltage protection Auto restart mode for openloop/overload protection Latch-off mode for adjustable output overvoltage protection Latch-off mode for Short-winding protection
Description
ICE2QS03 is a quasi-resonant PWM controller optimized for off-line switch power supply applications such as LCD TV, CRT TV and notebook adapter. The digital frequency reduction with decreasing load enables a quasi-resonant operation till very low load. As a result, the overall system efficiency is significantly improved compared to other conventional solutions. The active burst mode operation enables an ultra-low power consumption at standby mode with small and controllable output voltage ripple. Based on the BiCMOS technology, the product has a wide operation range (up to 26V) of IC power supply and lower power consumption. The numerous protection functions give a full protection of the power supply system in failure situations. All of these make the ICE2QS03 an outstanding controller for quasi-resonant flyback converter in the market.
Typical Application Circuit
Cbus 85 ~ 265Vac CVCC Dr1~Dr4 CZC HV Power Cell Gate Driver VCC ZC Q1 Rb1 CDS GATE Optocoupler Current Limitation Rb2 Rc1 Rovs1 CPS RVCC DVCC RZC2 RZC1 Wa Snubber Wp Ws CO DO Lf Cf VO
GND
Control Unit
Zero Crossing Detection Power Management Digital Process Block Active Burst Mode
CFB FB
Protection Block Current Mode Control ICE2QS03
CS RCS TL431 Cc1 Cc2 Rovs2
Type ICE2QS03
Version 2.0
Package PG-DIP-8-6
3 December 4, 2009
Quasi-Resonant PWM Controller ICE2QS03
Table of Contents 1 1.1 1.2 1.3 2 3 3.1 3.2 3.3 3.3.1 3.3.1.1 3.3.1.2 3.3.2 3.3.3 3.4 3.4.1 3.5 3.5.1 3.5.2 3.5.3 3.6 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 4.3.10 5 Page
Pin Configuration and Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Pin Configuration with PG-DIP-8-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Package PG-DIP-8-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Pin Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Representative Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 VCC Pre-Charging and Typical VCC Voltage During Start-up . . . . . . . . . . .7 Soft-start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Digital Frequency Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Up/down counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Zero crossing (ZC counter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Ringing suppression time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Switch Off Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Current Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Foldback Point Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Active Burst Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Entering Active Burst Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . .10 During Active Burst Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Leaving Active Burst Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Protection Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Supply Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Internal Voltage Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 PWM Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Current Sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Soft Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Foldback Point Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Digital Zero Crossing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Active Burst Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Gate Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Outline Dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
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Pin Configuration and Functionality
1
1.1
Pin Configuration and Functionality
Pin Configuration with PG-DIP8-6
Symbol ZC FB CS HV HV GATE VCC GND Function Zero Crossing Feedback Current Sense High Voltage Input High Voltage Input Gate Drive Output Controller Supply Voltage Controller Ground
1.3
Pin Functionality
ZC (Zero Crossing) At this pin, the voltage from the auxiliary winding after a time delay circuit is applied. Internally, this pin is connected to the zero-crossing detector for switch-on determination. Additionally, the output overvoltage detection is realized by comparing the voltage Vzc with an internal preset threshold. FB (Feedback) Normally, an external capacitor is connected to this pin for a smooth voltage VFB. Internally, this pin is connected to the PWM signal generator for switch-off determination (together with the current sensing signal), the digital signal processing for the frequency reduction with decreasing load during normal operation, and the Active Burst Mode controller for entering Active Burst Mode operation determination and burst ratio control during Active Burst Mode operation. Additionally, the open-loop / over-load protection is implemented by monitoring the voltage at this pin. CS (Current Sense) 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 voltage Vcs during on-time of the main power switch. GATE (Gate Drive Output) This output signal drives the external main power switch, which is a power MOSFET in most case. HV (High Voltage) The pin HV is connected to the bus voltage, externally, and to the power cell, internally. The current through this pin pre-charges the VCC capacitor with constant current once the supply bus voltage is applied. VCC (Power supply) VCC pin is the positive supply of the IC. The operating range is between VVCCoff and VVCCOVP. GND (Ground) This is the common ground of the controller.
Pin 1 2 3 4 5 6 7 8
1.2
Package PG-DIP-8-6
ZC
1
8
GND
FB
2
7
VCC
CS
3
6
GATE
HV
4
5
HV
Figure 1
Pin Configuration PG-DIP-8-6(top view)
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2
Figure 2
VCC
Zero Crossing
Startup Cell OTP Undervoltage Lockout
18V
Version 2.0
HV
Power Management
Voltage Reference Internal Bias &
10.5
ZC
Depl. CoolMOS(R) G1 Protection
VVCCOVP 1 S Q
VZCC
C1
clk
ZC counter
D1
Count=7
Comparator C12
10us
Up/down counter G7
tCOUNT
PWM Control
1
R Autorestart Protect SQ
C2
Soft-start
R latched Protect
G2
Representative Block diagram
Ringing Suppression
& G5 1 TOffMax S
VZCOVP
Delay tZCOVP
C3
VZCRS
C4 G4 G8
& G6 1 R Q
tOLP_B
VFBOLP
& G9
Gate Drive
GATE
TOnMax
Representative Block diagram
6
G3
f en sB OSC
VFBR1
C5
GND
Gate Drive C14
VCSSW
C6
VFBZH
VREF
C7
RFB
VFBZL
Regulation
C13 VCSB
Delay tCSSW
FB
Active Burst Mode
25kO
2pF PWM Comparator
VFBEB
C8 q
tBEB
C15
Foldback Correction
10kO 1pF D2
C9
VPWM
Leading Edge Blanking tLEB PWM OP
GPWM
CS
VFBBOn
C10 Active Burst Block Current Mode
Representative Block diagram
Quasi-Resonant PWM Controller ICE2QS03
December 4, 2009
VFBBOff
Current Limiting
Quasi-Resonant PWM Controller ICE2QS03
Functional Description
3
3.1
Functional Description
VCC Pre-Charging and Typical VCC Voltage During Start-up
then will reach a constant value depending on output load.
3.2
Soft-start
In ICE2QS03, a high voltage startup cell is integrated.(R). As shown in Figure 2, the start cell consists of a high voltage device and a controller, whereby the high voltage device is controlled by the controller. The startup cell provides a pre-charging of the VCC capacitor till VCC voltage reaches the VCC turned-on threshold VVCCon and the IC begins to operate. Once the mains input voltage is applied, a rectified voltage shows across the capacitor Cbus. The high voltage device provides a current to charge the VCC capacitor Cvcc. Before the VCC voltage reaches a certain value, the amplitude of the current through the high voltage device is only determined by its channel resistance and can be as high as several mA. After the VCC voltage is high enough, the controller controls the high voltage device so that a constant current around 1mA is provided to charge the VCC capacitor further, until the VCC voltage exceeds the turned-on threshold VVCCon. As shown as the time phase I in Figure 3, the VCC voltage increase near linearly and the charging speed is independent of the mains voltage level.
VVCC VVCCon VVCCoff i ii iii
At the time ton, the IC begins to operate with a soft-start. By this soft-start the switching stresses for the switch, diode and transformer are minimised. The soft-start implemented in ICE2QS03 is a digital time-based function. The preset soft-start time is 12ms with 4 steps. If not limited by other functions, the peak voltage on CS pin will increase step by step from 0.32V to 1V finally.
Vcs_sst (V) 1.00 0.83 0.66 0.49 0.32
ton
3
6
9
12
Time(ms)
Figure 4
Maximum current sense voltage during softstart
3.3
Normal Operation
t1
t2
t
Figure 3
VCC voltage at start up
The time taking for the VCC pre-charging can then be approximately calculated as: t V C VCCon vcc = ----------------------------------------1 I VCCch arg e2 [1]
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 switch-on and -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. 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.
where IVCCcharge2 is the charging current from the startup cell which is 1.05mA, typically. Exceeds the VCC voltage the turned-on threshold VVCCon of at time t1, the startup cell is switched off, and the IC begins to operate with a soft-start. Due to power consumption of the IC and the fact that still no energy from the auxiliary winding to charge the VCC capacitor before the output voltage is built up, the VCC voltage drops (Phase II). Once the output voltage is high enough, the VCC capacitor receives then energy from the auxiliary winding from the time point t2 on. The VCC
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Functional Description
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 VRL, VRH and VRM, at each clock period of 48ms. The up/down counter counts then upward, keep unchanged or count downward, as shown in Table 1. Table 1 vFB Always lower than VFBZL Once higher than VFBZL, but always lower than VFBZH Once higher than VFBZH, but always lower than VFBR1 Once higher than VFBR1 Operation of the up/down counter up/down counter action Count upwards till 7 Stop counting, no value changing Count downwards till 1 Set up/down counter to 1 threshold voltages, VFBZL and VFBZH, are changed internally depending on the line voltage levels.
clock T=48ms
VFB VFBR1 VFBZH VFBZL Up/down counter Case 1 Case 2 Case 3
t
t n+1 n+2 n+2 n+2 n+2 n+1 n-1 1 n 4 2 7 5 3 7 6 4 7 6 4 7 6 4 7 6 4 7 5 3 6 n 4 2 5 31 11 41
Figure 5
Up/down counter operation
In the ICE2QS03, 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 VFBR1 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 5 shows some examples on how up/down counter is changed according to the feedback voltage over time. The use of two different thresholds VFBZL and VFBZH 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
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 certain level. The ZC counter has a minimum value of 0 and maximum value of 7. After the internal MOSFET is turned off, every time when the falling voltage ramp of on ZC pin crosses the 100mV threshold, a zero crossing is detected and ZC counter will increase by 1. It is reset 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 during off-time of the main switch, the IC is latched off after a fixed blanking time. To achieve the switch-on at voltage valley, the voltage from the auxiliary winding is fed to a time delay network (the RC network consists of Dzc, 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 drainsource capacitor) minus the propagation delay from
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Functional Description
thedetected zero-crossing to the switch-on of the main switch tdelay, theoretically: T osc t = ------------ - t delay 4 [2] To avoid mistriggering caused by the voltage spike across the shunt resistor at the turn on of the main power switch, a leading edge blanking time, tLEB, is applied to the output of the comparator. In other words, once the gate drive is turned on, the minimum on time of the gate drive is the leading edge blanking time. 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.
This time delay should be matched by adjusting the time constant of the RC network which is calculated as: td =C R zc1 R zc2 -------------------------------zc R +R zc1 zc2 [3]
3.4
3.3.2 Ringing suppression time After MOSFET is turned off, 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 timer 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. 3.3.2.1 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 damps 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 off time is implemented. After gate drive has been remained off for the period of TOffMax, the gate drive will be turned on again regardless of the counter values and VZC. This function can effectively prevent the switching frequency from going lower than 20kHz, otherwise which will cause audible noise, during start up. 3.3.3 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: V 1 = 3.3 V CS + 0.7 [4]
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 constant maximum input power of the converter, the
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Functional Description
required maximum VCS versus various input bus voltage can be calculated, which is shown in Figure 6.
1
about Active Burst Mode operation are explained in the following paragraphs. 3.5.1 Entering Active Burst Mode Operation For determination of entering Active Burst Mode operation, three conditions apply: * the feedback voltage is lower than the threshold of VFBEB(1.25V). Accordingly, the peak current sense voltage across the shunt resistor is 0.17; * the up/down counter is 7; and * a certain blanking time (tBEB). Once all of these conditions are fulfilled, the Active Burst Mode flip-flop is set and the controller enters Active Burst Mode operation. This multi-condition determination for entering Active Burst Mode operation prevents mistriggering of entering Active Burst Mode operation, so that the controller enters Active Burst Mode operation only when the output power is really low during the preset blanking time. 3.5.2 During Active Burst Mode Operation After entering the Active Burst Mode the feedback voltage rises as VOUT starts to decrease due to the inactive PWM section. One comparator observes the feedback signal if the voltage level VBH (3.6V) is exceeded. In that case the internal circuit is again activated by the internal bias to start with swtiching. Turn-on of the power MOSFET is triggered by the timer. The PWM generator for Active Burst Mode operation composes of a timer with a fixed frequency of 52kHz, typically, and an analog comparator. Turn-off is resulted by comparison of the voltage signal v1 with an internal threshold, by which the voltage across the shunt resistor VcsB is 0.34V, accordingly. A turn-off can also be triggered by the maximal duty ratio controller which sets the maximal duty ratio to 50%. In operation, the output flip-flop will be reset by one of these signals which come first. If the output load is still low, the feedback signal decreases as the PWM section is operating. When feedback signal reaches the low threshold VBL(3.0V), the internal bias is reset again and the PWM section is disabled until next time regultaion siganl increases beyond the VBH threshold. If working in Active Burst Mode the feedback signal is changing like a saw tooth between 3.0V and 3.6V shown in Figure 7. 3.5.3 Leaving Active Burst Mode Operation The feedback voltage immediately increases if there is a high load jump. This is observed by one comparator. As the current limit is 34% during Active Burst Mode a certain load is needed so that feedback voltage can exceed VLB (4.5V). After leaving active busrt mode, maximum current can now be provided to stabilize VO. In addition, the up/down counter will be set to 1
0.9 Vcs-max(V)
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)
Figure 6
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 ICE2QS03, 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 I V BUS N a = -----------------------ZC R N ZC1 P [5]
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 6 is a nonlinear one, a digital block in ICE2QS03 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 7.
1
0.9 Vcs-max(V)
0.8
0.7
0.6 300 500 700 900 1100 1300 1500 1700 1900 2100 Iz c(uA)
Figure 7
VCS-max versus IZC
3.5
Active Burst Mode Operation
At light load condition, the IC enters Active Burst Mode operation to minimize the power consumption. Details
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Functional Description
immediately after leaving Active Burst Mode. This is helpful to decrease the output voltage undershoot. IC is reset and the main power switch is then kept off. After the VCC voltage falls below the threshold VVCCoff, the startup cell is activated. The VCC capacitor is then charged up. Once the voltage exceeds the threshold VVCCon, the IC begins to operate with a new soft-start. In case of open control loop or output over load, the feedback voltage will be pulled up . After a blanking time of 24ms, the IC enters auto-restart mode. The blanking time here enables the converter to provide a high power in case the increase in VFB is due to a sudden load increase. During off-time of the power switch, the voltage at the zero-crossing pin is monitored for output over-voltage detection. If the voltage is higher than the preset threshold vZCOVP, the IC is latched off after the preset blanking time. If the junction temperature of IC exceeds 140 C, the IC enter into autorestart mode. If the voltage at the current sensing pin is higher than the preset threshold vCSSW during on-time of the power switch, the IC is latched off. This is short-winding protection. During latch-off protection mode, when the VCC voltage drops to 10.5V,the startup cell is activated and the VCC voltage is charged to 18V then the startup cell is shut down again and repeats the previous procedure. There is also an maximum on time limitation inside ICE2QS03. Once the gate voltage is high longer than tOnMAx, it is turned off immediately.
VFB
VFBLB VFBBOn VFBBOff VFBEB
Entering Active Burst Mode
Leaving Active Burst Mode
Blanking Window (tBEB)
VCS
Current limit level during Active Burst Mode
t
1.0V VCSB
VVCC
t
VVCCoff
VO
Max. Ripple < 1%
t
t
Figure 8
Signals in Active Burst Mode
3.6
Protection Functions
The IC provides full protection functions. The following table summarizes these protection functions. Table 2 Protection features VCC Overvoltage VCC Undervoltage Overload/Open Loop Over temperature Output Overvoltage Short Winding Auto Restart Mode Auto Restart Mode Auto Restart Mode Auto Restart Mode Latched Off Mode Latched Off Mode
During operation, the VCC voltage is continuously monitored. In case of an under- or an over-voltage, the
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4
Note:
Electrical Characteristics
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 HV Voltage VCC Supply Voltage FB Voltage ZC Voltage CS Voltage GATE Voltage Maximum current out from ZC pin Junction Temperature Storage Temperature Thermal Resistance Junction -Ambient ESD Capability (incl. Drain Pin)
1)
Symbol VHV VVCC VFB VZC VCS VOUT IZCMAX Tj TS RthJA VESD -
Limit Values min. -0.3 -0.3 -0.3 -0.3 -0.3 3 -40 -55 max. 500 27 5.0 5.0 5.0 27 125 150 90 2
Unit V V V V V V mA C C K/W kV
Remarks
PG-DIP-8 Human body model1)
According to EIA/JESD22-A114-B (discharging a 100pF capacitor through a 1.5k series resistor)
4.2
Note: Parameter
Operating Range
Within the operating range the IC operates as described in the functional description. Symbol VVCC TjCon Limit Values min. max. VVCCOVP V 125 C VVCCoff -25 Unit Remarks
VCC Supply Voltage Junction Temperature of Controller
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Electrical Characteristics 4.3
4.3.1 Note:
Characteristics
Supply Section The electrical characteristics involve the spread of values within the specified supply voltage and junction temperature range TJ from - 25 C to 125 C. Typical values represent the median values, which are related to 25C. If not otherwise stated, a supply voltage of VCC = 18 V is assumed. Symbol min. IVCCstart IVCCcharge1 IVCCcharge2 IVCCcharge3 0.8 Limit Values typ. 300 5.0 1.0 0.2 1.5 300 max. 550 2 50 2.3 A mA mA mA mA A mA A VVCC =VVCCon -0.2V VVCC = 0V VVCC = 1V VVCC =VVCCon -0.2V VVCC =VVCCon -0.2V VDrain = 610V at Tj=100C output low IFB = 0A Unit Test Condition
Parameter Start Up Current VCC Charge Current
Maximum Input Current of Startup Cell and CoolMOS(R) Leakage Current of Startup Cell and CoolMOS(R) Supply Current in normal operation Supply Current in Auto Restart Mode with Inactive Gate Supply Current in Latch-off Mode Supply Current in Burst Mode with inactive Gate VCC Turn-On Threshold VCC Turn-Off Threshold VCC Turn-On/Off Hysteresis 4.3.2
IDrainIn IDrainLeak IVCCNM IVCCAR
IVCClatch IVCCburst
-
300 500
950
A A VFB = 2.5V, exclude the current flowing out from FB pin
VVCCon VVCCoff VVCChys
17.0 9.8 -
18.0 10.5 7.5
19.0 11.2 -
V V V
Internal Voltage Reference Symbol min. VREF 4.80 Limit Values typ. 5.00 max. 5.20 V Measured at pin FB IFB=0 Unit Test Condition
Parameter Internal Reference Voltage
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4.3.3 Parameter Feedback Pull-Up Resistor PWM-OP Gain Offset for Voltage Ramp Maximum on time in normal operation 4.3.4 Parameter Peak current limitation in normal operation Leading Edge Blanking time Peak Current Limitation in Active Burst Mode 4.3.5 Parameter Soft-Start time soft-start time step Internal regulation voltage at first step Internal regulation voltage step at soft start
1)
PWM Section Symbol min. RFB GPWM VPWM tOnMax 14 3.18 0.63 22 Limit Values typ. 23 3.3 0.7 30 max. 33 41 k V s Unit Test Condition
Current Sense Symbol min. VCSth tLEB VCSB 0.97 200 0.29 Limit Values typ. 1.03 330 0.34 max. 1.09 460 0.39 V ns V Unit Test Condition
Soft Start Symbol min. tSS tSS_S1) VSS11) VSS_S1) 8.5 Limit Values typ. 12 3 1.76 0.56 max. ms ms V V Unit Test Condition
The parameter is not subjected to production test - verified by design/characterization Foldback Point Correction Symbol min. IZC_FS IZC_LS VCSMF 0.35 1.8 Limit Values typ. 0.5 2 0.66 max. 0.621 2.2 mA mA V Izc=2.2mA, VFB=3.8V Unit Test Condition
4.3.6 Parameter
ZC current first step threshold ZC current last step threshold CS threshold minimum
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4.3.7 Parameter Digital Zero Crossing Symbol min. Zero crossing threshold voltage VZCCT Ringing suppression threshold Minimum ringing suppression time Maximum ringing suppression time Threshold to set Up/Down Counter to one Threshold for downward counting at low line Threshold for upward counting at low line Threshold for downward counting at hig line Threshold for upward counting at highline ZC current for IC switch threshold to high line ZC current for IC switch threshold to low line Counter time1) Maximum restart time in normal operation
1)
Limit Values typ. 100 0.7 2.5 25 3.9 3.2 2.5 2.9 2.3 1.3 0.8 48 30 42 57.5 max. 170 3.4 50 1.8 -
Unit mV V s s V V V V V mA mA ms s
Test Condition
VZCRS tZCRS1 tZCRS2 VFBR1 VFBZHL VFBZLL VFBZHH VFBZLH IZCSH IZCSL tCOUNT tOffMax
VZC > VZCRS VZC < VZCRS
The parameter is not subjected to production test - verified by design/characterization
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4.3.8 Parameter Feedback voltage for entering Active Burst Mode Minimum Up/down value for entering Active Burst Mode Blanking time for entering Active Burst Mode Feedback voltage for leaving Active Burst Mode Feedback voltage for burst-on Feedback voltage for burst-off Fixed Switching Frequency in Active Burst Mode Max. Duty Cycle in Active Burst Mode 4.3.9 Parameter VCC overvoltage threshold Over Load or Open Loop Detection threshold for OLP protection at FB pin Over Load or Open Loop Protection Blanking Time Output Overvoltage detection threshold at the ZC pin Blanking time for Output Overvoltage protection Threshold for short winding protection Blanking time for short-windding protection Over temperature protection1) Note: Protection Symbol min. VVCCOVP VFBOLP 24.0 Limit Values typ. 25.0 4.5 max. 26.0 V V Unit Test Condition Active Burst Mode Symbol min. VFBEB NZC_ABM tBEB VFBLB VFBBOn VFBBOff fsB DmaxB Limit Values typ. 1.25 7 24 4.5 3.6 3.0 52 0.5 ms V V V kHz max. V Unit Test Condition
tOLP_B VZCOVP tZCOVP VCSSW tCSSW TjCon
20 3.55
30 3.7 100
44 3.84
ms V s
1.63 -
1.68 190 140
1.78 -
V ns
0
C
The trend of all the voltage levels in the Control Unit is the same regarding the deviation except VVCCOVP
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4.3.10 Parameter Output voltage at logic low Output voltage at logic high Gate Drive Symbol min. VGATElow VGATEhigh 9.0 Limit Values typ. 10.0 1.0 117 27 max. 1.0 V V V V ns ns VVCC=18V IOUT = 20mA VVCC=18V IOUT = -20mA VVCC = 7V IOUT = 20mA COUT = 1.0nF VGATE= 2V ... 8V COUT = 1.0nF VGATE= 8V ... 2V Unit Test Condition
Output voltage active shut down VGATEasd Rise Time Fall Time trise tfall
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Outline Dimension
5
Outline Dimension
PG-DIP-8-6 / PG-DIP-8-9 (Leadfree Plastic Dual In-Line Outline)
Figure 9
PG-DSO-8 (Pb-free lead plating Plastic Dual Small Outline)
Dimensions in mm
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Throughout the corporation we also think in terms of Time Optimized Processes (top), greater speed on our part to give you that decisive competitive edge. Give us the chance to prove the best of performance through the best of quality - you will be convinced.
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