Magnetic field sensor and electrical current sensor therewith

• US 7,622,909 B2
• Filed: 02/18/2004
• Issued: 11/24/2009
• Est. Priority Date: 02/21/2003
• Status: Expired due to Fees

• Current Assignee: Liaisons Electroniques-Mecaniques LEM SA
• Original Assignee: Lem Heme Limited (LEM Holding SA)
• Inventors: Teppan, Wolfram
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): Velez; Roberto
• Application Number:
  US10/545,984
• Publication Number:
  US 20060226826A1
• Time in Patent Office: 2,106 Days
• Field of Search: 324/117.H, 324/117.R, 324/126, 324/127
• US Class Current: 324/126
• CPC Class Codes: G01R 15/185 with compensation or feedback windings or interacting coils, e.g. 0-flux sensors using galvano-magnetic field sensors G01R15/20; conversion of DC into AC using transductors G01R19/20
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 33/04 using the flux-gate principle

Abstract

A magnetic field sensor comprises a magnetic field sensing cell and a magnetic shield comprising at least two parts separated by an air-gap and surrounding the magnetic field sensing cell positioned in a cavity of the magnetic shield.

Claims

1. Electrical current sensor for measuring the electrical current I_p flowing in a primary conductor (1), comprising a magnetic circuit (3) having an air-gap (6) and a magnetic field sensor comprising a magnetic field sensing cell (10, 310) and a magnetic shield (9, 109, 209, 409) made of a magnetic material comprising at least two parts (12, 112, 212, 412) separated by an air-gap (20) and surrounding the magnetic field sensing cell positioned in a cavity (11) of the magnetic shield positioned in the air-gap, wherein the magnetic circuit comprises a core (5) of soft magnetic material surrounding the primary conductor, end faces (27a, 27b) of the core having extensions (28a, 28b) that reduce the width of the air-gap along an outer periphery of the magnetic core.

2. Electrical current sensor for measuring the electrical current I_p flowing in a primary conductor (1), comprising a magnetic circuit (3) having an air-gap (6) and a magnetic field sensor positioned in the air-gap, the magnetic field sensor comprising a magnetic field sensing cell (10, 310) and a magnetic shield (9, 109, 209, 409) made of a magnetic material comprising at least two parts (12, 112, 212, 412) separated by an air-gap (20) and surrounding the magnetic field sensing cell positioned in a cavity (11) of the magnetic shield the current sensor further comprising a circuit board (22) with conductive tracks thereon wherein the magnetic circuit (3) and the magnetic field sensor (4, 104, 204, 304, 404) is fixed directly on the circuit board, and wherein the magnetic field sensor comprises a flexible circuit (14, 214, 414) that is conductively connected to conductive traces on the circuit board that connect the magnetic field sensor to an ASIC (23) mounted on the circuit board for processing the sensor input and output signals.