Patent ID: 9048741
Filing Date: 2015-06-02
Classification: H02M,Y02B

Abstract:
1. A switching power supply device, comprising: a transformer including at least a primary winding and a secondary winding; a primary side circuit including a secondary side circuit including wherein a mutual inductance is formed equivalently through mutual induction between the primary winding and the secondary winding; a mutual capacitance is formed equivalently through interaction between the primary winding and the secondary winding; and a multi-resonant circuit is formed that includes a plurality of LC resonant circuits formed at least in each of the primary side circuit and the secondary side circuit, and wherein, with the multi-resonant circuit, the primary side resonant circuit and the secondary side resonant circuit resonate with each other, and electric power is transmitted from the primary side circuit to the secondary side circuit through an electromagnetic field resonant coupling in which currents flow in the mutual inductance and the mutual capacitance; energy that is not transmitted from the primary winding is retained in the primary side resonant circuit as resonant energy through a resonance phenomenon; of energy which the secondary winding has received, energy that is not supplied to an output is retained in the secondary side resonant circuit as resonant energy through a resonance phenomenon; and the secondary side resonant circuit forms a current path that is different from a current path in which the rectifying element is formed in series to transmit electric power from the primary winding to the secondary winding.