| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power supply equipment for electromagnetic induction heating which is not broken even in the case where a surge voltage such as thunder, momentary power failure, voltage drop or rising, or the like has occurred in a commercial AC voltage. <P>SOLUTION: An excessive surge voltage or abrupt voltage fluctuation of a DC voltage which has been smoothed with a both-wave rectification bridge 440 is detected with voltage division resistors 580, 590, and 620 as well as a speedup capacitor 630, and comparators 830 and 840 immediately stop operation of a switching element oscillation control circuit 790. The detection operation stops when the DC voltage returns to a normal value. The comparators 830 and 840 start operating the switching element oscillation control circuit 790, to gradually raise an energizing voltage and current to a switching element 520. Thanks to those operations, the power supply device is protected from breakage. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
