Hall-effect sensor isolator

• US 9,000,761 B2
• Filed: 01/19/2012
• Issued: 04/07/2015
• Est. Priority Date: 01/19/2012
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Tay, Gary, Ho, Dominique, Shie, Meng Yong
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US13/353,494
• Publication Number:
  US 20130187644A1
• Time in Patent Office: 1,174 Days
• Field of Search: 324/251
• US Class Current: 324/251
• CPC Class Codes: G01R 33/072 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

A coupler is disclosed that employs hall-effect sensing technology. Specifically, the coupler is configured to produce an output voltage by converting the magnetic field generated by a current conductor at an input side. The output and input sides may be electrically isolated from one another but may be coupled via the hall-effect sensing technology, such as a hall-effect sensor.

Claims

1. A coupler, comprising:

a leadframe including;

an input side;

and an output side that is electrically isolated from the input side; and

a sensor assembly including a sensor element that is configured to detect a magnetic field produced by current flowing through the input side, produce an output signal having at least one of a current and voltage that is proportional to a magnitude of the detected magnetic field, and provide the output signal to the output side of the leadframe, the sensor element being positioned in the sensor assembly such that no portion of the sensor element overlaps any portion of the input side that carries the current flowing through the input side, wherein the sensor assembly further comprises an insulator along its entire bottom surface and which has an outer boundary substantially coincident with an outer boundary of the sensor assembly, wherein the insulator operates as an adhesive layer between the input side and the sensor assembly, wherein the sensor assembly and coincident insulator are also positioned such that at least a portion of the sensor assembly and coincident insulator do not overlap a portion of the input side, and wherein neither the sensor assembly nor the coincident insulator overlap any portion of the output side.

2. The coupler of claim 1, wherein the input side comprises a current-directing feature that detours current flowing through the input side in a loop and around the sensor element thereby creating the magnetic field.

3. The coupler of claim 2, wherein the input side comprises a first section and a second section that are separated by at least one isolation gap of a first distance, but are also connected to one another via the current-directing feature, wherein the current-directing feature detours the current flowing through the input side to have a travel path longer than the first distance.

4. The coupler of claim 2, wherein the current-directing feature, the input side, and the output side are constructed from a single sheet of metal.

5. The coupler of claim 1, wherein the outer boundary of the sensor assembly is exactly the same size and shape as the outer boundary of the insulator.

6. The coupler of claim 1, wherein the insulator comprises plastic, wherein the sensor element comprises a silicon-based hall-effect sensor, and wherein the silicon-based hall-effector sensor overlaps the at least a portion of the insulator.

7. The coupler of claim 1, wherein the sensor assembly is attached to a top surface of the input side.

8. The coupler of claim 1, wherein the input side is directly connected to a voltage source of at least 5 kV and wherein the insulator and a gap between the input side and output side prohibit transients from the 5 kV input side from reaching the output side.

9. The coupler of claim 1, wherein the input side comprises a notch, wherein the at least a portion of the insulator completely overlaps the notch, and wherein the sensor element is positioned in an overlapping arrangement with the notch such that the magnetic field is maximized around the sensor element.

10. The coupler of claim 1, wherein the output side comprises a plurality of output sections, each of which comprise a lead that is electrically connected to a contact on the sensor assembly by a wire.

11. A hall effect sensor coupler, comprising:

an input side that is electrically connected to a first circuit and carries a first current;

an output side that is electrically connected to a second circuit and is electrically isolated from the input side and first circuit;

a sensor assembly including a sensor element positioned relative to the input side such that at least some of the sensor assembly fails to overlap the input side that carries the first current and such that a magnitude of a magnetic field produced by the first current is detectable by the sensor element, wherein the sensor element fails to overlap any of the input side and is further configured to generate an output signal based on the detected magnitude of the magnetic field; and

an insulator completely underlying the sensor assembly and having an outer boundary substantially coincident with an outer boundary of the sensor assembly, wherein the insulator operates as an adhesive between the sensor assembly and the input side, wherein a portion of the sensor assembly and coincident insulator extends beyond the input side, and wherein no portion of the sensor assembly and coincident insulator overlap any portion of the output side.

12. The coupler of claim 11, wherein the output signal is generated in proportion to the magnitude of the magnetic field.

13. The coupler of claim 12, wherein the sensor element is part of a sensor assembly that is connected to the input side.

14. The coupler of claim 13, wherein the sensor assembly comprises the insulator, and wherein the insulator physically and electrically separates the sensor carrier and sensor element from the input side.

15. The coupler of claim 14, wherein the sensor carrier comprises an Integrated Circuit, wherein the insulator comprises a plastic, wherein the sensor element comprises a hall-effect sensor that is positioned within the sensor carrier such that none of the hall-effect sensor overlaps the input side, and wherein the hall-effect sensor overlaps the insulator.

16. The coupler of claim 14, wherein the insulator is at least about 2 mils thick thereby enabling the insulator along with a gap between the input side and output side to prohibit transients of up to 5 kV from traveling from the input side to the output side.

17. The coupler of claim 14, wherein a shortest distance from the input side to the output side is less than a shortest distance from the insulator to the output side.

18. A method of operating a coupler, comprising:

connecting an input side of the coupler to a first circuit operating at no less than 5 kV;

sensing a magnetic field produced by current flowing through the input side with a sensor element that is included in a sensor assembly, wherein the sensor element is positioned relative to the input side such that the sensor element does not overlap the input side or the current flowing through the input side;

converting the sensed magnetic field into an output signal;

providing the output signal to an output side of the coupler that is electrically isolated from the input side of the coupler; and

insulating the sensor assembly and sensor element from the input side with an adhesive insulator that provides a high-voltage isolation between the sensor assembly and the current flowing through the input side, wherein an outer perimeter of the adhesive insulator coincides with an outer perimeter of the sensor assembly, wherein a portion of the adhesive insulator and sensor assembly extend beyond the input side, and wherein the sensor element overlaps the adhesive insulator over a notch formed in the input side.

19. The method of claim 18, wherein the current flowing through the input side is directed along a non-linear path by the notch of the input side.

20. The method of claim 18, wherein a thickness of the adhesive insulator is greater than a thickness of the sensor assembly.