Description
The FAN7930 is an active power factor correction (PFC) controller for boost PFC applications that operate in critical conduction mode (CRM). It uses a voltage-mode PWM that compares an internal ramp signal with the error amplifier output to generate a MOSFET turn-off signal. Because the voltage-mode CRM PFC controller does not need rectified AC line voltage information, it saves the power loss of an input voltage sensing network necessary for a current-mode CRM PFC controller.
FAN7930 provides over-voltage protection, open feedback protection, over-current protection, input voltage-absent detection, and under-voltage lockout protection. The PFC-ready pin can be used to trigger other power stages when PFC output voltage reaches the proper level with hysteresis. The FAN7930 can be disabled if the INV pin voltage is lower than 0.45V and the operating current decreases to a very low level. Using a new variable on-time control method, THD is lower than the conventional CRM boost PFC ICs.

Features
■ PFC Ready Signal
■ Input Voltage Absent Detection Circuit
■ Maximum Switching Frequency Limitation
■ Internal Soft-Start and Startup without Overshoot
■ Internal Total Harmonic Distortion (THD) Optimizer
■ Precise Adjustable Output Over-Voltage Protection
■ Open-Feedback Protection and Disable Function
■ Zero Current Detector
■ 150μs Internal Startup Timer
■ MOSFET Over-Current Protection
■ Under-Voltage Lockout with 3.5V Hysteresis
■ Low Startup and Operating Current
■ Totem-Pole Output with High State Clamp
■ +500/-800mA Peak Gate Drive Current
■ 8-Pin SOP

Applications
■ Adapter
■ Ballast
■ LCD TV, CRT TV
■ SMPS