Current detection device and core for detection of magnetic flux

• US 4,972,140 A
• Filed: 06/14/1988
• Issued: 11/20/1990
• Est. Priority Date: 06/14/1988
• Status: Expired due to Fees

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Sudo, Seiichi, Suzuki, Masashi, Kitamura, Hideki, Tanabe, Toru, Seto, Takao, Okazaki, Kunio
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): BURNS, WILLIAM
• Application Number:
  US07/206,598
• Time in Patent Office: 889 Days
• Field of Search: 307/309, 338/32 H, 338/32 R, 324/117 H, 324/117 R, 324/127, 324/251, 324/252, 336/178
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08

Abstract

The present invention provides a current detection device comprising a core skirt for accommodating therein a core, a core stopper for fixing the core and a magnetic-sensitive element mounted on a substrate, the substrate and the core skirt having engaging portions for locating the magnetic-sensitive element, respectively, provided thereon, and further provides a core for detection of a magnetic flux.

Claims

1. A current detection device wherein a magnetic-sensitive element is disposed in a gap provided in a ferrite core having a central opening an an air gap and a current value is detected from an output of said magnetic-sensitive element according to a current to be detected, the device comprising a core skirt for accommodating therein and surrounding said core which is releasably supported in and engages said skirt and a core stopper means to maintain the position of said core relative to said skirt for releasably fixing the core to said skirt, said magnetic-sensitive element being mounted on a substrate, said substrate and said core skirt having cooperating engaging portions for accurately locating the magnetic-sensitive element provided thereon;

the engaging portions of one of said substrate and said core skirt being projections and the engaging portions of the remaining one of said substrate and said core skirt being openings each for receiving one of said projections; and

said core skirt having a slot aligned with said air gap, said magnetic-sensitive element extending through said slot and into said air gap.

2. A current detection device comprising a detection portion in which a Hall element is inserted into a gap portion of a ring-like magnetic core with a gap and an electric wire allowing a current to be detected to flow is inserted into a hollow portion of the core, means for providing a current to said Hall element, amplifier means for amplifying a Hall voltage of said Hall element, means for applying a bias voltage for zero adjustment to said amplifier means, and a constant current output circuit having an MOS-FET for generating an output current.

3. Apparatus for detection of current through a conductor comprising:

a one-piece core provided with a central opening and an air gap;

a substrate having a magnetic field sensing element mounted thereon;

circuit means for developing an output from said magnetic field sensing element being mounted on said substrate;

skirt means for receiving said core and releasably positioning said core upon said substrate so that said magnetic field sensing element is properly located within said air gap;

a housing for receiving said substrate, said housing including a hollow integral projection extending through an opening in said substrate, an opening in said core positioning means and the central opening in said core, said hollow projection receiving said conductor;

means releasably joined to said projection and engaging a surface of said core for retaining said core, said positioning means, said substrate and hence said magnetic field sensing element assembled and in proper alignment.

4. The apparatus of claim 3 wherein said positioning means comprises a core skirt having a wall embracing said core and having an elongated slot through which said integral projection and said magnetic field sensing element extend at spaced locations therealong.

5. The apparatus of claim 4 wherein said core skirt and said substrate have interengaging elements for accurately positioning said core skirt relative to said substrate.

6. The apparatus of claim 5 wherein said interengaging elements respectively comprise at least one projection and an opening for receiving said projection.

7. The apparatus of claim 6 wherein said opening is provided in said substrate and said core skirt is provided with said projection.

8. The apparatus of claim 3 wherein said housing for receiving said substrate is comprised of a floor portion surrounded by integral sidewalls;

one of said sidewalls having a slot;

said substrate having a printed wiring arrangement;

a coupling element for coupling said printed wiring arrangement on said substrate to external circuitry;

a coupling housing for receiving said coupling element, said coupling housing having a projection slidably received within said slot for interlocking said first mentioned housing and said coupling housing.

9. Current detection apparatus comprising a magnetic core having a central opening and an air gap communicating with said central opening;

a magnetic field sensing element being positioned within said air gap;

first circuit means for controlling said magnetic field sensing means to regulate its output;

second circuit means coupled to said magnetic field sensing means for generating an output signal representative of the field in said air gap;

said first and second circuit means and said magnetic field sensing means and said core being formed as an integrated circuit comprising a unitary member having an opening aligned with the central opening of said core for receiving a current carrying winding and having electrical terminals arranged along the surface of said unit for coupling to external circuitry, said integrated circuit unit maintaining said magnetic field sensing means in proper position within said air gap.

10. The apparatus of claim 9 wherein said first circuit means includes means for adjusting the zero output of said magnetic field sensing element.

11. The apparatus of claim 9 wherein said second circuit means includes an output stage having an MOS FET for producing an output current representative of the magnetic field in said air gap.

12. Apparatus for current detection comprising:

a core provided with an air gap;

a first hollow housing open at one end thereof and having a floor at the opposite end thereof for supporting said core;

the sidewalls of said housing extending between said floor and said open end surrounding and having a shape adapted to retain said core in a fixed position in said first housing;

a substrate having a magnetic field sensing element mounted thereon;

circuit means for developing an output from said magnetic field sensing element being mounted on said substrate;

said substrate including interengaging means;

a second hollow housing for receiving said substrate and said first housing;

said second housing having cooperating interengaging means for coupling with the interengaging means of said circuit means for retaining said circuit means in a predetermined position within said second housing;

said core having a central opening;

the base of said first housing having an opening substantially in alignment with the opening in said core;

said second housing having a projection extending through the opening in the base of said first housing and through the opening in said core;

said projection being of a length sufficient to extend beyond said core; and

releasable locking means for engaging the portion of said projection extending beyond said core for locking said core, said first housing and said substrate to said second housing.

13. The apparatus of claim 12 wherein said first housing is provided with a plurality of projections extending toward said substrate;

said substrate being provided with a plurality of openings, each of said openings being aligned with an associated projection on said first housing;

said projections extending into the openings in said substrate when said first housing is mounted thereon to thereby precisely locate said sensing element in the air gap of said core.

14. The apparatus of claim 12 wherein the interengaging means of said substrate comprises a pair of undercut grooves and the interengaging means of said second housing comprises a pair of edges slidably received in said undercut grooves.