ABSTRACT
Anisotropic magneto-resistance sensors are often used as the sensing element in geomagnetic detection embedded systems, such as electronic compasses, etc. An AMR sensor is generally in the form of Wheatstone bridge, which is a bridge of four components. These bridge sensors can provide many features, but when they cannot detect any sensor stimulus signals, the bridge output voltage is called an “offset voltage.” This offset voltage may cause reduced performance of the sensor system if it is not compensated for. If that occurs, the performance of the sensor systemmay be degraded. With regard to traditional bridge offset voltage compensation methods, the Shunt Resistance Method, theAmplifier-biasNulling, and the Switching Feedback Method are used to eliminate bridge offset voltage that can be found in [1] and [2]. This document elaborates the property of AMR sensors’ bridge bias, it analyses the impact on sensor circuits, and it compensates for the offset voltage to obtain a better effect.
