| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to suppress the increasing capacitance of a smoothing capacitor connected to a control circuit of a switching power supply device, to use a small, low-cost smoothing capacitor, and reduce power consumption and audible sound produced by a transformer as well. SOLUTION: A switching power supply device includes a direct-current power source 1, an insulating transformer 3 having primary, secondary, and tertiary windings, and a switch element 2. High-frequency voltage produced in the secondary winding 3c of the insulating transformer 3 is rectified to obtain a direct-current output by turning on and off the switch element 2. It is made possible to reduce power consumption, especially, during standby (burst mode) by a control circuit 6 that controls the turn-on/off or the like of the element 2. COPYRIGHT: (C)2009,JPO&INPIT
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