US 11,237,231 B2Granted

Z-axis magnetic sensor with distributed flux guides

AssigneeRobert Bosch GmbH

InventorsAnuraag Mohan, Phillip Mather, Guido De Sandre

Life of this patent

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Abstract

An out-of-plane tunneling magnetoresistive (TMR) magnetic field sensor includes a sense element that defines a sense plane and a flux guide configured to direct a magnetic field perpendicular to the sense plane into the sense plane. The magnetic field sensor further includes a first coil arranged in a first plane, a second coil electrically insulated from the first coil and arranged in a spaced-apart second plane, and drive circuitry operatively connected to the first coil and the second coil. The drive circuitry in a first mode energizes the first and second coils to generate respective first and second fields that combine to set a magnetization of the flux guide. The drive circuitry in a second mode energizes only the first coil to generate the first field so as to set a magnetization of the sense element without changing the magnetization of the flux guide.

Claims20

Dependent claims

A magnetic field sensor, comprising:

a sense element arranged on a substrate of the sensor and defining a sense plane;
a flux guide arranged on the substrate and configured to direct a magnetic field perpendicular to the sense plane into the sense plane;
a first coil arranged substantially in a first plane;
a second coil arranged substantially in a second plane that is spaced apart from the first plane, the second coil electrically insulated from the first coil;
and
drive circuitry operatively connected to each of the first coil and the second coil, the drive circuitry configured:
(i) in a first reset mode to energize both the first coil and the second coil to generate a first field about the first coil and a second field about the second coil, respectively, that combine to set a predetermined magnetization direction of the flux guide, and
(ii) in a second reset mode to energize only the first coil to generate the first field so as to set a predetermined magnetization direction of the sense element without changing the predetermined magnetization direction of the flux guide.

5 more elements

A method of operating a magnetic field sensor, comprising:

sensing, by a magnetic field sensor including a sense element, a magnetic field perpendicular to a sense plane defined by the sense element, the magnetic field sensor further including a flux guide configured to direct the magnetic field into the sense plane, a first coil arranged substantially in a first plane, and a second coil electrically insulated from the first coil and arranged substantially in a second plane that is spaced apart from the first plane;
executing a first reset operation by selectively energizing both the first coil and the second coil to generate a first field about the first coil and a second field about the second coil, respectively, that combine to set a predetermined magnetization direction of the flux guide;
and
executing a second reset operation by selectively energizing only the first coil to generate the first field so as to set a predetermined magnetization direction of the sense element without changing the predetermined magnetization direction of the flux guide.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 16/957,719Filed 20 Dec 2018 · us provisional application
Priority: 26 Dec 2017
Published: US 2020/0371171 A126 Nov 2020
Granted: 1 Feb 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G01R 33/098
Magnetoresistive devices: comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
G01R 33/091
Magnetoresistive devices: constructional adaptation of the sensor to specific applications
G01R
Measuring electric variables