Near field communication (NFC) coexistance

Patent metadata

Field	Value
Publication number	US-10277058-B2
Application number	US-201615373561-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	May 16, 2016
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

Certain aspects of the present disclosure are generally directed to apparatus and techniques for protecting electronic devices that may be prone to damage by wireless charging fields. For example, the apparatus may include a wireless charging circuit configured to selectively generate a wireless charging field and an impedance detection circuit coupled to the wireless charging circuit and configured to detect an impedance change corresponding to the wireless charging field. In this case, a proximity detection circuit may selectively detect proximity of one or more electronic devices that are prone to damage by the wireless charging circuit. In some aspects, detecting the proximity of the one or more electronic devices is activated based on detecting the impedance change, and wherein generating the wireless charging field comprises reducing a transmit power of the wireless charging field based on detecting the impedance change.

First claim

What is claimed is:

1. An apparatus for wireless charging, comprising:
a wireless charging circuit configured to selectively generate a wireless charging field; and
an impedance detection circuit coupled to the wireless charging circuit and configured to detect an impedance change corresponding to the wireless charging field;
a proximity detection circuit configured to selectively detect proximity of one or more electronic devices that are prone to damage by the wireless charging circuit, wherein the proximity detection circuit is configured to transmit a detection field and detect modulations in the detection field to detect proximity of the one or more electronic devices, wherein detecting the proximity of the one or more electronic devices is activated based on detecting the impedance change, and wherein the wireless charging circuit is configured to reduce a transmit power of the wireless charging field based on detecting the impedance change.

2. The apparatus of claim 1 , wherein reducing the transmit power of the wireless charging field comprises disabling the generation of the wireless charging field.

3. The apparatus of claim 1 , wherein the one or more electronic devices comprise at least one of an near field communication (NFC) card or radio-frequency identification (RFID) card and the proximity detection circuit is configured to modulate the detection field for detecting the at least one NFC card or RFID card, wherein detecting the at least one NFC card or RFID card is based on receiving information via modulation of the detection field by the at least one NFC card or RFID card.

4. The apparatus of claim 1 , wherein:
the wireless charging circuit is configured to selectively transmit, during one or more first time intervals, one or more beacons for detection of one or more other electronic devices to be charged; and
the proximity detection circuit is configured to selectively detect proximity of the one or more electronic devices during one or more second time intervals that are different than the one or more first time intervals.

5. The apparatus of claim 4 , wherein transmitting the one or more beacons is disabled based on the proximity of the one or more electronic devices.

6. The apparatus of claim 4 , wherein the one or more electronic devices comprise at least one of an NFC card or a radio-frequency identification (RFID) card, wherein the transmitting the one or more beacons is disabled based on the detected proximity of the least one of the NFC card or the RFID card.

7. The apparatus of claim 4 , wherein the wireless charging circuit is configured to charge the one or more other electronic devices by generating the wireless charging field based on the detection of the one or more other electronic devices via the one or more beacons.

8. The apparatus of claim 1 , wherein detecting the impedance change comprises detecting a change in impedance of a signal presented to the wireless charging circuit while generating the wireless charging field.

9. The apparatus of claim 1 , wherein the wireless charging circuit and the proximity detection circuit share at least one coil.

10. The apparatus of claim 9 , wherein:
the at least one coil comprises a first coil and a second coil;
a first terminal of the first coil and a first terminal of the second coil are coupled to the wireless charging circuit; and
a second terminal of the first coil and a second terminal of the second coil are coupled to the proximity detection circuit.

11. The apparatus of claim 10 , wherein the first terminal of the first coil and the first terminal of the second coil are coupled when generating the wireless charging field is activated.

12. The apparatus of claim 10 , wherein the second terminal of the first coil and the second terminal of the second coil are coupled when detecting proximity of the one or more electronic devices is activated.

13. The apparatus of claim 10 , wherein:
the wireless charging circuit comprises a first amplifier having an output coupled to a first tuning circuit that is coupled to the first terminals of the first and second coils; and
the proximity detection circuit comprises a second amplifier having an output coupled to a second tuning circuit that is coupled to the second terminals of the first and second coils; and
the apparatus further comprises an isolation circuit configured to electrically couple the first terminals of the first and second coils during wireless charging and the second terminals of the first and second coils during proximity detection.

14. The apparatus of claim 13 , wherein the isolation circuit is configured to electrically couple the first and second terminals of the first and second coils to a reference potential.

15. The apparatus claim 1 , wherein the proximity detection circuit comprises an in-phase and quadrature (I/Q) demodulator configured to detect proximity of the one or more electronic devices, and wherein the I/Q demodulator is also used for detecting the impedance change corresponding to the wireless charging field.

16. The apparatus of claim 1 , wherein the proximity detection circuit is configured to modulate the detection field.

17. An apparatus for wireless charging, comprising:
a wireless charging circuit;
a proximity detection circuit;
a first coil having a first terminal coupled to the wireless charging circuit and a second terminal coupled to the proximity detection circuit;
a second coil having a first terminal coupled to the wireless charging circuit and a second terminal coupled to the proximity detection circuit;
at least one first switch coupled between the first terminals of the first coil and the second coil; and
at least one second switch coupled between the second terminals of the first coil and the second coil.

18. The apparatus of claim 17 , wherein:
the wireless charging circuit further comprises:
a first tuning circuit coupled to the first terminals of the first coil and the second coil; and
a first amplifier coupled to the first tuning circuit; and

the proximity detection circuit comprises:
a second tuning circuit coupled to the second terminals of the first coil and the second coil; and
a second amplifier coupled to the second tuning circuit.

19. The apparatus of claim 17 , wherein:
the second switch is closed during operation of the wireless charging circuit; and
the first switch is closed during operation of the proximity detection circuit.

20. A method for wireless charging, comprising:
selectively generating a wireless charging field;
detecting an impedance change corresponding to the wireless charging field; and
selectively detecting proximity of one or more electronic devices that are prone to damage by the wireless charging field, wherein detecting the proximity of the one or more electronic devices is activated based on detecting the impedance change, wherein detecting proximity of the one or more electronic devices comprises transmitting a detection field and detecting modulations in the detection field, and wherein generating the wireless charging field comprises reducing a transmit power of the wireless charging field based on detecting the impedance change.

21. The method of claim 20 , wherein the one or more electronic devices comprise at least one of an near field communication (NFC) card or radio-frequency identification (RFID) card, and wherein selectively detecting proximity of one or more electronic devices comprises modulating the detection field for detecting the at least

Assignees

• Qualcomm Inc

Inventors

• Wheeland Cody Burton
• Von Novak Iii William Henry
• Irish Linda Stacey

Classifications

• H02J50/20

  using microwaves or radio frequency waves · CPC title

• H02J50/90

  involving detection or optimisation of position, e.g. alignment · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H02J50/12

  of the resonant type · CPC title

• H02J50/10

  using inductive coupling · CPC title