| 摘要 |
<p>PURPOSE:To attain the successive actions of a microcomputer by providing a protection circuit which detects that either one of plural power supplies has the abnormality except the power supply for the microcomputer and then turns off those plural power supplies. CONSTITUTION:In a system power supply 10, a power supply circuit 33a for a microcomputer 31 is independent of the control of a decoder 32 and other power circuits 33b - 33n are selectively controlled by the output of the decoder 32. If the overvoltage surge, for example, is applied to the power supply 10, a protection circuit 11 detects the surge and turns off the decoder 32 and the power circuits 33b - 33n except the circuit 33a. As a result, the set parts connected to the circuits 33b - 33n are protected. Furthermore if some of circuits 33b - 33n has the short circuit of output, the circuit 11 detects the short circuit and turns off the circuits 33b - 33n to avoid the influence given to other power circuits. The power can be continuously supplied to the computer 31 when the circuit 11 performs a control action.</p> |
