Patent ID: 6366079
Filing Date: 2002-04-02
Classification: G01D,G01P,G01R

Abstract:
A rotation detector comprising:a biasing magnet, positioned to face a toothed rotor with a air gap therebetween, for generating a biasing magnetic field; and an MRE bridge patterned on an IC-chip and positioned in the biasing magnetic field to face the toothed rotor with a air gap therebetween, the MRE bridge including a first MRE circuit and a second MRE circuit, the first MRE circuit having a first MRE and a second MRE connected in series in this order between a power source and a ground, the second MRE circuit having a third MRE and a fourth MRE connected in series in this order between the power source and the ground, resistances of the first MRE and the second MRE being changed with a phase difference therebetween in response to changes of the biasing magnetic field, resistances of the third MRE and the fourth MRE being changed with a phase difference therebetween in response to changes of the biasing magnetic field, the MRE bridge detecting rotation of the toothed rotor based on an output voltage thereof, wherein: the first MRE in the first MRE circuit and the third MRE in the second MRE circuit are positioned symmetrically with respect to a center line of the biasing magnetic field; and the second MRE in the first MRE circuit and the fourth MRE in the second MRE circuit are positioned symmetrically with respect to the center line of the biasing magnetic field.