Current detection circuit for A/F sensor

Abstract

An object of the present invention is to achieve a highly flexible current detection circuit for an A/F sensor, that can readily provide for a change to an A/F sensor having a difference characteristic. To achieve the above object, the A/F sensor current detection circuit of the invention comprises: an operational amplifier for generating a voltage to be applied to the A/F sensor; a current-measuring first resistor connected between the operational amplifier and the A/F sensor; voltage-dividing second and third resistors connected in series with each other with one end thereof connected between the operational amplifier and the first resistor; a first output terminal provided between the operational amplifier and the first resistor; a second output terminal provided between the first resistor and the A/F sensor; and a third output terminal provided between the voltage-dividing second and third resistors. When measuring the sensor element admittance with this circuit, the third output terminal is used in place of the first output terminal.

Dependencies are inferred from the claim text.