MAGNETIC FIELD DETECTION DEVICE AND CURRENT SENSOR

• US 20120293170A1
• Filed: 12/28/2010
• Published: 11/22/2012
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Imai, Takakazu, Okuno, Reiji, Fukuda, Junya, Nakajima, Hiroyoshi, Daigo, Takuya
• Granted Patent: US 9,086,444 B2
• Time in Patent Office: Days
• US Class Current: 324/252
• 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 first magnetic field source that generates a magnetic field;

a first magnetic body provided so as to surround the first magnetic field source; and

a magnetic field detection element that detects a magnetic field, wherein

a first gap is formed in the first magnetic body, and

the magnetic field detection element is disposed at a position where a magnetic field generated from the first magnetic field source can be detected, the position being outside the first gap.

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

the first gap is constituted by two parallel first and second magnetic pole surfaces, and

the magnetic field detection element is disposed so as to be able to detect the magnetic flux going in and out of the first magnetic body through side surfaces in the vicinity of the first gap which are surfaces different from the first and second magnetic pole surfaces.

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

the first magnetic body includes a first end portion extending in a perpendicular direction to the first magnetic pole surface serving as an end surface of the first end portion, and

the magnetic field detection element is disposed at a lateral side of the first end portion.

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

the first magnetic body includes:

a second end portion having the second magnetic pole surface; and

an extension portion extending perpendicular to a gap direction of the first gap from the second end portion.

5. The magnetic field detection device according to claim 4, wherein

the first magnetic body includes a projection portion projecting toward the magnetic field detection element side from the extension portion.

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

at least a part of the magnetic field source is disposed in the first gap.

7. The magnetic field detection device according to claim 1 further comprising:

a second magnetic field source that generates a magnetic field; and

a second magnetic body provided so as to surround the second magnetic field source, wherein

a second gap is formed in the second magnetic body, and

the magnetic field detection element is disposed at a position where a magnetic field generated from the second magnetic field source can be detected, the position being outside the second gap.

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

the second gap is constituted by two parallel third and fourth magnetic pole surfaces, and

the magnetic field detection element is disposed so as to be able to detect also the magnetic flux going in and out of the second magnetic body through side surfaces in the vicinity of the second gap which are surfaces different from the third and fourth magnetic pole surfaces.

24. 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.

25. 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.

9. A magnetic field detection device comprising:

a magnetic field detection element that detects a magnetic field;

a first magnetic body core provided so as to surround the magnetic field detection element from four directions in a horizontal plane;

a second magnetic body core provided so as to surround the first magnetic body core from four direction in a first plane perpendicular to the horizontal surface; and

a first magnetic field source provided between a lower surface of the first magnetic body core and a lower side inner wall surface of the second magnetic body core, wherein

an upper surface of the first magnetic body core and an upper side inner wall surface of the second magnetic body core magnetically contact each other, and

the lower surface of the first magnetic body core and the lower side inner wall surface of the second magnetic body core are isolated from each other.

10. The magnetic field detection device according to claim 9 further comprising a second magnetic field source provided between the lower surface of the first magnetic body core and the lower side inner wall surface of the second magnetic body core, wherein

the first and second magnetic field sources are disposed on opposite sides in the first plane with respect to the magnetic field detection element.

11. The magnetic field detection device according to claim 10, 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 perpendicular to the first plane and which have the same PIN direction.

12. The magnetic field detection device according to claim 11, wherein

a PIN direction of the pair of magnetoresistive elements is different from an extending direction of the center line.

13. The magnetic field detection device according to claim 12, wherein

the PIN direction of the pair of magnetoresistive elements is perpendicular to the center line.

14. The magnetic field detection device according to claim 11, wherein

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

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

15. The magnetic field detection device according to claim 10, 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.

16. The magnetic field detection device according to claim 15, 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 form a conductor having a folded structure.

17. The magnetic field detection device according to claim 16, wherein

two conductors each having the folded structure are provided so as to overlap each other as viewed in a vertical direction.

18. The magnetic field detection device according to claim 17, wherein

the two conductors each having the folded structure are connected in parallel.

19. The magnetic field detection device according to claim 17, wherein

the two conductors each having the folded structure are connected in series.

20. The magnetic field detection device according to claim 9, wherein

the first and second magnetic body cores each constitute a line-symmetrical closed curve.

21. The magnetic field detection device according to claim 20, 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.

22. The magnetic field detection device according to claim 9, wherein

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

23. The magnetic field detection device according to claim 9 further comprising 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 lower surface of the magnetic field detection element and the second magnetic body core, and the lower surface of which magnetically contacts the second magnetic body core.

26. A current sensor which is the magnetic field detection device as claimed in claim 9, the first magnetic field source being a conductor through which a current flows.