| 摘要 |
<p>PURPOSE:To protect an actuator-controlling circuit from an abnormal current, by a system wherein an output voltage from an integrating circuit corresponding to the duration of an output signal obtained by ORing is compared with a voltage set corresponding to a reference time, and an abnormal condition is discriminated based on an output from a comparing circuit before a control signal is outputted for such a long time as to deteriorate or damage an actuator or a controlling circuit. CONSTITUTION:When a control signal SOL for a traction solenoid 4 is brought to a low level, an output signal from a point (a) of an OR circuit 21 is brought to a low level. When an output waveform from the point (a) is outputted through inversion by a buffer 22 and a resistor R1, a capacitor C is charged from an initial state to a saturated state. Therefore, waveforms of inputs to a comparator 23 are such that the input level at a point (b) is lower than that at a point (c) in an initial period, but the relation is inverted after the lapse of a reference time T. At this point t1, an output from a point (d) of the comparator 23 is changed to a high level, and an output from a point (e) of a one-shot multivibrator 24 is maintained at a low level for the period from the time t1 to the time t2. As a result, resetting is performed.</p> |
