Abstract: An oxygen concentration sensor input device (1) includes a sensor input circuit (4) that can freely supplies a flow-out current to an oxygen concentration sensor (2) that detects an oxygen concentration in exhaust gas of an internal combustion engine. The sensor input circuit includes an operational amplifier (12) that constitutes a voltage follower. A current value of the flow-out current is set such that a voltage waveform of a detection signal of the oxygen concentration sensor crosses a detection threshold on a low voltage side.

Abstract: A shortest distance (d) between a drive circuit (4) and an electric wire (8b) is set such that an electric field caused by an electric current flowing in the electric wire (8b) that electrically connects an ignition-voltage generating device (IG) and an ignition plug (6) induces a surge voltage to the drive circuit (4) via an electrostatic capacity (Cm) between the drive circuit (4) that can freely inject fuel from a fuel injection device (7) provided in an internal-combustion engine (5) to the internal-combustion engine (5) under control of a microcomputer and the electric wire (8b), and the surge voltage becomes equal to or lower than predetermined surge withstanding capability of the semiconductor power device.

Abstract: An internal combustion engine control apparatus includes an output-current abnormality-signal holding unit (112) that determines whether a current abnormality signal is being output from a current-abnormality detecting unit (108, 110), which compares a current value detected by a current detecting unit (R1, R2) with a predetermined threshold, and outputs a current abnormality signal when the current value is equal to or less than the predetermined threshold continuously for a predetermined time or longer, and outputs a current abnormality signal when the current abnormality signal is being output continuously for a predetermined time or longer, and does not output a current abnormality signal when the current abnormality signal is output continuously for less than the predetermined time.