Reverse link signaling via receive antenna impedance modulation

• US 8,965,461 B2
• Filed: 10/10/2008
• Issued: 02/24/2015
• Est. Priority Date: 05/13/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Toncich, Stanley Slavko, Von Novak, William H.
• Primary Examiner(s): Yun, Eugene
• Application Number:
  US12/249,873
• Publication Number:
  US 20090286476A1
• Time in Patent Office: 2,328 Days
• Field of Search: 455/41.1, 455/41.2, 455/572, 455/573, 455/193.2, 455/193.1, 340/567
• US Class Current: 455/572
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10178 including auxiliary means for focusing, repeating or boosting the electromagnetic interrogation field comparable booster antennas integrated on the record carrier itself G06K19/07794
• 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 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• 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 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• 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 50/50 using additional energy repeaters between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/502 the energy repeater being integrated together with the emitter or the receiver
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• 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: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/72 : for local intradevice communication
• CPC Class Codes: H04B 5/79 : for data transfer in combination with power transfer

Abstract

Exemplary embodiments are directed to wireless power transfer including generating an electromagnetic field at a resonant frequency of a transmit antenna to create a coupling-mode region within a near-field of the transmit antenna. A receive antenna placed within the coupling-mode region resonates at or near the resonant frequency. The receive antenna extracts energy from a coupling between the two antennas. Signaling from the receive antenna to the transmit antenna is performed by generating a first power consumption state for the receive antenna to signal a first receive signal state and generating a second power consumption state for the receive antenna to signal a second receive signal state. Signaling from the transmit antenna to the receive antenna is performed by enabling the resonant frequency on the transmit antenna to signal a first transmit signal state and disabling the resonant frequency on the transmit antenna to signal a second transmit signal state.

Claims

1. A wireless power receiver, comprising:

a resonant receive antenna circuit configured to wirelessly receive power via an electromagnetic field generated by a wireless power transmit antenna, the received power at a level sufficient to charge or power a load, the resonant receive antenna circuit further configured to resonate at a frequency of the electromagnetic field generated by the wireless power transmit antenna; and

a switching circuit operably coupled to the resonant receive antenna circuit, the switching circuit configured to change a resonant frequency of the resonant receive antenna circuit when the switching circuit is in a first state and configured to enable the resonant receive antenna circuit to resonate at the frequency of the electromagnetic field when the switching circuit is in a second state, the switching circuit configured to switch between the first state and the second state based on signaling values generated for sending information to the wireless power transmit antenna.

2. The wireless power receiver of claim 1, wherein the switching circuit comprises:

a first switch operably coupled between the resonant receive antenna circuit and a ground;

a rectifier, configured to convert an RF signal, generated by the resonant receive antenna circuit, to a DC signal for supplying power to the load; and

a second switch operably coupled between the resonant receive antenna circuit and the rectifier.

3. The wireless power receiver of claim 2, further comprising a signal extractor configured to receive the RF signal and detect an on/off keying modulation of the RF signal to extract a transmitted digital signal in response to the on/off keying modulation.

4. The wireless power receiver of claim 2, wherein:

in the first state the first switch is closed and the second switch is open; and

in the second state the first switch is open and the second switch is closed.

5. The wireless power receiver of claim 2, wherein:

in the first state the first switch is open and the second switch is open; and

in the second state the first switch is open and the second switch is closed.

6. A wireless power receiver, comprising:

a receive antenna configured to couple with an electromagnetic field generated by a transmit antenna to generate an RF signal;

a rectifier operably coupled to the receive antenna and configured to convert the RF signal to a DC signal for supplying power to a load; and

a signal extractor operably coupled to the receive antenna and configured to extract a transmitted digital signal in response to on/off keying modulation of the RF signal;

a switching circuit operably coupled to the receive antenna and configured to de-tune the receive antenna from coupling with the electromagnetic field when the switching circuit is in a first state and configured to enable the receive antenna to couple with the electromagnetic field when the switching circuit is in a second state,

wherein the switching circuit comprises;

a first switch configured to selectively couple the receive antenna to a capacitor coupled to a ground;

a second switch configured to selectively couple the DC signal to a dummy load coupled to the ground; and

a third switch configured to selectively couple the DC signal to the load.

7. The wireless power receiver of claim 6, wherein the first switch is operably coupled between the receive antenna and a ground and the second switch is operably coupled between the receive antenna and the rectifier.

8. A method for receiving power, comprising:

wirelessly receiving power by a resonant receive antenna circuit via an electromagnetic field generated by a wireless power transmit antenna, the received power at a level sufficient to charge or power a device;

changing a resonant frequency of the resonant receive antenna circuit when a switching circuit operatively coupled to the resonant receive antenna circuit is in a first state; and

enabling the resonant receive antenna circuit to resonate at a frequency of the electromagnetic field when the switching circuit is in a second state,

switching between the first state and the second state according to signaling values generated for sending information to the wireless power transmit antenna.

9. The method of claim 8, wherein the switching circuit comprises:

a first switch operably coupled between the resonant receive antenna and a ground;

a rectifier, configured to convert an RF signal, generated by the resonant receive antenna circuit to a DC signal for supplying power to the device; and

a second switch operably coupled between the resonant receive antenna circuit and the rectifier.

10. The method of claim 9, further comprising detecting an on/off keying modulation of the RF signal to extract a transmitted digital signal based on the on/off keying modulation.

11. The method of claim 9, wherein:

in the first state the first switch is closed, the second switch is open; and

in the second state the first switch is open and the second switch is closed.

12. The method of claim 9, wherein:

in the first state the first switch is open and the second switch is open; and

in the second state the first switch is open and the second switch is closed.

13. An apparatus for receiving power, comprising:

means for wirelessly receiving power from an electromagnetic field generated by a wireless power transmit antenna at a level sufficient to charge or power load, the means for wirelessly receiving power configured to resonate at a frequency of the electromagnetic field generated by the wireless power transmit antenna,

means for changing a resonant frequency of the means for wirelessly receiving power, the means for changing comprising means for switching the resonant frequency of the means for wirelessly receiving power, the means for switching operatively coupled to the means for wirelessly receiving power,

wherein the means for switching is configured to change the resonant frequency of the means for wirelessly receiving power when the means for switching is in a first state, and configured to enable the means for wirelessly receiving power to resonate at the frequency of the electromagnetic field when the means for switching is in a second state, the means for switching further configured to switch between the first and second states according to signaling values generated for sending information to the transmit antenna.

14. The apparatus of claim 13, wherein the means for switching further comprises

first means for switching operably coupled between the means for wirelessly receiving power and a ground;

means for converting an RF signal generated by the means for wirelessly receiving power to a DC signal for supplying power to the load, and

second means for switching operably coupled between the means for wirelessly receiving power and the converting means.

15. The apparatus of claim 13, further comprising means for signaling based on the on/off keying modulation.

16. The apparatus of claim 14, wherein:

in the first state the first means for switching is closed and the second means for switching is open; and

in the second state the first means for switching is open and the second means for switching is closed.

17. The apparatus of claim 14, wherein:

in the first state the first means for switching is open and the second means for switching is open; and

in the second state the first means for switching is open and the second means for switching is closed.

18. A wireless power receiver, comprising:

a receive antenna configured to couple with an electromagnetic field generated by a transmit antenna, the receive antenna further configured to generate an RF signal in response to the coupling; and

a switching circuit operably coupled to the receive antenna, the switching circuit configured to couple the receive antenna with the electromagnetic field, drawing a first amount of power from the electromagnetic field when the switching circuit is in a first state and configured to enable the receive antenna to couple with the electromagnetic field, drawing a second amount of power from the electromagnetic field when the switching circuit is in a second state, the first amount of power less than the second amount of power the switching circuit further configured to supply power to a load based on the generated RF signal when the switching circuit is in the second state, the switching circuit comprising;

a first switch configured to selectively couple the receive antenna to a capacitor coupled to a ground;

a second switch configured to selectively couple an output of a rectifier with a dummy load coupled to the ground; and

a third switch configured to selectively couple the output of the rectifier with the load.

19. The wireless power receiver of claim 18, wherein the rectifier is operably coupled to the receive antenna and configured to convert the RF signal to a DC signal for supplying power to the load.

20. The wireless power receiver of claim 19, wherein:

in the first state the first switch is closed, the second switch is open and the third switch is closed; and

in the second state the first switch is open, the second switch is open and the third switch is closed.

21. The wireless power receiver of claim 19, wherein:

in the first state the first switch is closed, the second switch is open and the third switch is closed; and

in the second state the first switch is open, the second switch is closed and the third switch is open.

22. The wireless power receiver of claim 19, wherein:

in the first state the first switch is open, the second switch is closed and the third switch is open; and

in the second state the first switch is open, the second switch is open and the third switch is closed.

23. A method for receiving power, comprising:

coupling, by a receive antenna, with an electromagnetic field generated by a transmit antenna;

generating, by the receive antenna, an RF signal in response to the coupling;

coupling the receive antenna with the electromagnetic field, drawing a first amount of power from the electromagnetic field when a switching circuit is in a first state; and

enabling the receive antenna to couple with the electromagnetic field, drawing a second amount of power when the switching circuit is in a second state, the first amount of power less than the second amount of power, the switching circuit configured to supply power to a load based on the generated RF signal when the switching circuit is in the second state, the switching circuit comprising;

a first switch configured to selectively couple the receive antenna to a capacitor coupled to a ground;

a second switch configured to selectively couple an output of a rectifier with a dummy load coupled to the ground; and

a third switch configured to selectively couple the output of the rectifier with the load.

24. The method of claim 23, further comprising:

converting, by a rectifier, the RF signal to a DC signal for supplying power to the load.

25. The method of claim 24, wherein:

in the first state the first switch is closed, the second switch is open and the third switch is closed; and

in the second state the first switch is open, the second switch is open and the third switch is closed.

26. The method of claim 24, wherein:

in the first state the first switch is closed, the second switch is open and the third switch is closed; and

in the second state the first switch is open, the second switch is closed and the third switch is open.

27. The method of claim 24, wherein:

in the first state the first switch is open, the second switch is closed and the third switch is open; and

in the second state the first switch is open, the second switch is open and third switch is closed.

28. An apparatus for receiving power, comprising:

means for coupling with an electromagnetic field generated by a transmit antenna;

means for generating an RF signal;

means for causing the means for coupling to draw a first amount of power from the electromagnetic field when means for switching is in a first state; and

means for enabling the means for coupling to couple with the electromagnetic field, drawing a second amount of power from the electromagnetic field, when the means for switching is in a second state, the first amount of power less than the second amount of power, the means for switching configured to supply power to a load based on the generated RF signal when the means for switching is in the second state, the means for switching comprising;

first means for switching to selectively couple the means for coupling to a capacitor coupled to a ground;

second means for switching to selectively couple an output of means for rectifying with a dummy load coupled to the ground; and

third means for switching to selectively couple the output of the means for rectifying with the load.

29. The apparatus of claim 28, further comprising:

means for converting the RF signal to a DC signal for supplying power to the receive device.

30. The apparatus of claim 29, wherein:

in the first state the first means is closed, the second means is open and the third means is closed; and

in the second state the first means is open, the second means is open and the third means is closed.

31. The apparatus of claim 29, wherein:

in the first state the first means is closed, the second means is open and the third means is closed; and

in the second state the first means is open, the second means is closed and the third means is open.

32. The apparatus of claim 29, wherein:

in the first state the first means is open, the second means is closed and the third means is open; and

in the second state the first means is open, the second means is open and the third means is closed.