A Novel Soft-switched Single-Switch Flyback Converter with Active Leakage Recovery Network

In this paper a new soft switched single switch flyback DC-DC converter is proposed with a simple and efficient leakage recovery network. The proposed converter achieves ZCS turn-on and ZVS turn-off of the switch without using any auxiliary switching network. The converter switching loss is reduced significantly enabling it to operate at high frequency and efficiency. All the diodes of the converter are turned on and turned off under ZCS, except the clamping diode. This diode is only turns off under ZCS. Moreover, use of no auxiliary switch reduces control complexity and component count significantly. The leakage energy recovery network allows the leakage energy to be transferred to output directly, which leads to reduced conduction loss of the converter. A detailed analysis of the proposed converter operation is presented along with design procedure. A 72 Volts, 60Watt converter is simulated in Orcad - Pspice and the simulated results are given to verify the theoretical analysis.