ADAPTIVE IMPEDANCE TUNING IN WIRELESS POWER TRANSMISSION

• US 20130113299A1
• Filed: 12/19/2012
• Published: 05/09/2013
• Est. Priority Date: 03/20/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Von Novak, William H., Wheatley, Charles E., Toncich, Stanley S., Ozaki, Emest T.
• Granted Patent: US 8,796,887 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: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Exemplary embodiments are directed to wireless power. A wireless power receiver includes a receive antenna for coupling with near field radiation in a coupling-mode region generated by a transmit antenna operating at a resonant frequency. The receive antenna generates an RF signal when coupled to the near filed radiation and a rectifier converts the RF signal to a DC input signal. A direct current (DC)-to-DC converter coupled to the DC input signal generates a DC output signal. A pulse modulator generate a pulse-width modulation signal to the DC-to-DC converter to adjust a DC impedance of the wireless power receiver by modifying a duty cycle of the pulse-width modulation signal responsive to at least one of a voltage of the DC input signal, a current of the DC input signal, a voltage of the DC output signal, and a current of the DC output signal.

Claims

1. A wireless power receiver, comprising:

a rectifier coupled to an antenna that is configured to receive a wireless power signal, the rectifier configured to convert the wireless power signal to a direct current input signal, the direct current input signal having voltage and current signals;

a direct current-to-direct current converter having an input impedance, the direct current-to-direct current converter configured to generate a direct current output signal based at least in part on the direct current input signal and configured to adjust the input impedance based at least in part on a control signal; and

a circuit configured to adjust an alternating current impedance of the wireless power receiver by adjusting the control signal based at least in part on one of the voltage signal or the current signal of the direct current input signal.

2. The wireless power receiver of claim 1, wherein the direct current-to-direct current converter is further configured to adjust a power output of the direct current output signal based in part on the voltage signal of the direct current input signal.

3. The wireless power receiver of claim 1, wherein the circuit comprises a pulse modulator.

4. The wireless power receiver of claim 3, wherein the pulse modulator is configured to adjust the control signal based at least in part on one of a voltage of the direct current output signal and a current of the direct current output signal.

5. The wireless power receiver of claim 1, wherein the circuit comprises a comparator configured to generate the control signal based in part on a comparison of the voltage signal of the direct current input signal and a reference signal.

6. The wireless power receiver of claim 1, wherein the pulse modulator comprises a processor configured to:

receive the direct current input signal;

sample a value of the direct current input signal; and

adjust the alternating current impedance of the wireless power receiver wherein adjusting comprises adjusting a duty cycle of the control signal based in part on the sampled value.

7. The wireless power receiver of claim 6, wherein the sampling comprises sampling at least one of the voltage of the direct current input signal, the current of the direct current input signal, a voltage of the direct current output signal, or a current of the direct current output signal.

8. The wireless power receiver of claim 1, wherein the circuit comprises a processor configured to:

receive the direct current input signal; and

sample a value of the direct current input signal, wherein adjusting the control signal is based in part on the sampled value from the direct current input signal to reduce a power output on the direct current output signal to a power level less than optimal and acceptable to a receiver device configured to receive the direct current output signal.

9. The wireless power receiver of claim 1, wherein the direct current-to-direct current converter comprises a buck converter or a boost converter configured to receive the direct current input signal, the control signal, and output the direct current output signal.

10. The wireless power receiver of claim 1 wherein the circuit is further configured to adjust a receive bandwidth of the wireless power receiver based at least in part on the alternating current impedance.

11. A method, comprising:

receiving a wireless power signal at a wireless power receiver;

rectifying the wireless power signal to a direct current input signal;

converting the direct current input signal to a direct current output signal;

modifying an alternating current impedance of the wireless power receiver by adjusting a power output of the direct current output signal based in part on the direct current input signal; and

adjusting a receive bandwidth of the wireless power receiver based at least in part on the alternating current impedance.

12. The method of claim 11, wherein the modifying the alternating current impedance of the wireless power receiver further comprises adjusting the power output of the direct current output signal based in part on one or more of a voltage of the direct current input signal and a current of the direct current input signal.

13. The method of claim 11, wherein the modifying the alternating current impedance of the wireless power receiver further comprises adjusting the power output of the direct current output signal based in part on one or more of a voltage of the direct current input signal, a voltage of the direct current output signal, and a current of the direct current output signal.

14. The method of claim 11, wherein the modifying the alternating current impedance of the wireless power receiver further comprises adjusting the power output of the direct current output signal based in part on one or more of a voltage of the direct current input signal, a current of the direct current input signal, a voltage of the direct current output signal and a current of the direct current output signal.

15. The method of claim 11, wherein modifying the alternating current impedance of the wireless power receiver is based in part on a comparison of the direct current input signal to a voltage reference signal.

16. A wireless power receiver, comprising:

means for receiving a wireless power signal;

means for rectifying the wireless power signal to a direct current input signal;

means for converting the direct current input signal to a direct current output signal; and

means for modifying an alternating current impedance of the wireless power receiver comprising a means for adjusting, based at least in part on the direct current input signal, an input impedance of the means for converting the direct current input signal to a direct current output signal.

17. The wireless power receiver of claim 16, wherein the means for modifying the alternating current impedance of the wireless power receiver further comprises means for adjusting the power output of the direct current output signal from the means for converting the direct current input signal to a direct current output signal based in part on one or more of a-voltage of the direct current input signal and a current of the direct current input signal.

18. The wireless power receiver of claim 16, wherein the means for modifying the alternating current impedance of the wireless power receiver further comprises means for adjusting the power output of the direct current output signal from the means for converting the direct current input signal to a direct current output signal based in part on one or more of a-voltage of the direct current input signal, a voltage of the direct current output signal, and a current of the direct current output signal.

19. The wireless power receiver of claim 16, wherein the means for modifying the alternating current impedance of the wireless power receiver further comprises means for adjusting the power output of the direct current output signal from the means for converting the direct current input signal to a direct current output signal based in part on one or more of the direct current input signal, a current of the direct current input signal, a voltage of the direct current output signal and a current of the direct current output signal.

20. The wireless power receiver of claim 16, further comprising means for comparing the direct current input signal to a voltage reference signal to determine a value, the means for modifying the alternating current impedance of the wireless power receiver configured to modify the alternating current impedance based in part on the value.

21. The wireless power receiver of claim 16, further comprising means for adjusting a receive bandwidth of the wireless power receiver based at least in part on the alternating current impedance.