General Description

The FAN4822 is a PFC controller designed specifically for high power applications. The controller contains all of the functions necessary to implement an average current boost PFC converter, along with a Zero Voltage Switch (ZVS) controller to reduce diode recovery and MOSFET turn-on losses.

The average current boost PFC circuit provides high power factor (>98) and low Total Harmonic Distortion (THD). Built-in safety features include undervoltage lockout, over voltage protection, peak current limiting, and input voltage brownout protection.

The ZVS control section drives an external ZVS MOSFET which, combined with a diode and inductor, soft switches the boost regulator. This technique reduces diode reverse recovery and MOSFET switching losses to reduce EMI and maximize efficiency.

Features

• Average current sensing, continuous boost, leading edge

PFC for low total harmonic distortion and near unity

power factor

• Built-in ZVS switch control with fast response for high

efficiency at high power levels

• Average line voltage compensation with brownout control

• Current fed gain modulator improves noise immunity and

provides universal input operation

• Overvoltage comparator eliminates output “runaway” due

to load removal

• UVLO, current limit, and soft-start

• Precision 1.3 reference