| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize the protective circuit for switch mode power supply easily by switching a power supply to stand-by mode upon occurrence of short circuit. SOLUTION: When a line 12 is short-circuited, a first converter 16 breaks the power supply voltage to a control stage 20 and thereby a signal S disappears along with a signal S'. Consequently, a switch mode power supply controller 11 switches a switch mode power supply 10 to stand-by mode. Similar operation takes place when a line 13 is short-circuited. When a line 14 is short-circuited, a transistor included in a second converter 17 switches a breathing signal to ground. Consequently, the signal S is blocked and the protection of controller 20 is triggered. Consequently, a stand-by mode being controlled by means of the switch mode power supply controller 11 is obtained.</p> |
