METHOD OF CONTROLLING SYNCHRONOUS RECTIFIER FOR POWER CONVERTER, CONTROL CIRCUIT, AND POWER CONVERTER THEREOF

摘要

A method for controlling a synchronous rectifier for a power converter, a control circuit, and a power converter thereof are provided. The method comprises the following steps: turning on a transistor by a rectifier; generating a switching-period signal in accordance with a period of a voltage-sensing signal; generating a turn-on-period signal in accordance with a turned-on period of the rectifier; generating a first disabling signal responding to the switching-period signal; and generating a second disabling signal in response to the turn-on-period signal. The transistor is turned off in response to the first disabling signal and the second disabling signal, and the voltage-sensing signal is related to the switching waveform of a transformer.