| 摘要 |
Provided is a technique of making the leakage inductance of a transformer serve as a current resonant reactor and connecting a stray capacitance Cf1 in parallel to the leakage inductance in a resonant switching power supply device, thereby making the resonant switching power supply device smaller as well as reducing costs. The resonant switching power supply device is equipped with switching elements QH and QL connected in series to an input direct-current power source Vin, a transformer T1 having secondary windings S1 and S2 and a primary winding P1, a resonant circuit where the primary winding P1 and a current resonant capacitor Cri are connected in series and which is connected in parallel to any one of the switching elements, and a rectifying circuit (D1+D2+Co) connected to the secondary winding to obtain an output voltage Vo; the transformer T1 is equipped with a primary winding P2 closely coupled to the primary winding P1, one terminal of the primary winding P2 is connected to one or the other terminal of the primary winding P1, and the other terminal is open. |
