| 摘要 |
PURPOSE:To establish the logic output circuit having the protective function against short circuit between the output terminal and GND, by comparing the logic level of input and output of the logic circuit and controlling the swtich circuit interrupting power supply or ground by means of the output. CONSTITUTION:In normal operation, the switch circuit 4 is ON and power supply 6 is fed to the logic circuit 2. The signal given to the input terminal 1 is outputted to the output terminal 3 as the signal corresponding to the input signal with the circuit 2. If the terminal 3 is in error shortened to GND or other output terminal, the output logic of the terminal 3 and the input logic of the terminal 1 are compared at the comparison circuit 5. The output of the circuit 5 turns off the switch circuit 4 to interrupt the power supply 6 of the circuit 2 and to block excess current flowing to the circuit 2. Thus, with low cost element constitution, even if the output terminals are shortened, the logic output circuit not damaged can be established. |
