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, openfeedback protection, over-current protection, inputvoltage-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.