Boundary Mode PFC Controller
Low Input Current THD
Controlled On-Time PWM
Cycle-by-Cycle Current Limiting
Leading-Edge Blanking Instead of RC Filtering
Low Start-up Current (10μA 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
Pin No. Symbol 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 0.1μF decoupling capacitor between the VCC
and GND pins
7 GD Totem-pole driver output to drive the external power MOSFET. The clamped gate output voltage is 16.5V.
8 VCC Driver and control circuit supply voltage
Power Factor Controller
© System General Corp. - 4 - www.sg.com.tw • www.fairchildsemi.com
Version 1.3.1 (IRO33.0028.B6) September 24, 2007
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
DC Supply Voltage* 25 V
-0.3 to 25.0 V
Others (INV, COMP, MOT, CS,) -0.3 to 7.0 V
Input Voltage to ZCD Pin -0.3 to 12.0 V
Thermal Resistance (Junction-to-Air)
Operating Junction Temperature -40 to + 150
Storage Temperature Range -65 to + 150
Lead Temperature (Wave Soldering or Infrared, 10 Seconds)
Electrostatic Discharge Capability, Human Body Model 2.0 kV
Electrostatic Discharge Capability, Machine Model 200 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