ELECTROMAGNETIC PROPORTIONAL CURRENT SENSOR

摘要

The current between elements is measured with high precision by eliminating any variation in the zero magnetic resistance (R0) and the temperature coefficient of resistance (TCR0). A magnetic field detection bridge circuit (13) is provided that comprises four magneto-resistive sensors (122a to 122c, and 123) the resistance of which changes with the application of an induction magnetic field from a current to be measured. The four magneto-resistive sensors (122a to 122c, and 123) have: a ferromagnetic solid layer, which is formed by antiferromagnetic coupling of a first ferromagnetic film and a second ferromagnetic film via an antiparallel coupling film; a nonmagnetic intermediate layer; and a free soft magnetic layer. The first and second ferromagnetic films have virtually the same Curie temperature, the difference in the amount of magnetization is essentially zero, the direction of magnetization of the ferromagnetic solid layers of the three magneto-resistive sensors (122a to 122c) is the same, and the direction of magnetization of the ferromagnetic solid layer of the one magneto-resistive sensor (123) is 180º different from the direction of magnetization of the ferromagnetic solid layers of the three magneto-resistive sensors (122a to 122c).