Packaging and details of a wireless power device

• US 8,855,554 B2
• Filed: 03/04/2009
• Issued: 10/07/2014
• Est. Priority Date: 03/05/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Cook, Nigel P., Sieber, Lukas, Widmer, Hanspeter
• Primary Examiner(s): Hiltunen, Thomas J
• Application Number:
  US12/398,179
• Publication Number:
  US 20090243397A1
• Time in Patent Office: 2,043 Days
• Field of Search: None
• US Class Current: 455/41.1
• 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. An apparatus for delivering power to a load via a wireless field, comprising:

an antenna coil;

a resonant circuit comprising said antenna coil and a capacitor in series with said antenna coil, said resonant circuit configured to receive power transmitted from a transmitter via a non-modulated wireless magnetic field at a frequency; and

a power converting circuit, coupled to said antenna coil, the power converting circuit configured to receive a signal at a receive power level from the antenna coil and to convert the received signal to a charging signal, the charging signal having a voltage and current satisfying the requirements of a battery and sufficient to charge the battery, the power converting circuit configured to vary an impedance based on the received power level to tune the resonant circuit such that the resonant circuit resonates at the frequency.

2. The apparatus of claim 1, wherein the power converting circuit comprises:

a variable load impedance; and

a circuit configured to vary said variable load impedance based on the received power level.

3. The apparatus of claim 2, wherein the variable load impedance comprises at least one of a variable inductor or a variable capacitor.

4. The apparatus of claim 1, wherein the power converting circuit comprises a step-down or step-up converter.

5. The apparatus of claim 1, wherein the power converting circuit comprises a variable load impedance which includes at least one of a variable resistive component or a variable reactive component.

6. The apparatus of claim 1, wherein the power converting circuit comprises a synchronous rectifier configured to synchronously rectify AC power into DC power.

7. The apparatus as in claim 6, wherein the received power level varies with time, and wherein said synchronous rectifier includes a plurality of transistors configured to switch synchronously based on the received power level.

8. The apparatus of claim 1, wherein the impedance of the power converting circuit is variable such that the impedance value is configured to adjust coupling between the antenna coil and the transmitter.

9. The apparatus of claim 1, wherein the impedance of the power converting circuit is variable such that the impedance value is configured to adjust at least one of an operating frequency, a power level transmitted to the battery, or an efficiency level of power transmitted to the battery relative to power transmitted by the transmitter.

10. The apparatus as in claim 1, wherein said power converting circuit includes a fixed capacitor part and a variable capacitor part.

11. The apparatus as in claim 10, wherein said variable capacitor part includes a switched capacitor with multiple switchable parts, each of said switchable parts configured to vary the impedance.

12. The apparatus as in claim 1, wherein said power converting circuit includes a mechanically adjustable ferrite core.

13. The apparatus as in claim 12, wherein said mechanically adjustable ferrite core has a portion thereof which is moved to change an inductance of said power converting circuit.

14. The apparatus as in claim 1, further comprising a circuit configured to apply a DC bias voltage to tune a capacitance level.

15. The apparatus as in claim 1, further comprising a circuit configured to apply a DC bias voltage to vary an inductance level.

16. The apparatus as in claim 1, wherein said power converting circuit includes an inductive component having a variable inductance, and wherein the inductive component is connected to the antenna coil, and connected to at least one switch configured to select one of a plurality of taps connected to said antenna coil.

17. A method comprising:

receiving power via a resonant circuit from a non-modulated wireless magnetic field at an operating frequency and at a receive power level;

converting the received power, so as to charge a battery, with a power converting circuit having an impedance value that is variable; and

varying the impedance value of the power converting circuit to tune the resonant frequency of the resonant circuit based on the received power level.

18. The method of claim 17, wherein varying the impedance of the power converting circuit comprises varying the impedance of at least one of a variable inductor or a variable capacitor.

19. The method of claim 17, wherein varying the impedance of the power converting circuit comprises varying the impedance of at least one of a variable resistive component or a variable reactive component.

20. The method of claim 17, wherein the power converting circuit comprises a synchronous rectifier configured to synchronously rectify AC power into DC power.

21. The method of claim 17, wherein varying the impedance of the power converting circuit comprises adjusting at least one of an operating frequency, a power level transmitted to the battery, or efficiency level of power transmitted to the battery relative to power received from the magnetic field.

22. The method of claim 17, wherein said power converting circuit includes a fixed capacitor part and a variable capacitor part.

23. The method of claim 22, wherein varying the impedance of the power converting circuit comprises operating a switchable part of a switchable capacitor part included in the variable capacitor part.

24. The method of claim 17, further comprising applying a DC bias voltage to tune at least one of a capacitance level or an inductance level.

25. An apparatus comprising:

means for receiving power via a resonant means from a non-modulated wireless magnetic field at an operating frequency and at a receive power level;

means for converting the received power, so as to charge a battery, the means for converting the received power having an impedance value that is variable; and

means for varying the impedance value of the means for converting the received power, to tune a resonant frequency of the resonant means based on the received power level.

26. The apparatus of claim 25, wherein the means for varying the impedance comprises means for varying the impedance of at least one of a variable inductor or a variable capacitor.

27. The apparatus of claim 25, wherein the means for converting the received power comprises a variable load impedance which includes at least one of variable resistive component or a variable reactive component.

28. The apparatus of claim 25, wherein the impedance of the means for converting the received power is variable such that the impedance value is adapted to adjust at least one of an operating frequency, a power level transmitted to the battery, and efficiency level of power transmitted to the battery relative to power received from the magnetic field.

29. The apparatus of claim 25, further comprising means for applying a DC bias voltage to tune at least one of a capacitance level or an inductance level.