Patent ID: 8089265

Claim:
A device to measure an electric current, comprising: a pair of conductive wires having corresponding first and second ends, said pair of wires being disposed so as to be equidistant over their full extents and said corresponding first ends being electrically connected to each other; on each of said wires, a magnetic sensor having top and bottom leads between which a voltage drop occurs in the presence of a magnetic field, each such sensor being divided into a group of mini MTJ sensing elements each of which includes a free layer and a reference layer that has a pinned magnetization, each of said mini MTJ sensing elements sharing said top and bottom leads and having, in plan view, an aspect ratio of at least 1.2 and a length dimension of at most 1 micron whereby each such free layer is domain stable in the presence of a magnetic field, each of said pinned magnetizations being in a direction that is perpendicular to said length direction; a constant current source connected so as to send a current between said corresponding second ends; means for measuring said voltage drops between said top and bottom leads; and a differential voltage amplifier for measuring a difference in magnitude between said measured voltage drops.