Passive contactless integrated circuit comprising a flag for monitoring an erase/programming voltage

• US 8,410,910 B2
• Filed: 03/06/2008
• Issued: 04/02/2013
• Est. Priority Date: 09/06/2005
• Status: Active Grant

• Current Assignee: Stmicroelectronics France (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Naura, David, Moreaux, Christophe, Kari, Ahmed, Rizzo, Pierre
• Primary Examiner(s): HOLLOWAY III, EDWIN C
• Application Number:
  US12/043,691
• Publication Number:
  US 20090066483A1
• Time in Patent Office: 1,853 Days
• Field of Search: 340/10.51, 340/10.1, 340/572.1, 342/44, 235/380, 235/492
• US Class Current: 340/10.51
• CPC Class Codes: G06K 19/0713 the arrangement including a power charge pump
• 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: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/30 Power supply circuits
• CPC Class Codes: G11C 5/142 Contactless power supplies, e.g. RF, induction, or IR

Abstract

A passive contactless integrated circuit includes an electrically programmable non-volatile data memory (MEM), a charge accumulation booster circuit for supplying a high voltage necessary for writing data in the memory. The integrated circuit includes a volatile memory point for memorizing an indicator flag, and circuitry for modifying the value of the indicator flag when the high voltage reaches a critical threshold for the first time after activating the booster circuit.

Claims

1. A passive contactless integrated circuit, comprising:

an electrically programmable non-volatile data memory;

a charge accumulation booster circuit to supply a high voltage sufficient to write data in the memory;

a volatile memory cell to store an indicator flag;

means for modifying the indicator flag when the high voltage reaches a threshold for a first time after activating the booster circuit; and

a switch circuit coupled between the charge accumulation booster circuit and the non-volatile data memory to apply the high voltage to the non-volatile data memory as long as the high voltage has reached the threshold at least once after activating the charge accumulation booster circuits.

2. The integrated circuit according to claim 1, further comprising means for preventing the switch circuit from applying the high voltage to the memory as long as the high voltage has not reached the threshold after activating the booster circuit.

3. The integrated circuit according to claim 1 wherein the switch circuit includes a ramp generator to progressively supply the high voltage to the memory.

4. The integrated circuit according to claim 1, further comprising a control unit configured to execute a command to write a datum in the memory and then to send a specific message of information when the flag indicates that the high voltage has not reached the threshold during execution of the write command.

5. The integrated circuit according to claim 1, further comprising a control unit configured to unconditionally perform, in response to a command to write a datum in the memory:

apply an activation signal to the booster circuit so that said booster circuit produces the high voltage;

apply to the memory a write address and a datum to be written; and

apply an activation signal to a switch circuit adapted to supply the high voltage to the memory.

6. The integrated circuit according to claim 1, further comprising a control unit configured to perform, upon reception of a command to write a datum in the memory:

apply an activation signal to the booster circuit, so that said booster circuit produces the high voltage;

apply to the memory a write address and the datum to be written;

if the high voltage reaches the threshold, apply an activation signal to a switch circuit adapted to supply the high voltage to the memory; and

if the high voltage has not reached the threshold at an end of a period of time, not apply the activation signal to the switch circuit and send a specific message of information indicating that the high voltage has not been applied to the memory.

7. The integrated circuit according to claim 1 wherein said means for modifying includes a detection circuit which monitors the high voltage and supplies a detection signal having a value that indicates if the high voltage is lower than the threshold or is superior or equal to the threshold.

8. The integrated circuit according to claim 1 wherein said means for modifying includes a regulator circuit supplying a regulation signal of the booster circuit having an active value each time the high voltage is superior or equal to a regulation threshold.

9. The integrated circuit according to claim 8 wherein the threshold is equal to the regulation threshold.

10. The integrated circuit according to claim 8 wherein said means for modifying includes a detection circuit which monitors the high voltage and supplies a detection signal having a value that indicates if the high voltage is lower than the threshold or is superior or equal to the threshold, wherein the regulation signal and the detection signal are same.

11. The integrated circuit according to claim 1 wherein the volatile memory cell includes a flip-flop having a first control input terminal to give the flag a first value meaning that the high voltage has reached the threshold, and a second control input terminal to give the flag a second value meaning that the high voltage has not reached the threshold.

12. The integrated circuit according to claim 11 wherein said means for modifying includes a detection circuit which monitors the high voltage and supplies a detection signal having a value that indicates if the high voltage is lower than the threshold or is superior or equal to the threshold, wherein the first control input terminal of the flip-flop receives the detection signal.

13. The integrated circuit according to claim 11 wherein the second input terminal of the flip-flop receives at least one of two signals:

a signal to deactivate the booster circuit and a signal to reset the integrated circuit.

14. The integrated circuit according to claim 1, further comprising a charge pump adapted to receive a voltage signal from an antenna and to produce a supply voltage by boosting the voltage signal, wherein the charge accumulation booster circuit is adapted to create the high voltage by boosting the supply voltage.

15. A portable electronic object, comprising:

a portable support and an integrated circuit carried thereby, the integrated circuit including an electrically programmable non-volatile data memory;

a charge accumulation booster circuit coupled to said memory to supply a high voltage sufficient to write data in the memory;

a volatile memory cell to store an indicator flag;

circuitry to modify the indicator flag when the high voltage reaches a threshold for a first time after activation of the booster circuit; and

a switch circuit coupled between the charge accumulation booster circuit and the non-volatile data memory to apply the high voltage to the non-volatile data memory as long as the high voltage has reached the threshold at least once after activating the charge accumulation booster circuit.

16. The portable electronic object according to claim 15 wherein the integrated circuit includes a control unit adapted to execute a command to write a datum in the memory and then to send a specific message of information when the flag indicates that the high voltage has not reached the threshold during execution of the write command.

17. The portable electronic object according to claim 15 wherein the integrated circuit includes a control unit configured to unconditionally perform, in response to a command to write a datum in the memory:

apply an activation signal to the booster circuit so that said booster circuit produces the high voltage;

apply to the memory a write address and a datum to be written; and

apply an activation signal to a switch circuit adapted to supply the high voltage to the memory.

18. The portable electronic object according to claim 15 wherein the integrated circuit includes a control unit configured to perform, upon reception of a command to write a datum in the memory:

apply an activation signal to the booster circuit, so that said booster circuit produces the high voltage;

apply to the memory a write address and the datum to be written;

if the high voltage reaches the threshold, apply an activation signal to a switch circuit adapted to supply the high voltage to the memory; and

if the high voltage has not reached the threshold at an end of period of time, not apply the activation signal to the switch circuit and send a specific message of information indicating that the high voltage has not been applied to the memory.

19. The portable electronic object according to claim 15 wherein the volatile memory cell includes a flip-flop having a first control input terminal to give the flag a first value meaning that the high voltage has reached the threshold, and a second control input terminal to give the flag a second value meaning that the high voltage has not reached the threshold.

20. A method for writing a datum in an electrically programmable non-volatile memory of a passive contactless integrated circuit, the method comprising:

initializing an indicator flag in a volatile memory cell of the integrated circuit;

activating a charge accumulation booster circuit supplying a high voltage sufficient to write the datum in the memory;

changing the indicator flag if the high voltage reaches a threshold for a first time after activating the booster circuit; and

activating a switch circuit coupled between the charge accumulation booster circuit and the non-volatile memory to apply the high voltage to the non-volatile memory as long as the high voltage has reached the threshold at least once after activating the booster circuit.

21. The method according to claim 20, further comprising unconditionally executing stages aimed at writing the datum in the memory, and then sending a message of information concerning the indicator flag if the flag indicates that the high voltage has not reached the threshold during execution of the stages.

22. The method according to claim 20, further comprising regulating the high voltage around a regulation threshold.

23. The method according to claim 22 wherein the threshold is equal to the regulation threshold.

24. The method according to claim 22 wherein the indicator flag is managed by a flip-flop having a control input terminal to which a detection signal is applied having a value that indicates whether the high voltage is inferior to the threshold or is superior or equal to the threshold.

25. The method according to claim 24 wherein the flip-flop is reset when the booster circuit is not active.