| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply unit for suppressing reverse recovery currents flowing through respective rectifier elements at secondary side without decreasing conversion efficiency. SOLUTION: A switching power supply unit includes a choke coil having first winding (9a) connected between an anode of a flywheel diode (10) and a terminal at reference potential side of an output smoothing capacitor (8), and a second winding (9b) magnetically connected to the first winding (9a). One end of the second winding (9b) is connected to a connecting point for the anode of the flywheel diode (10) and first winding (9a), and the other end of the second winding (9b) is connected between a cathode of the flywheel diode (10) and the terminal at output potential side of the output smoothing capacitor (8) via a reflux diode (11).Since the reverse recovery current flowing through respective diodes (7, 10, 11) at secondary side can be decreased without increasing the resistances of the first and the second windings (9a, 9b) of the choke coil (9), the reverse recovery current flowing through the respective diodes (7, 10, 11) at secondary side can be suppressed without degrading conversion efficiency. COPYRIGHT: (C)2007,JPO&INPIT
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