Packaging and Details of a Wireless Power device

• US 20090243397A1
• Filed: 03/04/2009
• Published: 10/01/2009
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Nigel Power LLC (Qualcomm, Inc.)
• Inventors: Widmer, Hanspeter, Sieber, Lukas, Cook, Nigel P.
• Granted Patent: US 8,855,554 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• 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 7/00045 Authentication, i.e. circuits for checking compatibility between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04B 5/0037 for power transfer
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication

Abstract

A wireless power system includes a power source, power receiver, and components thereof. The system can also include a parasitic antenna that can improve the coupling to the power source in various modes. The antenna can have both a variable capacitor and a variable inductor, and both of those can be changed in order to change characteristics of the matching.

Claims

1. A wireless power system, comprising:

a magnetically resonant antenna including an inductor having a variable inductance and a capacitor, having a variable capacitance;

a power conversion circuit, coupled to said magnetically resonant antenna, and connecting with a magnetically resonant wireless power via said antenna, said circuit determining a measure of wireless power transfer, and producing a control signal indicative of said measure about how well information from said wireless power is being coupled, and provides a control signal to said magnetically resonant antenna, and wherein said magnetically resonant antenna adjusts at least one of said inductor and said capacitor value based on said signal.

2. A system as in claim 1, wherein said capacitor includes a fixed capacitor part and a variable capacitor part.

3. A system as in claim 2, wherein said capacitor part includes a switched capacitor with multiple switchable parts, each said part changing a total capacitance.

4. A system as in claim 1, wherein said variable inductance includes a coil, and at least one switch selecting one of the tabs on said antenna coil.

5. A system as in claim 1, wherein said circuit includes a mechanically adjustable ferrite core.

6. A system as in claim 5, wherein said mechanically adjustable ferrite core has a portion thereof which is moved to change said inductance.

7. A system as in claim 1, wherein said magnetically resonant antenna uses a DC bias voltage to tune a capacitance level.

8. A system as in claim 1, wherein said tuning uses a DC bias voltage to tune and inductance.

9. A system as in claim 1, wherein said antenna is used in a transmitter.

10. A system as in claim 1, wherein said antenna is used in a receiver.

11. A wireless power system, comprising:

a magnetically resonant antenna tuned for wireless power, said antenna including an inductor and a capacitor, wherein said inductor is a variable inductor that includes a ferrite core that is moved relative to another part of the inductor, and wherein a movement of said ferrite core changes an amount of inductance in the antenna; and

a power circuit that processes electric power, connected to said magnetically resonant antenna.

12. A system as in claim 11, wherein said ferrite core is moved by a micro-actuator.

13. A system as in claim 11, further comprising an electronic circuit, that determines an amount by which said ferrite core needs to be moved.

14. A system as in claim 12, wherein said ferrite core is a flat core.

15. A system as in claim 12, wherein said ferrite core is a cylindrical core.

16. A system as in claim 14, wherein said ferrite core is integrated into a cover of a mobile device.

17. A wireless power system, comprising:

an antenna coil;

a capacitor, in series with said antenna coil, said antenna coil and capacitor tuned to receive wireless transmission of power;

a power converting circuit, coupled to said antenna coil, and receiving power therefrom, and converting said power;

a tunable load impedance, in series with said coil and capacitor, said tunable load impedance having a variable impedance; and

a circuit which varies said tunable load impedance, in order to improve matching with said capacitor and said coil.

18. A method of coupling wireless power, comprising:

varying both a capacitance and an inductance of a magnetically resonant antenna that is formed of a coil part forming an inductor, and a variable capacitance;

coupling power via said magnetically resonant antenna to or from a remote source, to transmit power wirelessly or to receive power wirelessly using said magnetically resonant antenna,

determining a measure of wireless power transfer being carried out by said transmit or said receive, and producing a control signal indicative of said measure about how well information from said wireless power is being coupled; and

providing a control signal to said magnetically resonant antenna, and wherein said magnetically resonant antenna causes one of said capacitance or said inductance to be varied based on said signal.

19. A method as in claim 18, wherein said capacitance includes a fixed capacitor part and a variable capacitor part, and said varying varies only said variable capacitor part.

20. A method as in claim 19, wherein said varying comprises selecting one of multiple different switchable parts, each said part changing a total capacitance.

21. A method as in claim 18, wherein said variable inductance includes a coil with multiple taps, and further comprising selecting connecting to at least one of said taps, and at least one switch selecting one of the tabs on said antenna coil.

22. A method as in claim 18, wherein said variable inductance circuit includes a mechanically adjustable ferrite core and said varying comprises changing an adjustment of said core.

23. A method as in claim 18, wherein said antenna is used in a transmitter.

24. A method as in claim 18, wherein said antenna is used in a receiver.

25. A method, comprising:

transmitting power wirelessly from a transmitter to a receiver;

detecting, in the transmitter, a change in coupling factor between said transmitter and said receiver;

based on said detecting, adapting the transmitter by changing a polarization of said transmitting.

26. A method as in claim 25, wherein said detecting senses feedback that is produced from the receiver.

27. A method as in claim 26, wherein said feedback is sent over a short range communication protocol that is also used by the receiver for communication

28. A method as in claim 25, further comprising using an interface both for sensing feedback from a receiver and also for identification of said device

29. A method as in claim 25, wherein said detecting uses a local model of the receiver, in the transmitter, to detect said change in coupling factor.

30. A method as in claim 25, wherein said detecting senses feedback that is produced from the receiver in a first mode of operation, and wherein said detecting uses a local model of the receiver, in the transmitter, to detect said change in coupling factor in a second mode of operation.

31. A method as in claim 25, further comprising tuning an antenna used for said transmitting wherein said tuning comprises tuning at least one of inductance or capacitance.

32. A method as in claim 25, further comprising tuning an antenna used for said transmitting wherein said tuning comprises tuning both of inductance and capacitance.

33. A method as in claim 31, further comprising tuning an antenna used for said transmitting for one of:

extraneous objects, detuned power receivers in close proximity, or a variation of load impedance.

34. A method, comprising:

transmitting power wirelessly from a transmitter to a receiver;

detecting, in the transmitter, tuning information for said transmitter that depends on loading by said receiver; and

based on said detecting, adapting the transmitter by tuning said transmitter in a way that improves a coupling to said receiver as a function of said loading.

35. A method as in claim 34, wherein said detecting senses feedback from the receiver.

36. A method as in claim 35, wherein said feedback uses a short range communication protocol that is also used by the receiver for communication.

37. A method as in claim 34, further comprising using an interface both for sensing feedback from a receiver and also for identification of said device.

38. A method as in claim 34, wherein said detecting uses a local model of the receiver, in the transmitter, to detect said change in coupling factor.

39. A method as in claim 34, further comprising tuning an antenna used for said transmitting, wherein said tuning comprises tuning at least one of inductance or capacitance of said antenna.

40. A method as in claim 34, further comprising tuning an antenna used for said transmitting, wherein said tuning comprises tuning both of inductance and capacitance of said antenna.