Variable attenuation circuit for a differential variable reluctance sensor with temperature compensation for an initial threshold and passive RC filter

摘要

A variable reluctance sensor interface module (25) having a variable attenuation circuit (24) and a rectifier and differential to single-ended conversion circuit (32) for operating in a current mode to attenuate a differential input voltage. The variable attenuation circuit (24) receives an input differential voltage from a magnetic sensor (15), converts the differential voltage to current, and variably attenuates the current. The rectifier and differential to single-ended conversion circuit (32) converts the variably attenuated current to a voltage output. The input circuit includes an RC filter (400) that attenuates high frequency signals. An initial threshold circuit (410) generates an initial threshold voltage that compensates for internal resistance variations, caused e.g. by temperature variations.