Unified Model of Magnetoresistive Angular Position Sensors with Manufacturing Tolerances

This paper presents a unified model of magnetoresistive angular position sensors, applicable to sensors based on the three major sensor technologies: Anisotropic Magnetoresistance, Giant Magnetoresistance, and Tunnel Magnetoresistance magnetoresistive elements. Theoretical models of the three different magnetoresistive elements, including manufacturing tolerances, have been derived first. The models are then employed to derive a realistic model of a magnetoresistive measurement bridge. In order to construct a model of a magnetoresistive magnetic field direction sensor, besides bridge models, a novel model of a free ferromagnetic layer has been developed. Finally, a unified magnetoresistive angular position sensor model has been obtained by combining the magnetic field direction sensor and a simple model of a permanent magnet. The experimental results confirmed the validity of the proposed model.