Soft switching forward-flyback converter with one magnetic component and current doubler rectification circuit

An active clamped forward-flyback converter comprising a current doubler scheme, which boosts the application range of MOSFETs for efficient rectification in low-voltage power supplies, is investigated first approximately and second including commutations. Design equations and issues are given for the magnetic integration of filter inductors on the outer core legs of the transformer. The circuit allows soft switching in the relevant operation range, while keeping the reactive power low. Thus, the resulting efficiency of nearly 90% using Schottky diodes is increased compared to hard switching or resonant topologies.