Wireless power transfer in an electronic device having a tuned metallic body

• US 10,333,334 B2
• Filed: 08/08/2016
• Issued: 06/25/2019
• Est. Priority Date: 01/29/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jeong, Seong Heon, Wheatley, Charles Edward, Carobolante, Francesco, White, II, Mark
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Shiao, David A
• Application Number:
  US15/231,325
• Publication Number:
  US 20170222481A1
• Time in Patent Office: 1,051 Days
• CPC Class Codes: H01F 27/02 Casings
• CPC Class Codes: H01F 27/34 Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An electronic apparatus may include an electrically conductive body configured to magnetically couple to a first magnetic field. A first tuning element may be connected to the electrically conductive body. An electrically conductive coil may be wound about an opening defined by the electrically conductive body, and configured to magnetically couple to a second magnetic field.

Claims

1. An electronic apparatus for wireless power transfer, the apparatus comprising:

a housing comprising an electrically conductive portion configured to magnetically couple to a first magnetic field incident upon the apparatus and to generate a second magnetic field in response to being coupled to the first magnetic field;

a first tuning element electrically connected to the electrically conductive portion, the first tuning element comprising one or more capacitors;

an electrically conductive coil wound about an opening defined by the electrically conductive portion, the electrically conductive coil configured to magnetically couple to the second magnetic field to provide power received via the second magnetic field to a load; and

a controller configured to control a capacitance of the one or more capacitors to change a resonant frequency of the electrically conductive portion to adjust an amount of power delivered to the load.

2. The apparatus of claim 1, further comprising a second tuning element electrically connected to the electrically conductive coil.

3. The apparatus of claim 2, wherein the second tuning element comprises one or more capacitors.

4. The apparatus of claim 3, wherein either or both of the first tuning element and the second tuning element comprises one or more inductors.

5. The electronic apparatus of claim 3, wherein the controller is configured to control a capacitance of the one or more capacitors of the second tuning element to change a resonant frequency of the electrically conductive coil to adjust the amount of power delivered to the load.

6. The apparatus of claim 1, wherein the first magnetic field is an externally generated magnetic field generated by a wireless power transmitter and the electrically conductive portion is configured to generate the second magnetic field in response to being coupled to the externally generated magnetic field.

7. The apparatus of claim 6, further comprising a rectifier connected to the electrically conductive coil, the rectifier configured to rectify current induced in the electrically conductive coil to provide power to electronics that comprise the apparatus.

8. The apparatus of claim 1, further comprising:

a printed circuit board having disposed thereon the first tuning element; and

a connector that electrically connects the first tuning element to the electrically conductive portion.

9. The apparatus of claim 1, further comprising a printed circuit board, the electrically conductive coil disposed between the electrically conductive portion and the printed circuit board.

10. The apparatus of claim 9, further comprising ferrite material disposed between the electrically conductive coil and the printed circuit board.

11. The apparatus of claim 1, wherein the first tuning element and the electrically conductive portion constitute a circuit, and wherein the resonant frequency is defined by the first tuning element.

12. The apparatus of claim 11, further comprising a second tuning element electrically connected to the electrically conductive coil to define a circuit having a resonant frequency substantially equal to the resonant frequency of the circuit comprising the first tuning element and the electrically conductive portion.

13. The apparatus of claim 11, further comprising a second tuning element electrically connected to the electrically conductive coil to define a circuit having a resonant frequency different from the resonant frequency of the circuit comprising the first tuning element and the electrically conductive portion.

14. The apparatus of claim 1, further comprising a metallic enclosure configured to house electronics, the metallic enclosure comprising the electrically conductive portion.

15. The apparatus of claim 1, further comprising a non-metallic enclosure configured to house electronics that comprise the apparatus, the electrically conductive portion and the electrically conductive coil housed within the enclosure.

16. The apparatus of claim 1, wherein the apparatus is a wearable electronic device.

17. The electronic apparatus of claim 1, wherein the electrically conductive portion defines the opening through the electrically conductive portion and defines a slot through the electrically conductive portion.

18. The electronic apparatus of claim 17, wherein the slot extends between the opening and an edge at a periphery of the electrically conductive portion.

19. A method for wireless power transfer to an electronic device, the method comprising:

magnetically coupling to an externally generated magnetic field via an electrically conductive structure, that comprises a housing for the electronic device, to produce an induced magnetic field that emanates from the electrically conductive structure responsive to coupling to the externally generated magnetic field;

magnetically coupling to the induced magnetic field via a power receiving element to induce current in the power receiving element, the power receiving element electrically isolated from the electrically conductive structure; and

producing power for a load from the current induced in the power receiving element, wherein producing power from the current induced in the power receiving element comprises controlling a capacitance of one or more capacitors of a tuning element coupled to the electrically conductive structure to change a resonant frequency of the electrically conductive structure to adjust an amount of power delivered to the load.

20. The method of claim 19, wherein a resonant frequency of a circuit that includes the electrically conductive structure is substantially equal to a frequency of the externally generated magnetic field.

21. The method of claim 19, wherein a resonant frequency of a circuit that includes the power receiving element is substantially equal to a frequency of the externally generated magnetic field.

22. The method of claim 19, wherein magnetically coupling to the externally generated magnetic field via the electrically conductive structure includes inducing current in a first circuit comprising the electrically conductive structure electrically connected to a first tuning element, wherein magnetically coupling to the induced magnetic field via the power receiving element includes inducing current in a second circuit comprising the power receiving element electrically connected to a second tuning element.

23. The method of claim 22, wherein a resonant frequency of either or both the first circuit and the second circuit is substantially equal to a frequency of the externally generated magnetic field.

24. The method of claim 19, wherein producing power includes rectifying the current induced in the power receiving element.

25. An apparatus for wirelessly receiving power, the apparatus comprising:

a housing configured to enclose electronic components that comprise the apparatus, the housing comprising a metallic portion;

a first tuning element connected to the metallic portion of the housing, the first tuning element comprising one or more capacitors, the metallic portion of the housing having a shape that allows a flow of current to be induced therein in response to being magnetically coupled to an externally generated magnetic field incident upon the apparatus, wherein an induced magnetic field emanates from the metallic portion in response to the flow of current;

an electrically conductive coil, a flow of current being induced in the electrically conductive coil in response to being magnetically coupled to the induced magnetic field to provide power received via the induced magnetic field to a load;

a rectifier configured to rectify current induced in the electrically conductive coil to provide power to the load; and

a controller configured to control a capacitance of the one or more capacitors to change a resonant frequency of the metallic portion to adjust an amount of power delivered to the load.

26. The apparatus of claim 25, wherein the metallic portion of the housing defines an opening therethrough and defines a slot from the opening to a periphery of the metallic portion.

27. The apparatus of claim 25, wherein the rectifier is electrically connected to the electrically conductive coil.

28. The apparatus of claim 25, wherein the first tuning element and the metallic portion of the housing define the resonant frequency to be substantially equal to a resonant frequency defined by a second tuning element and the electrically conductive coil.

29. The apparatus of claim 25, wherein the first tuning element and the metallic portion of the housing define a resonant frequency different from the resonant frequency defined by a second tuning element and the electrically conductive coil.

30. An apparatus for wirelessly receiving power in an electronic device, the apparatus comprising:

means for housing electronics of the electronic device, the means for housing have a metallic portion comprising means for magnetically coupling to an externally generated magnetic field incident to device to produce an induced magnetic field that emanates from the means for magnetically coupling to the externally generated magnetic field, wherein the means for magnetically coupling to the externally generated magnetic field is electrically connected to means for tuning the means for magnetically coupling to the externally generated magnetic field to resonate at a resonant frequency;

means for magnetically coupling to the induced magnetic field to induce current, the means for magnetically coupling to the induced magnetic field electrically isolated from the means for magnetically coupling to the externally generated magnetic field; and

means for producing power from the current induced in the means for magnetically coupling to the induced magnetic field to deliver power to a load; and

means for controlling a capacitance of one or more capacitors to change the resonant frequency of the means for magnetically coupling to the externally generated magnetic field to adjust an amount of power delivered to the load.

31. The apparatus of claim 30, wherein either or both the means for magnetically coupling to the externally generated magnetic field and the means for magnetically coupling to the induced magnetic field have a resonant frequency substantially equal to a frequency of the externally generated magnetic field.

32. The apparatus of claim 30, wherein the means for magnetically coupling to the induced magnetic field comprises an electrically conductive coil.