CM6903A

CM6903A Low Pin Count PFC/PWM CONTROLLER COMBO GENERAL DESCRIPTION FEATURES The CM6903A 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 compliant to IEC1000-3-2 specifications. ‹ The CM6903A includes circuits for the implementation of a leading edge, input current shaping technique “boost” type ‹ PFC and a trailing edge, PWM. ‹ The CM6903A’s PFC and PWM operate at the same ‹ frequency, 67.5kHz. A PFC OVP comparator 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 compatible 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 Feed forward IAC pin to do the automatic slope c...