CURRENT SENSOR

• US 20120081110A1
• Filed: 09/30/2011
• Published: 04/05/2012
• Est. Priority Date: 10/01/2010
• Status: Active Grant

• Current Assignee: Melexis Technologies NV (Sensinnovat BVBA)
• Original Assignee: Melexis Technologies NV (Sensinnovat BVBA)
• Inventors: Racz, Robert
• Granted Patent: US 9,176,170 B2
• Time in Patent Office: Days
• US Class Current: 324/252
• 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 19/20 using transductors , i.e. a magnetic core transducer the saturation of which is cyclically reversed by an AC source on the secondary side

Abstract

A current sensor comprises a flat housing made of plastic having an underside and an upper side and electrical connections, a current conductor through which the current to be measured flows, and a semiconductor chip having two magnetic field sensors, wherein the component of the magnetic field detected by the two magnetic field sensors points in opposite directions at the locations of the two magnetic field sensors. The semiconductor chip is connected as flipchip to the electrical connections. The current conductor extends from one side wall to the opposite side wall of the housing, is embedded flat in the underside of the housing and is therefore exposed on the underside of the housing. The opposing surfaces of the semiconductor chip and the current conductor are separated by an electrical insulation layer.

Claims

1. A current sensor, comprising

a flat housing made of plastic having an underside, an upper side and four side walls, electrical connections and a current conductor through which the current to be measured flows, and

a semiconductor chip having two magnetic field sensors, wherein the component of the magnetic field detected by the two magnetic field sensors points in opposite directions at the locations of the two magnetic field sensors, wherein the semiconductor chip is connected as flipchip to the electrical connections, wherein

the current conductor extends from one side wall to the opposite side wall of the housing, is embedded flat in the underside of the housing and is exposed on the underside of the housing,

the mutually opposite ends of the current conductor substantially have the same width as the entirety of the electrical contacts that would have room at a side wall of the housing accommodating an end of the current conductor, and

the opposing surfaces of the semiconductor chip and the current conductor are separated by an electrical insulation layer.

2. The current sensor according to claim 1, wherein the magnetic field sensors are disposed in the area of the two lateral edges of the current conductor, wherein a distance A between centres of symmetry of the magnetic field sensors lies in the range of 0.9*W≦

A≦

W, where W designates the width of the current conductor in the area of the magnetic field sensors.

3. The current sensor according to claim 1, wherein the electrical connections are integrated flat in the underside of the housing.

4. The current sensor according to claim 2, wherein the electrical connections are integrated flat in the underside of the housing.

5. The current sensor according to claim 1, wherein a rear side of the semiconductor chip is coated with a ferromagnetic layer.

6. The current sensor according to claim 2, wherein a rear side of the semiconductor chip is coated with a ferromagnetic layer.

7. The current sensor according to claim 3, wherein a rear side of the semiconductor chip is coated with a ferromagnetic layer.

8. The current sensor according to claim 4, wherein a rear side of the semiconductor chip is coated with a ferromagnetic layer.

9. A device for measuring current, comprising

a printed circuit board having a conductor path, and

a current sensor for measurement of the current flowing in the conductor path, wherein

the current sensor comprises

a flat housing made of plastic having an underside, an upper side and four side walls, electrical connections and a current conductor through which the current to be measured flows, and

a semiconductor chip having two magnetic field sensors, wherein the component of the magnetic field detected by the two magnetic field sensors points in opposite directions at the locations of the two magnetic field sensors, wherein the semiconductor chip is connected as flipchip to the electrical connections, wherein

the current conductor extends from one side wall to the opposite side wall of the housing, is embedded flat in the underside of the housing and is exposed on the underside of the housing,

the mutually opposite ends of the current conductor substantially have the same width as the entirety of the electrical contacts that would have room at a side wall of the housing accommodating an end of the current conductor, and

the opposing surfaces of the semiconductor chip and the current conductor are separated by an electrical insulation layer, and wherein

the conductor path is interrupted at a predetermined point, the printed circuit board has at least one metallic, electrically free-floating surface which is either soldered to the current conductor of the current sensor and/or is connected to the conductor path.

10. The device according to claim 9, wherein the electrical connections are integrated flat in the underside of the housing.

11. The device according to claim 10, wherein a surface-mountable component is mounted on at least one of said at least one metallic surface.

12. The device according to claim 10, wherein a magnetic shielding is mounted on the printed circuit board on the side facing away from the current sensor.

13. The device according to claim 11, wherein a magnetic shielding is mounted on the printed circuit board on the side facing away from the current sensor.