Computing device with NFC and active load modulation for mass transit ticketing
An RFID card includes a smartcard controller that receives power from a host device. The RFID card also includes a small inductive device capable of inductive coupling with an RFID reader. The small inductive device is small enough to fit in the form factor of a memory card or SIM card. Enhancement circuits enhance the usable read and write distance of the RFID card.
1. A computing device comprising:
a smartcard controller;
an inductive element to interact with a near field communication (NFC) reader, wherein the inductive element is too small to power the smartcard controller when placed in an interrogating radio frequency field; and
an active transmit driver coupled between the smartcard controller and the inductive element to transmit digital data for mass transit ticketing.
2. The computing device of claim 1 wherein the smartcard controller is coupled to receive power from the computing device.
3. The computing device of claim 1 wherein the inductive element is tuned to be resonant at 13.56 MHz.
4. The computing device of claim 3 wherein the smartcard controller is coupled to receive power from the computing device.
5. The computing device of claim 1 wherein the active transmit driver includes a load modulation driver circuit.
6. The computing device of claim 5 wherein the smartcard controller is coupled to receive power from the computing device.
7. The computing device of claim 1 wherein the mobile device comprises a mobile phone.
8. The computing device of claim 1 wherein the computing device comprises a mobile computing device.
9. A computing device comprising:
a smartcard controller;
an inductive element to interact with a near field communication (NFC) reader, wherein the inductive element is too small to power the smartcard controller when placed in an interrogating radio frequency field; and
a load modulation circuit coupled between the smartcard controller and the inductive element to transmit digital data for mass transit ticketing.
10. The computing device of claim 9 wherein the smartcard controller is coupled to receive power from the computing device.
11. The computing device of claim 9 wherein the inductive element is tuned to be resonant at 13.56 MHz.
12. The computing device of claim 9 wherein the smartcard controller is coupled to receive power from the computing device.
13. The computing device of claim 12 wherein the smartcard controller is coupled to receive power from the computing device.
14. The computing device of claim 9 wherein the computing device comprises a mobile phone.
15. The computing device of claim 9 wherein the computing device comprises a mobile computing device.
16. A computing device comprising:
a smartcard controller;
an inductive element to interact with a near field communication (NFC) reader, wherein the inductive element is too small to power the smartcard controller when placed in an interrogating radio frequency field; and
a performance enhancement circuit coupled between the smartcard controller and the inductive element, the performance enhancement circuit including a load modulation driver circuit to drive the inductive element to transmit digital data for mass transit ticketing.
17. The computing device of claim 16 wherein the smartcard controller is coupled to receive power from the computing device.
18. The computing device of claim 16 wherein the inductive element is tuned to be resonant at 13.56 MHz.
19. The computing device of claim 16 wherein the computing device comprises a mobile phone.
20. The computing device of claim 16 wherein the performance enhancement circuit further includes an amplifier coupled to receive a signal from the inductive coil.