Patent ID: 8619438

Claim:
A resonant converter, comprising: first and second input terminals configured to receive an input voltage; first and second output terminals configured to provide an output voltage; a transformer comprising a primary winding and a secondary winding, wherein the primary winding has a first terminal and a second terminal and wherein the secondary winding has a first terminal and a second terminal; a series resonant circuit comprising a capacitive element and the primary winding of the transformer, wherein the capacitive element is coupled between the second terminal of the primary winding and the second input terminal; a switching circuit connected between the first and second input terminals and the series resonant circuit, wherein the switching circuit comprises a first switch and a second switch; a control circuit configured to control the switching circuit, wherein for a first period of time, the first switch is open and the second switch is closed, for a second period of time, the switch is closed and the second switch is open, for a third period of time, the first switch and the second switch are open, wherein the third period of time is between the first period of time and the second period of time, for a forth period of time, the first switch is open and the second switch is closed, and for a fifth period of time, the first switch and the second switch are open, wherein the fifth period of time is between the second period of time and the forth period of time; a rectifier circuit connected between the secondary winding and the first and second output terminals; and a clamping circuit connected between the first input terminal and the second input terminal comprising a first clamping element coupled between the second terminal of the primary winding and the first input terminal, and a second clamping element coupled between the second terminal of the primary winding and the second input terminal.