A novel current-feed soft-switching two-switch forward resonant DC-DC Transformer (DCX)

In this paper, a current-feed resonant two-switch forward DC-DC Transformer (DCX) is proposed for high-efficiency and high-density unregulated bus converter applications. With a resonant capacitor in series with the leakage inductance of the transformer, ZCS turn-on and nearly ZCS turn-off can be achieved for the primary switches and there is no body diode and reverse recovery losses in the SR. Meanwhile, the magnetizing current is used to achieve ZVS turn-off for the primary switches. The circuit operating principle and design considerations are discussed. An 110W prototype is built up to verify the theoretical analysis.