| 摘要 |
A switching power supply which is capable of lessening recovery current. The switching power supply is provided with a magnetic element connected to one terminal of a power supplying section, a switch with its one terminal connected to one terminal of the magnetic element and the other terminal connected to the other terminal of the power supplying section, a capacitor for smoothing connected between the magnetic element and the other terminal of the power supplying section, and a diode connected between the magnetic element and the capacitor for smoothing, with its forward direction wherein current is allowed to flow from the power supplying section to the capacitor for smoothing through the magnetic element. A second magnetic element is inserted in the path of recovery current which is caused to flow to the switch from the diode when the switch is closed, and a second capacitor connected to the first magnetic element is installed in parallel with the switch. Between the first magnetic element and the diode, a resonance circuit is formed with the second magnetic element, the switch, and the second capacitor. The second capacitor is charged with current from the first magnetic element when the switch is opened, and it discharges current when the switch is closed.
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