Patent ID: 8169796
Filing Date: 2012-05-01
Classification: H01F,H02M

Abstract:
1. An isolated switching power supply apparatus comprising: a DC power input portion to which a DC input voltage is input; a transformer including a first primary winding, a first secondary winding, and a second secondary winding magnetically coupled with one another; a first inductor connected in series to the second primary winding; a second inductor connected in series to the first primary winding; a rectifier circuit including a first rectifier device arranged to rectify a sum of a current generated in the first secondary winding and a current generated in the second secondary winding and a second rectifier device arranged to rectify a current generated in the second secondary winding; a first switch circuit including a first switching device, a first capacitor, and a first diode, that are connected in parallel with one another; a second switch circuit including a second switching device, a second capacitor, and a second diode, that are connected in parallel with one another; a third capacitor; a first series circuit that is connected to both terminals of the DC power input portion and in which the first primary winding or the second primary winding, and the first switch circuit are connected in series with one another; and a second series circuit that is connected to both ends of the first switch circuit, both ends of the first primary winding, or both ends of the second primary winding and in which the second switch circuit and the third capacitor are connected in series with one another; wherein the first switch circuit and the second switch circuit are arranged to complementarily and repeatedly enter on/off states with a period therebetween in which both are in off states; windings of the transformer are arranged such that energy is transmitted from a primary side to a secondary side complementarily by the first secondary winding or the second secondary winding in synchronization with complementary on/off operations of the first switch circuit and the second switch circuit; magnetic polarities of the first secondary winding and the second secondary winding are opposite to each other; and an output voltage is output to the secondary side via the third inductor.