Patent ID: 8030918

Claim:
A magnetic field sensor, comprising: a magnetic field sensing element supported by a substrate, the magnetic field sensing element for generating an output signal comprising a magnetic-field-responsive signal portion, wherein the magnetic-field-responsive signal portion has a sensitivity to a first magnetic field; a feedback circuit, comprising: a first piezoresistor supported by the substrate, the first piezoresistor having a node at which a first piezoelectric output signal is generated, wherein the first piezoelectric output signal is responsive to a strain of the substrate in a first direction; a second piezoresistor supported by the substrate, each one of the first and second piezoresistors having a respective primary response axis, wherein the first and second piezoresistors are disposed in a relative orientation so that their respective primary response axes are generally perpendicular, the second piezoresistor having a node at which a second piezoelectric output signal is generated, wherein the second piezoelectric output signal is responsive to a strain of the substrate in a second direction generally perpendicular to the first direction; and a combining circuit having first and second input nodes coupled to receive signals related to the first and second piezoelectric output signals and having an output node at which a gain-adjustment signal is generated; and a gain-adjustment circuit supported by the substrate and having a gain-adjustment node coupled to receive the gain-adjustment signal, wherein the gain-adjustment circuit is configured to adjust the sensitivity of the magnetic-field-responsive signal portion in response to the gain-adjustment signal.