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Electronic circuit for driving a hall effect element with a current compensated for substrate stress

  • US 9,638,764 B2
  • Filed: 04/08/2015
  • Issued: 05/02/2017
  • Est. Priority Date: 04/08/2015
  • Status: Active Grant
First Claim
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1. An electronic circuit, comprising:

  • a semiconductor substrate having a surface;

    epitaxial layer disposed over the surface of the semiconductor substrate, the epitaxial layer having a first surface distal from the semiconductor substrate and a second surface proximate to the semiconductor substrate;

    a planar Hall effect element, at least a portion of the planar Hall effect element disposed in the epitaxial layer; and

    a current generator configured to generate a drive current that passes through the planar Hall effect element, wherein the current generator comprises;

    a first resistor for receiving a reference voltage resulting in a reference current passing through the first resistor, the reference current related to the drive current, the first resistor disposed in the epitaxial layer, wherein a resistance of the first resistor, the reference current, and the drive current change in accordance with changes of a stress in the semiconductor substrate, wherein the first resistor comprises;

    first and second pickups implanted upon and diffused into the first surface of the epitaxial layer; and

    a first buried structure disposed under the first surface of the epitaxial layer and under the first and second pickups, wherein the first buried structure has a density of atoms that results in a first low resistance path a first resistance lower than a resistance of the epitaxial layer, wherein the reference current passes from the first pickup, through a first region of the epitaxial layer, through the first buried structure, and through a second region of the epitaxial layer to the second pickup.

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