Inductive charging system

• US 7,211,986 B1
• Filed: 07/01/2004
• Issued: 05/01/2007
• Est. Priority Date: 07/01/2004
• Status: Expired due to Fees

• Current Assignee: Plantronics, Inc.
• Original Assignee: Plantronics, Inc.
• Inventors: Huddart, David, Flowerdew, Peter M.
• Primary Examiner(s): Easthom; Karl
• Assistant Examiner(s): Berhanu; Samuel
• Application Number:
  US10/882,961
• Time in Patent Office: 1,034 Days
• Field of Search: 320/107, 320/108, 320/110, 320/112, 320/113, 320/114, 320/115, 320/116
• US Class Current: 320/108
• CPC Class Codes: H02J 5/00 Circuit arrangements for transfer of electric power between ac networks and dc networks H02J3/36 takes precedence
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries

Abstract

An apparatus for inductive charging a battery. The apparatus includes a housing with a lower surface and a charging surface. A rechargeable device with a rechargeable battery may be placed on the charging surface. The apparatus further includes a controller for driving an oscillator, wherein the controller receives power from a power source. A first charger coil and second charger coil are disposed within the housing and are coupled to the oscillator. The first charger coil and second charger coil create a substantially horizontal magnetic field in the volume of space above the charging surface.

Claims

1. An apparatus for inductive charging a battery comprising:

a housing with a lower surface and a charging surface, wherein a rechargeable device with a rechargeable battery may be variably placed on the charging surface;

a controller for driving an oscillator, wherein the controller receives power from a power source;

a first charger coil disposed within the housing;

a second charger coil disposed within the housing, wherein the first charger coil and the second charger coil are coupled to the oscillator and create a substantially horizontal magnetic field in a volume of space above the charging surface; and

one or more permeable tiles disposed on or below the charging surface and above the first charger coil and the second charger coil, wherein the one or more permeable tiles form a controlled permeable path to limit field leakage from the charging surface.

2. The apparatus of claim 1, wherein the first charger coil and the second charger coil have a core comprising air or a non-permeable material.

3. The apparatus of claim 1, wherein the first charger coil and the second charger coil have a core comprising a permeable material.

4. The apparatus of claim 1, further comprising a permeable material disposed in the housing above the lower surface and below the first charger coil and the second charger coil.

5. The apparatus according to claim 4, wherein the permeable material comprises ferrite.

6. The apparatus according to claim 4, wherein the permeable material is disposed within a non-permeable carrier.

7. The apparatus according to claim 4, wherein the permeable material is ferrite loaded thermoplastic.

8. The apparatus according to claim 4, wherein the permeable material is over-moulded with thermoplastic.

9. The apparatus according to claim 4, wherein the permeable material is integrated with a core permeable material disposed within the first charger coil and the second charger coil.

10. The apparatus of claim 1, wherein the first charger coil ad the second charger coil create a first substantially horizontal magnetic field along a first direction above the charging surface, the apparatus further comprising:

a third charger coil disposed within the housing; and

a fourth charger coil disposed within the housing, wherein the third charger coil and fourth charger coil create a second substantially horizontal magnetic field along a second direction above the charging surface, wherein the first direction is orthogonal to the second direction.

11. The apparatus of claim 10, wherein the first substantially horizontal magnetic field and the second substantially horizontal magnetic field have the same frequency and a phase difference of 90 degrees.

12. The apparatus of claim 10, further comprising a fifth charger coil disposed within the housing for creating a substantially vertical magnetic field.

13. The apparatus of claim 12, wherein a substantially vertical magnetic field phase is alternated between a first horizontal magnetic field phase and a second horizontal magnetic field phase.

14. The apparatus of claim 1, further comprising a resonance tuning circuit for operating the first charging coil and the second charging coil in a resonance circuit with one or more rechargeable devices placed on the charging surface.

15. The apparatus of claim 14, wherein the resonance turning circuit comprises a variable capacitance which is adjusted when a rechargeable device is placed on the charging surface.

16. The apparatus or claim 14, wherein the resonance tuning circuit varies the frequency of the first charging coil and the second charging coil when a rechargeable device is placed on the charging surface.

17. The apparatus of claim 1, wherein the charging surface is a concave surface.

18. The apparatus of claim 17, wherein the first charging coil and the second charging coil are disposed adjacent to the concave surface at an inward angle with respect to a vertical axis.

19. The apparatus of claim 1, wherein the charging surface crises a plurality of recessed areas for simultaneous charging of a plurality of rechargeable devices.

20. The apparatus of claim 1, wherein the power source is an electronic device.

21. The apparatus of claim 1, wherein the power source is coupled to the controller via a USB port.

22. The apparatus of claim 1, wherein the first charging coil and the second charging coil receive a drive voltage from the oscillator that is modulated in frequency, phase, amplitude, or any combination thereof to convey data to the rechargeable device.

23. The apparatus of claim 22, wherein a high frequency carrier is modulated with a lower frequency such that only the lower frequency produces significant magnetic flux.

24. The apparatus of claim 23, wherein the high frequency carrier is a square-wave carrier and the lower frequency is a sine wave.

25. The apparatus of claim 1, wherein the oscillator provides an A.C. signal with a frequency between 10 kHz and 40 kHz.

36. The apparatus of claim 1, wherein the one or more permeable tiles comprise ferrite.

26. A system for inductive charging comprising:

a charger comprising;

a housing with a lower surface and a charging surface, wherein a rechargeable device with a rechargeable battery may be variably placed on the charging surface;

a controller for driving an oscillator, wherein the controller receives power from a power source;

a first charger coil disposed within the housing;

a second charger coil disposed within, the housing, wherein the first charger coil and the second charger coil are coupled to the oscillator and create a substantially horizontal magnetic field in a volume of space above the charging surface; and

one or more permeable tiles disposed on or below the charging surface and above the first charger coil and the second charger coil, wherein the one or more permeable tiles form a controlled permeable path to limit field leakage from the charging surface,

wherein the rechargeable device comprises;

a receive coil for coupling to the substantially horizontal magnetic field and producing an induced voltage; and

a rectifier for producing a rectified induced voltage to charge the battery in the rechargeable device.

27. The system of claim 26, wherein the rectified induced voltage further provides operating power to the rechargeable device.

28. The system of claim 26, wherein the rechargeable device sends data to the charger.

29. The system of claim 28, wherein data is sent with the receive coil.

30. The system of claim 29, wherein the charger receives data with the first charging coil and the second charging coil.

31. The system of claim 29, wherein the charger further comprises a charger receive coil for receiving data from the rechargeable device.

32. The system of claim 28, wherein the rechargeable device sends data to the charger with a radio signal.

33. The system of claim 28, wherein the rechargeable device sends data to the charger with an infrared signal.

34. The system of claim 28, wherein the charger further comprises a USB port and wherein data received from the rechargeable device is transferred to a personal computer through the USB port.

35. The system of claim 26, wherein the receive coil is a solenoidal coil.

37. An apparatus for inductive charging a battery comprising:

a housing having a concave charging surface;

a controller for driving an oscillator, wherein the controller receives power from a power source;

a first angled charger coil disposed within the housing adjacent the concave charging surface; and

a second angled charger coil disposed within the housing adjacent the concave charging surface, wherein the first angled charger coil and the second angled charger coil are coupled to the oscillator and crate a substantially horizontal magnetic field in a volume of space above the concave charging surface; and

one or more permeable tiles disposed on or below the concave charging surface and above the fit angled charger coil and the second angled charger coil, wherein the one or more permeable tiles form a controlled permeable path to limit field leakage from the concave charging surface.

38. The apparatus of claim 37, wherein the first angled charger coil and the second angled charger coil have a core comprising a permeable material.

39. The apparatus of claim 38, further comprising a permeable material disposed in the housing below the first angled charger coil and the second angled charger coil.

40. The apparatus of claim 39, wherein the permeable material comprises ferrite.

41. The apparatus of claim 39, wherein the permeable material is disposed within a non-permeable carrier.

42. The apparatus of claim 39, wherein the permeable material is ferrite loaded thermoplastic.

43. The apparatus of claim 39, wherein the permeable material is over-moulded with thermoplastic.

44. The apparatus of claim 39, wherein the permeable material is integrated with a core permeable material disposed within the first angled charger coil and the second angled charger coil.

45. The apparatus of claim 37, wherein the first angled charger coil and the second angled charger coil create a first substantially horizontal magnetic field along a first direction above the concave charging surface, the apparatus further comprising:

a third angled charger coil disposed within the housing; and

a fourth angled charger coil disposed within the housing, wherein the third angled charger coil and fourth angled charger coil create a second substantially horizontal magnetic field along a second direction above the concave charging surface, wherein the first direction is orthogonal to the second direction.

46. The apparatus of claim 45, wherein the first substantially horizontal magnetic field and the second substantially horizontal magnetic field have a same frequency and a phase difference of 90 degrees.

47. The apparatus of claim 45, further comprising a fifth charger coil disposed within the housing for creating a substantially vertical magnetic field.

48. The apparatus of claim 47, wherein a substantially vertical magnetic field phase is alternated between a first horizontal magnetic field phase and a second horizontal magnetic field phase.

49. The apparatus or claim 37, further comprising a resonance turning circuit for operating the first angled charger coil and the second angled charger coil in a resonance circuit with one or more rechargeable devices placed on the concave charging surface.

50. The apparatus of claim 49, wherein the resonance tuning circuit comprises a variable capacitance which is adjusted when a rechargeable device is placed on the concave charging surface.

51. The apparatus of claim 49, wherein the resonance turning circuit varies the frequency of the first angled charging coil and the second angled charging coil when a rechargeable device is placed on the concave charging surface.

52. The apparatus of claim 37, wherein the concave charging surface comprises a plurality of recessed areas for simultaneous charging of a plurality of rechargeable devices.