Patent ID: 8736256
Filing Date: 2014-05-27
Classification: B82Y,G01D,G01R

Abstract:
1. A rotating field sensor for detecting an angle that a direction of a rotating magnetic field in a reference position forms with respect to a reference direction, the rotating field sensor comprising: a first detection circuit that detects an intensity of a component of the rotating magnetic field in a first direction and outputs a first signal indicating the intensity; a second detection circuit that detects an intensity of a component of the rotating magnetic field in a second direction and outputs a second signal indicating the intensity; and an arithmetic circuit that calculates, based on the first and second signals, a detected angle value having a correspondence relationship with the angle that the direction of the rotating magnetic field in the reference position forms with respect to the reference direction, wherein: each of the first and second detection circuits includes at least one row of magnetoresistive elements; each of the at least one row of magnetoresistive elements is composed of a plurality of magnetoresistive elements connected in series; each of the plurality of magnetoresistive elements has a magnetization pinned layer whose magnetization direction is pinned, a free layer whose magnetization direction varies according to the direction of the rotating magnetic field, and a nonmagnetic layer disposed between the magnetization pinned layer and the free layer; the number of the plurality of magnetoresistive elements forming each row of magnetoresistive elements is an even number not smaller than two; the plurality of magnetoresistive elements forming each row of magnetoresistive elements include one or more pairs of magnetoresistive elements; the magnetization directions of the magnetization pinned layers in two magnetoresistive elements making up any of the one or more pairs form a predetermined relative angle other than 0° and 180°; the at least one row of magnetoresistive elements in the first detection circuit does not include any magnetoresistive element that has a magnetization pinned layer whose magnetization direction is pinned in the first direction or in a direction opposite to the first direction; and the at least one row of magnetoresistive elements in the second detection circuit does not include any magnetoresistive element that has a magnetization pinned layer whose magnetization direction is pinned in the second direction or in a direction opposite to the second direction.