Patent ID: 8873259

Claim:
A DC-DC converter circuit, comprising: a switching circuit which switches a DC power supply with two or more primary side switching elements; a transformer, to a primary side winding of which the output of said switching circuit is applied, and which outputs a voltage which has been changed by a predetermined voltage change ratio to a secondary side winding; a secondary diode circuit including a plurality of secondary diodes for current adjustment, connected to said secondary side winding of said transformer; a regeneration snubber circuit connected in parallel with said secondary diode circuit, and including a series circuit of a discharge blocking diode and a snubber capacitor, and a switching element for regeneration connected in parallel with said discharge blocking diode; a filter circuit connected between rectification outputs of said secondary diode circuit; and a control unit which a) turns said switching element for regeneration ON a predetermined time period during which all primary side switching elements are OFF, and b) turns said switching element for regeneration OFF during the predetermined time period and prior to a subsequent time period during which any of the primary side switching elements is ON such that the switching element for regeneration is never ON a time period during which any of the primary side switching elements are ON; wherein said predetermined time period is set to approximately the time period during which the charge, accumulated in said snubber capacitor due to reverse recovery time when any one of said secondary diodes in said secondary diode circuit has been turned OFF, discharges.