Wireless power system with capacitive proximity sensing

• US 9,154,189 B2
• Filed: 10/11/2012
• Issued: 10/06/2015
• Est. Priority Date: 08/17/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Von Novak, William H, Monat, Pavel, Kallal, Edward
• Primary Examiner(s): DEBERADINIS, ROBERT L
• Application Number:
  US13/649,843
• Publication Number:
  US 20140049422A1
• Time in Patent Office: 1,090 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: H02J 50/05 using capacitive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

This disclosure provides systems, methods and apparatus for tuning a transmit coil for operation in a plurality of frequency bands. In one aspect, a method of wireless power transmission is provided. The method includes exciting a first part of a wireless power transmission system, via a wireless power transmitter. The method further includes detecting, in the presence of a non-charging object, a first change in a first parameter. The first parameter is indicative of a coupling between the non-charging object and the first part. The method further includes varying a characteristic of the wireless power transmission based on said first change.

Claims

1. A method of wireless power transmission comprising:

exciting a first part of a wireless power transmission system, via a wireless power transmitter;

detecting, in the presence of a non-charging object, a first change in a first parameter indicative of a capacitive coupling between the non-charging object and the first part; and

varying a characteristic of the wireless power transmission based on said first change.

2. The method of claim 1, wherein the wireless power transmitter excites the first part via an antenna capacitively coupled with the first part.

3. The method of claim 1, wherein the first part comprises a conducting plate.

4. The method of claim 3, wherein the conducting plate comprises a metal.

5. The method of claim 1, wherein the non-charging object comprises a living object.

6. The method of claim 1, wherein the non-charging object comprises a parasitic receiver.

7. The method of claim 1, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

8. The method of claim 7, wherein said varying comprises reducing the transmit power when the first change is detected.

9. The method of claim 7, wherein said varying comprises increasing the transmit power when the first change is detected.

10. The method of claim 1, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

11. A method of determining a distance of an object from a transmit antenna comprising:

exciting, via the transmit antenna, a first and second part of a wireless power transmission system, the second part being displaced from the first part;

detecting, in the presence of a non-charging object, a first change in a first parameter indicative of a coupling between the non-charging object and the first part;

detecting, in the presence of the non-charging object, a second change in a second parameter indicative of a coupling between the non-charging object and the second part; and

comparing said first and second changes to determine a location of said object.

12. The method of claim 11, wherein the coupling comprises a capacitive coupling.

13. The method of claim 11, wherein the first and second parts each comprise a conducting plate.

14. The method of claim 13, wherein each conducting plate comprises a metal.

15. The method of claim 11, wherein the non-charging object comprises a living object.

16. The method of claim 11, wherein the non-charging object comprises a parasitic receiver.

17. The method of claim 11, further comprising varying a characteristic of the wireless power transmission based on the determined location of said object.

18. The method of claim 17, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

19. The method of claim 18, wherein said varying comprises reducing the transmit power based on the determined location.

20. The method of claim 18, wherein said varying comprises increasing the transmit power based on the determined location.

21. The method of claim 17, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

22. The method of claim 11, further comprising controlling a device input based on the determined location.

23. The method of claim 22, wherein the device input comprises at least one of:

a charging rate, a music control, a data synchronization, and a power control.

24. The method of claim 11, further comprising determining an orientation of the object.

25. A system configured to provide wireless power transmission comprising:

a first metal plate;

a transmit antenna configured to provide wireless power and to excite the first metal plate; and

a circuit configured to detect a first change in capacitance between said transmit antenna and said first metal plate.

26. The system of claim 25, further comprising a controller configured to vary a characteristic of the wireless power transmission based on the detected first change.

27. The system of claim 26, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

28. The system of claim 27, wherein said varying comprises reducing the transmit power when the first change is detected.

29. The system of claim 27, wherein said varying comprises increasing the transmit power when the first change is detected.

30. The system of claim 26, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

31. A system configured to determine a location of a foreign object in a vicinity of a wireless charging system comprising:

a first metal plate;

a second metal plate displaced from the first metal plate;

a transmit antenna configured to provide wireless power and to excite the first and second metal plates;

a circuit configured to detect a first change in capacitance between said transmit antenna and said first metal plate;

a circuit configured to detect a second change in capacitance between said transmit antenna and said second metal plate; and

a circuit configured to compare said first change to said second change to determine the location of said foreign object.

32. The system of claim 31, further comprising a controller configured to vary a characteristic of the wireless power transmission based on the determined location of said object.

33. The system of claim 32, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

34. The system of claim 33, wherein said varying comprises reducing the transmit power based on the determined location.

35. The system of claim 33, wherein said varying comprises increasing the transmit power based on the determined location.

36. The system of claim 32, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

37. The system of claim 31, further comprising a controller configured to control a device input based on the determined location.

38. The system of claim 37, wherein the device input comprises at least one of:

a charging rate, a music control, a data synchronization, and a power control.

39. The system of claim 31, further comprising a circuit configured to determine an orientation of the object.

40. An apparatus for wireless power transmission comprising:

means for transmitting wireless power and for exciting a first part of a wireless power transmission system;

means for detecting, in the presence of a non-charging object, a first change in a first parameter indicative of a capacitive coupling between the non-charging object and the first part; and

means for varying a characteristic of the wireless power transmission based on said first change.

41. The apparatus of claim 40, wherein the means for transmitting excites the first part via an antenna capacitively coupled with the first part.

42. The apparatus of claim 40, wherein the first part comprises a conducting plate.

43. The apparatus of claim 42, wherein the conducting plate comprises a metal.

44. The apparatus of claim 40, wherein the non-charging object comprises a living object.

45. The apparatus of claim 40, wherein the non-charging object comprises a parasitic receiver.

46. The apparatus of claim 40, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

47. The apparatus of claim 46, further comprising means for reducing the transmit power when the first change is detected.

48. The apparatus of claim 46, further comprising means for increasing the transmit power when the first change is detected.

49. The apparatus of claim 40, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

50. An apparatus for determining a distance of an object from a transmit antenna comprising:

means for transmitting wireless power and for exciting a first and second part of a wireless power transmission system, the second part being displaced from the first part;

means for detecting, in the presence of a non-charging object, a first change in a first parameter indicative of a coupling between the non-charging object and the first part;

means for detecting, in the presence of the non-charging object, a second change in a second parameter indicative of a coupling between the non-charging object and the second part; and

means for comparing said first and second changes to determine a location of said object.

51. The apparatus of claim 50, wherein the coupling comprises a capacitive coupling.

52. The apparatus of claim 50, wherein the first and second parts each comprise a conducting plate.

53. The apparatus of claim 52, wherein each conducting plate comprises a metal.

54. The apparatus of claim 50, wherein the non-charging object comprises a living object.

55. The apparatus of claim 50, wherein the non-charging object comprises a parasitic receiver.

56. The apparatus of claim 50, further comprising means for varying a characteristic of the wireless power transmission based on the determined location of said object.

57. The apparatus of claim 56, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

58. The apparatus of claim 57, further comprising means for reducing the transmit power based on the determined location.

59. The apparatus of claim 57, further comprising means for increasing the transmit power based on the determined location.

60. The apparatus of claim 56, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

61. The apparatus of claim 50, further comprising means for controlling a device input based on the determined location.

62. The apparatus of claim 61, wherein the device input comprises at least one of:

a charging rate, a music control, a data synchronization, and a power control.

63. The apparatus of claim 50, further comprising means for determining an orientation of the object.

64. A non-transitory computer-readable medium comprising code that, when executed, causes an apparatus to:

excite a first part of a wireless power transmission system, via a wireless power transmitter;

detect, in the presence of a non-charging object, a first change in a first parameter indicative of a coupling between the non-charging object and the first part; and

vary a characteristic of the wireless power transmission based on said first change.

65. The medium of claim 64, wherein the coupling comprises a capacitive coupling.

66. The medium of claim 64, wherein the first part comprises a conducting plate.

67. The medium of claim 66, wherein the conducting plate comprises a metal.

68. The medium of claim 64, wherein the non-charging object comprises a living object.

69. The medium of claim 64, wherein the non-charging object comprises a parasitic receiver.

70. The medium of claim 64, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

71. The medium of claim 70, further comprising code that, when executed, causes the apparatus to reduce the transmit power when the first change is detected.

72. The medium of claim 70, further comprising code that, when executed, causes the apparatus to increase the transmit power when the first change is detected.

73. The medium of claim 64, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

74. A non-transitory computer-readable medium comprising code that, when executed, causes an apparatus to:

excite, via a transmit antenna, a first and second part of a wireless power transmission system, the second part being displaced from the first part;

detect, in the presence of a non-charging object, a first change in a first parameter indicative of a coupling between the non-charging object and the first part;

detect, in the presence of the non-charging object, a second change in a second parameter indicative of a coupling between the non-charging object and the second part; and

compare said first and second changes to determine a location of said object.

75. The medium of claim 74, wherein the coupling comprises a capacitive coupling.

76. The medium of claim 74, wherein the first and second parts each comprise a conducting plate.

77. The medium of claim 76, wherein each conducting plate comprises a metal.

78. The medium of claim 74, wherein the non-charging object comprises a living object.

79. The medium of claim 74, wherein the non-charging object comprises a parasitic receiver.

80. The medium of claim 74, further comprising code that, when executed, causes the apparatus to vary a characteristic of the wireless power transmission based on the determined location of said object.

81. The medium of claim 80, wherein the varied characteristic of the wireless power transmission comprises a transmit power.

82. The medium of claim 81, further comprising code that, when executed, causes the apparatus to reduce the transmit power based on the determined location.

83. The medium of claim 81, further comprising code that, when executed, causes the apparatus to increase the transmit power based on the determined location.

84. The medium of claim 80, wherein the varied characteristic of the wireless power transmission comprises a transmit frequency.

85. The medium of claim 74, further comprising code that, when executed, causes the apparatus to control a device input based on the determined location.

86. The medium of claim 85, wherein the device input comprises at least one of:

a charging rate, a music control, a data synchronization, and a power control.

87. The medium of claim 74, further comprising code that, when executed, causes the apparatus to determine an orientation of the object.