High accuracy differential current sensor for applications like ground fault interrupters

摘要

A sensor with multiple magnetic field sensing elements for use in current sensing and other applications is presented. In one configuration, the sensor can obtain differential and absolute current measurements of current in current-carrying conductors. When employed in a ground fault interrupter (GFI) application, a first magnetic field sensing element can be used to measure the absolute current flowing in the phase conductor (phase current), a second magnetic field sensing element can be used to measure the absolute current flowing in the neutral conductor (neutral current) and a difference between the phase and neutral currents can be measured by a third magnetic field sensing element or determined from measurements of the first and second magnetic field sensing elements. In another configuration, the sensor can obtain a measure of the difference between currents and/or the sum of currents in current-carrying conductors.

主权项

1. A differential current sensor comprising:
a first current conduction path having a first input terminal and a first output terminal and a second current conduction path electrically isolated from the first current conduction path and having a second input terminal and a second output terminal; magnetic field sensing elements including a first sensing element to sense a magnetic field associated with a first current carried by the first current conduction path and a second sensing element to sense a magnetic field associated with a second current carried by the second current conduction path; circuitry, coupled to the magnetic field sensing elements, to provide an output signal; and wherein the output signal comprises a difference signal indicative of a difference between a magnitude of the first current and a magnitude of the second current.