Reduced-resonant-current zero-voltage-switched forward converter with unsaturated-region resonance of saturable inductor

A zero-voltage-switching resonant technique with a saturable inductor is proposed. It uses the unsaturated-region inductance of a small saturable inductor as a part of the resonant inductance to realize zero voltage switching. This technique leads to high efficiency over a wide load range. Forward converters that applied this technique are described. The method reduces resonant current in the switching device, the resonant components, and the windings of the transformer. Experimental results for a 5 V-10 A forward converter with a saturable inductor in the primary side are presented