CM6903 Datasheet | Champion Microelectronic

DESCRIPTION CM6903/4 Low Pin Count PFC/PWM CONTROLLER BO FEATURES The CM6903/4 is a space-saving PFC-PWM controller for power factor corrected, switched mode power supplies that offers very low start-up and operating currents. For the power supply less than 500Watt, its input current shaping PFC performance could be very close to CM6800 or ML4800 architecture. Power Factor Correction (PFC) offers the use of smaller, lower cost bulk capacitors, reduces power line loading and stress on the switching FETs, and results in a power supply fully pliant to IEC1000-3-2 specifications. The CM6903/4 includes circuits for the implementation of a leading edge, input current shaping technique “boost” type PFC and a trailing edge, PWM. The CM6903’s PFC and PWM operate at the same frequency, 67k Hz. The PFC frequency of the CM6904 is automatically set at half that of the 134k Hz PWM. This higher frequency allows the user to design with smaller PWM ponents while maintaining the optimum operating frequency for the PFC. An PFC OVP parator shuts down the PFC section in the event of a sudden decrease in load. The PFC section also includes peak current limiting for enhanced system reliability. Patent Number #5,565,761, #5,747,977, #5,742,151, #5,804,950, #5,798,635 Pin to pin patible with FAN6903/4 Enable lowest BOM for power supply with PFC Internally synchronized PFC and PWM in one IC Patented slew rate enhanced voltage error amplifier with advanced input current shaping technique Universal Line Input Voltage CCM boost or DCM boost with leading edge modulation PFC using Input Current Shaping Technique Feedforward IAC pin to do the automatic slope pensation PFCOVP, PFC VCCOVP, Precision -1V PFC ILIMIT, Tri-Fault Detect parator to meet UL1950 No bleed resistor required Low supply currents; start-up: 100u A typical, operating current: 2m A typical. Synchronized leading PFC and trailing edge modulation PWM to reduce ripple current in the storage capacitor between the PFC and PWM sections...