| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply corresponding to an AC stop that stops a DC output and stops the operation of a load side device without the requirement of additional parts including a breaker, the instance an AC power supply switch is turned off upon an emergency or the like. SOLUTION: This switching power supply comprises a signal generation means 6 that generates a sampling frequency fs of high frequency, a voltage level detection means 7 that detects voltage levels of rectified waveforms at the timing of the sampling frequency fs, a judgment means 8 that judges the stop of AC power supply, if the voltage level detection means 7 detects a bottom voltage Vbo prescribed number of times continuously, and a switch control means 9 that outputs switch information Js, if the judgment means 8 judges the stop of the AC power supply. Furthermore, a control means 3 is provided that detects the AC stop simply and surely and performs the control of DC stop in a very short period of time from the AC stop, because a DC output is stopped by controlling switching means based on the sampling frequency fs. COPYRIGHT: (C)2007,JPO&INPIT
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