| 摘要 |
PURPOSE: To prevent the flash-on phenomenon of a transistor at the time of supplying power by simple constitution and to shorten off delay time as well. CONSTITUTION: This device is provided with an output circuit 1 provided with a FET 145 for switching whose drain and source are serially connected to a current path from a power source VD to an output detection part (lead) L, a resistor 147 connected between the gate and the source and a photo voltaic coupler 49 for supplying a driving voltage between the gate and the source of the FET 145 corresponding to the output of an internal circuit 151. A differentiation circuit composed of a capacitor 7 and the resistors 5 and 9 is provided between the drain and the source of the FET 145 and the transistor 3 whose collector and emitter are connected between the gate and the source of the FET 145 is driven by the charging current of the capacitor 7. As a result, when the rise of a voltage occurs between the drain and the source of the FET 145, the transistor 3 is turned on and the FET 145 is forcedly turned off. |
