A clamped transformer power supply producing zero voltage resonant transitions over the full-load range

A circuit is described that employs zero-voltage-resonant transition (ZVRT) switching. The full-bridge inverter drives the transformer in a manner so that the transformer primary current during the off times circulates in the low side bridge switches. The amplitude of the circulating current at light loads is sufficiently enhanced by a current doubler output rectifier circuit to maintain ZVRT. The operation of the circuit is explained and analyzed. Data is presented on a breadboard that produces 5 V at 60 A from a 150 VDC source.<
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