| 摘要 |
<p>PURPOSE:To obviate an increase of a load of a software and a high speed problem of a monitor signal which are generated at the time of detecting a fault of an external device by providing a flip-flop (F/F) or a circuit having the same function as the F/F on an input terminal of a monitor input signal, and also, constituting it so that an output value of its F/F can be monitored. CONSTITUTION:A driving device 2 is operated by a PWM output signal 3, and when it is operated normaly, a monitor input signal 4 is fed back. An F/F 5 which receives this monitor input signal 4 inverts a value of the F/F 5 at a variation point of its rise or fall. By monitoring this value of the F/F 5, and investigating whether it is different from a value of the previous PWM period or not, a fault of the driving device 2 is detected. In the case the PWM period becomes a higher speed, and it becomes impossible to monitor the value in a single period, a fault is detected by a single monitor operation against the PWM period of several times by increasing the F/F 5 to several stages and constituting it as an input counter. In such a way, a fault of an external device is detected surely, and a load of a software is curtailed.</p> |
