Magnetic Field Sensor For Orientation Independent Speed And Direction Measurement

摘要

A magnetic field sensor that provides target speed and direction detection that is independent of sensor-to-target orientation includes at least three differential channels, each responsive to a pair of magnetic field sensing elements to generate a respective magnetic field channel signal. A combining element is configured to generate a combined signal based on the first, second, and third magnetic field channel, signals and control circuitry responsive to the combined signal and to at least one of the first, second, and third magnetic field channel signals generates a sensor output signal that indicative of target speed and direction.

主权项

1. A magnetic field sensor comprising at least first, second, and third spaced magnetic field sensing elements, each providing a respective first, second, and third magnetic field signal having an amplitude proportional to a magnetic field associated with a target, comprising:
a first differential channel comprising a first pair of the first, second, and third magnetic field sensing elements and configured to provide a first channel signal based on a difference between the magnetic field signals provided by the first pair of magnetic field a sensing elements; a second differential channel comprising a second pair of the first, second, and third magnetic field sensing elements and configured to provide a second channel signal based on a difference between the magnetic field signals provided by the second pair of magnetic field sensing elements; a third differential channel comprising a third pair of the first, second, and third magnetic field sensing elements and configured to provide a third channel signal based on a difference between the magnetic field signals provided by the third pair of magnetic field sensing elements; a combining element to generate a combined signal based on the first, second, and third magnetic field signals; and control circuitry, responsive to the combined signal and to at least one of the first, second, and third channel signals, to generate a sensor output signal that is indicative of a speed of motion and a direction of motion of the target and that is independent of an installation angle of the magnetic field sensor relative to the target.