| 摘要 |
PURPOSE:To prevent the malfunction at power supply application and disconnection, by constituting the gate element at the control signal output stage of the internal logic circuit of the digital control unit with the gate element possible for grounding the output terminal. CONSTITUTION:The output terminal of the open collector gate element 8 being the output stage of the internal logic circuit 2 is connected to one of the input terminals of the output stage gate element 3 with one terminal of the switch 4. The switch 4 is OFF at normal operation and the control signal from the internal logic circuit 2 is delivered from the gate element 3 to the controlled unit 7. At the application or disconnection of the power supply, the switch 4 is ON, one output of the gate element 3 is grounded and this is made OFF. Thus, at the application and disconnection of the power supply, the noise due to abnormal operation of the internal logic circuit 2 is blocked to be delivered to the controlled unit 7, enabling to prevent the malfunction of the internal logic circuit 6 of the controlled unit 7. |
