Forward-flyback dc-dc converter using resonant lc output circuit

Abstract

A forward-flyback DC-DC converter topology includes a transformer, a main switch, a clamp circuit, first and second rectifying switches, an LC resonant circuit and an output capacitor; a primary winding of the transformer and the main switch are connected in series between a first input terminal and a second input terminal, the clamp circuit constituted by a clamp capacitor and a clamp switch connected in series is connected in parallel with the primary winding or with the main switch, a secondary winding of the transformer includes a forward winding and a flyback winding, a terminal of the primary winding through which current flows into is a dotted terminal of the primary winding, and a connecting mode of a secondary side of the transformer is: the dotted terminal of the forward winding being connected with a first output terminal via the first rectifying switch, a dotted terminal of the flyback winding being connected with a second output terminal via the second rectifying switch, the LC resonant circuit being connected with the first and the second output terminals and an unlike terminal of the forward winding and the flyback winding so that the first and the second rectifying switches implement zero-current switching, and the output capacitor being connected between the first and the second output terminals.