POWER FACTOR CORRECTION (PFC) CONTROLLER AND METHOD USING A FINITE STATE MACHINE TO ADJUST THE DUTY CYCLE OF A PWM CONTROL SIGNAL

摘要

A power factor correction (PFC) controller and method uses a finite state machine to adjust the duty cycle of a pulse width modulation (PWM) switching control signal. The PFC controller has a target current generator that receives the link output voltage and generates a target current proportionate to the rectified line input voltage. The PFC controller further includes a comparator which outputs a two-level current comparison result signal. The finite state machine responsive to the two-level current comparison result signal, generates a switch control signal that has a duty cycle which is adjusted for controlling the switch so that the sensed current is approximately proportionate to the rectified line input voltage, such that power factor correction is performed.