Sensing device utilizing magneto electric transducers

• US 5,049,809 A
• Filed: 04/11/1988
• Issued: 09/17/1991
• Est. Priority Date: 04/09/1987
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Shimizu, Nobuyoshi, Endoh, Michiko, Wakatsuki, Noboru, Kurashima, Shigemi, Tanaka, Akira, Yoda, Hideaki, Kojima, Yuji
• Primary Examiner(s): Karlsen, Ernest F.
• Application Number:
  US07/180,120
• Time in Patent Office: 1,254 Days
• Field of Search: 324/117 R, 324/117 H, 324/252, 324/127, 338/32 R, 307/309
• US Class Current: 324/117.00R
• CPC Class Codes: G01R 15/205 using magneto-resistance devices, e.g. field plates
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A sensing device for measuring electric current and electric power including a plurality of magneto-electric transducers for detecting a magnetic field about a conductor carrying the electric current. The magneto-electric transducers can include Barber-Pole type elements, each element being positioned on a substrate at approximately the same distance from the central point of a substrate.

Claims

1. A device for sensing a magnetic field due to a current in a conductor comprising:

a substrate; and

a plurality of Barber-Pole magneto-resistive elements, disposed on said substrate, each of said Barber-Pole magneto-resistive elements comprising;

a plurality of strips, each of said strips being formed in a direction substantially along a radius emanating from a central point of said substrate and being connected to an adjacent one of said strips so as to form a zig-zag pattern, said plurality of Barber-pole resistive elements being arranged in a ring with adjacent ones of said elements arranged side by side and connected to each other; and

a pair of output terminals formed on said substrate and connected to selected ones of said Barber-pole magneto-resistive elements.

2. A sensing device according to claim 1, wherein each of said strips has an angle of ≦

5°

with respect to the radius.

3. A sensing device according to claim 1, wherein each of said strips has a substantially constant width.

4. A sensing device according to claim 1, wherein each of said strips has a width that increases in a direction away from the central point.

5. A sensing device according to claim 1, wherein each of said magneto-resistive elements has an initial magnetization direction oriented substantially along the radius.

6. A sensing device according to claim 5, wherein each of said initial magnetization direction is selected to be one of:

toward the central point and radially outward from the central point.

7. A sensing device according to claim 5, wherein said initial magnetization directions for adjacent Barber-Pole magneto-resistive elements are respectively towards the central point and radially outward from the central point.

8. A sensing device according to claim 1, wherein each of said Barber-pole magneto-resistive elements has an initial magnetization direction oriented substantially along a radius emanating from the central point.

9. A sensing device according to claim 8, wherein each of said initial magnetization direction is selected to be one of:

toward the central point and radially outward from the central point.

10. A sensing device according to claim 8, wherein said initial magnetization directions for adjacent Barber-Pole magneto-resistive elements are respectively towards the central point and radially outward from the central point.

11. A sensing device according to claim 2, wherein each of said Barber-pole magneto-resistive elements has an initial magnetization direction oriented substantially along the radius.

12. A sensing device according to claim 11, wherein each of said initial magnetization direction is selected to be one of:

toward the central point and radially outward from the central point.

13. A sensing device according to claim 12, wherein said initial magnetization directions for adjacent Barber-Pole magneto-resistive elements are respectively towards the central point and radially outward from the central point.

14. A sensing device according to claim 3, wherein each of said Barber-pole magneto-resistive elements has an initial magnetization direction oriented substantially along the radius.

15. A sensing device according to claim 14, wherein each of said initial magnetization direction is selected to be one of:

toward the central point and radially outward from the central point.

16. A sensing device according to claim 14, wherein said initial magnetization directions for adjacent Barber-Pole magneto-resistive elements are respectively towards the central point and radially outward from the central point.

17. A sensing device according to claim 4, wherein each of said Barber-pole magneto-resistive elements has an initial magnetization direction oriented substantially along the radius.

18. A sensing device according to claim 17, wherein each of said initial magnetization direction is selected to be one of:

toward the central point and radially outward from the central point.

19. A sensing device according to claim 17, wherein said initial magnetization directions for adjacent Barber-Pole magneto-resistive elements are respectively towards the central point and radially outward from the central point.

20. A sensing device according to claim 1, wherein said substrate has a through-hole formed therein for accepting the conductor, said through-hole being formed inside the ring of said Barber-pole magneto-resistive elements.

21. A sensing device according to claim 4, wherein said substrate has a through hole formed therein, said through-hole positioned about the central point, and said sensing device further comprising:

conductive layer positioned on said substrate about said through-hole and within said through-hole.

22. A sensing device according to claim 1, wherein said plurality of Barber-pole magneto-resistive elements is connected in series and at least a pair of said elements is connectable to an outside circuit.

23. A sensing device according to claim 1, wherein said plurality of Barber-pole magneto-resistive elements are connected as a bridge circuit with a pair of input terminals connectable to a source and a pair of output terminals.

24. A sensing device according to claim 23, wherein the output terminals are connectable to a load having a current flowing therethrough, and said device further comprises:

means for providing the current, wherein a resistance of said magneto-resistive elements varies in response to the current.

25. A sensing device according to claim 1, wherein said magneto-resistive elements are connected in series.

26. A sensing device according to claim 22, wherein the input terminals are connectable to a power source which is connected to a load providing a current to the conductor;

and wherein the output terminals are connectable to provide a voltage proportional to a magnetic field about the conductor.

27. A sensing device according to claim 23, further comprising:

amplifier means connected to the output terminals for providing an output.

28. A sensing device according to claim 27, further comprising:

integrator means for integrating said output and for providing a signal varying in accordance with said integration.

29. A sensing device according to claim 1, wherein said conductor carrying an electric current is closely disposed to said substrate surface parallel thereto.

30. A sensing device according to claim 29, wherein said conductor has a rectangular cross-section.

31. A sensing device according to claim 24, further comprising:

means for providing a load voltage, wherein said bridge circuit is connected so that the voltage responsive to both said load current and said load voltage appears across said bridge circuit.

32. A sensing device according to claim 20, wherein said substrate comprises silicon material and said through-hole is formed by an etching technology thereto.

33. A sensing device according to claim 32, wherein said through-hole is formed by a wet anisotropic etching technology.

34. A sensing device according to claim 33, wherein said through-hole has a rhombus shape on a first surface of said silicon substrate and a hexagon shape on a second surface thereof, thereby (1,1,0) silicon surface utilized.

35. A sensing device according to claim 33, wherein said through-hole has a pyramid shape within the silicon substrate, thereby (1,0,0) silicon surface utilized.