APPARATUS, SYSTEM, AND METHOD FOR BACK-CHANNEL COMMUNICATION IN AN INDUCTIVE WIRELESS POWER TRANSFER SYSTEM

• US 20130260676A1
• Filed: 03/30/2012
• Published: 10/03/2013
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Singh, Manjit
• Granted Patent: US 8,942,624 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• 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 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/45 Transponders
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An inductive wireless power transfer device comprises a transmitter that comprises a transmit coil configured to generate a wireless power signal to a coupling region in response to an input voltage, and a modulator configured to modulate the wireless power signal and encode data with the wireless power signal to establish a back-channel communication link from the transmitter to a receiver. An inductive wireless power receiving device comprises a receiver that comprises a receive coil configured to generate a time varying signal in response to receiving a modulated wireless power signal from a transmitter in a coupling region, and a demodulator configured to demodulate the modulated wireless power signal from an established back-channel communication link from the transmitter to a receiver. Related inductive wireless power transfer systems and methods for back-channel communication from the transmitter to the receiver of an inductive wireless power transfer system are disclosed.

Claims

1. An inductive wireless power transfer device, comprising:

a transmitter, comprising;

a transmit coil configured to generate a wireless power signal to a coupling region in response to an input voltage; and

a modulator configured to modulate the wireless power signal and encode data with the wireless power signal to establish a back-channel communication link from the transmitter to a receiver.

2. The inductive wireless power transfer device of claim 1, wherein modulator is configured to modulate a conversion gain transfer function of the wireless power signal.

3. The inductive wireless power transfer device of claim 2, wherein the conversion gain transfer function is defined as an output voltage of the receiver divided by the input voltage of the transmitter.

4. The inductive wireless power transfer device of claim 1, wherein the transmitter further includes an inverter configured to generate a time varying current through the transmit coil having a frequency for the wireless power signal.

5. The inductive wireless power transfer device of claim 4, wherein the inverter includes a switch network controlled by a processor according to a switching frequency, wherein the modulator is configured to adjust a control characteristic of the inverter to modulate the wireless power signal.

6. The inductive wireless power transfer device of claim 5, wherein the control characteristic is one of a switching frequency of the switch network and a duty cycle of the switch network.

7. The inductive wireless power transfer device of claim 5, wherein the modulator is configured to increase the control characteristic from a baseline level to be a logic ‘

1’

bit, and decrease the control of the control characteristic from the baseline level to be a logic ‘

0’

bit.

8. The inductive wireless power transfer device of claim 1, wherein the modulator is configured to adjust an impedance of the transmitter to modulate the wireless power signal.

9. The inductive wireless power transfer device of claim 8, wherein the modulator includes an impedance element serially coupled with a switch, and coupled with the transmit coil, wherein the modulator is configured to enable and disable the switch to adjust the impedance of the transmitter.

10. The inductive wireless power transfer device of claim 1, wherein the modulator is configured to adjust the input voltage of the transmitter to modulate the wireless power signal.

11. The inductive wireless power transfer device of claim 1, wherein the modulator is configured to adjust an effective input voltage received by the transmit coil to modulate the wireless power signal.

12. The inductive wireless power transfer device of claim 11, wherein the transmitter further includes an inverter a switch network controlled by a processor, wherein the modulator is configured to adjust phases of control signals to the switch network to modulate the wireless power signal.

13. An inductive wireless power receiving device, comprising:

a receiver, comprising;

a receive coil configured to generate a time varying signal in response to receiving a modulated wireless power signal from a transmitter in a coupling region; and

a demodulator configured to demodulate the modulated wireless power signal from an established back-channel communication link from the transmitter to a receiver.

14. The inductive wireless power receiving device of claim 13, wherein the receiver further comprises a rectifier operably coupled with the receive coil and configured to generate an output voltage from the time varying signal generated by the receive coil, and to transmit the output voltage a load.

15. The inductive wireless power receiving device of claim 14, wherein the modulator includes a frequency/duty cycle discriminator that monitors drive circuitry of the rectifier to determine one of the frequency and the duty cycle of the modulated wireless power signal from the transmitter.

16. The inductive wireless power receiving device of claim 14, wherein the modulator is operably coupled to the rectifier and configured to monitor fluctuations of at least one of the time varying signal and the output voltage and generate a demodulated signal to a processor to recover a message from the demodulated signal.

17. The inductive wireless power receiving device of claim 16, wherein the modulator includes a low pass filter, a differential gain amplifier, and a Schmitt trigger serially coupled to receive at least one of the time varying signal and the output voltage and to generate the demodulated signal.

18. An inductive wireless power transfer system, comprising:

a transmitter having a transmit coil configured to generate a modulated wireless power signal in a coupling region for wireless power transfer; and

a receiver having a receive coil configured to couple with the transmit coil by receiving the modulated wireless power signal and to generate an output signal in response thereto to provide power to a load, wherein the modulated wireless power signal includes a characters.

19. The inductive wireless power transfer system of claim 18, further comprising a mobile electronic device that includes the transmitter.

20. The inductive wireless power transfer system of claim 18, wherein the transmitter includes a modulator that is configured to modulate a conversion gain of an input voltage of the transmitter and an output voltage of the receiver.

21. The inductive wireless power transfer system of claim 20, wherein the modulator is configured to adjust a frequency of the modulated wireless power signal to modulate the conversion gain.

22. The inductive wireless power transfer system of claim 20, wherein the modulator is configured to adjust an impedance of the transmitter to modulate the conversion gain.

23. The inductive wireless power transfer system of claim 20, wherein the modulator is configured to adjust the input voltage of the transmitter to modulate the conversion gain.

24. The inductive wireless power transfer system of claim 20, wherein the modulator is configured to adjust an effective input voltage received by the transmit coil to modulate the conversion gain.

25. A method for communicating between a transmitter to a receiver in an inductive wireless power transfer system, the method comprising:

generating a wireless power signal through a transmit coil of a transmitter to a receive coil of a receiver; and

modulating the wireless power signal on the transmitter side for communicating data over the wireless power signal from the transmitter to the receiver.

26. The method of claim 25, wherein modulating the wireless power signal on the transmitter side includes adjusting a switching frequency of switches of an inverter of the transmitter.

27. The method of claim 25, wherein modulating the wireless power signal on the transmitter side includes adjusting a duty cycle of switches of an inverter of the transmitter.

28. The method of claim 25, wherein modulating the wireless power signal on the transmitter side includes adjusting an impedance of the transmitter.

29. The method of claim 25, wherein modulating the wireless power signal on the transmitter side includes adjusting an effective voltage received by the transmit coil of the transmitter.

30. The method of claim 29, wherein adjusting an effective voltage received by the transmit coil of the transmitter includes controlling a switch network of an inverter of the transmitter to have offsetting phases.

31. The method of claim 25, wherein modulating the wireless power signal on the transmitter side includes adjusting an input voltage to the transmitter.