Current sensor

• US 8,878,531 B2
• Filed: 11/18/2010
• Issued: 11/04/2014
• Est. Priority Date: 11/18/2010
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Ausserlechner, Udo, Scherr, Wolfgang
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): NGUYEN, TRUNG Q
• Application Number:
  US12/949,419
• Publication Number:
  US 20120126805A1
• Time in Patent Office: 1,447 Days
• Field of Search: 702/138, 702/145, 702/130, 73766-767, 737/74, 737/77, 737/79, 324/163, 324/173, 324/174, 32420711-20715
• US Class Current: 324/252
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 33/07 Hall effect devices

Abstract

Embodiments of the invention provide a current sensor including a conductive element and at least two magnetic field sensors. The conductive element includes at least three terminal areas and a common conductive area, wherein each of the at least three terminal areas is connected to the common conductive area to guide a current applied to the respective terminal area into the common conductive area. The at least two magnetic field sensors are arranged at different geometric positions adjacent to the common conductive area, wherein each of the at least two magnetic field sensors is configured to sense a magnetic field component of each current flowing into the common conductive area to provide a sensor signal based on the sensed magnetic field component.

Claims

1. A current sensor, comprising:

a conductive element with at least three separate terminal areas and a common conductive area, wherein each of the at least three separate terminal areas is connected separately to the common conductive area to guide separately a current applied to the respective terminal area into the common conductive area; and

at least two magnetic field sensors arranged at different geometric positions adjacent to the common conductive area, wherein each of the at least two magnetic field sensors is configured to sense a magnetic field component of the current flowing into the common conductive area to provide a sensor signal based on the sensed magnetic field component;

wherein the at least two magnetic field sensors are arranged adjacent to the common conductive area such that the current sensor can measure separately the currents guided by the at least three separate terminal areas into the common conductive area.

2. The current sensor according to claim 1, further comprising an evaluator configured to determine a value of each current flowing into the common conductive area based on the sensor signals of the at least two magnetic field sensors.

3. The current sensor according to claim 2, wherein the evaluator is configured to derive a value of a background magnetic field based on the sensor signals of the at least two magnetic field sensors, and to determine evaluate the value of each current flowing into the common conductive area further based on the value of the background magnetic field.

4. The current sensor according to claim 2, wherein the evaluator comprises an output for outputting the value of each current flowing into the common conductive area.

5. The current sensor according to claim 1, wherein each current flowing into the common conductive area generates a magnetic field through each of the at least two magnetic field sensors.

6. The current sensor according to claim 1, wherein the at least two magnetic field sensors are arranged on different positions of the conductive element corresponding to a geometric circle.

7. The current sensor according to claim 1, wherein the at least two magnetic field sensors are arranged symmetrically on different positions of the conductive element corresponding to a geometric circle.

8. The current sensor according to claim 1, wherein each of the at least two magnetic field sensors is arranged between two adjacent terminal areas.

9. The current sensor according to claim 1, wherein each of the at least three terminal areas is arranged to define a center line associated therewith, wherein the center lines of the at least three separate terminal areas intercept in a center point, and wherein each of the at least two magnetic field sensors is arranged at a defined distance from the center point on the center line of the respective terminal area.

10. The current sensor according to claim 9, wherein each of the at least two magnetic field sensors is arranged at an equal distance from the center point on the center line of the respective terminal area.

11. The current sensor according to claim 1, wherein the at least two magnetic field sensors are discrete sensors.

12. The current sensor according to claim 1, wherein the at least two magnetic field sensors are part of an integrated circuit.

13. The current sensor according to claim 1, wherein each current flowing into the common conductive area provides a mean temperature increase to each of the at least two magnetic field sensors, wherein a maximum tolerance in increase of temperature between two magnetic field sensors amounts to 10% of the mean temperature increase.

14. The current sensor according to claim 1, wherein the at least three separate terminal areas are in an area outside of the common conductive area isolated from each other by an isolating material.

15. The current sensor according to claim 1, wherein the conductive element is a circular-shaped sheet-like conductor with at least three cut-out slots to form the at least three separate terminal areas.

16. The current sensor according to claim 1, wherein the at least three separate terminal areas are arranged symmetrically along a geometric circle.

17. The current sensor according to claim 1, wherein in a plan view the common conductive area is surrounded by the at least two magnetic field sensors.

18. The current sensor according to claim 1, wherein the conductive element comprises a homogenous electric conducting material with a electrical conductivity of at least 3*10^7 S/m.

19. The current sensor according to claim 1, wherein each of the at least two magnetic field sensors comprises a sensor lead, and wherein the conductive element is arranged geometrically in a first plane, wherein the sensor leads of the at least two magnetic field sensors are arranged geometrically in a second plane, wherein the first plane and the second plane are adjacent and isolated from each other, wherein the isolation is adapted to provide a breakdown voltage of at least 400 V.

20. A current sensor, comprising:

a sheet-like conductive element with at least three cut-out slots to form at least three separate terminal areas that are, outside of a common conductive area, isolated from each other, and each configured to guide separately a current applied to the respective terminal area into the common conductive area; and

at least three magnetic field sensors arranged on a circumferential line at different geometric positions adjacent to the common conductive area, wherein the circumferential line comprises a geometrical symmetrical form with respect to a center point of the common conductive area, and wherein each of the at least three magnetic field sensors is configured to sense a magnetic field component of the current flowing into the common conductive area to provide a sensor signal based on the sensed magnetic field component,

wherein the at least three magnetic field sensors are arranged on the circumferential line at different geometric positions adjacent to the common conductive area such that the current sensor can measure separately the currents guided by the at least three separate terminal areas into the common conductive area.

21. A current sensor, comprising:

a conductive element with n separate terminal areas, wherein n is at least three, and a common conductive area, wherein each of the n separate terminal areas is connected separately to the common conductive area and configured to guide separately a current applied to the respective terminal area into the common conductive area; and

m magnetic field sensors, wherein m is at least two, arranged at different geometric positions adjacent to the common conductive area, wherein each of the m magnetic field sensors is configured to sense a magnetic field component of the current flowing into the common conductive area to provide a sensor signal based on the sensed magnetic field component,

wherein the m magnetic field sensors are arranged at different geometric positions adjacent to the common conductive area such that the current sensor can measure separately the currents guided by the n separate terminal areas into the common conductive area.

22. The current sensor according to claim 21, wherein m=n.

23. The current sensor according to claim 21, wherein m=n−

1.

24. The current sensor according to claim 21, wherein m=n+1.

25. A method for measuring at least three separate currents in a measuring node, wherein the measuring node comprises at least two magnetic field sensors and a conductive element with at least three separate terminal areas and a common conductive area, wherein each of the at least three separate terminal areas is separately connected to the common conductive area to separately guide one of the at least three currents applied to the respective terminal area into the common conductive area, wherein the at least two magnetic field sensors are arranged adjacent to the common conductive area such that values of the at least three currents separately guided by the at least three separate terminal areas into the common conductive area are separately evaluated, comprising:

sensing separately magnetic field components of the at least three separate currents flowing into the measuring node with the at least two magnetic field sensors; and

evaluating separately the values of the at least three separate currents flowing into the measuring node based on the separately sensed magnetic field components.

26. The method for measuring at least three currents in a measuring node according to claim 25, further with the following steps:

evaluating a value of a background magnetic field based on the sensed magnetic field component; and

evaluating the value of each current flowing into the measuring node further based on the value of the background magnetic field.

27. A computer readable non-transitory digital storage medium having stored thereon a computer program having a program code for performing, when running on a computer, a method for measuring at least three currents in a measuring node, wherein the measuring node comprises at least three magnetic field sensors and a conductive element, wherein the conductive element comprises at least three separate terminal areas and a common conductive area, wherein each of the at least three separate terminal areas is separately connected to the common conductive area to separately guide one of the at least three currents applied to the respective terminal area into the common conductive area, wherein the at least two magnetic field sensors are arranged adjacent to the common conductive area such that values of the at least three currents separately guided by the at least three separate terminal areas into the common conductive area are separately evaluated, comprising:

sensing separately a magnetic field component of each current flowing into a measuring node with the at least two magnetic field sensors; and

evaluating separately the value of each current flowing into the measuring node based on the sensed magnetic field component.