NFC READER HAVING A PASSIVE OPERATING MODE WITH LOW ELECTRICAL CONSUMPTION

• US 20090101716A1
• Filed: 04/15/2008
• Published: 04/23/2009
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Rizzo, Pierre, Mani, Christophe, Dell'Ova, Francis
• Granted Patent: US 7,975,921 B2
• Time in Patent Office: Days
• US Class Current: 235/441
• 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 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H04B 5/0056 for use in interrogation, identification or read/write systems record carriers G06K7/00, G06K19/00; for railways B61L3/12
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

An inductive coupling reader includes a passive interface circuit for modulating the impedance of an antenna circuit and extracting from the antenna circuit a data signal and a RF clock signal, and circuitry for coupling the reader to a removable security module. The reader includes an emulation circuit for opening a RF transmission channel with another reader, a non-removable electrical link linking the emulation circuit to the passive interface circuit, by which the data signal and the RF clock signal are supplied to the emulation circuit, and a data bus clocked by a bus clock signal having a frequency inferior to the frequency of the RF clock signal, for linking the emulation circuit to the removable security module. The reader has low electrical consumption.

Claims

1. An inductive coupling reader, comprising:

a passive interface circuit to modulate an impedance of an antenna circuit and to extract from the antenna circuit a data signal and a RF clock signal;

means for coupling the reader to a removable security module;

an emulation circuit to open a RF transmission channel with another reader, to transfer to the removable security module application data received through the RF transmission channel, and to send in the RF transmission channel application data received from the removable security module;

a non-removable electrical link to link the emulation circuit to the passive interface circuit, by which the data signal and the RF clock signal are supplied to the emulation circuit; and

a data bus clocked by a bus clock signal, having a frequency inferior to a frequency of the RF clock signal, to link the emulation circuit to the removable security module.

2. The reader according to claim 1 wherein the passive interface circuit and the emulation circuit are arranged on a same semi-conductor chip.

3. The reader according to claim 1 wherein the emulation circuit includes an identification register having at least one identifier used by the emulation circuit to identify the reader during opening of the RF transmission channel.

4. The reader according to claim 1 wherein the emulation circuit includes a buffer memory to store application data received via the RF transmission channel, before transfer of said data to the removable security module.

5. The reader according to claim 4 wherein the buffer memory includes at least one FIFO buffer having an input terminal to receive data received via the RF transmission channel and an output terminal linked to the data bus to send these data to the removable security module.

6. The reader according to claim 1 wherein the passive interface circuit extracts from the antenna circuit a continuous supply voltage, the emulation circuit and the removable security module being exclusively powered by this continuous supply voltage.

7. The reader according to claim 1 wherein the data bus includes a ISO 7816 bus.

8. The reader according to claim 1 wherein the bus clock signal has said frequency at least 25 times inferior to the frequency of the RF clock signal.

9. The reader according to claim 1, further comprising a Global System for Mobile Communications (GSM) telephony circuit linked to a Subscriber Identification Module (SIM) card via another data bus.

10. The reader according to claim 9 wherein the SIM card and the removable security module form only one module.

11. The reader according to claim 10 wherein the emulation circuit and the GSM telephony circuit access the removable security module by a common bus shared through a bus multiplexing circuit.

12. A portable device of a personal digital assistant (PDA)-type or mobile phone, comprising a reader according to claim 1.

13. A method for implementing a passive operating mode in an inductive coupling reader having a passive interface circuit and a removable security module, the passive interface circuit being adapted to modulate an impedance of an antenna circuit and to extract from the antenna circuit a data signal and a RF clock signal, the removable security module being adapted to manage a secure application, the method comprising:

providing an emulation circuit distinct from the removable security module and coupling the emulation circuit to the passive interface circuit through a non-removable electrical link by which the data signal and the RF clock signal are supplied to the emulation circuit;

opening a RF transmission channel using the emulation circuit, transferring to the removable security module application data received by the emulation circuit through the RF transmission channel, and sending in the RF transmission channel application data received from the removable security module by the emulation circuit; and

linking the emulation circuit to the removable security module using a data bus clocked by a bus clock signal having a frequency inferior to a frequency of the RF clock signal.

14. The method according to claim 13 wherein the passive interface circuit and the emulation circuit are arranged on a same semi-conductor chip.

15. The method according to claim 13, further comprising providing, in the emulation circuit, an identification register having at least one identifier usable by the emulation circuit to identify the reader during the opening of the RF transmission channel.

16. The method according to claim 13, further comprising providing, in the emulation circuit, a buffer memory to store application data received via the RF transmission channel, before transferring said data to the removable security module.

17. The method according to claim 15, further comprising providing, in the emulation circuit, at least one FIFO buffer having an input terminal to receive data received via the RF transmission channel and an output terminal linked to the data bus to send these data to the removable security module.

18. The method according to claim 13, further comprising extracting a continuous supply voltage from the antenna circuit and applying this voltage to the emulation circuit and to the removable security module as exclusive supply voltage.

19. The method according to claim 13 wherein the data bus used includes a ISO 7816 bus.

20. The method according to claim 13 wherein the bus clock signal has said frequency at least 25 times inferior to the frequency of the RF clock signal.

21. The method according to claim 13 wherein the reader is associated to a Global System for Mobile Communications (GSM) telephony circuit linked to a Subscriber Identification Module (SIM) card, and wherein the SIM card and the removable security module form only one module.

22. The method according to claim 21, further comprising providing a common bus shared by the emulation circuit and the GSM telephony circuit to access the removable security module.

23. An inductive coupling reader formed as an integrated circuit on a semi-conductor chip, the reader comprising:

a first port to couple the integrated circuit to an antenna circuit and a second port to couple the integrated circuit to a removable security module;

a passive interface circuit to modulate an impedance of an antenna circuit and to extract from the antenna circuit a data signal and a RF clock signal;

an emulation circuit to open a RF transmission channel with another reader, then to transfer to the second port application data received through the RF transmission channel, and to send in the RF transmission channel application data received via the second port; and

a non-removable electrical link to link the emulation circuit to the passive interface circuit, by which the data signal and the RF clock signal are supplied to the emulation circuit.

24. The reader according to claim 23 wherein the emulation circuit includes an identification register having at least one identifier used by the emulation circuit to identify the reader during opening of the RF transmission channel.

25. The reader according to claim 23 wherein the emulation circuit includes a buffer memory to store application data received via the RF transmission channel, before transfer of said data to the second port.

26. The reader according to claim 25 wherein the buffer memory includes at least one FIFO buffer having an input terminal to receive data received via the RF transmission channel and an output terminal linked to the second port to send these data to the removable security module.

27. The reader according to claim 23 wherein the passive interface circuit includes a circuit to extract from the antenna circuit a continuous supply voltage and wherein the emulation circuit and the removable security module are exclusively powered by this continuous voltage.

28. The reader according to claim 23, further comprising a contactless chip reader circuit, arranged to apply to the first port a signal to excite the antenna circuit, and a third port linked to the reader circuit, to couple the integrated circuit to an external circuit to control the reader circuit.

29. The reader according to claim 23, further comprising a bus management circuit linked to the second port, and a circuit to extract from the RF clock signal a bus clock signal having a frequency inferior to a frequency of the RF clock signal, and to apply the bus clock signal to the bus management circuit.

30. The reader according to claim 29 wherein the bus management circuit is adapted to manage a ISO 7816 bus.

31. The reader according to claim 29 wherein the circuit to extract from the RF clock signal said bus clock signal is arranged to supply said bus clock signal having said frequency that is at least 25 times inferior to the frequency of the RF clock signal.

32. The reader according to claim 29, further comprising a bus multiplexing circuit having an output terminal linked to the second port, a first input terminal linked to the bus management circuit, and a second input terminal linked to a fourth port of the integrated circuit.

33. An apparatus, comprising:

an antenna circuit;

a passive interface circuit coupled to said antenna circuit, and adapted to modulate an impedance of said antenna circuit and to extract from the antenna circuit a data signal and a RF clock signal;

an emulation circuit coupled to the passive interface circuit to receive the data signal and the RF clock signal from the passive interface circuit, the emulation circuit being adapted to open a RF channel through which to carry application data; and

a data bus coupled to the emulation circuit and clocked by a bus clock signal having a frequency inferior to a frequency of the RF clock signal.

34. The apparatus of claim 33 wherein said data bus is adapted to link said emulation circuit to a security module.

35. The apparatus of claim 34 wherein said application data carried on said RF channel includes application data received through said RF channel and to be transferred to said security module by said emulation circuit, and application data received from said security module by said emulation circuit and to be sent in said RF channel.

36. The apparatus of claim 33 wherein the passive interface circuit and the emulation circuit are arranged on a same semi-conductor chip.

37. The apparatus of claim 33 wherein said emulation circuit includes:

an identification register having at least one identifier usable by the emulation circuit to provide identification during opening of the RF channel; and

a buffer memory to store application data received via the RF channel, before transfer of said data by said emulation circuit.