SENSOR CONTROL DEVICE

摘要

A gas sensor control device (2) includes a digital control unit (31) (CPU 91 in detail) functioning as a digital filter unit (99). Even when high-frequency noise components are superimposed on an electrical signal transmitted to a digital control unit (31) from the electromotive force cell (24), the high-frequency noise components are eliminated by the digital filter unit (99). Therefore, a terminal voltage Vs across both terminals of the electromotive force cell (24) generated according to oxygen concentration can be suitably extracted. The digital control unit (31) can suitably perform feedback control of the pump current Ip based on the terminal voltage Vs generated across both terminals of the electromotive force cell (24) while suppressing the influence of high-frequency noise components.

主权项

1. A sensor control device for controlling a sensor, the sensor including a diffusion chamber into which a gas to be measured flows through a diffusion rate controlling layer, an electromotive force cell which generates a detection voltage according to concentration of a particular gas component within the diffusion chamber and a pump cell which pumps the particular gas component into or out of the diffusion chamber according to an externally supplied pump current, the sensor control device comprising:
a control unit configured to feedback-control the pump current based on the detection voltage so that the detection voltage generated at the electromotive force cell approaches a target voltage; and a low pass filter unit configured to extract a predetermined low frequency component from the detection voltage, wherein the control unit feedback controls the pump current based on the low frequency component extracted by the low pass filter unit.