Denso Corporation

Satoshi Ichikawa

Hiroyuki Ban

Shinya Uemura

Shinichiro Nakata

An air-fuel ratio sensor control device, connected with two-cell type air-fuel ratio sensor having electromotive force and oxygen pump cells with first to third two-cell terminals or a one-cell type air-fuel ratio sensor having a single cell with first and second one-cell terminals, includes: first to third connection terminals for connecting the one-cell or two-cell type air-fuel ratio sensor; a control circuit that is switchable between a two-cell circuit configuration for controlling the two-cell type air-fuel ratio sensor through the first to third connection terminals and a one-cell circuit configuration for controlling the one-cell type air-fuel ratio sensor through the first and second connection terminals; and a control unit that sets a circuit configuration of the control circuit to the one-cell or two-cell circuit configuration.

Air-fuel ratio sensor control device

An input protection circuit comprises a reverse flow preventing diode, a series circuit of a diode and a Zener diode, and a current path forming resistor or diode. The reverse flow preventing diode is connected between an input terminal and an internal circuit. The series circuit is connected between the input terminal and a ground. The current path forming resistor or diode is connected between a first common connection point of the reverse flow preventing diode and the internal circuit and a second common connection point of the series circuit, and sets a potential at the first common connection point to be less than a potential at the input terminal when the surge voltage is applied to the input terminal.

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Gamagori, Japan

Satoshi Ichikawa