| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To efficiently ensure a control power supply even if output power from a switching circuit is fluctuated in a wide range, in a switching power supply having the switching circuit for power-converting a DC voltage obtained by rectifying and smoothing an AC voltage. <P>SOLUTION: A power supply voltage Vcc of a control integrated circuit IC1 is ensured from a flyback winding n4 in a DC-DC converter to a smoothing capacitor C23 through a diode D71 at least during the maximum output. The power supply voltage Vcc is ensured from a feed forward winding n3 through a second control power supply circuit 14 when the output decreases. The power supply voltage Vcc is ensured from a rectifying/smoothing circuit 12 through a third control power supply circuit 15 at least when the converter stops. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
