Electronic circuit for driving a hall effect element with a current compensated for substrate stress
First Claim
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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Accused Products
Abstract
An electronic circuit can be disposed upon a semiconductor substrate. An epitaxial layer can be disposed over the semiconductor substrate. The electronic circuit can include a Hall effect element, at least a portion of the Hall effect element disposed in the epitaxial layer. The electronic circuit can further include a current generator configured to generate a drive current that passes through the Hall effect element. The current generator can include a resistor disposed in the epitaxial layer and having characteristics such that a resistance of the resistor can vary with a stress of the semiconductor substrate, resulting in changes of the drive current, to compensate for variations in the sensitivity of the Hall effect element with the stress of the substrate.
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Citations
25 Claims
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1. An electronic circuit, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 25)
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22. A method of biasing a planar Hall effect element, comprising:
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generating a reference current by generating a voltage reference across a resistor disposed in an epitaxial layer over a semiconductor substrate, the epitaxial layer having a first surface distal from the semiconductor substrate and a second surface proximate to the semiconductor substrate; and injecting a drive current into the planar Hall effect element, wherein the planar Hall effect element is disposed over the semiconductor substrate, wherein the drive current is related to the reference current, wherein a resistance of the 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 with 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. - View Dependent Claims (24)
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Specification