# US 11,906,553 B2 · Magnetic current sensor comprising a magnetoresistive differential full bridge

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- Number: US 11,906,553 B2
- Document ID: US11906553B2
- Status: Granted
- Kind: B2
- Application number: 17/597,352
- Filed: 2020-06-26
- Published: 2022-08-25
- Granted: 2024-02-20
- Earliest claimed: 2019-07-05
- Assignees: Crocus Technology SA
- Applicants: Crocus Technology SA
- Inventors: Andrey Timopheev
- Web page: https://patentgrep.com/patent/US11906553B2

## CPC

- G01R 15/205: {using magneto-resistance devices, e.g. field plates}
- G01R 33/0005: {Geometrical arrangement of magnetic sensor elements; Apparatus combining different magnetic sensor types (G01R33/0206 takes precedence)}
- G01R 33/098: {comprising tunnel junctions, e.g. tunnel magnetoresistance sensors}
- G01R 15/207: {Constructional details independent of the type of device used}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

Magnetic current sensor, including: a sensor bridge circuit including a first and second half-bridges, each including two series-connected and diagonally opposed tunnel magnetoresistive (TMR) sensor elements, the TMR sensor elements including a reference layer oriented a single predetermined direction and a sense layer having a sense magnetization; a field line configured for passing a field current generating a magnetic field adapted for orienting the sense magnetization of the diagonally opposed TMR sensor elements of the first half-bridge and of the diagonally opposed TMR sensor elements of the second half-bridge in an opposite direction; such that a non-null differential voltage output between the TMR sensor elements of the first half-bridge and the TMR sensor elements of the second half-bridge is measurable when the field current is passed in the field line; the differential voltage output being insensitive to the presence of an external uniform magnetic field.

## Claims

### Claim 1

Magnetic current sensor, comprising:
a sensor bridge circuit comprising:
a first half-bridge comprising two series-connected and diagonally opposed tunnel magnetoresistive (TMR) sensor elements; and
a second half-bridge comprising two series-connected and diagonally opposed TMR sensor elements,
each TMR sensor element comprising a tunnel barrier layer, a reference layer having a pinned reference magnetization and a sense layer having a sense magnetization that can be freely oriented, the TMR sensor elements having their reference magnetization oriented substantially in the same direction; and
a field line configured to pass a field current generating a magnetic field such that the sense magnetization of the diagonally opposed TMR sensor elements of the first half-bridge is oriented along the direction of the magnetic field and in a direction opposite to the diagonally opposed TMR sensor elements of the second half-bridge,
wherein a non-null differential voltage output between the TMR sensor elements of the first half-bridge the TMR sensor elements of the second half-bridge is measurable when the field current is passed in the field line,
wherein the differential voltage output is insensitive to the presence of an external uniform magnetic field, and
wherein the pinning direction in each of the TMR sensor elements is oriented at about 45° relative to a tangent line of the field line.

### Claim 2 (depends on 1)

Magnetic sensing circuit according to claim 1, wherein the sensor bridge circuit forms a Wheatstone bridge.

### Claim 3 (depends on 2)

Magnetic sensing circuit according to claim 2, wherein the field line is configured such that the magnetic field is directed symmetrical about a central point in the center of the sensor bridge circuit.

### Claim 4 (depends on 3)

Magnetic sensing circuit according to claim 3, wherein the field line forms a circular loop.

### Claim 5 (depends on 4)

Magnetic sensing circuit according to claim 4, wherein the field line comprises a first portion and a second portion electrically isolated from the first portion.

### Claim 6 (depends on 5)

Magnetic sensing circuit according to claim 5, wherein the first portion and the second portion are symmetrical.

### Claim 7 (depends on 3)

Magnetic sensing circuit according to claim 3, wherein the TMR sensor elements are equidistant to a said central point, such that each TMR sensor element is exposed to substantially the same magnitude of the magnetic field.

### Claim 8 (depends on 2)

Magnetic sensing circuit according to claim 2, wherein the field line forms a quadrate.

### Claim 9 (depends on 8)

Magnetic sensing circuit according to claim 8, wherein the field line is configured such that the magnetic field is directed substantially orthogonal to the sensor elements of the sensor bridge circuit.