Resonant power supply circuit

摘要

A resonant power supply circuit includes a flyback transformer. A first FET and a power supply are connected to a primary winding of the flyback transformer. A resonant capacitor and a damper diode are connected between the drain and the source of the first FET. A clamping circuit that includes a diode and a second FET is connected in parallel to the primary winding of the flyback transformer. A control circuit controls the first FET and the second FET. After a flyback pulse is generated, the second FET is turned ON. After the second FET is turned OFF, the first FET is turned ON. When T represents a period of a ringing pulse that is generated after the second FET is turned OFF, the first FET is turned ON after a period of approximately (3T/4) elapses from the time that the second FET is turned OFF.