ANALOG SIGNAL INPUT CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide an analog signal input circuit capable of conducting a pin-open fault check on an A/D input port of a microcomputer without influencing on a fail-safe circuit.SOLUTION: An analog signal input circuit includes: a microcomputer 3 that includes an A/D input port to which a detection signal of a thermocouple 2 measuring a temperature of a fuel cell module is input; a fail-safe circuit 11 to which a detection signal of a monitoring unit 10 provided between the A/D input port and the thermocouple 2 is input; a normal-operation confirmation circuit 21 outputting a predetermined confirmation signal to the A/D input port so as to confirm whether the A/D input port normally operates; and a voltage follower 8 that permits transmission of the detection signal from the thermocouple 21 to the A/D input port but that restricts transmission of the confirmation signal from the A/D input port to the monitoring unit 10.