Pulse-width modulation (PWM) controlling apparatus using auxiliary winding voltage for flyback converter

摘要

A Pulse-Width Modulation (PWM) controlling apparatus includes a valley detector configured to detect a valley of an auxiliary winding voltage of a flyback converter, an output voltage controller configured to output a first PWM control signal by performing averaging and sampling of the auxiliary winding voltage, an output current controller configured to output a second PWM control signal by performing an average current mode method on a current signal (CS) voltage, a latch configured to output a gate control signal after being supplied with the result of a logical OR operation of the first PWM control signal output by the output voltage controller and the second PWM control signal output by the output current controller, or an output signal of the valley detector, and a gate controller configured to perform a turning-on or turning-off operation of a first switch based on the gate control signal.