Magneto-resistive angle sensing device with a temperature-stable zero point

TLDR: In this paper, a contactless magneto-resistive angle sensing device is presented, where two sensor components (10,11) oriented at a fixed angle relative to each other, a controllable power supply (PW) to heat and maintain the sensor components at different temperatures, a magnet (MG) producing a magnetic field, and an evaluating device (12) to receive output signals (U1,U2) from sensor components, each sensor component is mounted on a rotatable part whose angular position is to be subsequently measured at an angular position in relation to

Abstract: The contactless magneto-resistive angle sensing device (1) includes two sensor components (10,11) oriented at a fixed angle relative to each other, a controllable power supply (PW) to heat and maintain the sensor components (10,11) at different temperatures, a magnet (MG) producing a magnetic field (B) in which the sensor components are arranged and an evaluating device (12) to receive output signals (U1,U2) from the sensor components (10,11). Each sensor component (10,11) includes magneto-resistive resistors (MR) connected in a respective bridge (B1,B2) having input terminals (I1,I1';I2,I2') for supply of current and output terminals (O1,O1';O2,O2') for the output signal (U1,U2). In a rotating magnetic field the evaluating device (12) analyzes the output signals (U1,U2) as a function of field angle and temperature to determine a reference angle at which the output signals of the angle sensing device have a minimum temperature dependence and stores the reference angle as a zero point for subsequent angular measurements. The sensor components are then mounted on a rotatable part whose angular position is to be subsequently measured at an angular position in relation to a stationary magnetic corresponding to the reference angle.