General Description

The 8 pin single PFC controller with 50% PWM clock , CM6503/4 is a space-saving 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 performance could be very close to CM6800 or ML4800 architecture. Its IAC has dual function. 8 pin CM6503/4 does not require and bleed resistors. It use IAC pin during the start up condition to start up CM6503/4. After CM6503/4 is on, IAC will switch itself back to the IAC function.

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 CM6503/4 includes circuits for the implementation of a leading edge, average current "boost" type PFC and a trailing edge, PWM Clock signal which will not turn on until PFC boost output reaches steady state.

The CM6503's PFC and PWM Clock operate at the same frequency, 67kHz. The PFC frequency of the CM6504 is automatically set at half that of the 134kHz PWM. This higher frequency allows the user to design with smaller PWM components while maintaining the optimum operating frequency for the PFC. An 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.

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Features

• Enable lowest BOM for power supply with PFC
• Patented slew rate enhanced voltage error amplifier with advanced input current shaping technique
• Universal Line Input Voltage
• No bleed resistor required
• CCM boost or DCM boost with leading edge modulation PFC using Input Current Shaping Technique
• Feedforward IAC pin to do the automatic slope compensation
• PFCOVP, TriFault Detect, PFC VCCOVP, Precision -1V PFC ILIMIT
• Low supply currents; start-up: 100uA typical, operating current: 2mA typical
• Synchronized leading PFC and trailing edge modulation PWM Clock for the down stream DC to DC stage to reduce ripple current in the storage capacitor between the PFC and PWM sections and to reduce switching noise in the system
• VINOK Comparator to guarantee to enable PWM Clock when PFC reach steady state
• UVLO, REFOK, and brownout protection

• Desktop PC Power Supply
• Internet Server Power Supply
• IPC Power Supply
• UPS
• Battery Charger
• DC Motor Power Supply
• Monitor Power Supply
• Telecom System Power Supply
• Distributed Power

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Packages

• CM6503IP: 8-PIN PDIP (P08)
• CM6503IS: 8-PIN Wide SOP (S08))
• CM6504IP: 8-PIN PDIP (P08)
• CM6504IS: 8-PIN Wide SOP (S08)

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