| 摘要 |
A train of pulses within a predetermined cycle is produced at a first port of a microcomputer when the microcomputer is operating normally. An operational amplifier compares a voltage obtained by rectifying the pulse train with a reference potential. The microcomputer is reset, depending on the comparison result obtained at the output terminal of the operational amplifier. The output of a power supply circuit is used as a reference potential. When an overcurrent flows in peripheral circuits connected to the microcomputer, the output voltage of the power supply circuit is decreased. This decrease varies the reference potential applied to the operational amplifier. The microcomputer outputs a power supply control pulse from a second port, after it is reset. A relay turns off the power of the power supply circuit to the peripheral circuits. |
