GENERAL DESCRIPTION The FAN4803 is a power factor space saving controller corrected, switching mode power supply that provides very low start-up and operating currents. The Power Factor Correction (PFC) function provides smaller, lower cost using large capacitors, reduces power line loading and stress on switching FETs, and results in power supply fully compliant to IEC1000-3-2 specifications. The included FAN4803 circuit is used to implement the leading edge, average current "boost" type PFC and trailing edge, PWM. The PFC and PWM of the FAN4803-1 work at the same frequency of 67kHz. The frequency of the FAN4803-2 PFC is automatically set to half the 134kHz PWM. This high frequency allows the use of smaller user-designed PWM components while maintaining the frequency of the optimal operating PFC. The overvoltage comparator shuts down the PFC section in a sudden event while reducing the load. Part of the PFC also includes peak current limiting for improved system reliability.

Features • Internal synchronization on an 8-pin PFC and PWM IC • Patented one-pin input current shaping technology with advanced voltage error amplifier • Peak or average current, continuous boost, leading edge Power Factor Correction (input current shaping technology)
• High efficiency trailing edge current mode PWM
• Low Supply Current; Startup: 150µA Typical, Operational: . 2mA current typical.
• Synchronous leading and trailing edge modulation • Capacitor for reduced ripple current between PFC and PWM sections in storage • Overvoltage, undervoltage lockout, and brownout protection • PFC VCCOVP soft-start with PFC