Magnetometer with dual purpose reset and calibration coil

摘要

The present invention discloses a magnetic field sensing device that utilizes a single coil for calibrating the response of the sensor to compensate for temperature dependent sensitivity drift and also for resetting the magnetic field sensor in order to eliminate hysteresis. The single coil configuration is advantageous since it reduces the size of the sensor chip by decreasing the number of contact pads on the chip and also because it wastes less space, which permits an increase in the density of the magnetoresistive elements on the sensor chip.

主权项

1. A magnetic field sensor, comprising:
at least one magnetoresistive sensor element; and an electric conductor in the proximity of the magnetoresistive sensor element in order to generate a magnetic field, wherein the magnetic field sensor is configured to bias the magnetoresistive sensor element with a magnetic offset field equal to the coercivity of the magnetoresistive sensor element, wherein the magnetic field sensor is configured to apply an electric current to the electric conductor to generate a magnetic biasing field parallel to a sensing axis of the magnetoresistive sensor element, wherein the magnetic field sensor is configured to apply a first electric current to reset the magnetic field sensor, and apply a second current to calibrate the magnetic field sensor.