Magnetic field detection device and current sensor

• US 9,086,444 B2
• Filed: 12/28/2010
• Issued: 07/21/2015
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Nakajima, Hiroyoshi, Imai, Takakazu, Daigo, Takuya, Okuno, Reiji, Fukuda, Junya
• Primary Examiner(s): Assouad, Patrick
• Assistant Examiner(s): Brown, Lamarr
• Application Number:
  US13/519,802
• Publication Number:
  US 20120293170A1
• Time in Patent Office: 1,666 Days
• Field of Search: 324/252, 324126-129, 324/244, 324/251, 324/253, 324/117.H, 324/117.R, 324260-263
• US Class Current: 1/1
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00

Abstract

Provided is a magnetic field detection device and a current sensor capable of increasing the degree of freedom in selecting the type of the magnetic field detection element.

A magnetic field detection device 1 includes a conductor 3 that generates a magnetic field; a C core 2 provided so as to surround the conductor 3; and a magnetic field detection element 4 that detects a magnetic field. The C core 2 has a gap G1, and the magnetic field detection element 4 is disposed at a position where the magnetic field generated from the conductor 3 can be detected, the position being outside the gap G1. Since the direction of the magnetic flux varies outside of the gap G1 from place to place, the direction of the magnetic flux that passes through the magnetic field detection element 4 can be arbitrarily selected by arbitrarily selecting the installation location of the magnetic field detection element 4. Therefore, the degree of freedom in selecting the type of the magnetic field detection element 4 is increased.

Claims

1. A magnetic field detection device comprising:

a magnetic field detection element that detects a magnetic field;

a first magnetic body core extending in a first direction to surround the magnetic field detection element, the first magnetic body core having a first surface facing the magnetic field detection element, a second surface opposite to the first surface, a third surface between the first surface and the second surface, and a fourth surface opposite to the third surface;

a second magnetic body core extending in a second direction, perpendicular to the first direction, to surround the first magnetic body core, the second magnetic body core having a fifth surface facing the first magnetic body core, and a sixth surface opposite to the fifth surface; and

a first magnetic field source provided between third surface of the first magnetic body core and a part of the fifth surface of the second magnetic body core, the part of the fifth surface of the second magnetic body core facing the third surface of the first magnetic body core, wherein

the fourth surface of the first magnetic body core and another part of the fifth surface of the second magnetic body core magnetically contact each other, the another part of the fifth surface of the second magnetic body core facing the fourth surface of the first magnetic body core, and

the third surface of the first magnetic body core and the part of the fifth surface of the second magnetic body core are isolated from each other.

2. The magnetic field detection device according to claim 1 further comprising a second magnetic field source provided between the third surface of the first magnetic body core and the part of the fifth surface of the second magnetic body core, wherein

the first and second magnetic field sources both extend in a third direction different from the first and second directions, and

the first and second magnetic field sources are disposed so that that the magnetic field detection element is located between the first magnetic field source and the second magnetic field source.

3. The magnetic field detection device according to claim 2, wherein

the magnetic field detection element has a pair of magnetoresistive elements which are provided on opposite sides with respect to a center line of the first and second magnetic field sources, the center line being perpendicular to the third direction, and which have the same pinned layer magnetization direction.

4. The magnetic field detection device according to claim 3, wherein the pinned layer magnetization direction of the pair of magnetoresistive elements is different from an extending direction of the center line.

5. The magnetic field detection device according to claim 4, wherein the pinned layer magnetization direction of the pair of magnetoresistive elements is perpendicular to the center line.

6. The magnetic field detection device according to claim 3, wherein

the pair of magnetoresistive elements have the same free layer magnetization direction, and

the magnetic field detection device further comprises a third magnetic field source that generates a magnetic field parallel to the free layer magnetization direction.

7. The magnetic field detection device according to claim 2, wherein

the first and second magnetic field sources are each a linear conductor that generates a magnetic field when a current flows therethrough, and

an extending direction of each of the first and second magnetic field sources is perpendicular to the first plane.

8. The magnetic field detection device according to claim 7, wherein one end of the linear conductor serving as the first magnetic field source and one end of the linear conductor serving as the second magnetic field source are electrically connected to each other to form a first conductor.

9. The magnetic field detection device according to claim 8, further comprising a second conductor having first and second magnetic field sources, wherein

the first and second conductors have the same shape as each other, and the second conductor is disposed on the first conductor.

10. The magnetic field detection device according to claim 9, wherein the first and second conductors are connected in parallel.

11. The magnetic field detection device according to claim 9, wherein the first and second conductors are connected in series.

12. The magnetic field detection device according to claim 1, wherein the first and second magnetic body cores each constitute a line-symmetrical closed curve.

13. The magnetic field detection device according to claim 12, wherein a normal vector of the closed curve constituted by the first magnetic body core and a normal vector of the closed curve constituted by the second magnetic body core are perpendicular to each other.

14. The magnetic field detection device according to claim 1, wherein

the magnetic field detection element has a seventh surface facing the part of the fifth surface of the second magnetic body core, and an eighth surface facing the another part of the fifth surface of the second magnetic body core, and

at least a part of the third surface of the first magnetic body core is positioned above the seventh surface of the magnetic field detection element.

15. The magnetic field detection device according to claim 1, wherein the magnetic field detection element has a seventh surface facing the part of the fifth surface of the second magnetic body core, and an eighth surface facing the another part of the fifth surface of the second magnetic body core,

the magnetic field detection device further comprises a third magnetic body core which is disposed at a position overlapping the magnetic field detection element as viewed in the vertical direction, the position being between the seventh surface of the magnetic field detection element and the second magnetic body core, and the third magnetic body core magnetically contacts the second magnetic body core.

16. The magnetic field detection device according to claim 1 further comprising two fourth magnetic body cores which are disposed between the first and second magnetic field sources and a lower surface of the first magnetic body core, respectively, one end of each of the fourth magnetic body cores magnetically contacting the second magnetic body core.

17. A current sensor which is the magnetic field detection device as claimed in claim 1, the first magnetic field source being a conductor through which a current flows.