Current sensor

• US 7,250,749 B2
• Filed: 10/19/2006
• Issued: 07/31/2007
• Est. Priority Date: 10/21/2005
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Itoh, Tomoki
• Primary Examiner(s): Nguyen; Ha Tran
• Assistant Examiner(s): Nguyen; Tung X.
• Application Number:
  US11/583,010
• Publication Number:
  US 20070090826A1
• Time in Patent Office: 285 Days
• Field of Search: 324/117.H, 324/765, 324/158.1, 324/127, 324/126, 324/117.R
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used

Abstract

A current sensor includes a first magnetic core that surrounds a portion of a conductor as a current path and has gaps therein, each of which is defined by adjacent ends spaced from each other by a first distance, a magnetic sensing element placed in at least one of the gaps, and a second magnetic core placed near the surrounded portion of the conductor to divide the conductor into channels. The second magnetic core is spaced from the first magnetic core by a second distance smaller than the first distance. Therefore, a magnetic resistance of the second magnetic core is smaller than that of the first magnetic core in a magnetic circuit formed by the first and second magnetic cores. As a result, a disturbance magnetic field mainly passes through the second magnetic core.

Claims

1. A current sensor for detecting current flowing through a conductor, the current sensor comprising:

a first magnetic core that is shaped like a ring to surround a portion of the conductor, the first magnetic core having at least two gaps therein, each of which is defined by adjacent ends spaced from each other by a first distance;

a magnetic sensing element placed in at least one of the gaps to detect a magnetic field induced in the first magnetic core by the current flowing through the conductor; and

a second magnetic core placed near the surrounded portion of the conductor to divide the conductor into at least two channel portions, wherein

a second distance between the first and second magnetic cores is smaller than the first distance.

2. The current sensor according to claim 1, wherein

the second magnetic core penetrates through the surrounded portion of the conductor.

3. The current sensor according to claim 1, wherein

each of the channel portions has a same width.

4. The current sensor according to claim 3, wherein

the second magnetic core divides the conductor into two channel portions.

5. The current sensor according to claim 1, wherein

the first and second magnetic cores touch each other.

6. The current sensor according to claim 1, wherein

the first and second magnetic cores are unitary with each other.

7. The current sensor according to claim 1, wherein

the first magnetic core includes a plurality of core members, and

each of the gaps is defined by adjacent ends of the core members.

8. The current sensor according to claim 7, wherein

the first magnetic core includes a pair of C-shaped core members, a pair of U-shaped core members, or a pair of one C-shaped core member and one U-shaped core member.

9. The current sensor according to claim 1, wherein

the second magnetic core is shaped like a column.

10. The current sensor according to claim 9, wherein

the second magnetic core is shaped like a cylindrical column or a polygonal column.

11. The current sensor according to claim 1, wherein

the conductor is connected to a battery of a vehicle.