| 摘要 |
<p>PURPOSE:To detect the abnormality of an actuator independently of the trouble state (short-circuit or disconnection) of the actuator by including a potential detecting means which detects the change of the potential at the connection point between a driving signal generating means and the actuator. CONSTITUTION:The rise of a driving signal at a connection point (d) is detected by a potential detecting means 14, and a transistor TR (t) of a time detecting circuit 15 is turned on to discharge the electric charge charged in a capacitor (c) when said signal rises. Through the capacitor (c) is charged with the electric charge when the TR (t) is turned off, the potential at an output terminal (e) of the time detecting circuit 15 is kept at the GND level approximately if an actuator 12 is operated normally. If the point (d) is short-circuited to VAA or GND or is disconnected, the TR (t) of the time detecting circuit 15 is not turned on because the potential detecting circuit 14 does not detect the change of potential. Thus, the capacitor (c) is continuously charged with the electric charge and the potential of the output terminal (e) exceeds the threshold voltage of an inverter 16 finally, and the output of the inverter is changed from the high level to the low level to diagnose the trouble.</p> |
