Efficiency improvement for SR forward converters with LC snubber

A novel circuit is proposed to alleviate the problems associated with using synchronous rectifiers in forward converters. The proposed circuit employed an LC snubber in the primary side of the converter as opposed to conventional schemes of employing an additional active switch to improve the efficiency. For the proposed forward converter with 40 W output, 91% efficiency at 3.3 V and 4 A output is obtained. In this paper, the circuit operation of this converter is described with the aid of simulation waveforms and the design criteria are also established.