Magnetic field sensor with double wheatstone bridge having magneto- resistive elements

摘要

A magnetic field sensor has a substrate on which a plurality of resistive elements form a double Wheatstone bridge circuit, at least one of the resistive elements in each bridge having a magneto-resistive characteristic. The two bridges are identical except in that, if a given magneto-resistive element in a given branch in one bridge has a positive output polarity, then the corresponding magneto-resistive element in the same branch in the other bridge will have a negative output polarity. By adding the output signals of the two Wheatstone bridges a zero-point offset of the sensor can be determined and eliminated. There is no need to employ the so-called flipping technique employed for that purpose in conventional sensors, which requires increased power consumption.