High linearity, low offset interface for hall effect devices

Abstract

A Hall effect sensor or device may be used in a variety of embodiments, such as measuring current within an associated conductor by helping to measure flux density within a gap of a ferromagnetic power meter core, such as in a power meter. A high linearity interface for a Hall effect device is provided for minimizing offset effects without using complicated electronic circuits. Hall effect device is characterized by first and second opposing surfaces, first and second device inputs, and first and second device outputs. A substrate is layered adjacent to one of the first and second opposing surfaces of the Hall effect device and is electrically connected to an output pin of the Hall effect device to eliminate any effects caused by asymmetry of the voltage appearing in the channel relative to the substrate. The net effect of the high linearity interface is to eliminate any adverse effects to linearity of the system, especially at low magnetic flux levels where the output voltage of the Hall device would be relatively small compared to the offset voltage levels involved. The interface virtually eliminates adverse effects from operational amplifier input offset voltages, Hall effect device output offset voltages, and any common mode voltages.