Method and apparatus for high current measurement

• US 7,728,578 B2
• Filed: 05/15/2008
• Issued: 06/01/2010
• Est. Priority Date: 05/15/2008
• Status: Expired due to Fees

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Coffey, Donald K., Etter, Brett E., Alfano, Donald E., Dupuis, Timothy J.
• Primary Examiner(s): TANG, MINH NHUT
• Application Number:
  US12/121,024
• Publication Number:
  US 20090284248A1
• Time in Patent Office: 747 Days
• Field of Search: None
• US Class Current: 324/126
• CPC Class Codes: G01R 1/203 Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils

Abstract

In order to extend the measurement range of a current sensor, a current divider is formed by a first conductor formed in a current sensor that is mounted on a printed circuit board and a second conductor on the printed circuit board that electrically shorts at least one input terminal of the current sensor to at least one output terminal of the current sensor. The input terminal of the current sensor supplies the current to be measured to the first conductor and the output terminal supplies the measured current back to the printed circuit board.

Claims

1. An apparatus comprises:

a printed circuit board (PCB);

a current sensor coupled to the printed circuit board, the current sensor including a first conductor portion to carry a first current to be measured by the current sensor;

a second conductor portion to carry a second current;

wherein the first conductor portion and the second conductor portion form a current divider to divide a third current;

wherein the current sensor includes one or more input terminals to receive the first current from the PCB and one or more output terminals to supply the first current to the PCB; and

wherein the second conductor is directly electrically connected to at least one of the one or more input terminals and at least one of the one or more output terminals.

2. The apparatus as recited in claim 1, wherein the third current is larger than the first current.

3. The apparatus as recited in claim 1, wherein the first current is from about 1 to about 20 A.

4. The apparatus as recited in claim 1, wherein the second conductor portion is a conductive trace on the printed circuit board.

5. The apparatus as recited in claim 1, wherein the first and second conductor portions are formed of a substantially similar conductive material.

6. The apparatus as recited in claim 5, wherein the first and second conductor portions are formed substantially of copper.

7. The apparatus as recited in claim 1 wherein the first and second currents combine into the third current of from about 30 A to about 100 A.

8. The apparatus as recited in claim 1 wherein the current sensor includes a package in which the first conductor portion is formed.

9. A method for measuring a current comprising:

dividing a first current in a current divider formed by a first conductor of a current sensor and a second conductor of a printed circuit board, the second conductor being directly connected to at least one input terminal of the current sensor and at least one output terminal of the current sensor, the dividing forming a second and third current, the first conductor receiving the second current from the at least one input terminal and supplying the second current to the at least one output terminal of the current sensor, the second conductor receiving the third current; and

measuring in the current sensor, the second current in the first conductor.

10. The method as recited in claim 9 further comprising adjusting the measured current to reflect the current divider.

11. The method as recited in claim 9, wherein the first current is larger than the second current by at least about 60 percent.

12. The method as recited in claim 9, wherein the second current is from about 1 to about 20 A.

13. The method as recited in claim 9 wherein the first current is from about 30 A to about 100 A.

14. The method as recited in claim 9 further comprising reforming the first current by combining the second current flowing in the first conductor between the at least one input and the at least one output terminal with the third current flowing in the second conductor between the at least one input terminal and the at least one output terminal, the combining occurring where the output terminal is directly connected to the second conductor.

15. An apparatus comprising:

a current divider formed by a first conductor in a package of a current sensor and a second conductor on a printed circuit board that electrically shorts at least one input terminal of the current sensor to at least one output terminal of the current sensor, the second conductor being directly electrically connected to the at least one input terminal and the at least one output terminal;

wherein the at least one input terminal of the current sensor is coupled to supply current to be measured to the first conductor and the at least one output terminal is coupled to supply the measured current to the printed circuit board.

16. The apparatus as recited in claim 15 wherein the current sensor further comprises:

an integrated circuit die; and

the package in which the first conductor is formed adjacent to the integrated circuit die.

17. The apparatus as recited in claim 15, wherein the first and second conductors are formed of a substantially similar conductive material.

18. The apparatus as recited in claim 15, wherein the first and second conductors are formed substantially of copper.