| 摘要 |
PROBLEM TO BE SOLVED: To quickly detect anomaly when a control circuit that includes a microcomputer fails.SOLUTION: A fixed cycle signal monitoring circuit includes; a signal input terminal 21a for inputting a watch dog signal SGw/d; a positive edge detection section 23 that detects rising edge timing of the SGw/d pulses; a negative edge detection section 24 that detects falling edge timing of the SGw/d pulses; and a timer section 25 that measures a period of time without detection of a positive or negative edge on the basis of output from the positive edge detection section and negative edge detection section, and generates a predefined anomaly detection signal when the measured time period exceeds a threshold. Thus, time required for clearing the timer section 25 on each edge is significantly reduced, enabling quick detection of anomaly thereby. |
