Patent ID: 7499299
Filing Date: 2009-03-03
Classification: H02M,Y02B

Abstract:
1. A switching power converter, comprising: an input voltage source; a switching circuit having a first switch and a second switch connected in series to form a first leg, and a third switch and a fourth switch connected in series to form a second leg, each of the legs connected in parallel with the input voltage source; a transformer having a primary winding and a secondary winding, one end of the primary winding being connected to a first node between the first switch and the second switch and the other end of the primary winding being connected to a second node between the third switch and the fourth switch; a rectifying circuit having at least one synchronous rectifier and connected to the secondary winding of the transformer for providing an output voltage of the power converter; a primary control circuit connected to the switching circuit, a secondary control circuit connected to the primary control circuit, wherein the secondary control circuit receives a plurality of drive signals from the primary control circuit, controls operation of the at least one synchronous rectifier based on at least two of the plurality of drive signals, determines a delay based on a load current, and adjusts a cycle of at least one of the at least two drive signals with the delay.