Methods and apparatus for implementing presence and usage pattern detection in wireless charging applications

• US 10,411,512 B2
• Filed: 04/05/2016
• Issued: 09/10/2019
• Est. Priority Date: 04/10/2015
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Govindaraj, Arvind, Von Novak, III, William Henry, Chi, Mei-Li
• Primary Examiner(s): Donovan, Lincoln D
• Assistant Examiner(s): Cheng, Diana J.
• Application Number:
  US15/090,920
• Publication Number:
  US 20160301252A1
• Time in Patent Office: 1,253 Days
• Field of Search: 307104, 320108
• 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 for charging a chargeable device in response to being driven with a time-varying current, the wireless field being at a power level that is sufficient to charge the chargeable device;

a measurement circuit configured to determine a parasitic capacitance between the coupler and ground based on a presence of one or more objects in the wireless field while the coupler generates the wireless field;

a communication circuit configured to receive a connection request from the chargeable device; and

a controller circuit configured to;

determine a presence of a foreign object in response to the determined parasitic capacitance satisfying a detection criteria; and

determine a presence of the chargeable device for wireless charging in response to determining the presence of the foreign object and receiving the connection request.

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, wherein the communication circuit is further configured to receive a signal from the chargeable device, the signal indicating the presence of the chargeable device for wireless charging, and wherein the controller circuit is further 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 the 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 for charging a chargeable device when driven with a time-varying current, the wireless field being at a power level that is sufficient to charge the chargeable device;

determining a parasitic capacitance between the coupler and ground based on a presence of one or more objects in the wireless field while the coupler generates the wireless field;

receiving, at a communication circuit, a connection request from the chargeable device;

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

determining a presence of the chargeable device for wireless charging in response to determining the presence of the foreign object and receiving the connection request.

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 the chargeable device, the signal indicating the 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 the 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 for charging a chargeable device when driven with a time-varying current, the wireless field being at a power level that is sufficient to charge the chargeable device;

means for determining a parasitic capacitance between the means for generating and ground based on a presence of one or more objects in the wireless field while the means for generating generates the wireless field;

means for receiving a connection request from the chargeable device;

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

means for determining a presence of the chargeable device for wireless charging in response to determining the presence of the foreign object and receiving the connection request.

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 the chargeable device, the signal indicating the 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 the chargeable device via a magnetic field component of the wireless field.