Low power detection of wireless power devices

• US 9,419,470 B2
• Filed: 05/08/2014
• Issued: 08/16/2016
• Est. Priority Date: 09/23/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Von Novak, William Henry III, Carobolante, Francesco, Braun, Weston Daniel
• Primary Examiner(s): Diao, M'Baye
• Application Number:
  US14/273,234
• Publication Number:
  US 20150084586A1
• Time in Patent Office: 831 Days
• Field of Search: 320/108, 307/104
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• 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 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

Exemplary embodiments are directed to detection and validation of wirelessly chargeable devices positioned within a charging region of a wireless power transmitter. A device may include a detection circuit comprising an oscillator, the detection circuit configured to detect a change in a frequency of the oscillator. The device may also include a wireless power transmitter configured to determine whether a chargeable device is positioned within a charging region of the transmitter upon the detection circuit detecting the change in the frequency of the oscillator, wherein the transmitter further configured to be selectively electrically isolated from the detection circuit.

Claims

1. A device for providing wireless power, comprising:

a detection circuit comprising an oscillator, the detection circuit configured to detect a change in a frequency of the oscillator; and

a wireless power transmitter configured to determine whether a chargeable device is positioned within a charging region of the transmitter upon the detection circuit detecting the change in the frequency of the oscillator, wherein the transmitter further configured to be electrically isolated from the detection circuit, wherein the transmitter is further configured to operate in one of at least a first and second power state, the first power state having a lower power output from the transmitter than the second power state, wherein the transmitter is configured to transition from the first power state to the second power state based on detecting the change in the frequency of the oscillator.

2. The device of claim 1, further comprising an isolator configured to couple the detection, circuit to the transmitter, wherein the isolator comprises a switch, directional coupler, transformer, or separate coupling coil.

3. The device of claim 1, wherein the detection circuit comprises a coil coupled to a coil of the transmitter, wherein the detection circuit coil is configured to excite the transmitter coil.

4. The device of claim 1, wherein the detection circuit is selectively operational based on an operational characteristic of the transmitter.

5. The device of claim 1, wherein the transmitter is further configured to attempt to establish a communication link with the chargeable device, or attempt to charge the chargeable device, to determine whether the chargeable device is present within an associated charging region.

6. The device of claim 1, wherein the transmitter is further configured to transmit a periodic signal in response to detecting the change in the frequency of the oscillator.

7. The device of claim 1, wherein the change in frequency of the oscillator is a result of a change in a resonant frequency of a resonant circuit, the resonant circuit comprising a transmit resonator of the transmitter.

8. A device for providing wireless power, comprising:

a detection circuit configured to detect a change in a phase of a signal measured by the detection circuit; and

a wireless power transmitter configured to determine whether a chargeable device is positioned within a charging region of the transmitter upon the detection circuit detecting the change in the phase of the signal, wherein the transmitter is further configured to operate in one of at least a first and second power state, the first power state having a lower power output from the transmitter than the second power state, wherein the transmitter is configured to transition from the first power state to the second power state based on detecting the change in the phase of the signal measured by the detection circuit.

9. The device of claim 8, wherein the detection circuit comprises a phase locked loop or a reference clock and a phase comparator.

10. The device of claim 8, wherein the detection circuit is further configured to be selectively electrically isolated from the transmitter by coupling the detection circuit to the transmitter via a switch, directional coupler, transformer, or separate coupling coil.

11. The device of claim 8, wherein the detection circuit comprises a coil coupled to a coil of the transmitter, wherein the detection circuit coil is configured to excite the transmitter coil.

12. The device of claim 8, wherein the detection circuit is selectively operational based on an operational characteristic of the transmitter.

13. The device of claim 8, wherein the transmitter is further configured to attempt to establish a communication link with the chargeable device, or attempt to charge the chargeable device, to determine whether the chargeable device is present within an associated charging region.

14. The device of claim 8, wherein the transmitter is further configured to transmit a periodic signal in response to detecting the change in the phase of the signal.

15. The device of claim 8, wherein the change in phase of the signal is a result of a change in a phase of a resonant circuit, the resonant circuit comprising a transmit resonator of the transmitter.

16. A device for providing wireless power, comprising:

a detection circuit comprising a differential antenna, the detection circuit configured to detect a change in a voltage or current at a center tap point of the differential antenna; and

a wireless power transmitter configured to determine whether a chargeable device is positioned within a charging region of the transmitter upon the detection circuit detecting the change in the voltage or current at the center tap point.

17. The device of claim 16, wherein the detection circuit further configured to be selectively electrically isolated from the transmitter via a switch, directional coupler, transformer, or separate coupling coil.

18. The device of claim 16, wherein the detection circuit comprises a coil coupled to a coil of the transmitter, wherein the detection circuit coil is configured to excite the transmitter coil.

19. The device of claim 16, wherein the detection circuit is selectively operational based on an operational characteristic of the transmitter.

20. The device of claim 16, wherein the transmitter is further configured to attempt to establish a communication link with the chargeable device, or attempt to charge the chargeable device, to determine whether the chargeable device is present within an associated charging region.

21. The device of claim 16, wherein the transmitter is further configured to operate in one of at least a first and, second power state, the first power state having a lower power output from the transmitter than the second power state, wherein the transmitter is configured to transition from the first power state to the second power state based on detecting the change in the voltage or current.

22. The device of claim 16, wherein the transmitter is further configured to transmit a periodic signal in response to detecting the change in the voltage or current.

23. A method for providing wireless power, comprising:

detecting a change in a frequency of an oscillator of a detection circuit;

determining whether a chargeable device is positioned within a charging region of a wireless power transmitter upon detecting the change in the frequency of the oscillator; and

transitioning from a first power state to a second power state based on detecting the change in the frequency of the oscillator, the first Rower state having a lower power output from the transmitter than the second power state.

24. The method of claim 23, wherein the detection circuit is selectively operational based on an operational characteristic of the transmitter.

25. The method of claim 23, wherein determining whether the chargeable device is positioned within a charging region further comprises attempting to establish a communication link with the chargeable device or attempting to charge the chargeable device to determine whether the chargeable device is present within an associated charging region in response to detecting the change in the frequency.

26. The method of claim 23, further comprising transmitting a periodic signal in response to detecting the change in the voltage or current.

27. The method of claim 23, wherein the change in the frequency of the oscillator is a result of a change in a frequency of a resonant circuit, the resonant circuit comprising a transmit resonator of the transmitter.