Bipolar chopping for 1/F noise and offset reduction in magnetic field sensors

A magnetoresistance field sensor for sensing magnetic fields, the sensor comprising:

• a first bridge circuit comprising a plurality of magnetoresistance elements, each magnetoresistance element within the plurality of magnetoresistance elements comprising a first ferromagnetic layer and a second ferromagnetic layer separated by a non-magnetic insulating barrier;
• a second circuit adjacent to the first bridge circuit and configured to apply a bipolar current signal adjacent to each of the magnetoresistance elements, wherein the second circuit is coupled to a bipolar current source, and wherein the bipolar current signal induces a magnetic field that enables cancellation of at least a portion of 1/f noise generated from at least one of the magnetoresistance elements within the plurality of magnetoresistance elements.

A magnetoresistance field sensor for sensing magnetic fields, the sensor comprising:

• a first bridge circuit comprising a plurality of magnetoresistance elements, wherein each of the plurality of magnetoresistance elements comprises first and second ferromagnetic layers separated by a non-magnetic insulating barrier;
• and
• a second circuit coupled to a bipolar current source and configured to apply a bipolar current signal via a plurality of current lines placed adjacent to each of the plurality of magnetoresistance elements, wherein the second circuit comprises a muxed H bridge circuit for controlling a current path in each of the plurality of current lines, wherein the bipolar current signal induces a magnetic field that enables cancellation of at least a portion of 1/f noise generated from at least one of the magnetoresistance elements within the plurality of magnetoresistance elements.