| 摘要 |
PURPOSE:To contrive an integrated circuit to be lower in cost through the elimination of need for employing a clamping diode of large capacity, by grounding the rush current due to a back induced electromotive force generated in a load. CONSTITUTION:Driving circuits 23, 25 are connected to the ends of an inductive load 26, respectively. The circuits 23, 25 are controlled by a control signal fed from input terminal 18 so as to drive the load 26. A comparator circuit 24 makes comparison between the potential of the control signal and the potential at one end of the load 26 thereby to control the circuit 25. When the level of the control signal from the terminal 18 is high, the circuits 23, 25 drive the load 26. When the control signal level is switched to low, both the circuits 23, 25 stop driving the load 26. At the moment the circuits 23, 25 stop driving the load 26, a back induced electromotive force is generated at a point A, and the potential at the point A rises toward a potential much higher than the supply voltage. The circuit 24 makes comparison between the potential at the point A and the potential of the control signal, and when detecting an abnormal potential at the point A the circuit 24 controls the circuit 25. |
