PFC / PWM Combination IC FA5533/34 Features Features underdevelopment development under BlockDiagram Diagram Block •Critical mode Power Factor Correction and PWM AC MUL COMP are combined : suitable for smaller power supply PFC_ IS ZCD LIGHT_ LOAD •Internal start-up circuit with 500V rating and low ZCD ERR PFC_ FB - frequency operation achieves 340mW input R TIMER R MUL + 1shot Overvoltage detection at no load when PFC stops. OVP LV S OVP + Q R - RESTART UVLO PFC_ REG_ OK PFC_ OUT LIGHT_ LOAD PFC section UVLO_ AC • Small Output Capacitance : Linearly reduced UVLO_ AC LV LV VCC UVLO_ VCC UVLO_ AC - - frequency for light load makes small ripple voltage. LIGHT_ LOAD + + + PFC_ REG_ OK REG_ PFC PW M_ REG_ OK REG_ PW M START - off on VH Common section AC detect ACD • PFC stops below half load ( only for FA5533 ) PWM section •Vcc rating 28V allows no series regulator for auxiliary winding to clamp Vcc voltage. PW M OSC FOSC T T Q CLR 1shot + + •Brown-Out below 70Vac and 70Vdc of PFC Output - + PW M + - + CS easy Full Load Start-up PW M_ OUT - VCC RESTART UVLO RESTART UVLO PW M_ REG_ OK LV UVLO_ AC + - •Adjustable Start-up sequence for PFC and PWM: R Q slope PW M OVP •Auto-Restart Over Load Protection S PW M_ DELAY VCC •Adjustable Soft Start time •16 pins package ( DIP/SO ) Dma Q VCO PW M_ FB •Auto-Restart Over-Voltage Protection for Vcc on PW M_ REG + PW M_ REG RESTART + LIGHT_ LOAD delay LIGHT_ LOAD Overload PW M_ IS Usage : Notebook PC, LCD Monitor, LCD-TV, Laser Beam Printer etc. GND PFC / PWM Combination IC FA5533/34 underdevelopment development under ApplicationCircuit Circuit Application PFCsection section PFC PWM PW M section section PFC / PWM Combination IC FA5533/34 underdevelopment development under TimingChart Chart((FA5533 FA5533)) Timing PFC Gate of PFC OUTPUT MOSFET (drive) AC Line AC line voltage voltage AC Line AC line voltage voltage PFC PFC output OUTPUT voltage voltage VCC pin Vcc voltage voltage PW M Gate of PWM OUTPUT Vcc VCC pin voltage voltage GatePFC of OUTPUT PFC (drive) MOSFET PFC Gate of OUTPUT PFC (drive) MOSFET (drive) MOSFET PWM Output DC voltage OUTPUT PFC PFC output OUTPUT voltage voltage PFC PFC output OUTPUT voltage voltage Full load Heavy Load Light load Light Load Stop ( Power-OFF ) Start-up ( Power-ON ) Heavy Load → Light Load → Heavy Load Full load Heavy Load CS pin CS pin voltage PW M Gate of PWM 0.5V 0.5V → OUTPUT (drive) MOSFET Gate of PWM PW M PWMOutput DC voltage OUTPUT OUTPUT MOSFET (drive) Output PWMvoltage DC OUTPUT 5m s 5ms 70Vdc