NFC reader having a passive operating mode with low electrical consumption

• US 7,975,921 B2
• Filed: 04/15/2008
• Issued: 07/12/2011
• Est. Priority Date: 10/17/2005
• Status: Expired due to Fees

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Dell'Ova, Francis, Rizzo, Pierre, Mani, Christophe
• Primary Examiner(s): Le; Thien M.
• Assistant Examiner(s): STANFORD, CHRISTOPHER J
• Application Number:
  US12/103,570
• Publication Number:
  US 20090101716A1
• Time in Patent Office: 1,183 Days
• Field of Search: 235/487, 235/492, 235/441
• 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 5/77 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 to modulate an impedance of an antenna and to extract from the antenna a data signal and a radio-frequency clock signal;

a security module interface configured to couple the reader to at least one removable security module including a Subscriber Identification Module (SIM) card;

an emulator configured to open a radio-frequency transmission channel with another reader, to transfer to the removable security module interface application data received through the radio-frequency transmission channel, and to send in the radio-frequency transmission channel application data received through the security module interface;

an electrical link coupling the emulator to the passive interface by which the data signal and the radio-frequency clock signal are supplied to the emulator;

a baseband communication interface configured to couple the reader to at least one baseband device;

an emulator data bus clocked by a bus clock signal, having a frequency inferior to a frequency of the radio-frequency clock signal and coupled to the emulator; and

a common multiplexed bus coupled to the emulator data bus, to the baseband communication interface and to the security module interface, wherein the emulator and baseband device access the removeable security module through the common multiplexed bus.

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

3. The reader according to claim 1 wherein the emulator includes an identification register having at least one identifier used by the emulator to identify the reader during opening of the radio-frequency transmission channel.

4. The reader according to claim 1 wherein the emulator includes a buffer memory configured to store application data received via the radio-frequency transmission channel, before transfer of said data to the removable security module interface.

5. The reader according to claim 4 wherein the buffer memory includes at least one first-in-first-out buffer having an input terminal configured to receive data received via the radio-frequency transmission channel and an output terminal linked to the emulator data bus to send these data to the security module interface.

6. The reader according to claim 1, further comprising a removeable security module coupled to the security module interface, wherein the passive interface is configured to extract from the antenna a continuous supply voltage, the emulator and the removable security module being exclusively powered by this continuous supply voltage.

7. The reader according to claim 1 wherein the emulator data bus includes an International Organization for Standardization (ISO) 7816 bus.

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

9. The reader according to claim 1 wherein the baseband communication interface is coupled to a Global System for Mobile Communications (GSM) telephony block configured to the SIM card.

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

11. A method for implementing a passive operating mode in an inductive coupling reader having a passive interface and a removable security module, the passive interface being adapted to modulate an impedance of an antenna and to extract from the antenna a data signal and a radio-frequency (RF) clock signal, the removable security module including a Subscriber Identification Module (SIM) card and being adapted to manage a secure application, the method comprising:

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

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

linking the emulator to an emulator data bus clocked by a bus clock signal having a frequency inferior to a frequency of the RF clock; and

coupling the emulator data bus and a baseband communication block to the removable security module through a common multiplexed bus, wherein the emulator and the baseband communication block access the removable security module through the common multiplexed bus.

12. The method according to claim 11 wherein the passive interface and the emulator are arranged on a same semi-conductor chip.

13. The method according to claim 11, further comprising providing, in the emulator, an identification register having at least one identifier usable by the emulator to identify the reader during the opening of the RF transmission channel.

14. The method according to claim 13, further comprising providing, in the emulator, at least one first-in-first-out 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.

15. The method according to claim 11, further comprising providing, in the emulator, a buffer memory to store application data received via the RF transmission channel, before transferring said data to the removable security module.

16. The method according to claim 11, further comprising extracting a continuous supply voltage from the antenna and applying this voltage to the emulator and to the removable security module as exclusive supply voltage.

17. The method according to claim 11 wherein the emulator data bus used includes an International Organization for Standardization (ISO) 7816 bus.

18. The method according to claim 11 wherein the emulator bus clock signal has said frequency at least 25 times inferior to the frequency of the RF clock signal.

19. The method according to claim 11 wherein the baseband communication block is a Global System for Mobile Communications (GSM) telephony block linked tothe SIM card.

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

a first port configured to couple the integrated circuit to an antenna and a second port configured to couple the integrated circuit to a removable security module including a Subscriber Identification Module (SIM) card;

a passive interface coupled to the first port and configured to modulate an impedance of the antenna and to extract from the antenna a data signal and a radio-frequency (RF) clock signal;

an emulator coupled to the passive interface and configured to open a RF transmission channel with another reader, 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;

a third port configured to receive control signals to control the reader; and

a common multiplexed bus system coupled to the second port, to the emulator and to a fourth port of the integrated circuit, wherein the emulator and a baseband device coupled to the fourth port assess the removable security module through the common multiplexed bus system.

21. The reader according to claim 20 wherein the emulator includes an identification register having at least one identifier used by the emulator to identify the reader during opening of the RF transmission channel.

22. The reader according to claim 20 wherein the emulator includes a buffer memory to store application data received via the RF transmission channel, before transfer of said data to the second port.

23. The reader according to claim 22 wherein the buffer memory includes at least one first-in-first-out buffer having an input terminal to receive data received via the RF transmission channel and an output terminal coupled to the second port through the common multiplexed bus system.

24. The reader according to claim 20 wherein the passive interface includes a circuit to extract from the antenna a continuous supply voltage and wherein the emulator and the removable security module are configured to be exclusively powered by this continuous voltage.

25. The reader according to claim 20, further comprising a contactless chip reader arranged to apply to the first port a signal to excite the antenna.

26. The reader according to claim 20, further comprising 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 an emulator bus coupling the common multiplexed bus system to the emulator.

27. The reader according to claim 26 wherein the emulator bus is an International Organization for Standardization (ISO) 7816 bus.

28. The reader according to claim 26 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.

29. An apparatus, comprising:

an antenna module;

a first interface configured to couple to a baseband module;

a passive interface coupled to said antenna module, and adapted to modulate an impedance of said antenna module and to extract from the antenna module a data signal and a radio-frequency (RF) clock signal;

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

a common multiplexed bus system configured to couple the emulator and the first interface to a second interface configured to couple to a removable security module including a Subscriber Identification Module (SIM), wherein the emulator and the baseband module access the removable security module through the common multiplexed bus system.

30. The apparatus of claim 29, further comprising an emulator data bus adapted to link said emulator to the common multiplexed bus system, wherein the emulator data bus is clocked by a bus clock signal having a frequency lower than a frequency of the RF clock signal.

31. The apparatus of claim 30 wherein said application data carried on said RF channel includes application data received through said RF channel and to be transferred to said second interface by said emulator, and application data received from said second interface by said emulator and to be sent in said RF channel.

32. The apparatus of claim 29 wherein the passive interface and the emulator are arranged on a same semi-conductor chip.

33. The apparatus of claim 29 wherein said emulator includes:

an identification register having at least one identifier usable by the emulator 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 emulator.