| 摘要 |
<p>PURPOSE: To prevent the occurrence of burning, etc., caused by the short-circuit of the wire harness of a power source section with an inexpensive constitution without impairing a power source backing-up function. CONSTITUTION: In a power unit which supplies the output of a battery 1 to loads 5-8 through a control switch 4, a normally-opened relay switch 9 is connected between the positive terminal of a battery 1 which is grounded on its negative terminal side and input-side terminal of the switch 4 and a serial circuit of a current limiting element 10 and circuit breaker 11 is connected in parallel with the switch 9. In addition, a relay driving circuit 12 which closes the switch 9 by closing the switch 4 is connected between the output-side terminal of the switch 4 and ground. Therefore, the burning of a wire harness 16 can be prevented even when the wire harness 16 is short-circuited to the input- side terminal of the switch 4, because the circuit breaker 11 becomes opened state due to a large current flowing through the limiting element 10 and circuit breaker 11.</p> |
