RFID-UHF integrated circuit

1. A contactless integrated circuit comprising:

a radiofrequency identification (RFID) communication interface comprising an antenna coil that receives a first induced alternating voltage when the integrated circuit is in the presence of a radiofrequency magnetic field,

an ultrahigh frequency (UHF) communication interface comprising a UHF antenna that receives a second induced alternating voltage when the contactless integrated circuit is in the presence of a UHF electric field signal,

a data processing unit equipped with an electrically programmable and erasable memory,

an interface multiplexer that couples the data processing unit to the RFID communication interface or the UHF communication interface,

a communication mode detection circuit that delivers a mode signal, the value of which indicates which communication interface is active,

a first modulation and demodulation circuit that sends and receives data via the antenna coil,

a second modulation and demodulation circuit that sends and receives data via the UHF antenna, and

multiplexer and demultiplexer circuits driven by the mode signal to link the data processing unit to one of the two modulation and demodulation circuits.

2. The contactless integrated circuit according to claim 1 , comprising:

a first electrical supply circuit that extracts a first supply voltage from the first induced alternating voltage,

a second electrical supply circuit that extracts a second supply voltage from the second induced alternating voltage,

a line that distributes an internal electrical supply voltage, the line being coupled to the first electrical supply circuit and to the second electrical supply circuit.

3. The contactless integrated circuit according to claim 2 , further comprising:

at least one switch having a terminal coupled to the distribution line and a terminal coupled to the first or the second electrical supply circuit, and

a circuit that controls the switch and that is configured to close the switch when a supply voltage is present on the terminal coupled to the first or the second electrical supply circuit.

4. The contactless integrated circuit according to claim 3 , wherein the control circuit is configured to open the switch as a priority when the mode signal has a value corresponding to a communication mode in which an electric voltage is not present or should not be present on the terminal coupled to the first or the second electrical supply circuit.

5. The contactless integrated circuit according to claim 1 , wherein the mode signal is applied to the data processing unit, the data processing unit is configured to implement at least one RFJD data transmission protocol and a UHF data transmission protocol and to select one of the UHF and RFID protocols according to the value of the mode signal.

6. The contactless integrated circuit according to claim 1 , wherein the communication mode detection circuit is configured to detect the first induced voltage at the terminals of the coil and to set the mode signal to a determined value when the first induced voltage is detected.

7. The contactless integrated circuit according to claim 1 , wherein the communication mode detection circuit comprises a detector of oscillations of the first induced voltage.

8. The contactless integrated circuit according to claim 3 , wherein the circuit that controls the switch comprises a booster circuit delivering a voltage that closes the switch.

9. The contactless integrated circuit according to claim 1 , wherein the contactless integrated circuit is arranged on a portable medium and forms one of an electronic tag and a contactless smart card.

10. A contactless integrated circuit comprising:

a radiofrequency identification (RFID) communication interface comprising an antenna coil that receives a first induced alternating voltage when the integrated circuit is in the presence of a radiofrequency magnetic field,

an ultrahigh frequency (UHF) communication interface comprising a UHF antenna that receives a second induced alternating voltage when the contactless integrated circuit is in the presence of a UHF electric field signal,

a data processing unit equipped with an electrically programmable and erasable memory,

an interface multiplexer that couples the data processing unit to the RFID communication interface or the UHF communication interface,

a distribution line that distributes an internal electrical supply voltage,

a communication mode detection circuit that delivers a mode signal, the value of which indicates which communication interface is active,

a first clock generator configured to extract a first clock signal from the first induced voltage, by dividing the frequency of the first induced voltage,

a second clock generator comprising an oscillator that delivers a second clock signal, and

a circuit that activates the second clock generator when the contactless integrated circuit receives data through the UHF communication interface,

wherein the second clock generator is powered through the distribution line and is activated by the mode signal when the mode signal has a determined value.

11. The contactless integrated circuit according to claim 10 , further comprising:

a first electrical supply circuit that extracts a first supply voltage from the first induced alternating voltage,

a second electrical supply circuit that extracts a second supply voltage from the second induced alternating voltage, and

wherein the distribution line is coupled to the first electrical supply circuit and to the second electrical supply circuit.

12. The contactless integrated circuit according to claim 10 , further comprising:

at least one switch having a terminal coupled to the distribution line and a terminal coupled to the first or the second electrical supply circuit, and

a circuit that controls the switch and that is configured to close the switch when a supply voltage is present on the terminal coupled to the first or the second electrical supply circuit.

13. The contactless integrated circuit according to claim 12 , wherein the control circuit is configured to open the switch as a priority when the mode signal has a value corresponding to a communication mode in which an electric voltage is not present or should not be present on the terminal coupled to the first or the second electrical supply circuit.

14. The contactless integrated circuit according to claim 10 , wherein the mode signal is applied to the data processing unit, the data processing unit is configured to implement at least one RFID data transmission protocol and a UHF data transmission protocol and to select one of the UHF and RFID protocols according to the value of the mode signal.

15. The contactless integrated circuit according to claim 10 , wherein the communication mode detection circuit is configured to detect the first induced voltage at the terminals of the coil and to set the mode signal to a determined value when the first induced voltage is detected.

16. The contactless integrated circuit according to claim 10 , wherein the communication mode detection circuit comprises a detector of oscillations of the first induced voltage.

17. The contactless integrated circuit according to claim 10 , wherein the communication mode detection circuit comprises a threshold detector to detect a threshold of the first induced voltage.

18. The contactless integrated circuit according to claim 10 , wherein the contactless integrated circuit is arranged on a portable medium and forms one of an electronic tag and a contactless smart card.

19. A contactless integrated circuit comprising:

a radiofrequency identification (RFID) communication interface comprising an antenna coil that receives a first induced alternating voltage when the integrated circuit is in the presence of a radiofrequency magnetic field,

an ultrahigh frequency (UHF) communication interface comprising a UHF antenna that receives a second induced alternating voltage when the contactless integrated circuit is in the presence of a UHF electric field signal,

a data processing unit equipped with an electrically programmable and erasable memory,

an interface multiplexer that couples the data processing unit to the RFID communication interface or the UHF communication interface,

a communication mode detection circuit that delivers a mode signal, the value of which indicates which communication interface is active,

a first clock generator configured to extract a first clock signal from the first induced voltage, by dividing the frequency of the first induced voltage,

a second clock generator comprising an oscillator that delivers a second clock signal,

a circuit that activates the second clock generator when the contactless integrated circuit receives data through the UHF communication interface, and

a multiplexer circuit driven by the mode signal, the multiplexer receiving the output of the first clock generator and the output of the second clock generator at input and delivering an internal clock signal applied to the data processing unit.

20. The contactless integrated circuit according to claim 19 , further comprising:

a first electrical supply circuit that extracts a first supply voltage from the first induced alternating voltage,

a second electrical supply circuit that extracts a second supply voltage from the second induced alternating voltage, and

a line that distributes an internal electrical supply voltage, the line being coupled to the first electrical supply circuit and to the second electrical supply circuit.

21. The contactless integrated circuit according to claim 19 , further comprising:

at least one switch having a terminal coupled to the distribution line and a terminal coupled to the first or the second electrical supply circuit, and

a circuit that controls the switch and that is configured to close the switch when a supply voltage is present on the terminal coupled to the first or the second electrical supply circuit.

22. The contactless integrated circuit according to claim 21 , wherein the control circuit is configured to open the switch as a priority when the mode signal has a value corresponding to a communication mode in which an electric voltage is not present or should not be present on the terminal coupled to the first or the second electrical supply circuit.

23. The contactless integrated circuit according to claim 19 , wherein the mode signal is applied to the data processing unit, the data processing unit is configured to implement at least one RFID data transmission protocol and a UHF data transmission protocol and to select one of the UHF and RFID protocols according to the value of the mode signal.

24. The contactless integrated circuit according to claim 19 , wherein the communication mode detection circuit is configured to detect the first induced voltage at the terminals of the coil and to set the mode signal to a determined value when the first induced voltage is detected.

25. The contactless integrated circuit according to claim 19 , wherein the communication mode detection circuit comprises a detector of oscillations of the first induced voltage.

26. The contactless integrated circuit according to claim 19 , wherein the communication mode detection circuit comprises a threshold detector to detect a threshold of the first induced voltage.

27. The contactless integrated circuit according to claim 19 , wherein the contactless integrated circuit is arranged on a portable medium and forms one of an electronic tag and a contactless smart card.