초록 ▼

A switching power supply having low loss includes two sub switching elements connected in series, which are then connected in parallel with a bridge circuit. A resonance coil and a sub primary winding are connected between a connection point of the series connection circuits and an output terminal o

A switching power supply having low loss includes two sub switching elements connected in series, which are then connected in parallel with a bridge circuit. A resonance coil and a sub primary winding are connected between a connection point of the series connection circuits and an output terminal of the bridge circuit. Resonance capacitors are respectively connected in parallel with each main switching element constituting the bridge circuit so as to resonate with the resonance coil. Voltages across the two ends of A phase and B phase sub secondary windings magnetically coupled to the sub primary winding are clamped to the supply voltage. A fixed voltage in proportion to the turns ratio is generated in the sub primary winding. A voltage applied to the resonance coil becomes small, and current fluctuation becomes small. Also, two sub switching elements connected in series are then connected in parallel with a main bridge circuit; and a resonance coil and auxiliary primary winding are connected between a connection point C of the series connection circuits and an output terminal B of the main bridge circuit. Resonance capacitors are respectively connected in parallel with each main switching element constituting the main bridge circuit. The auxiliary primary winding is magnetically coupled to a main primary winding H-bridge connected to the main bridge circuit, the main bridge circuit being controlled during resonance of the resonance coil, and the resonance being terminated using a voltage induced in the auxiliary primary winding.

대표청구항 ▼

[ What is claimed is:] [1.]1. A power supply, comprising:a main bridge circuit, having four main switching elements bridge connected, connected so as to supply current from a D.C. voltage source;a main primary winding located inside a main transformer and H-bridge connected to said main bridge circu

[ What is claimed is:] [1.]1. A power supply, comprising:a main bridge circuit, having four main switching elements bridge connected, connected so as to supply current from a D.C. voltage source;a main primary winding located inside a main transformer and H-bridge connected to said main bridge circuit;A phase and B phase main secondary windings located inside said main transformer and magnetically coupled to said main primary winding;a main rectification and smoothing circuit for rectifying and smoothing a voltage induced in said A phase and B phase main secondary windings and supplying power to a load;a resonance capacitor connected in parallel with each of said main switching elements;a rectifier element inversely connected in parallel with each of said main switching elements;an A phase sub switching element and a B phase sub switching element connected in series with each other, with said series circuit connected in parallel with said main bridge circuit;a resonance coil between one end of said main primary winding and a connection point between said A phase sub switching element and said B phase sub switching element;a sub primary winding connected in series with said resonance coil and inserted between said connection point and the one end of said main primary winding; anda sub secondary winding magnetically coupled to said sub primary winding, and constructed so as to have a voltage induced by current flowing in said sub primary winding.