FOLDING CURRENT SENSOR

• US 20100001715A1
• Filed: 07/03/2008
• Published: 01/07/2010
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Dickinson, Richard, Taylor, William P., Doogue, Michael C.
• Granted Patent: US 7,936,164 B2
• Time in Patent Office: Days
• US Class Current: 324/117.H
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used

Abstract

The invention provides a current sensor that may be folded over a conductor without the need to sever the conductor or thread the conductor through the current sensor. In one embodiment, the current sensor includes an outer body having a first folding portion and a second folding portion coupled to the first folding portion. The current sensor also includes a soft ferromagnetic body disposed within the outer body comprising a first core element and a second core element. The first and second core elements form a lumen when the first and second folding portions are folded. The lumen is configured to receive a conductor. The current sensor also includes a magnetic field detector to sense a current in the conductor. The magnetic field detector is disposed at least partially between the first and second core elements when the first and second folding portions are folded.

Claims

1. A current sensor comprising:

a soft ferromagnetic body forming a lumen configured to receive a conductor, the soft ferromagnetic body having first and second folding portions to enclose the conductor within the lumen; and

a magnetic field detector having at least a portion disposed within the first and second folding portions.

2. The current sensor of claim 1, further comprising a rotator element to rotatably couple the first and second folding portions of the soft ferromagnetic body, wherein the portion of the magnetic field detector is disposed within a side of the soft ferromagnetic body opposite to the rotator element.

3. The current sensor of claim 1, wherein one of the folding portions comprises an extension and the magnetic field detector has at least a portion disposed between the extension and the other of the folding portions.

4. The current sensor of claim 3, wherein soft ferromagnetic body has an inner wall facing the lumen and an outer wall opposite to the inner wall and the extension extends at least a portion of a distance between the inner wall and the outer wall.

5. The current sensor of claim 4, wherein the extension extends from the inner wall to the outer wall.

6. The current sensor of claim 1, wherein the first folding portion comprises a first extension, the second folding portion comprises a second extension, and the magnetic field detector has at least a portion disposed between the first and second extensions.

7. The current sensor of claim 1, wherein a recess is formed in one of the folding portions and the magnetic field detector has at least a portion disposed between the recess and the other of the folding portions.

8. The current sensor of claim 1, wherein the first folding portion is adjacent to the second folding portion in an area adjacent to the magnetic field detector when the conductor is enclosed in the lumen.

9. The current sensor of claim 8, wherein the first folding portion is in contact with the second folding portion adjacent to the magnetic field detector when the conductor is enclosed in the lumen.

10. The current sensor of claim 1, wherein a first recess is formed in the first folding portion, a second recess is formed in the second folding portion, and the magnetic field detector has at least a portion disposed within the first and second recesses.

11. The current sensor of claim 1, wherein the magnetic field detector comprises:

a magnetic field transducer; and

a magnetic field concentrator in proximity to the magnetic field transducer.

12. A current sensor comprising:

an outer body having a first folding portion and a second folding portion coupled to the first folding portion;

a soft ferromagnetic body disposed within the outer body and comprising a first core element and a second core element, the first and second core elements forming a lumen when the first and second folding portions are folded, the lumen configured to receive a conductor; and

a magnetic field detector to sense a current in the conductor, the magnetic field detector having at least a portion disposed between the first and second core elements when the first and second folding portions are folded.

13. The current sensor of claim 12, further comprising a rotator element to rotatably couple the first and second folding portions of the outer body.

14. The current sensor of claim 13, wherein the portion of the magnetic field detector is disposed in a side of the soft ferromagnetic body opposite to the rotator element.

15. The current sensor of claim 12, wherein the soft ferromagnetic body comprises a material selected from the group consisting of a ferrite material, steel, iron alloy, NiFeMo, Supermalloy, a nickel alloy, a cobalt alloy, and Permalloy.

16. The current sensor of claim 12, wherein one of the core elements has an extension and the magnetic field detector is positioned adjacent to the extension and the other of the core elements.

17. The current sensor of claim 16, wherein the extension is tapered in a direction towards the magnetic field detector.

18. The current sensor of claim 12, wherein the first core element has a first extension and the second core element has a second extension, wherein the magnetic field detector is positioned adjacent to the first and second extensions.

19. The current sensor of claim 12, wherein a recess is formed in one of the folding portions and the magnetic field detector has at least a portion disposed between the recess and the other of the folding portions.

20. The current sensor of claim 12, wherein a first recess is formed in the first core element and a second recess is formed in the second core element, and the magnetic field detector has at least a portion disposed within the first and second recesses.

21. The current sensor of claim 12, wherein the magnetic field detector comprises:

a magnetic field transducer; and

at least one magnetic field concentrator in proximity to the magnetic field transducer.

22. The current sensor of claim 21, wherein the magnetic field transducer is one of a Hall effect element, a giant magnetoresistance element, or an anisotropic magnetoresistance element.

23. A current sensor for sensing current in at least one loop of a conductor comprising:

an outer body having a first folding portion and a second folding portion, the first and second folding portions rotatably coupled by at least one rotator element;

a soft ferromagnetic core comprising a first core element disposed in the first folding portion of the outer body, and a second core element disposed in the second folding portion of the outer body, such that when the first and second folding portions are folded at the rotator element, the first and second core elements form a lumen to receive the at least one loop of the conductor; and

a magnetic field detector disposed at least partially within the outer body and, when the first and second folding portions are folded at the at least one rotator element, the magnetic field detector further disposed at least partially between the first and second core elements.

24. The current sensor of claim 23, wherein one of the core elements has an extension and the magnetic field detector is disposed between the extension and the other of the core elements.

25. The current sensor of claim 23, wherein soft ferromagnetic core has an inner wall facing the lumen and an outer wall opposite to the inner wall and the extension extends at least a portion of a distance between the inner wall and the outer wall.

26. The current sensor of claim 23, wherein the magnetic field detector is one of a Hall effect element, a giant magnetoresistance element, or an anisotropic magnetoresistance element.

27. The current sensor of claim 23, wherein the magnetic field detector comprises a package comprising:

a magnetic field transducer; and

a magnetic field concentrator comprised of a soft magnetic material and positioned in proximity to the magnetic field transducer.

28. The current sensor of claim 27, wherein the package further comprises:

a insulator layer disposed between the magnetic field transducer and the magnetic field concentrator.

29. The current sensor of claim 23, wherein the magnetic field detector is flush-mounted with respect to the outer body and comprises at least one bent lead.

30. The current sensor of claim 23, wherein when the first and second folding portions are fully folded, the first and second core elements form a longitudinal gap there between.

31. The current sensor of claim 23, wherein the at least one loop of the conductor is at least two loops.

32. The current sensor of claim 23, wherein the soft ferromagnetic core is a tube having an outer surface coupled to the outer body, and an inner surface forming the lumen, the outer and inner surfaces defining a wall of the tube along a length of the tube, the first and second core elements coupled along the wall adjacent to the at least one rotator element when the first and second folding portions are folded.

33. The current sensor of claim 32, wherein the tube has a c-shaped cross-section such that the first and second core elements are not in contact along the wall of the tube opposing the at least one rotator element.

34. The current sensor of claim 32, wherein the first and second core elements are in contact along at least one portion of the wall of the tube opposing the at least one rotator element.

35. A method comprising:

providing a soft ferromagnetic body having first and second folding portions and a magnetic field detector coupled to one of the first and second folding portions;

folding the first and second folding portions of the soft ferromagnetic body to form a lumen to receive a conductor carrying a current, wherein at least a portion of the magnetic field detector is disposed within the first and second folding portions; and

sensing the current carried in the conductor with the magnetic field detector.

36. The method of claim 35, further comprising rotatably coupling the first and second folding portions of the soft ferromagnetic body, wherein folding further comprises rotating the first and second folding portions until the portion of the magnetic field detector is disposed on a side of the soft ferromagnetic body opposing the rotator element.

37. The method of claim 35, further comprising securing the folded first and second folding portions with a securing body.