Magnetic sensor

Patent metadata

Field	Value
Publication number	US-9625496-B2
Application number	US-201514682635-A
Country	US
Kind code	B2
Filing date	Apr 9, 2015
Priority date	May 1, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A magnetic sensor includes a magnetic detection element, and a correcting section to correct an output voltage of the magnetic detection element and output the corrected output voltage. The correcting section is configured to compute a magnetic flux density from the output voltage of the magnetic detection element, compute and output the corrected output voltage having a linear relationship to the computed magnetic flux density.

First claim

What is claimed is:

1. A magnetic sensor, comprising:
a single magnetic detection element that detects an electric current conducted through a single current path by outputting a voltage that is dependent upon a magnetic flux density generated by the electric current, wherein the relationship between the output voltage and the magnetic flux density is nonlinear; and
a correcting section that corrects the output voltage of the magnetic detection element such that the relationship between the output voltage and the magnetic flux density is linear and outputs the corrected output voltage,
wherein the correcting section is configured to compute a magnetic flux density from the corrected output voltage of the magnetic detection element, and to compute and output a value of the electric current that generated the magnetic flux density.

2. The magnetic sensor according to claim 1 , wherein the correcting section is configured to output a corrected output voltage V out , by, when a relationship between a magnetic flux density B and an output voltage V at the magnetic detection element is expressed by equation (1) below, computing the corrected output voltage V out from equation (2) below:
V=f ( B )  (1)

V out =m·B=m·f 1 ( V )  (2)

where m is a coefficient, and f 1 (V) is the inverse function of f(B).

3. The magnetic sensor according to claim 2 , wherein the magnetic detection element is an anisotropic magnetoresistance element.

4. The magnetic sensor according to claim 3 , wherein equation (3) or (4) below is used as the relationship between the magnetic flux density B and the output voltage V at the magnetic detection element:
V=f ( B )= a { cos( bB+c )} 2 +d   (3)

where a, b, c, and d are coefficients;
V=f ( B )= a { sin( bB+c )} 2 +d   (4)

where a, b, c, and d are coefficients.

5. The magnetic sensor according to claim 2 , wherein the magnetic detection element is a giant magnetoresistance element.

6. The magnetic sensor according to claim 5 , wherein equation (5) or (6) below is used as the relationship between the magnetic flux density B and the output voltage V at the magnetic detection element:
V=f ( B )= a { cos( bB+c )}+ d   (5)

where a, b, c, and d are coefficients;
V=f ( B )= a { sin( bB+c )}+ d   (6)

where a, b, c, and d are coefficients.

7. A magnetic sensor, comprising:
a single magnetic detection element that detects an electric current conducted through a single current path by outputting a voltage that is dependent upon a magnetic flux density generated by the electric current, wherein the relationship between the output voltage and the magnetic flux density is nonlinear; and
a correcting section that corrects the output voltage of the magnetic detection element such that the relationship between the output voltage and the magnetic flux density is linear and outputs the corrected output voltage,
wherein the correcting section is configured to compute a magnetic flux density from the corrected output voltage of the magnetic detection element, and to compute and output a value of the electric current that generated the magnetic flux density,
wherein the single magnetic detection element is one of an anisotropic magnetoresistance element and a giant magnetoresistance element.

8. The magnetic sensor according to claim 7 , wherein the correcting section is configured to output a corrected output voltage V out , by, when a relationship between a magnetic flux density B and an output voltage V at the magnetic detection element is expressed by equation (1) below, computing the corrected output voltage V out from equation (2) below:
V=f ( B )  (1)

V out =m·B=m·f 1 ( V )  (2)

where m is a coefficient, and f 1 (V) is the inverse function of f(B).

9. The magnetic sensor according to claim 8 , wherein equation (3) or (4) below is used as the relationship between the magnetic flux density B and the output voltage V at the magnetic detection element:
V=f ( B )= a { cos( bB+c )} 2 +d   (3)

where a, b, c, and d are coefficients;
V=f ( B )= a { sin( bB+c )} 2 +d   (4)

where a, b, c, and d are coefficients.

10. The magnetic sensor according to claim 9 , wherein equation (5) or (6) below is used as the relationship between the magnetic flux density B and the output voltage V at the magnetic detection element:
V=f ( B )= a { cos( bB+c )}+ d   (5)

where a, b, c, and d are coefficients;
V=f ( B )= a { sin( bB+c )}+ d   (6)

where a, b, c, and d are coefficients.

Assignees

• Hitachi Metals Ltd

Inventors

• Futakuchi Naoki
• Ikeda Yukio
• Takahashi Kazuhisa

Classifications

• G01R33/093

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• G01R33/0029

  Treating the measured signals, e.g. removing offset or noise · CPC title

• G01R35/00

  Testing or calibrating of apparatus covered by the other groups of this subclass · CPC title

• G01R33/096

  anisotropic magnetoresistance sensors · CPC title

• G01R15/205 Primary

  using magneto-resistance devices, e.g. field plates · CPC title