Patent ID: 9093904
Filing Date: 2015-07-28
Classification: H02M,Y02B

Abstract:
1. A resonant switching power supply device, comprising: a first switch and a second switch connected in series to terminals into which a direct current voltage is input; a series circuit of a resonant capacitor, at least one of a resonant inductor and transformer leakage inductor, and a first winding on a primary side of a transformer, connected to the first switch or the second switch; a resonant current detector unit that detects a resonant current flowing through the series circuit; a winding voltage detector unit that detects a winding voltage, which is a voltage across a first winding of the transformer; and a control and drive unit that drives the first switch and second switch to be turned on and off alternately, wherein the control and drive unit has a protection function whereby, in the event that, after detection occurs that a polarity of the winding voltage detected by the winding voltage detector unit has been inverted, either the first switch or the second switch is not in an off-state, when detection occurs that the resonant current detected by the resonant current detector unit has exceeded a threshold value with respect to another resonant current immediately before the inversion of the polarity of the winding voltage, the first switch or second switch that is not in an off-state is turned off.