| 摘要 |
PURPOSE:To avoid an electric shock due to a short circuit of a switch element and a malfunction of the switch element due to noises, by providing a means for collating the signal that informs an indication of the application of a power supply and the signal that detects the power supply at the rear stage of the switch element. CONSTITUTION:A power supply application cutoff indicating circuit 5 indicates the application and cutoff of a power supply to the switch elements P0-Pn and at the same time delivers a power supply application detecting signal N to a discriminating circuit 4. The circuit 4 detects by a signal L that an input power supply is supplied through the input power supply detecting circuits O0-On which are provided at the rear stages of the switch elements. Then dissidence is discriminated between the signals N and L when an input power supply is detected through the circuits O0-On and although the application of the power supply is indicated by the circuit 5. Then a cutoff indication of the power supply is given to a protecting circuit 3. A delaying circuit 6 is set between the circuits 4 and 5 to prevent the operation of the circuit 3. |
