| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply circuit which facilitates a beat countermeasure. SOLUTION: A standby dedicated output winding N5 is provided in a switching transformer T01. An output of this output winding N5 is rectified and smoothed by a rectifying and smoothing circuit 15 having a diode D26 and a capacitor C26. A switch circuit 16 receives power from the rectifying and smoothing circuit 15. Since the switch circuit 16 is turned on only at a standby time to apply the power from the rectifying and smoothing circuit 15 to an IC 21 for a regulator, the power is supplied to a CPU at the standby time. Thus, a capacity value of the capacitor C26 can be freely selected without restricting by negative power of a Low B (12V), and can easily deal with a problem of a sound (beat). COPYRIGHT: (C)2004,JPO
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