
Fairchild Semiconductor
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