Apparatus and method for sequentially resetting elements of a magnetic sensor array

摘要

A semiconductor process and apparatus provide a high-performance magnetic field sensor with three differential sensor configurations which require only two distinct pinning axes, where each differential sensor is formed from a Wheatstone bridge structure with four unshielded magnetic tunnel junction sensor arrays, each of which includes a magnetic field pulse generator for selectively applying a field pulse to stabilize or restore the easy axis magnetization of the sense layers to orient the magnetization in the correct configuration. prior to measurements of small magnetic fields. The field pulse is sequentially applied to groups of the sense layers of the Wheatstone bridge structures, thereby allowing for a higher current pulse or larger sensor array size for maximal signal to noise ratio.

主权项

1. A magnetic field sensor comprising:
a first bridge circuit including a first plurality of magnetic sense elements configured to sense a magnetic field in a first dimension, the first plurality of magnetic sense elements including i groups of magnetic sense elements, where i is greater than or equal to 2, and wherein each group of the i groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in the first dimension; a second bridge circuit including a second plurality of magnetic sense elements configured to sense the magnetic field in a second dimension, the second plurality of magnetic sense elements including j groups of magnetic sense elements, where j is greater than or equal to 2, and wherein each group of the j groups of magnetic sense elements includes a plurality of magnetic sense elements to sense the magnetic field in the second dimension; and circuitry configured to generate a first plurality of current pulses and a second plurality of current pulses, the first plurality of current pulses sequentially applied adjacent to each of the i groups of the first plurality of magnetic sense elements and thereafter the second plurality of current pulses sequentially applied adjacent to each of the j groups of the second plurality of magnetic sense elements, wherein the sequential application of current pulses adjacent to the i and j groups of magnetic sense elements results in a larger current applied adjacent to each of the i and j groups of magnetic sense elements, for a given voltage, than if the first plurality and second plurality of current pulses had been applied adjacent to the i and j groups of magnetic sense elements simultaneously.