| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching power supply that makes it possible to start its low power consumption state surely and stably. <P>SOLUTION: The switching power supply having a power factor improvement function is provided with a DC-DC converter 11 that converts an output voltage of a step-up chopper circuit 7 and supplies DC voltages to a plurality of loads, and a control microcomputer 8 that outputs control signals for switching on or off the power factor improvement function of the step-up chopper circuit 7 and the DC-DC converter 11, and that outputs a control signal for operating the DC-DC converter 11 after the lapse of a prescribed period of time from the output of the control signals for operating the power factor improvement function of the step-up chopper circuit 7. The power factor improvement function inside the step-up chopper circuit 7 is operated by the control signals for operating the power factor improvement function generated by the control microcomputer 8 during the prescribed period of time only when a standby state, which is the low power consumption state, is started. <P>COPYRIGHT: (C)2007,JPO&INPIT |
