Controlling field distribution of a wireless power transmitter

• US 10,084,321 B2
• Filed: 09/25/2015
• Issued: 09/25/2018
• Est. Priority Date: 07/02/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Von Novak, III, William Henry, Carobolante, Francesco
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Dhillon, Jagdeep
• Application Number:
  US14/864,938
• Publication Number:
  US 20170005481A1
• Time in Patent Office: 1,096 Days
• Field of Search: 307104, 307108, 307 91, 455129, 455130, 455132, 342367, 342365, 343876, 343879, 343871
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

Exemplary embodiments are directed to an apparatus for controlling magnetic field distribution including a wireless transmit antenna configured to generate a magnetic field for wirelessly transferring power to a charge-receiving device with the wireless transmit antenna, a parasitic antenna located near the wireless transmit antenna, and a switch configured to selectively enable the parasitic antenna to modify the magnetic field in response to an antenna parameter that indicates the presence of the charge-receiving device relative to the parasitic antenna.

Claims

1. An apparatus for controlling magnetic field distribution, comprising:

a wireless transmit antenna configured to generate a magnetic field for wirelessly transferring power to a charge-receiving device with the wireless transmit antenna; and

a plurality of parasitic antennas, each of the plurality of parasitic antennas configured to momentarily and sequentially be activated by a respective switch to determine a location of the charge-receiving device on a charging surface,

wherein at least one selected parasitic antenna of the plurality of parasitic antennas is configured to be enabled to modify the magnetic field in response to an antenna parameter that indicates the presence of the charge-receiving device relative to the at least one selected parasitic antenna in a location on the charging surface having no charge-receiving device.

2. The apparatus of claim 1, wherein the antenna parameter comprises at least one of a voltage parameter at the wireless transmit antenna, a voltage parameter at a wireless receive antenna at a receiver, a reactance parameter at the wireless transmit antenna, and a reactance parameter at the wireless receive antenna at the receiver.

3. The apparatus of claim 1, wherein at least one of the plurality of parasitic antennas is configured to amplify the magnetic field in response to the antenna parameter.

4. The apparatus of claim 1, wherein at least one of the plurality of parasitic antennas is configured to operate in a resonant tuned state in response to the antenna parameter.

5. The apparatus of claim 1, wherein at least one of the plurality of parasitic antennas is configured to operate in a resistive state in response to the antenna parameter.

6. The apparatus of claim 1, wherein at least one of the plurality of parasitic antennas is configured to change an impedance of the wireless transmit antenna in response to the antenna parameter.

7. The apparatus of claim 1, wherein at least one of the plurality of parasitic antennas is configured to operate in at least one of a capacitive tuned state or an inductive tune state in response to the antenna parameter.

8. The apparatus of claim 1, further comprising a housing defining a charging surface for placement of a plurality of charge-receiving devices including the charge-receiving device, the housing configured to house the wireless transmit antenna and the plurality of parasitic antennas.

9. The apparatus of claim 1, further comprising:

a first circuit wirelessly coupled to the magnetic field, the first circuit configured to generate a power signal in response to power coupled via the magnetic field, the power signal configured to power a second circuit that controls the switch.

10. The apparatus of claim 9, wherein the second circuit is electrically coupled to the first circuit, the second circuit configured to generate a control signal to control a state of the switch, the control signal responsive to the power signal and a modulation signal developed by the wireless transmit antenna.

11. A method for controlling magnetic field distribution, comprising:

generating a magnetic field for wirelessly transferring power to a charge-receiving device using a wireless transmit antenna;

momentarily and sequentially activating each of a plurality of parasitic antennas in a set of parasitic antennas;

determining a location of the charge-receiving device on a charging surface; and

enabling selected parasitic antennas of the plurality of parasitic antennas to modify the magnetic field in locations on the charging surface having no charge-receiving device.

12. The method of claim 11, further comprising activating selected parasitic antennas of the plurality of parasitic antennas responsive to any of a voltage parameter and a reactance parameter at the wireless transmit antenna.

13. The method of claim 11, further comprising amplifying the magnetic field in response to an antenna parameter that indicates the presence of the charge-receiving device relative to at least one selected parasitic antenna of the plurality of parasitic antennas.

14. The method of claim 11, further comprising operating at least one of the plurality of parasitic antennas in a resonant tuned state in response to an antenna parameter that indicates the presence of the charge-receiving device relative to at least one selected parasitic antenna of the plurality of parasitic antennas.

15. The method of claim 11, further comprising changing an impedance of the wireless transmit antenna in response to an antenna parameter that indicates the presence of the charge-receiving device relative to at least one selected parasitic antenna of the plurality of parasitic antennas.

16. The method of claim 15, further comprising operating at least one of the plurality of parasitic antennas in any of a capacitive tuned state and an inductive tuned state in response to the antenna parameter.

17. The method of claim 11, further comprising operating at least one of the plurality of parasitic antennas in a resistive state in response to an antenna parameter that indicates the presence of the charge-receiving device relative to at least one selected parasitic antenna of the plurality of parasitic antennas.

18. The method of claim 11, further comprising generating a power signal in response to the magnetic field, the power signal configured to power a switch that momentarily and sequentially activates each of the plurality of parasitic antennas.

19. The method of claim 18, further comprising generating a control signal to control a state of the switch, the control signal responsive to the power signal and a modulation signal developed by the wireless transmit antenna.

20. The method of claim 11, wherein determining a location of the charge-receiving device further comprises detecting a voltage change at the wireless transmit antenna.

21. The method of claim 11, wherein determining a location of the charge-receiving device further comprises detecting a reactance change at the wireless transmit antenna.

22. A device for controlling magnetic field distribution, comprising:

means for generating a first magnetic field for wirelessly transferring power to a charge-receiving device;

means for generating a second magnetic field that alters the first magnetic field;

means for momentarily and sequentially activating each of a plurality of parasitic antennas in a set of parasitic antennas;

means for determining a location of the charge-receiving device on a charging surface; and

means for enabling selected parasitic antennas of the plurality of parasitic antennas to modify the magnetic field in locations on the charging surface having no charge-receiving device.