TUNEABLE NFC-ENABLED DEVICE

• US 20130281018A1
• Filed: 06/20/2013
• Published: 10/24/2013
• Est. Priority Date: 02/24/2005
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Broadcom Innovision Limited (Broadcom, Inc.)
• Inventors: WILSON, Robin
• Granted Patent: US 9,305,192 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• 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 7/10237 the reader and the record carrier being capable of selectively switching between reader and record carrier appearance, e.g. in near field communication [NFC] devices where the NFC device may function as an RFID reader or as an RFID tag

Abstract

An NFC-enabled device configured at least in part as an integrated circuit, the integrated circuit including a controller and a plurality of capacitors. The controller is operable to control one or more of the plurality of capacitors to vary an operating parameter of the NFC-enabled device.

Claims

1. A near field communications (NFC)-enabled device, comprising:

a magnetic field sensor configured to sense a magnetic field strength and provide a sensed field strength signal when the magnetic field is less than a threshold; and

a controller configured to vary an operating parameter of the NFC-enabled device in response to the sensed field strength signal.

2. The NFC-enabled device of claim 1, wherein the controller is further configured to:

change, using a peak detection process, the operating parameter in a plurality of increments until a final increment adversely affects the operating parameter; and

set the operating parameter to an increment immediately before the final increment.

3. The NFC-enabled device of claim 1, further comprising:

a plurality of capacitors, coupled to the controller, at least one of the plurality of capacitors being configurable to vary the operating parameter.

4. The NFC-enabled device of claim 3, wherein:

the at least one of the plurality of capacitors is configurable by the controller; and

the operating parameter comprises a capacitance of the at least one of the plurality of capacitors.

5. The NFC-enabled device of claim 3, further comprising:

a plurality of switches, each switch from among the plurality of switches being associated with at least one capacitor from among the plurality of capacitors,

wherein the controller is configured to control at least one of the plurality of switches to activate or deactivate its associated at least one capacitor to vary the operating parameter.

6. The NFC-enabled device of claim 3, wherein the at least one capacitor comprises a varicap diode.

7. The NFC-enabled device of claim 3, wherein:

the at least one capacitor comprises first and second conductive track portions provided in a common layer of the NFC-enabled device, the first and second conductive track portions being spaced from one another to form, respectively, first and second electrodes of a first capacitor; and

the first and second electrodes each include a plurality of transversely extending spaced conducting tabs, the first and second electrodes being arranged such that the plurality of transversely extending spaced conducting tabs of the first electrode are interleaved with the plurality of transversely extending spaced conducting tabs of the second electrode.

8. The NFC-enabled device of claim 1, further comprising:

an inductive coupler;

wherein the controller is further configured to vary the operating parameter of the NFC-enabled device to vary a resonant frequency of the inductive coupler.

9. A communications device, comprising:

a magnetic field sensor configured to sense a magnetic field strength and provide a sensed field strength signal when the magnetic field is less than a threshold; and

a controller configured to vary an operating parameter of the communications device in response to the sensed field strength signal.

10. The communications device of claim 9, wherein the controller is further configured to:

change, using a peak detection process, the operating parameter in a plurality of increments until a final increment adversely affects the operating parameter; and

set the operating parameter to an increment immediately before the final increment.

11. The communications device of claim 9, further comprising:

a plurality of capacitors, coupled to the controller, at least one of the plurality of capacitors being configurable to vary the operating parameter.

12. The communications device of claim 11, wherein:

the at least one of the plurality of capacitors is configurable by the controller; and

the operating parameter comprises a capacitance of the at least one of the plurality of capacitors.

13. The communications device of claim 11, wherein the at least one capacitor comprises a varicap diode.

14. The communications device of claim 11, wherein:

the at least one capacitor comprises first and second conductive track portions provided in a common layer of the NFC-enabled device, the first and second conductive track portions being spaced from one another to form, respectively, first and second electrodes of a first capacitor; and

the first and second electrodes each include a plurality of transversely extending spaced conducting tabs, the first and second electrodes being arranged such that the plurality of transversely extending spaced conducting tabs of the first electrode are interleaved with the plurality of transversely extending spaced conducting tabs of the second electrode.

15. The communications device of claim 9, wherein the communications device comprises a near-field communications (NFC)-enabled device, the NFC-enabled device further comprising:

an inductive coupler;

wherein the controller is further configured to vary the operating parameter of the NFC-enabled device to vary a resonant frequency of the inductive coupler.

16. A near field communications (NFC)-enabled device, comprising:

an inductive coupler configured to inductively receive a signal;

a magnetic field sensor configured to sense a magnetic field strength of the signal and generate a sensed field strength signal when the magnetic field strength is less than a threshold; and

a controller configured to vary an operating parameter of the NFC-enabled device in response to an operating condition of the NFC-enabled device.

17. The NFC-enabled device of claim 16, wherein the operating condition comprises at least one of:

the NFC-enabled device configured to operate as a NFC reader; and

the NFC-enabled device configured to operate as a NFC tag.

18. The NFC-enabled device of claim 16, wherein:

the NFC-enabled device is coupled with a host device; and

the operating condition comprises the receipt of a control signal from the host device.

19. The NFC-enabled device of claim 18, wherein the control signal is generated by the host device based on at least one of:

the attachment of a new battery to the host device; and

the attachment of a new casing to the host device.

20. The NFC-enabled device of claim 16, further comprising:

a plurality of capacitors, coupled to the controller, at least one of the plurality of capacitors being configurable by the controller to vary the operating parameter;

wherein the operating parameter comprises a capacitance of the at least one of the plurality of capacitors.

21. The NFC-enabled device of claim 16, wherein:

the operating condition comprises the sensed field strength signal; and

the controller is configured to vary the operating parameter of the NFC-enabled device in response to the sensed field strength signal.