Current detector utilizing hall effect

• US 6,545,457 B2
• Filed: 06/29/2001
• Issued: 04/08/2003
• Est. Priority Date: 07/07/2000
• Status: Active Grant

• Current Assignee: Sanken Electric Company Limited
• Original Assignee: Sanken Electric Company Limited
• Inventors: Goto, Hirokazu, Kato, Takasi, Ohtsuka, Koji, Kumakura, Hiromichi
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US09/893,937
• Publication Number:
  US 20020011841A1
• Time in Patent Office: 648 Days
• Field of Search: 324/251, 324/235, 324/207.2, 324/117.H, 338/32.H, 360/112, 257/422
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

A Hall-effect semiconductor device is formed on a metal-made baseplate, as of nickel-plated copper, via a magnetic layer of Permalloy or the like. Higher in magnetic permeability than the baseplate, the magnetic layer is designed to reduce the magnetic resistance of the flux path. A plastic encapsulation thoroughly encloses the semiconductor device, magnetic layer, and baseplate.

Claims

1. An apparatus for detecting an electric current, comprising:

(a) a metal-made baseplate having a known magnetic permeability and a known electrical conductivity;

(b) a magnetic layer formed on the baseplate, the magnetic layer being higher in magnetic permeability than the baseplate;

(c) semiconductor means mounted to the baseplate, the semiconductor means including a Hall-effect device for generating a voltage proportional to the strength of an applied magnetic field;

(d) an encapsulation of electrically insulating material enveloping the baseplate and the magnetic layer and the semiconductor means; and

(e) a conductor for carrying current to be detected, the conductor being disposed contiguous the Hall-effect device in order to cause the Hall-effect device to generate the Hall voltage in response to a magnetic field due to the current flowing through the conductor, and the conductor being disposed opposite the magnetic layer via the Hall-effect device.

2. The apparatus of claim 1 wherein the magnetic layer is of Permalloy.

3. The apparatus of claim 2 wherein the baseplate is of copper.

4. The apparatus of claim 3 wherein the baseplate has a nickel plating.

5. The apparatus of claim 1 wherein the magnetic layer is formed on one of a pair of opposite major surfaces of the baseplate, and wherein the semiconductor means is mounted to the baseplate via the magnetic layer.

6. The apparatus of claim 1 wherein the magnetic layer is formed on one of a pair of opposite major surfaces of the baseplate, and wherein another similar magnetic layer is formed on the other major surface of the baseplate.