Plural parallel resonant switching power supplies

Claim 1

A switching power supply comprising a plurality of converter circuits each having two switching elements, a transformer, a resonant circuit and an output rectifier smoothing circuit; wherein: said two switching elements in each converter circuit are connected in series to form a serial circuit of which two ends are led to a DC source to be driven alternately; said transformer in each converter circuit includes at least a primary winding and a secondary winding; said resonant circuit in each converter circuit has a resonant capacitor and a resonant inductor; said resonant capacitor, resonant inductor and primary winding in each converter circuit are connected in series to form a serial circuit of which two ends are connected between a connecting point of said two switching elements and one end of said serial circuit which is constituted of said two switching elements; said output rectifier smoothing circuit in each converter circuit is connected to said secondary winding of said transformer; output ends of each of said output rectifier smoothing circuits included in each of said plurality of converter circuits are connected to each other; and each of said resonant circuits included in said plurality of converter circuits are connected with each other.