METHODS AND APPARATUS FOR IMPLEMENTING PRESENCE AND USAGE PATTERN DETECTION IN WIRELESS CHARGING APPLICATIONS

• US 20160301252A1
• Filed: 04/05/2016
• Published: 10/13/2016
• Est. Priority Date: 04/10/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Govindaraj, Arvind, Von Novak, William Henry III, Chi, Mei-Li
• Granted Patent: US 10,411,512 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• 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 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An apparatus for wirelessly transferring charging power is provided. The apparatus comprises a coupler configured to generate a wireless field when driven with a time-varying current. The apparatus comprises a measurement circuit configured to determine a parasitic capacitance between the coupler and ground while the coupler generates the wireless field. The apparatus comprises a controller circuit configured to determine a presence of a foreign object in response to the determined parasitic capacitance satisfying a detection criteria. The detection criteria may comprises a time-varying pattern of the determined parasitic capacitance predetermined to correspond to presence of a presence of the foreign object. The detection criteria may also comprises a threshold change in the determined parasitic capacitance predetermined to correspond to presence of a presence of the foreign object.

Claims

1. An apparatus for wirelessly transferring charging power, comprising:

a coupler configured to generate a wireless field in response to being driven with a time-varying current;

a measurement circuit configured to determine a parasitic capacitance between the coupler and ground while the coupler generates the wireless field; and

a controller circuit configured to determine a presence of a foreign object in response to the determined parasitic capacitance satisfying a detection criteria.

2. The apparatus of claim 1, wherein the detection criteria comprises a time-varying pattern of the determined parasitic capacitance predetermined to correspond to a presence of the foreign object.

3. The apparatus of claim 1, wherein the detection criteria comprises a threshold change in the determined parasitic capacitance.

4. The apparatus of claim 1, wherein the controller circuit is configured to adjust the time varying current driving the coupler in response to determining the presence of the foreign object.

5. The apparatus of claim 1, wherein:

the measurement circuit is configured to determine the parasitic capacitance at each of a plurality of time instants; and

the controller circuit is configured to determine the presence of the foreign object in response to a correlation of the determined parasitic capacitance at each of the plurality of time instants satisfying a predetermined relationship.

6. The apparatus of claim 1, further comprising a communication circuit configured to receive a signal from a chargeable device, the signal indicating a presence of the chargeable device for wireless charging,

wherein the controller circuit is configured to adjust at least one operating parameter of the coupler in response to the communication circuit receiving the signal from the chargeable device.

7. The apparatus of claim 1, wherein the foreign object comprises a human, another living animal, or a non-metallic object.

8. The apparatus of claim 1, wherein the coupler is further configured to wirelessly transfer the charging power to a chargeable device via a magnetic field component of the wireless field.

9. A method for wirelessly transferring charging power, comprising:

generating, at a coupler, a wireless field when driven with a time-varying current;

determining a parasitic capacitance between the coupler and ground while the coupler generates the wireless field; and

determining a presence of a foreign object in response to the determined parasitic capacitance satisfying a detection criteria.

10. The method of claim 9, wherein the detection criteria comprises a time-varying pattern of the determined parasitic capacitance predetermined to correspond to a presence of the foreign object.

11. The method of claim 9, wherein the detection criteria comprises a threshold change in the determined parasitic capacitance predetermined to correspond to a presence of the foreign object.

12. The method of claim 9, further comprising adjusting the time varying current driving the coupler in response to determining the presence of the foreign object.

13. The method of claim 9, further comprising:

determining the parasitic capacitance at each of a plurality of time instants; and

determining the presence of the foreign object in response to a correlation of the determined parasitic capacitance at each of the plurality of time instants satisfying a predetermined relationship.

14. The method of claim 9, further comprising:

receiving a signal from a chargeable device, the signal indicating a presence of the chargeable device for wireless charging; and

adjusting at least one operating parameter of the coupler in response to receiving the signal from the chargeable device.

15. The method of claim 9, wherein the foreign object comprises a human, another living animal, or a non-metallic object.

16. The method of claim 9, further comprising wirelessly transferring the charging power to a chargeable device via a magnetic field component of the wireless field.

17. An apparatus for wirelessly transferring charging power, comprising:

means for generating a wireless field when driven with a time-varying current;

means for determining a parasitic capacitance between the means for generating and ground while the means for generating generates the wireless field; and

means for determining a presence of a foreign object in response to the determined parasitic capacitance satisfying a detection criteria.

18. The apparatus of claim 17, wherein the detection criteria comprises a time-varying pattern of the determined parasitic capacitance predetermined to correspond to a presence of the foreign object.

19. The apparatus of claim 17, wherein the detection criteria comprises a threshold change in the determined parasitic capacitance predetermined to correspond to a presence of the foreign object.

20. The apparatus of claim 17, further comprising means for adjusting the time varying current driving the means for generating in response to determining the presence of the foreign object.

21. The apparatus of claim 17, further comprising:

means for determining the parasitic capacitance at each of a plurality of time instants; and

means for determining the presence of the foreign object in response to a correlation of the determined parasitic capacitance at each of the plurality of time instants satisfying a predetermined relationship.

22. The apparatus of claim 17, further comprising:

means for receiving a signal from a chargeable device, the signal indicating a presence of the chargeable device for wireless charging; and

means for adjusting at least one operating parameter of the means for generating in response to receiving the signal from the chargeable device.

23. The apparatus of claim 17, wherein means for generating a wireless field wirelessly transfers the charging power to a chargeable device via a magnetic field component of the wireless field.