Patent ID: 8203855
Filing Date: 2012-06-19
Classification: H01F,H02M,Y02B

Abstract:
1. A power supply unit that includes a complex inductor; a first switching leg in which a first switching element and a second switching element are connected in series; a second switching leg in which a third switching element and a fourth switching element are connected in series; a first smoothing capacitor connected in parallel to the first and second switching legs and a DC power supply; a series-connection body including a resonant inductor and a primary transformer winding, the series-connection body being connected between a series-connection point of the first and second switching elements and another series-connection point of the third and fourth switching elements; a transformer in which the primary transformer winding and a secondary transformer winding are magnetically coupled; a rectifying circuit for rectifying a voltage generated in the secondary transformer winding; a smoothing inductor; and a second smoothing capacitor for smoothing, together with the smoothing inductor, the voltage rectified by the rectifying circuit; the power supply unit supplying power to a load connected in parallel to the second smoothing capacitor, wherein the complex inductor includes a magnetic member having at least a first closed magnetic path and a second closed magnetic path, the magnetic member being structured so that a magnetic resistance of the magnetic member increases as a magnetic flux flowing in the closed magnetic paths increase; a first inductor including one winding or a plurality of windings formed around at least part of the first and second closed magnetic paths, the windings being mutually connected; and a second inductor including one winding or a plurality of windings formed around at least part of the first and second closed magnetic paths, the windings being mutually connected; and wherein, when currents flow in both the first and second inductors, a magnetic flux generated by a current flowing in the first inductor and a magnetic flux generated by a current flowing in the second inductor strengthen each other in one of the first and second closed magnetic paths and weaken each other in the other of the first and second closed magnetic paths; and wherein the first and second inductors are used as the smoothing inductor and the resonant inductor.