Patent ID: 7362598

Claim:
A power converter, comprising: a transformer having a primary winding, a first secondary winding, and a second secondary winding; a bridge input circuit comprising at least two primary power switches for coupling input power to the primary winding; a self-driven synchronous rectifier circuit connected to the second secondary winding, wherein the self-driven synchronous rectifier circuit includes a first self-driven synchronous rectifier for rectifying a voltage across the first secondary winding, and wherein a control terminal of the first synchronous rectifier is controlled by a voltage across the second secondary winding; a gate drive circuit comprising a first diode connected to the control terminal of the first synchronous rectifier for introducing a positive dc level shift thereto when the at least two primary switches are off; and a gate drive shutdown circuit connected to the first diode of the gate drive circuit, the gate drive shutdown circuit including a switch for removing the dc level shift from the control terminal of the first synchronous rectifier when operation of the bridge input circuit is terminated.