| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To determine a power-on reset time and a reset time in time of detection of runaway by one timer circuit, to determine a runaway monitoring time by the other timer circuit, and to reset a microcomputer. <P>SOLUTION: The circuit generating a microcomputer reset signal upon the fluctuation of a power supply voltage and upon the runaway of the microcomputer includes: a voltage fluctuation detection circuit 22; a pulse generation circuit 24 generating a pulse according to a clock signal outputted by the microcomputer; the first timer circuit 26 performing countup in a period except a period wherein the reset is performed by the pulse from the pulse generation circuit and the microcomputer reset signal; and the second timer circuit 28 performing countup in a period except a period wherein the reset is performed by a timeup signal from the first timer circuit and a voltage fluctuation signal from the voltage fluctuation detection circuit, and outputting the microcomputer reset signal in a period wherein the timeup is not performed. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
