A novel magnetoresistive wheel speed sensor with low temperature drift and high stray field immunity

Abstract

Especially in the automotive domain wheel speed sensors face increasing quality and reliability requirements due to novel vehicle concepts as well as new legal regulations. From this follows, that next generation sensors have to possess a higher robustness against harsh environmental conditions. A large operating temperature range as well as a high stray field immunity are key-requirements. In this paper a novel magnetoresistive wheel speed sensor is presented, whereby its transfer function is linearized in the frequency domain. From this follows directly an improvement of the sensor reliability, since temperature and lifetime drift are significantly reduced. Moreover, the concept enables measurement of disturbing fields perpendicular to sensing direction, which cannot be detected by existing speed sensors. Furthermore, promising measurement results validate the feasibility and performance of the presented sensory system.