| 摘要 |
<p>PURPOSE:To decrease the number of delay circuits by ORing the voltage at a reset terminal with the output of a runaway detecting circuit. CONSTITUTION:The control circuit of a microcomputer consists of a comparator IC1 for the reset terminal voltage, an IC2 which ORs the outputs of the runaway detecting circuit and comparator IC1, resistances R1 and R2 for setting a comparative voltage, a hysteresis resistance R3, a resistance R4 and a capacitor C1 for power-on reset time delay, and a monostable multivibrator for runaway detection. Then, the comparator IC1 is provided with hysteresis in power-on operation to vary the comparative voltage during the output of the comparator IC1. The time form when the microcomputer starts operating after the voltage at the reset terminal is delay to when the output of the runaway detecting circuit 3 becomes effective is provided and pulses are outputted from the microcomputer during this period to perform normal operation.</p> |
