| 摘要 |
PROBLEM TO BE SOLVED: To prevent an AC/DC switching power supply output from becoming unstable even if a DC/DC converter short-circuits in an audio apparatus or the like.SOLUTION: A switching power supply circuit includes: an AC/DC switching power supply (SMPS) 10; a DC/DC converter 12; a protection circuit 20 for outputting a detection signal upon detecting a short circuit; a switch circuit 18 for switching the detection signal; and a microcomputer 16 for controlling an on/off operation of the switch circuit 18, and controlling the operation of the DC/DC converter 12 upon receiving the detection signal. In a monitoring state, the microcomputer 16 turns on the switch circuit 18 to monitor the detection signal, and if receiving the detection signal, controls the DC/DC converter 12 by turning it off. |
