Patent ID: 6304074
Filing Date: 2001-10-16
Classification: G01B,G01D,G01R

Abstract:
A method for the offset calibration of a magnetoresistive angle sensor for the determination of the directions of magnetic fields, which sensor comprises at least a Wheatstone bridge with at least four magnetoresistive resistors, said Wheatstone bridge receives an input signal at its input side and which Wheatstone bridge supplies an angle signal at its output side in dependence on the direction of a magnetic field which acts on the Wheatstone bridge, said Wheatstone bridge comprising a first and a second pair of mutually opposed, substantially parallel magnetoresistive resistors, the first and the second pair being arranged substantially at right angles to one another, while the direction of the magnetic field is determined from the angle signal supplied by the Wheatstone bridge by means of an evaluation circuit, characterized in that in a first step the Wheatstone bridge is acted upon by a direct magnetic field which is so aligned that it is neither substantially perpendicular to the magnetoresistive resistors of the first pair nor substantially perpendicular to the magnetoresistive resistors of the second pair of the Wheatstone bridge, in that in a second step the direct magnetic field is removed, and in that in a third step an evaluation circuit determines an offset calibration signal, the angle signal supplied by the Wheatstone bridge without direct magnetic field being a measure for the offset of the Wheatstone bridge.