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Product Specification Power Factor Controller
SG6961 DESCRIPTION
The SG6961 is an 8-pin boundary mode PFC controller IC intended for controlling PFC pre-regulators. The SG6961 provides a controlled on-time to regulate the output DC voltage and achieve natural power factor correction. The maximum on-time of the external switch is programmable to ensure safe operation during AC brownouts. An innovative multi-vector error amplifier is built in to provide rapid transient response and precise output voltage clamping. A built-in circuit disables the controller if the output feedback loop is opened. The start-up current is lower than 20A and the operating current is under 4.5mA. The supply voltage can be up to 20V, maximizing application flexibility.
FEATURES
Boundary Mode PFC Controller Low Input Current THD Controlled On-Time PWM Zero-Current Detection Cycle-by-Cycle Current Limiting Leading-Edge Blanking Instead of RC Filtering Low Start-up Current (10A Typical) Low Operating Current (4.5mA Typical) Feedback Open-Loop Protection Programmable Maximum On-Time (MOT) Output Over-Voltage Clamping Protection Clamped Gate Output Voltage 16.5V
APPLICATIONS
Electric Lamp Ballasts AC-DC Switching Mode Power Converter Open-Frame Power Supplies and Power Adapters Flyback Power Converters with ZCS/ZVS
TYPICAL APPLICATION
Vo
VAC
ZCD VCC
MOT
COMP
INV
GD
SG6961
GND
CS
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-1-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961 PIN CONFIGURATION
MARKING DIAGRAMS
SG6961TP
XXXXXXXXYWWV
T: D=DIP, S=SOP P : Z=Lead Free + ROHS Compatible Null=regular package XXXXXXXX: Wafer Lot Y: Year; WW: Week V: Assembly Location
INV COMP MOT CS
VCC GD GND ZCD
ORDERING INFORMATION
Part Number
SG6961SZ SG6961DZ
Pb-Free
Package
8-Pin SOP 8-Pin DIP
PIN DESCRIPTIONS
Pin No.
1 2 3 4
Symbol
INV COMP MOT CS
Description
Inverting input of the error amplifier. INV is connected to the converter output via a resistive divider. This pin is also used for over-voltage clamping and open-loop feedback protection. The output of the error amplifier. To create a precise clamping protection, a compensation network between this pin and GND is suggested. A resistor from MOT to GND is used to determine the maximum on-time of the external power MOSFET. The maximum output power of the converter is a function of the maximum on-time. Input to the over-current protection comparator. When the sensed voltage across the sense resistor reaches the internal threshold (0.82V), the switch is turned off to activate cycle-by-cycle current limiting. Zero Current Detection. This pin is connected to an auxiliary winding via a resistor to detect the zero crossing of the switch current. When the zero crossing is detected, a new switching cycle is started. If it is connected to GND, the device is disabled. The power ground and signal ground. Placing a 0.1F decoupling capacitor between the VCC and GND pins is recommended. Totem-pole driver output to drive the external power MOSFET. The clamped gate output voltage is 16.5V. Driver and control circuit supply voltage.
5
ZCD
6 7 8
GND GD VCC
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
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www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
BLOCK DIAGRAM
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-3-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
ABSOLUTE MAXIMUM RATINGS
Symbol
VDD VHIGH VLOW Vzcd PD RJ-A TJ TSTG TL ESD
Parameter
DC Supply Voltage* GD Others (INV, COMP, MOT, CS,) Input Voltage to ZCD Pin Power Dissipation Thermal Resistance (Junction-to-Air) Operating Junction Temperature Storage Temperature Range Lead Temperature (Wave Soldering or Infrared, 10 Seconds) Electrostatic Discharge Capability, Human Body Model Electrostatic Discharge Capability, Machine Model DIP-8 SOP-8 DIP-8 SOP-8
Value
25 -0.3 to 25.0 -0.3 to 7.0 -0.3 to 12.0 800 400 48.45 62.70 -40 to + 150 -65 to + 150 260 2.0 200
Unit
V V V V mW C/W C C C kV V
* All voltage values, except differential voltages, are given with respect to GND pin. * Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device.
ELECTRICAL CHARACTERISTICS
VCC=15V, TA=-20C~125C, unless otherwise noted.
VCC Section
Symbol
VOP VTH-ON VTH-OFF ICC-ST ICC-OP VCC-OVP TVCC-OVP
Parameter
Continuously Operating Voltage Turn-On Threshold Voltage Turn-Off Voltage Start-Up Current Operating Current VCC Over-Voltage Protection* VCC OVP Debounce Time*
Test Condition
Min.
11 8.2
Typ.
12 9.5 10 4.5 24 30
Max.
20 13 10.5 20 6.0
Unit
V V V A mA V s
VCC=VTH-ON -0.16V VCC=12V, VCS=0, CL=3nF, FSW=50KHz
* Guaranteed by design.
Error Amplifier Section
Symbol
VREF Gm VINVH VINVL VOUT HIGH VOZ VINV-OVP VINV-UVP ICOMP
Parameter
Reference Voltage Transconductance* Clamp High Feedback Voltage Clamp Low Feedback Voltage Output High Voltage Zero Duty Cycle Output Voltage Over-Voltage Protection for INV Input* Under-Voltage Protection for INV Input Source Current Sink Current
Test Condition
TA=25C
Min.
2.45 100 2.22 4.8 1.15 0.40
Typ.
2.50 125 2.65 2.30 1.35 2.75 0.45 20 800 20
Max.
2.55 150 2.70
Unit
V mho V V V
1.45 0.50
V V V A A A
VINV=2.35V, VCOMP=1.5V VINV=1.5V VINV=2.65V, VCOMP=5V
7 450 10
* Guaranteed by design.
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-4-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
Current Sense Section (VLIMIT)
Symbol
VPK TPKD TBNK
Parameter
Threshold Voltage for Peak Current Limit Cycle-by-Cycle Limit Propagation Delay Leading-Edge Blanking Time
Test Condition
VCOMP=5V
Min.
0.77
Typ.
0.82
Max.
0.87 200
Unit
V ns ns
RMOT=24k
400
550
Gate Section
Symbol
VZ-OUT VOL VOH TR TF
Parameter
Output Voltage Maximum (Clamp) Output Voltage Low Output Voltage High Rising Time Falling Time
Test Condition
VCC=20V VCC=15V, IO=100mA VCC=14V, IO=100mA VCC=12V, CL=3nF, 20~80% VCC=12V, CL=3nF, 80~20%
Min.
15.5 8 50 30
Typ.
16.5
Max.
17.5 1.4
Unit
V V V
80 40
160 70
ns ns
Zero Current Detection Section
Symbol
VZCD HYS of VZCD VZCD-HIGH VZCD-LOW TDEAD TRESTART TINHIB VDIS TZCD-DIS
Parameter
Input Threshold Voltage Rising Edge Threshold Voltage Hysteresis Upper Clamp Voltage Lower Clamp Voltage Maximum Delay from ZCD to Output Turn-On Restart Time Disable Threshold ZCD Disable Debounce Time
Test Condition
VZCD Increasing VZCD Decreasing IZCD=3mA IZCD=-0.5mA VCOMP=5V, FSW=60KHz
Min.
1.9 0.25 8 0 100
Typ.
2.1 0.35 10
Max.
2.3 0.50 12 400
Unit
V V V V ns s s mV s
Output Turned Off by ZCD 300 1.5 200 RMOT=24k, ZCD=100mV 800
500 2.5 250
700 3.0 300
Inhibit Time (Maximum Switching Frequency Limit) RMOT=24k
Maximum On-Time Section
Symbol
VMOT TON-MAX
Parameter
MOT Voltage
Test Condition
Min.
1.25 21
Typ.
1.30 25
Max.
1.35 27
Unit
V s
RMOT=24k, VCS=0, Maximum On-Time Programming (Resistor Based) VCOMP=5V
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-5-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
TYPICAL CHARACTERISTICS
Turn-on Threshold Voltage (Vref) vs Temperature
2.515 2.51 5
Continuously Operating Voltage (Icc_op) vs Temperature
Icc_op (mA)
-40 -25 -10 5 20 35 50 65 80 95 110 125
Vref (V)
2.505 2.5 2.495 2.49 2.485
4.6 4.2 3.8 3.4 3 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ()
Temperature ()
Maximum On-Time Programming-resistor based (Ton_max) vs Temperature
Turn-on Threshold Voltage (Vth_on) vs Temperature
12.35
25.4
Ton_max(uSec)
25.2 24.8 24.6 24.4 24.2 24 23.8 23.6 -40 -25 -10 5 20 35 50 65 80 95 110 125
12.3
Vth_on (V)
25
12.25 12.2 12.15 12.1 12.05 12 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ()
Temperature ()
Turn-off Voltage (Vth_off) vs Temperature
10.20 10.00
Start_Up Current (Icc_st) vs Temperature
16 14
Vth_off (V)
Icc_st (uA)
-40 -25 -10 5 20 35 50 65 80 95 110 125
9.80 9.60 9.40 9.20 9.00 8.80 8.60
12 10 8 6 4 2 0 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ()
Temperature ()
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
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www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
VCC Over Voltage Protection (V CC_ovp) vs Temperature
25.1
SG6961
Output Voltage Maximum-clamp (VZ_out) vs Temperature
16.6 16.5
VCC_ovp(V )
25.05 25 24.95 24.9 24.85 24.8 24.75 -40 -25 -10 5 20 35 50 65 80 95 110 125
VZ_out (V)
16.4 16.3 16.2 16.1 16.0 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ()
Temperature ()
MOT Voltage (Vmot) vs Temperature
1.289 1.287
Threshold Voltage for Peak Current Limit Cycle by Cycle Limit (Vpk) vs Temperature
0.822 0.82
Vmot (V)
1.285 1.283 1.281 1.279 1.277 1.275 -40 -25 -10 5 20 35 50 65 80 95 110 125
Vpk (V)
0.818 0.816 0.814 0.812 0.81 0.808 -40 -25 -10 5 20 35 50 65 80 95 110 125
Temperature ()
Temperature ()
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-7-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
OPERATION DESCRIPTION Error Amplifier
The inverting input of the error amplifier is referenced to INV. The output of the error amplifier is referenced to COMP. The non-inverting input is internally connected to a fixed 2.5V 2% voltage. The output of the error amplifier is used to determine the on-time of the PWM output and regulate the output voltage. To achieve a low input current THD, the variation of the on-time within one input AC cycle should be very small. A multi-vector error amplifier is built in to provide fast transient response and precise output voltage clamping. For SG6961, connecting a capacitance, such as 1F, between COMP and GND is suggested. The error amplifier is a transconductance amplifier that converts voltage to current with a 125mho.
Peak Current Limiting
The switch current is sensed by one resistor. The signal is fed into CS pin and an input terminal of a comparator. A high voltage in the CS pin terminates a switching cycle immediately and cycle-by-cycle current limit is achieved. The designed threshold of the protection point is 0.82V.
Leading-Edge Blanking
A turn on spike on CS pin occurs when the power MOSFET is switched on. At the beginning of each switching pulse, the current-limit comparator is disabled for ~400ns to avoid premature termination. The gate drive output cannot be switched off during the blanking period. Conventional RC filtering is not necessary; the propagation delay of current limit protection can be minimized.
Start-Up Current
Typical start-up current is less than 20A. This ultra-low start-up current allows the usage of a high resistance, low-wattage start-up resistor. For example, 1M /0.25W start-up resistor and a 10F/25V (VCC hold-up) capacitor are recommended for an AC-to-DC power adaptor with a wide input range 85 to 265VAC.
Under-Voltage Lockout (UVLO)
The turn-on and turn-off threshold voltages are fixed internally at 12V/9.5V for SG6961. This hysteresis behavior guarantees a one-shot start-up with proper start-up resistor and hold-up capacitor. With an ultra-low start-up current of 20A, one 1M resistor, RIN, is sufficient for start-up under low input line voltage, 85VRMS. Power dissipation on RIN is less than 0.1W even under high line (VAC=265VRMS) conditions.
Operating Current
Operating current is typically 4.5mA. The low operating current enables better efficiency and reduces the requirement of VCC hold-up capacitance.
Maximum On-Time Operation
Given a fixed inductor value and maximum output power, the relation between on-time and line voltage is:
Output Driver
With low on resistance and high current driving capability, the output driver can drive an external capacitive load larger than 3000pF. Cross conduction current is avoided to minimize heat dissipation, such that efficiency and reliability can be improved. This output driver is internally equipped with clamped by a 16.5V Zener diode.
ton =
2 L Po -------------------------------------Vrms 2
(1)
If the line voltage is too low or the inductor value is too high, TON is too long. To avoid extra low operating frequency and achieve brownout protection, the maximum value of TON is programmable by a resistor, RI, connected between MOT and GND. A 24k resistor RI generates corresponds to 25s maximum on-time.
ton (max) = RI (k )
25 (s)--------------24
(2)
The range of the maximum on-time is designed as 10 ~ 50s.
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-8-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
Zero Current Detection
The zero current detection of the inductor is achieved using its auxiliary winding. When the stored energy of the inductor is fully released to output, the voltage on ZCD goes down and a new switching cycle is enabled after a ZCD trigger. The power MOSFET is always turned on with zero inductor current, such that turn-on loss and noise can be minimized. The converter works in boundary mode, such that the peak inductor current is always exactly twice of the average current. Moreover, a natural power factor correction function is achieved with the low-bandwidth on time modulation. An inherent maximum off-time is built in to ensure proper start-up operation. In addition, this pin can be used as a synchronous input.
Noise Immunity
Noise on the current sense or control signal can cause significant pulse-width jitter, particularly in the boundary-mode operation. Slope compensation and built-in debounce circuitry alleviate this problem. Note that the SG6961 has a single ground pin; therefore, high sink current at the output cannot be returned separately. Good high-frequency or RF layout practices should be followed. Avoid long PCB traces and component leads. Locating compensation and filter components near to the SG6961 and increasing the power MOSFET gate resistance improve performance.
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
-9-
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
REFERENCE CIRCUIT: SG6961 180W
BOM
Component
Resistor 1M +/- 5% SMD 1206 Resistor 33K +/- 1% SMD 1206 Resistor 0 +/- 1% SMD 1206 Metal-Oxide Resistor 1W-S 022 +/-5% Resistor 430K +/-1% SMD 0805 Resistor 330K +/-1% SMD 1206 Resistor 24K +/-1% SMD 1206 Resistor 68K +/-5% SMD 1206 Resistor 100 +/-5% SMD 1206 Resistor 10 +/-1% SMD 1206 Resistor 20K +/-1% SMD 1206 Electrolytic Capacitor 1F 50V 105C MLCC 105P 50V SMD 1206 X1 Capacitor 0.47F 275V +/-20% MPE Capacitor 0.47F 450V +/-10% MLCC 221P 50V +/-10% SMD 0805 Electrolytic Capacitor 22F 50V 85C MLCC 103P 50V +/-10% SMD 1206 Electrolytic Capacitor 120F 450V 105C FUSE 250V 5A Ceramic Time-Lag TRN0194 Common Choke 4.5mH TRN0195 Common Choke 7.5mH(min) TRN0193 Inductor(T80-26) 350H
Symbol
R1,R2,R3,R4,R5,R18,R19 R6 R8 R9,R10 R11 R12,R13 R14 R15 R16 R17 R20 C1 C2 C4 C5,C6 C7 C8 C11 C12 F1 L1 L2 L3
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
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www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller Component
TRN0196 PFC Choke 210H PQ-26/25 Varistor 14 471 JUMPER WIRE 0.8(mm) Rectifier KBL06 4A 600V Diode FR103 TAPING Zener Diode1/2W 18V Diode UF3005 3A 600V Diode Fairchild RHRP1560 15A 600V TO-220 Diode 1N4148 SMD ZENER Diode 1/2W 24V SMD Diode 2N7002 SMD MOSFET Infineon 16N50C3 16A 500V TO-220
SG6961
Symbol
L4A MOV1 JP1,JP2,JP3,JP4,TR1 BD1 D1 D2 D3 D4 D5 ZD1 Q1 Q2
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
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www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
PACKAGE INFORMATION 8PINS-DIP(D)
D
8 5
X
E1
E
eB
1
4
A1
A2
L b1 b e
Dimensions
Symbol
A A1 A2 b b1 D E E1 e L eB
Millimeter Min. Typ.
0.381 3.175 3.302 1.524 0.457 9.271 7.620 6.350 2.540 3.302 9.017 7
A
Inch Min.
0.015 0.125
Max.
5.334 3.429
Typ.
0.130 0.060 0.018 0.365 0.300 0.250 0.100 0.130 0.355 7
Max.
0.210 0.135
9.017 6.223 2.921 8.509 0
10.160 6.477 3.810 9.525 15
0.355 0.245 0.115 0.335 0
0.400 0.255 0.150 0.375 15
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
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www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
8PINS-SOP(S)
C
8
5
1 b
4 e
D
A1
A
Dimensions
Symbol
A A1 b c D E e F H L
Millimeter Min. Typ.
1.346 0.101 0.406 0.203 4.648 3.810 1.016 5.791 0.406 0
Max.
1.752 0.254
1.270 0.381X45
4.978 3.987 1.524 6.197 1.270 8
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
H F
E
L
Inch Min.
0.053 0.004
Typ.
0.016 0.008
Max.
0.069 0.010
0.183 0.150 0.040 0.228 0.016 0
0.050 0.015X45
0.196 0.157 0.060 0.244 0.050 8
- 13 -
www.sg.com.tw * www.fairchildsemi.com September 24, 2007
Product Specification Power Factor Controller
SG6961
(c) System General Corp. Version 1.3.1 (IRO33.0028.B6)
- 14 -
www.sg.com.tw * www.fairchildsemi.com September 24, 2007

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