ADAPTIVE POWER CONTROL FOR WIRELESS CHARGING

• US 20100181961A1
• Filed: 11/10/2009
• Published: 07/22/2010
• Est. Priority Date: 01/22/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Novak, William Von, Braden, Stanton C., Fevrier, Ian J., Toncich, Stanley S.
• Granted Patent: US 8,497,658 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• 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 50/20 using microwaves or radio frequency waves
• 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 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 52/04 TPC

Abstract

Exemplary embodiments are directed to wireless power transfer. A transmitter generates an electromagnetic field at a resonant frequency with a transmit antenna to create a coupling-mode region within a near field of the transmit antenna. The transmitter defines a beginning of a recurring period by on-off keying the electromagnetic field during a synchronization portion of the recurring period. During a power transmission portion of the recurring period, the transmitter couples portions of the electromagnetic field to different receive antennas of various receiver devices within the coupling-mode region. The transmitter also determines a power allocation within the recurring period for the various receiver devices disposed within the coupling-mode region and adjusts a power level of the near field radiation responsive to power requirements received from the receiver devices.

Claims

1. A wireless power transmitter, comprising:

a transmit antenna for generating a coupling-mode region of near field radiation for coupling to receive antennas on a plurality of receiver devices; and

a controller operably coupled to the transmit antenna, wherein the controller;

determines a power allocation within a recurring period for one or more of the plurality of receiver devices disposed within the coupling-mode region; and

adjusts a power level of the near field radiation responsive to a power requirement received from at least one of the plurality of receiver devices.

2. The wireless power transmitter of claim 1, further comprising:

an amplifier for applying an Radio Frequency (RF) signal to the transmit antenna; and

a power amplifier regulator operably coupled to the amplifier and the controller; and

wherein the controller further;

defines a plurality of power allocation periods during the recurring period, each power allocation period for one or more specific receiver devices of the plurality of receiver devices; and

controls the power amplifier regulator to set the power level of the amplifier to a first power level for the at least one of the plurality of power allocation periods and a second power level for other allocation periods of the plurality of power allocation periods.

3. The wireless power transmitter of claim 2, wherein the power amplifier regulator comprises a buck converter with a potentiometer operably coupled to the controller for adjusting a power level of the amplifier.

4. The wireless power transmitter of claim 2, wherein the power amplifier regulator comprises a buck converter and the controller is further configured to sample a power level of the amplifier and adjust a power output of the buck converter responsive to the sampled power level.

5. The wireless power transmitter of claim 2, wherein the controller further determines the first power level to share power between more than one of the plurality of receiver devices.

6. The wireless power transmitter of claim 1, further comprising:

an amplifier for applying an Radio Frequency (RF) signal to the transmit antenna; and

wherein the recurring period includes time-multiplexed portions and the controller further;

during a synchronization portion of the recurring period, enables the amplifier to apply the RF signal to the transmit antenna to generate the near field radiation; and

during a power transmission portion of the recurring period;

continues the enabling the amplifier when there is at least one receiver device within the coupling-mode region designated to accept power from the near field radiation; and

disables the amplifier from applying the RF signal to the transmit antenna when there are no receiver devices within the coupling-mode region designated to accept power from the near field radiation.

7. The wireless power transmitter of claim 1, wherein the controller further adjusts the power level of the near field radiation responsive to a power request level received from a receiver device of the plurality of receiver devices.

8. The wireless power transmitter of claim 7, further comprising an amplifier for applying an RF signal to the transmit antenna and wherein the controller further adjusts the power level of the near field radiation by adjusting a voltage level to the amplifier responsive to a voltage indicator received from a receiver device of the plurality of receiver devices.

9. The wireless power transmitter of claim 7, further comprising an amplifier for applying an RF signal to the transmit antenna and wherein the controller further adjusts the power level of the near field radiation by adjusting a current level to the amplifier responsive to a current indicator received from a receiver device of the plurality of receiver devices.

10. The wireless power transmitter of claim 1, further comprising:

an amplifier for applying an Radio Frequency (RF) signal to the transmit antenna; and

a load sensing circuit operably coupled to the amplifier and the controller, the load sensing circuit for detecting changes in power consumption by the amplifier and generating a serial response signal to the controller representative of the changes in power consumption; and

wherein the controller is further for decoding the serial response to determine at least one of a presence of a new receiver device in the coupling-mode region or receiver information of an existing receiver device in the coupling-mode region.

11. The wireless power transmitter of claim 1, wherein the controller further communicates to the one or more receiver devices of the plurality of receiver devices during a signaling portion of the recurring period to indicate a portion of the recurring period that the receiver device should be disabled from receiving power from the near field radiation.

12. A wireless power transmitter, comprising:

a transmit antenna for generating a coupling-mode region of near field radiation for coupling to receive antennas on a plurality of receiver devices;

a controller operably coupled to the transmit antenna, wherein the controller;

determines a coupling ratio to one or more receiver devices within the coupling-mode region by receiving a transmission indicating an amount of power received from the receiver device;

determines a radiated power not received by any receiver devices within the coupling-mode region responsive to the coupling ratio for each receiver device and a total transmitted power; and

adjusts a power level of the near field radiation if the radiated power is above a predetermined threshold.

13. A method of wireless power transfer, comprising:

generating an electromagnetic field at a resonant frequency with a transmit antenna of a transmitter to create a coupling-mode region within a near field of the transmit antenna;

defining a beginning of a recurring period by on-off keying the electromagnetic field during a synchronization portion of the recurring period; and

during a power transmission portion of the recurring period;

coupling the electromagnetic field to a receive antenna of a first receiver device within the coupling-mode region; and

coupling the electromagnetic field to a receive antenna of a second receiver device within the coupling-mode region.

14. The method of claim 13, further comprising adjusting an amount of power that is delivered to each receiver device by adjusting a transmitted power from the transmit antenna, adjusting an amount of time the power is transmitted for each receiver device, or a combination thereof.

15. The method of claim 13, wherein:

a first portion of the electromagnetic field is coupled to the receive antenna of the second receiver device;

a second portion of the electromagnetic field is coupled to the receive antenna of the second receiver device; and

the first portion and the second portion are responsive to placement of the first receiver device and the second receiver device relative to the transmit antenna.

16. The method of claim 13, further comprising:

determining when there are a plurality of receivers within the coupling-mode region designated to accept power from the electromagnetic field;

allocating time-multiplexed segments of the power transmission portion to each of the plurality of receivers designated to accept power; and

communicating the time-multiplexed segment allocated to each of the plurality of receivers during the synchronization portion.

17. The method of claim 13, further comprising:

determining a coupling ratio of each of the first receiver device and the second receiver device indicating a portion of the power from the coupling-mode region that each receiver device is consuming; and

allocating time-multiplexed segments of the power transmission portion responsive to the coupling ratio of at least one of the first receiver device and the second receiver device.

18. The method of claim 13, further comprising adjusting a power output level of the transmit antenna to at least two different levels for at least two different time-multiplexed segments of the power transmission portion.

19. The method of claim 18, wherein adjusting the power output level comprises adjusting a voltage to an amplifier operably coupled to the transmit antenna.

20. The method of claim 18, wherein adjusting the power output level comprises adjusting a current to an amplifier operably coupled to the transmit antenna.

21. The method of claim 18, wherein adjusting the power output level is responsive to a power request level received from the first receiver device, the second receiver device, or a combination thereof

22. A power transfer system, comprising:

means for generating an electromagnetic field at a resonant frequency with a transmit antenna of a transmitter to create a coupling-mode region within a near field of the transmit antenna;

means for defining a beginning of a recurring period by on-off keying the electromagnetic field during a synchronization portion of the recurring period; and

during a power transmission portion of the recurring period;

means for coupling the electromagnetic field to a receive antenna of a first receiver device within the coupling-mode region; and

means for coupling the electromagnetic field to a receive antenna of a second receiver device within the coupling-mode region.

23. The power transfer system of claim 22, further comprising means for adjusting an amount of power that is delivered to each receiver device by adjusting a transmitted power from the transmit antenna, adjusting an amount of time the power is transmitted for each receiver device, or a combination thereof

24. The power transfer system of claim 22, wherein:

a first portion of the electromagnetic field is coupled to the receive antenna of the second receiver device;

a second portion of the electromagnetic field is coupled to the receive antenna of the second receiver device; and

wherein the first portion and the second portion are responsive to placement of the first receiver device and the second receiver device relative to the transmit antenna.

25. The power transfer system of claim 22, further comprising:

means for determining when there are a plurality of receivers within the coupling-mode region designated to accept power from the electromagnetic field;

means for allocating time-multiplexed segments of the power transmission portion to each of the plurality of receivers designated to accept power; and

means for communicating the time-multiplexed segment allocated to each of the plurality of receivers during the synchronization portion.

26. The power transfer system of claim 22, further comprising:

means for determining a coupling ratio of each of the first receiver device and the second receiver device indicating a portion of the power from the coupling-mode region that each receiver device is consuming; and

means for allocating time-multiplexed segments of the power transmission portion responsive to the coupling ratio of at least one of the first receiver device and the second receiver device.

27. The power transfer system of claim 22, further comprising means for adjusting a power output level of the transmit antenna to at least two different levels for at least two different time-multiplexed segments of the power transmission portion.

28. The power transfer system of claim 27, wherein the means for adjusting the power output level comprises means for adjusting a voltage to an amplifier operably coupled to the transmit antenna.

29. The power transfer system of claim 27, wherein the means for adjusting the power output level comprises means for adjusting a current to an amplifier operably coupled to the transmit antenna.

30. The power transfer system of claim 27, wherein the means for adjusting the power output level is responsive to a power request level received from the first receiver device, the second receiver device, or a combination thereof.

31. A wireless power receiver, comprising:

a receive antenna for coupling with a coupling-mode region of near field radiation from a transmit antenna;

a radio frequency (RF) to direct current (DC) converter operably coupled to the receive antenna for converting the coupled near filed radiation to a DC signal;

a DC-DC converter operably coupled to the RF to DC converter for converting the DC signal to an output signal; and

a processor operably coupled to the receive antenna, the RF to DC converter, and the DC-DC converter, wherein the processor;

determines a desired power level for a receiver device operably coupled to the output signal; and

controls the DC-DC converter to adjust the power level on the output signal to the desired power level.

32. The wireless power receiver of claim 31, wherein the processor further controls the DC-DC converter to adjust the power level on the output signal by adjusting a voltage level of the output signal responsive to a desired voltage level for the receiver device.

33. The wireless power receiver of claim 31, wherein the processor further controls the DC-DC converter to adjust the power level on the output signal by adjusting a current level of the output signal responsive to a desired current level for the receiver device.

34. The wireless power receiver of claim 31, further comprising:

switching circuitry operably coupled between the receive antenna and the RF to DC converter for adjusting a load perceived by the transmit antenna through the coupling with the coupling-mode region; and

wherein the processor is further for communicating with a transmit device operably coupled to the transmit antenna by generating a serial signal on the receive antenna through control of the switching circuitry.

35. The wireless power receiver of claim 34, wherein the desired power level is communicated to the transmit device by the control of the switching circuitry by the processor.

36. The wireless power receiver of claim 35, wherein the desired power level communicated to the transmit device includes a desired current level.

37. The wireless power receiver of claim 35, wherein the desired power level communicated to the transmit device includes a desired voltage level.

38. A method for wireless charging a plurality of devices, comprising:

receiving power requirements from said plurality of devices; and

sequentially charging ones of said plurality of devices in connection with cloaking on each device to be charged and cloaking off devices not receiving charging.

39. A method as recited in claim 38, wherein receiving power requirements occurs in connection with receiving signals via on-off keying.

40. A method as recited in claim 38, further comprising monitoring power levels delivered to said plurality of devices and changing charging parameters in response thereto.

41. A method as recited in claim 40, wherein said charging parameters include current and voltage levels for delivery to said plurality of devices.

42. A method as recited in claim 38, wherein said wireless charging is accomplished using near field wireless charging methods.

43. A wireless charger, comprising:

a receiver for wirelessly receiving power requirements from devices to be charged;

a power component threshold detector; and

a processor operable to change a power component of a signal to be transmitted in connection with monitoring readings from said power component threshold detector so as to meet said power requirements.