Half-bridge flyback converter with lossless passive snubber and interleaved technique

Hard-switching flyback converters are widely used in the low power application but suffer from high electromagnetic emissions, current ripples, and low efficiency. To overcome these problems, a half-bridge flyback converter with a new lossless passive snubber is proposed using an interleaved structure. All switches of the proposed converter turn on under zero current switching and turn off under zero voltage switching which decreases the switching losses and electromagnetic interference (EMI). Theoretical analysis of the proposed converter is presented and verified by the experimental results of a 200 W prototype. In addition to the 7% efficiency improvement, the proposed converter has lower EMI in comparison with its hard-switching converter.