Current sensor using hall-effect device with feedback
AssigneeGeneral Electric Company
InventorRobert P. Alley
Life of this patent
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Abstract
A current sensor for use with a conductor with known cross-sectional characteristics is an electronic circuit having a monolithic Hall-effect element disposed substantially perpendicular to the conductor first major surface. A conductive loop substantially encircles the element and is oriented such that its flux is substantially orthogonal to the element surface. An amplifier sets current flow in the loop responsive to minimization of the differential Hall voltage across element. The loop current, at null, will be related to the conductor current by the ratio of the conductor flux path length to the loop flux path length.
Claims15
A current sensor for measurement, by the amplitude and direction of a signal to a meter external to the sensor, of a current I.sub.m flowing in a conductor external to the sensor, comprising:
- a Hall-effect element having a surface disposable substantially perpendicular to a magnetic flux .PHI..sub.m responsive to said current I.sub.m, said element having first electrode means for providing a voltage V.sub.h having a magnitude responsive to the net magnetic flux passing through said surface;
- a single conductive loop substantially encircling the element and oriented to cause a magnetic loop flux .PHI..sub.m therefrom, responsive to a current I.sub.1 in said loop, to be substantially perpendicular to the element surface, said current I.sub.1 being proportional to, but different from, said current I.sub.m ;
- and
- means, responsive to said element voltage V.sub.h, for establishing said loop current I.sub.1 to generate said loop flux .PHI..sub.1 with magnitude and polarity to cancel said flux .PHI..sub.m in said element, said establishing means providing said signal to said external meter proportional to the loop current.
Dependencies are inferred from the claim text.