Power factor correction circuit for regulating operating frequency control circuit of power factor correction circuit and control method thereof, electronic apparatus, and power adapter

Abstract

A control circuit of a power factor correction circuit including two channels, each of which includes a switching transistor, an inductor and a rectification element, includes: an error amplifier amplifying an error of a feedback signal according to output voltage of the power factor correction circuit and target value of the feedback signal and generating an error signal; a pulse modulator generating first and second pulse modulated signals in current critical mode in response to the error signal; a first driver driving the switching transistor of first channel based on the first pulse modulated signal; and a second driver driving the switching transistor of second channel based on the second pulse modulated signal, wherein the pulse modulator switches between a first mode where phase difference between the first and second pulse modulated signals is 180° and a second mode where the first and second channels are exclusively and alternately used.