Magnetic field sensor with increased linearity

Patent metadata

Field	Value
Publication number	US-9910106-B2
Application number	US-201615134134-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Apr 29, 2015
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A magnetic field sensor includes a plurality of transducer legs coupled together as a first circuit to sense a magnetic field, wherein each transducer leg comprises a plurality of magnetoresistance sense elements. The magnetic field sensor also includes a second circuit including a first plurality of current lines, wherein each current line of the first plurality of current lines is adjacent to a corresponding plurality of magnetoresistance sense elements of a transducer leg of the plurality of transducer legs. When at least one current line of the first plurality of current lines is energized, a magnetization of each magnetoresistance sense element of the transducer leg is aligned in a first direction or a second direction opposite to the first direction. A routing pattern of the at least one current line is configured to generate an equal population of magnetoresistance sense elements with magnetization aligned in the first and second directions.

First claim

What is claimed is:

1. A magnetic field sensor, comprising:
a plurality of transducer legs coupled together as a first circuit to sense a magnetic field, wherein each transducer leg comprises a plurality of magnetoresistance sense elements; and
a second circuit comprising a first plurality of current lines, wherein each current line of the first plurality of current lines is adjacent to a corresponding plurality of magnetoresistance sense elements of a transducer leg of the plurality of transducer legs;
wherein, when at least one current line of the first plurality of current lines is energized, a magnetization of each magnetoresistance sense element of the transducer leg is aligned in a first direction or a second direction opposite to the first direction, and wherein a routing pattern of the at least one current line is configured to generate an equal population of magnetoresistance sense elements with magnetization aligned in the first and second directions.

2. The magnetic field sensor of claim 1 , wherein the plurality of magnetoresistance sense elements are arranged in a sense element matrix having a plurality of columns and a plurality of rows, and
wherein each current line of the first plurality of current lines is configured to generate a magnetic field to align the magnetization of the plurality of magnetoresistance sense elements.

3. The magnetic field sensor of claim 2 , wherein, when the at least one current line is energized, the routing pattern of the at least one current line is configured to generate a magnetic field that causes a magnetization of the magnetoresistance sense elements of a first column of the plurality of columns to have an opposite alignment to a magnetization of the magnetoresistance sense elements in a column adjacent to the first column.

4. The magnetic field sensor of claim 2 , wherein, when the at least one current line is energized, the routing pattern of the at least one current line is configured to generate a magnetic field that causes a first magnetization direction of a first magnetoresistance sense element of a first column of the plurality of columns and a first row of the plurality of rows to have an opposite alignment to a magnetization direction of a second magnetoresistance sense element in a column adjacent to the first column and in the first row, and causes the first magnetization direction to be opposite to the magnetization direction of a third magnetoresistance sense element in a row adjacent to the first row and in the first column.

5. The magnetic field sensor of claim 2 , wherein, when the at least one current line is energized, the routing pattern of the at least one current line is configured to generate a magnetic field that causes magnetoresistance sense elements of a first group of adjoining M columns to have an opposite alignment to the reference magnetization direction of magnetoresistance sense elements in a second directly adjacent group of adjoining M columns.

6. The magnetic field sensor of claim 2 , wherein, when the at least one current line is energized the routing pattern of the at least one current line is configured to generate a magnetic field that causes magnetoresistance sense elements of a first pair of adjoining columns of the plurality of columns to have an opposite alignment to the reference magnetization direction of magnetoresistance sense elements in a second pair of adjoining columns adjacent to the first pair of adjoining columns.

7. The magnetic field sensor of claim 2 , wherein, when the at least one current line is energized, the routing pattern of the at least one current line is configured to generate a magnetic field that causes magnetoresistance sense elements of a first group of adjoining N rows to have an opposite alignment to the reference magnetization direction of magnetoresistance sense elements in a second directly adjacent group of adjoining N rows.

8. The magnetic field sensor of claim 1 , wherein each magnetoresistance sense element of the plurality of magnetoresistance sense elements includes a first ferromagnetic layer and a second ferromagnetic layer separated by a non-magnetic, insulating barrier.

9. The magnetic field sensor of claim 8 , wherein the first ferromagnetic layer includes a magnetization direction free to rotate in a magnetic field, and wherein a magnetization of the second ferromagnetic layer is the reference magnetization direction.

10. The magnetic field sensor of claim 1 , wherein the plurality of magnetoresistance sense elements includes one or more tunneling magnetoresistance sense elements, giant magnetoresistance sense elements, and/or anisotropic magnetoresistance sense elements.

11. The magnetic field sensor of claim 1 , further comprising:
a second circuit comprising a second plurality of current lines, wherein each current line of the second plurality of current lines is adjacent to a corresponding magnetoresistance sense element of the plurality of magnetoresistance sense elements.

12. The magnetic field sensor of claim 11 , wherein at least one current line of the second plurality of current lines is positioned below a current line of the first plurality of current lines.

13. The magnetic field sensor of claim 11 , wherein at least one current line of the second plurality of current lines is positioned above a current line of the first plurality of current lines.

14. The magnetic field sensor of claim 1 , wherein at least one magnetoresistance sense element of the plurality of magnetoresistance sense elements includes at least one flux guide.

15. The magnetic field sensor of claim 14 , wherein the at least one flux guide is a high aspect ratio vertical bar comprising a high permeability magnetic material.

16. The magnetic field sensor of claim 14 , wherein the at least one flux guide is positioned above the at least one magnetoresistance sense element.

17. The magnetic field sensor of claim 14 , wherein the at least one flux guide is positioned below the at least one magnetoresistance sense element.

18. The magnetic field sensor of claim 1 , wherein the first circuit is a half bridge circuit or a full bridge circuit.

19. The magnetic field sensor of claim 1 , wherein the magnetoresistance sense elements are arranged in columns and rows, and wherein the routing pattern of the at least one current line is configured to generate a first magnetization in a first column in the first direction and a second magnetization in a second column in the second direction, wherein the second column is adjacent to the first column.

20. The magnetic field sensor of claim 1 , wherein the magnetoresistance sense elements are arranged in columns and rows, and wherein the routing pattern of the at least one current line is configured to generate a first magnetization in a first row in the first direction and a second magnetization in a second row in the second direction, wherein the second row is adjacent to the first row.

Assignees

• Everspin Technologies Inc

Inventors

• Mather Phillip G
• Engel Bradley Neal
• De Sandre Guido

Classifications

• G01R33/096

  anisotropic magnetoresistance sensors · CPC title

• G01R33/098

  comprising tunnel junctions, e.g. tunnel magnetoresistance sensors · CPC title

• G01R33/091 Primary

  Constructional adaptation of the sensor to specific applications · CPC title