Patent ID: 9030850
Filing Date: 2015-05-12
Classification: H02M,Y02B

Abstract:
1. A switching power supply comprising: a transformer having a primary winding, a secondary winding, and an auxiliary winding, the auxiliary winding being disposed in a primary side of the transformer and detecting variation in a voltage across the primary winding; a series-connected circuit including a first semiconductor switch and a second semiconductor switch, the series-connected circuit being connected in parallel to a DC power source; a series-connected resonance circuit including series-connected components of a resonance capacitor, an inductance element of a leakage inductance of the transformer, and the primary winding of the transformer; a differentiating circuit for detecting a timing of an inversion beginning timing or an inversion ending timing of the voltage detected by the auxiliary winding after receiving a first trigger signal for turning OFF of the first semiconductor switch or the second semiconductor switch; a dead time adjusting circuit for generating a second trigger signal at a timing of turn ON the first semiconductor switch or the second semiconductor switch delaying a predetermined time period from the timing detected by the differentiating circuit of the inversion beginning timing or the inversion ending timing of the voltage detected by the auxiliary winding; and a voltage control oscillator including an ON width determining means that comprises a minimum dead time-generating circuit for generating a minimum dead time on receiving the first trigger signal and starts up operation to determine an ON width of the first semiconductor switch or the second semiconductor switch after the minimum dead time.