Magnetic field sensor to detect a magnitude of a magnetic field in any direction

Patent metadata

Field	Value
Publication number	US-9897464-B2
Application number	US-201715638876-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	May 24, 2013
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

In one aspect, a magnetic field sensor includes first and second magnetic field sensing elements having respective first and second maximum response axes. The first and second maximum response axes point along respective first and second different coordinate axes. In response to a magnetic field, the first and second magnetic field sensing elements are operable to generate first and second magnetic field signals. The magnetic field sensor includes an electronic circuit coupled to receive the first and the second magnetic field signals. The electronic circuit is configured to determine a magnitude of a vector sum of the first and the second magnetic field signals and provide one or more signals in response to the magnitude of the vector sum determined.

First claim

What is claimed is:

1. A magnetic field sensor, comprising:
first and second magnetic field sensing elements having respective first and second maximum response axes, the first and second maximum response axes pointing along respective first and second different coordinate axes, wherein, in response to a magnetic field, the first and second magnetic field sensing elements are operable to generate first and second magnetic field signals, the first and the second magnetic field sensing elements being chopped;
a common circuit channel comprising a switched capacitor notch filter having a first notch at a frequency selected to remove products of the chopping; and
an electronic circuit coupled to receive the first and the second magnetic field signals,
wherein the electronic circuit is configured to:
determine a magnitude of a vector sum of the first and the second magnetic field signals; and
provide one or more signals in response to the magnitude of the vector sum determined.

2. The magnetic field sensor of claim 1 , wherein the first and second coordinate axes represent orthogonal Cartesian coordinates.

3. The magnetic field sensor of claim 1 , wherein the first magnetic field sensing element comprises a planar Hall element and the second magnetic field sensing element comprises a first vertical Hall element.

4. The magnetic field sensor of claim 1 , wherein the first magnetic field sensing element comprises a first vertical Hall element and the second magnetic field sensing element comprises a second vertical Hall element.

5. The magnetic field sensor of claim 1 , wherein the first magnetic field sensing element comprises a planar Hall element and the second magnetic field sensing element comprises a first magnetoresistance circuit.

6. The magnetic field sensor of claim 1 , wherein the first magnetic field sensing element comprises a first magnetoresistance circuit and the second magnetic field sensing element comprises a second magnetoresistance circuit.

7. The magnetic field sensor of claim 1 , wherein the first magnetic field sensing element is chopped with a chopping frequency of Fchop, and wherein the electronic circuit comprises a switched capacitor notch filter coupled to the first magnetic field sensing element and having a first notch at a frequency of Fchop.

8. The magnetic field sensor of claim 1 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit configured to provide a warning signal if the vector sum of the magnetic field exceeds a threshold value.

9. The magnetic field sensor of claim 8 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit further configured to provide a signal indicating the magnitude of the vector sum.

10. The magnetic field sensor of claim 1 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit further configured to provide one or more signals in response to the magnitude of the vector sum determined exceeding an adjustable threshold.

11. The magnetic field sensor of claim 1 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit configured to provide a signal indicating the magnitude of the vector sum.

12. A magnetic field sensor, comprising:
first, second, and third magnetic field sensing elements having respective first, second and third maximum response axes, the first, second and third maximum response axes pointing along respective first, second, and third different coordinate axes, wherein, in response to a magnetic field, the first, second, and third magnetic field sensing elements are operable to generate first, second, and third magnetic field signals, the first and the second magnetic field sensing elements being chopped;
a common circuit channel comprising a switched capacitor notch filter having a first notch at a frequency selected to remove products of the chopping; and
an electronic circuit coupled to receive the first, the second and the third magnetic field signals,
wherein the electronic circuit is configured to:
determine a magnitude of a vector sum of the first, the second and the third magnetic field signals; and
provide one or more signals in response to the magnitude of the vector sum determined.

13. The magnetic field sensor of claim 12 , wherein the first, second, and third coordinate axes represent orthogonal Cartesian coordinates.

14. The magnetic field sensor of claim 12 , wherein the first magnetic field sensing element comprises a planar Hall element, the second magnetic field sensing element comprises a first vertical Hall element, and the third magnetic field sensing element comprises a second vertical Hall element.

15. The magnetic field sensor of claim 12 , wherein the first magnetic field sensing element comprises a planar Hall element, the second magnetic field sensing element comprises a first magnetoresistance circuit, and the third magnetic field sensing element comprises a second magnetoresistance circuit.

16. A magnetic field sensor, comprising:
first, second, and third magnetic field sensing elements having respective first, second and third maximum response axes, the first, second and third maximum response axes pointing along respective first, second, and third different coordinate axes, wherein, in response to a magnetic field, the first, second, and third magnetic field sensing elements are operable to generate first, second, and third magnetic field signals; and
an electronic circuit coupled to receive the first, the second and the third magnetic field signals,
wherein the electronic circuit is configured to:
determine a magnitude of a vector sum of the first, the second and the third magnetic field signals; and
provide one or more signals in response to the magnitude of the vector sum determined,

wherein the first magnetic field sensing element comprises a planar Hall element, the second magnetic field sensing element comprises a first magnetoresistance circuit, and the third magnetic field sensing element comprises a second magnetoresistance circuit,
wherein the first magnetic field sensing element is chopped with a chopping frequency of Fchop, and wherein the electronic circuit comprises a switched capacitor notch filter coupled to the first magnetic field sensing element and having a first notch at a frequency of Fchop.

17. The magnetic field sensor of claim 12 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit configured to provide a warning signal if the vector sum of the magnetic field exceeds a threshold value.

18. The magnetic field sensor of claim 17 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit further configured to provide a signal indicating the magnitude of the vector sum.

19. The magnetic field sensor of claim 12 , wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined comprises an electronic circuit further configured to provide one or more signals in response to the magnitude of the vect

Assignees

• Allegro Microsystems Llc

Inventors

• Judkins Iii Joseph James
• Metivier Ryan Jon
• Monreal Gerardo A
• Uberti Bruno Luis

Classifications

• G01D5/142 Primary

  using Hall-effect devices (measuring magnetic variables using Hall-effect or other galvanomagnetic devices G01R33/06) · CPC title

• G01B7/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title

• G01R33/0206

  Three-component magnetometers · CPC title

• G01D5/16

  by varying resistance · CPC title

• G01R33/0023 Primary

  Electronic aspects, e.g. circuits for stimulation, evaluation, control; Treating the measured signals; calibration (G01R33/0017 takes precedence) · CPC title