Radio frequency data communications device

• US 6,735,183 B2
• Filed: 05/02/2000
• Issued: 05/11/2004
• Est. Priority Date: 05/13/1996
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Ovard, David K., Tuttle, John R., Rotzoll, Robert R., Tuttle, Mark E., Lowrey, Tyler, Higgins, Brian P., Yu, Shu-Sun, Devereaux, Kevin M., Pax, George E., OʼToole, James E.
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US09/563,092
• Publication Number:
  US 20030099210A1
• Time in Patent Office: 1,470 Days
• Field of Search: 370/311, 340/10.1, 340/10.33, 340/10.34, 340/7-2-, 342/42, 342/44, 342/51, 342/572.1
• US Class Current: 370/311
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• CPC Class Codes: G06K 19/0716 at least one of the integrated circuit chips comprising a sensor or an interface to a sensor
• 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 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
• 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: G06K 7/10059 transponder driven
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H03L 7/0995 the oscillator comprising a ring oscillator
• CPC Class Codes: H03L 7/148 said digital means comprising a counter or a divider

Abstract

A radio frequency identification device comprises an integrated circuit including a receiver, a transmitter, and a microprocessor. The receiver and transmitter together define an active transponder. The integrated circuit is preferably a monolithic single die integrated circuit including the receiver, the transmitter, and the microprocessor. Because the device includes an active transponder, instead of a transponder which relies on magnetic coupling for power, the device has a much greater range.

Claims

1. A radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device and having an output coupled to the microprocessor, the receiver including an amplifier powered by a selectively engageable voltage source, and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the integrated circuit at times switching between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode, the integrated circuit being configured to switch from the receiver on mode to a microprocessor on mode in response to the wake-up timer circuit determining that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode.

2. The radio frequency device of claim 1, wherein the selectively engageable voltage source is engaged in the receiver on mode but not in the sleep mode, the amplifier including first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output, selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

3. The radio frequency device of claim 2, further comprising a voltage divider, wherein the first mentioned and second resistances are coupled to the voltage source via the voltage divider.

4. The radio frequency device of claim 2, wherein the first mentioned resistances comprise respective transistors.

5. The radio frequency device of claim 2 wherein the first mentioned resistances comprise respective p-type transistors.

6. The radio frequency device of claim 2 wherein the second resistances comprise respective transistors.

7. The radio frequency device of claim 2 wherein the second resistances comprise respective p-type transistors.

8. The radio frequency device of claim 1, further comprising a transmitter configured to transmit a signal indentifying the device to the interrogator in response to a command from the microprocessor.

9. A method of operating a radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device, the receiver including an amplifier, the receiver having an output coupled to the microprocessor, and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the method comprising:

switching the integrated circuit between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode;

determining when the signal received by the receiver is a radio frequency command from the interrogation device; and

switching the integrated circuit to a microprocessor on mode from the receiver on mode when the integrated circuit determines that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode.

10. The method of claim 9, further comprising:

powering the amplifier by a selectively engageable voltage source engaged in the receiver on mode but not in the sleep mode, the amplifier including first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, the amplifier including a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output;

engaging first selectively engageable resistances between the voltage source and respective inputs of the differential amplifier; and

engaging second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

11. The method of claim 10, further comprising;

turning on transistors forming the first selectively engageable resistances in response to the receiver on mode;

waiting for a predetermined interval; and

turning off the transistors forming the first selectively engageable resistances while maintaining the receiver on mode.

12. The method of claim 10, further comprising:

turning on transistors forming the first and second selectively engageable resistances in response to the receiver on mode;

waiting for a predetermined interval; and

turning off the transistors forming the first selectively engageable resistances but not the transistors forming the second selectively engageable resistances while maintaining the receiver on mode.

13. The method of claim 10, further comprising;

turning on p-type transistors forming the first selectively engageable resistances in response to the receiver on mode;

waiting for a predetermined interval; and

turning off the p-type transistors forming the first selectively engageable resistances while maintaining the receiver on mode.

14. The method of claim 10, further comprising:

turning on p-type transistors forming the first and second selectively engageable resistances in response to the receiver on mode;

waiting for a predetermined interval; and

turning off the p-type transistors forming the first selectively engageable resistances but not the p-type transistors forming the second selectively engageable resistances while maintaining the receiver on mode.

15. The method of claim 9, wherein determining comprises determining, via logic in the wake-up timer circuit contained in the integrated circuit, when the signal received by the receiver is a radio frequency comand from the interrogator.

16. The method of claim 9, wherein the inetgarted circuit includes a transmitter, the method further comprising transmitting a signal identifying the device from the transmitter to the interrogator in response to commands from the microprocessor.

17. A radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device and having an output coupled to the microprocessor, a transmitter configured to transmit a signal identifying the device to the interrogator in response to a command from the microprocessor and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the integrated circuit at times switching between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode, the receiver including an amplifier powered by a selectively engageable voltage source engaged in the receiver on mode but not in the sleep mode, the integrated circuit being configured to switch from the receiver on mode to a microprocessor on mode in response to the wake-up timer circuit determining that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode.

18. The radio frequency device of claim 17, wherein the amplifier includes first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output, selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

19. The radio frequency device of claim 18, further comprising a voltage divider, wherein the first mentioned and second resistances are coupled to the voltage source via the voltage divider.

20. The radio frequency device of claim 18, wherein the first mentioned resistances comprise respective transistors.

21. A method of operating a radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device, the receiver including an amplifier, the receiver having an output coupled to the microprocessor, and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the method comprising:

switching the integrated circuit between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode;

determining when the signal received by the receiver is a radio frequency command from the interrogation device;

switching the integrated circuit to a microprocessor on mode from the receiver on mode when the integrated circuit determines that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode; and

powering the amplifier by a selectively engageable voltage source engaged in the receiver on mode but not in the sleep mode, the amplifier including first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, the amplifier including a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output.

22. The method of claim 21, further comprising:

engaging first selectively engageable resistances between the voltage source and respective inputs of the differential amplifier; and

engaging second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

23. The method of claim 22, further comprising;

turning on transistors forming the first selectively engageable resistances in response to the receiver on mode;

waiting for a predetermined interval; and

turning off the transistors forming the first selectively engageable resistances while maintaining the receiver on mode.

24. The method of claim 22, further comprising:

turning on transistors forming the first and second selectively engageable resistances in response to the receiver on mode;

waiting for a predetermined interval; and

turning off the transistors forming the first selectively engageable resistances but not the transistors forming the second selectively engageable resistances while maintaining the receiver on mode.

25. A radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device and having an output coupled to the microprocessor, the receiver including an amplifier powered by a selectively engageable voltage source, a transmitter configured to transmit a signal identifying the device to the interrogator in response to a command from the microprocessor and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the integrated circuit at times switching between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode, the integrated circuit being configured to switch from the receiver on mode to a microprocessor on mode in response to the wake-up timer circuit determining that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode.

26. The radio frequency device of claim 25, wherein the selectively engageable voltage source is engaged in the receiver on mode but not in the sleep mode, wherein the amplifier includes first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output, selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

27. The radio frequency device of claim 26, further comprising a voltage divider, wherein the first mentioned and second resistances are coupled to the voltage source via the voltage divider.

28. The radio frequency device of claim 27, wherein the first mentioned resistances comprise respective transistors.

29. An integrated circuit comprising:

a microprocessor;

a receiver configured to receive radio frequency commands from an interrogation device and having an output coupled to the microprocessor, the receiver including an amplifier powered by a selectively engageable voltage source; and

a control circuit coupled to the receiver and the microprocessor, the control circuit being configured to;

determine when a signal received by the receiver is a radio frequency command from the interrogation device;

switch the integrated circuit between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode; and

switch the integrated circuit from the receiver on mode to a microprocessor on mode in response determining that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode.

30. The radio frequency device of claim 29, wherein the selectively engageable voltage source is engaged in the receiver on mode but not in the sleep mode, the amplifier including first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output, selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

31. The radio frequency device of claim 30, further comprising a transmitter configured to transmit a signal identifying the integrated circuit to the interrogator in response to a command from the microprocessor.

32. A radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device and having an output coupled to the microprocessor, a transmitter configured to transmit a signal identifying the device to the interrogator in response to a command from the microprocessor, and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the radio frequency command from the interrogator including data transition pulses, the integrated circuit at times switching between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode, the integrated circuit switching from the receiver on mode to a microprocessor on mode when logic in a wake-up timer circuit determines that a signal received by the receiver is a radio frequency command from the interrogation device, the logic configured to perform a plurality of tests, each test including counting at least some of the data transition pulses, the determination being made in response to the plurality of tests, the receiver further including an amplifier powered by a selectively engageable voltage source engaged in the receiver on mode but not in the sleep mode, the amplifier including first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output, selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode.

33. The radio frequency device of claim 32, wherein the first mentioned resistances comprise respective transistors.

34. The radio frequency device of claim 32, wherein the first mentioned resistances comprise respective p-type transistors.

35. The radio frequency device of claim 32, further comprising a voltage divider, wherein the first mentioned and second resistances are coupled to the voltage source via the voltage divider.

36. The radio frequency device of claim 32, further comprising a transmitter configured to transmit a signal identifying the device to the interrogator in response to a command from the microprocessor.

37. The radio frequency device of claim 32, wherein the second resistances comprise respective transistors.

38. The radio frequency device of claim 32, wherein the second resistances comprise respective p-type transistors.

39. A method of operating a radio frequency device comprising an integrated circuit including a microprocessor, a receiver configured to receive radio frequency commands from an interrogation device, the radio frequency commands including data transition pulses, the receiver including an amplifier, the receiver having an output coupled to the microprocessor, the integrated circuit including a transmitter configured to transmit a signal identifying the device to the interrogator in response to commands from the microprocessor and a wake-up timer circuit coupled to the receiver and configured to determine when a signal received by the receiver is a radio frequency command from the interrogation device, the method comprising:

switching the integrated circuit between a sleep mode and a receiver on mode, more power being consumed in the receiver on mode than in the sleep mode;

powering the amplifier by a selectively engageable voltage source engaged in the receiver on mode but not in the sleep mode, the amplifier including first and second inputs for receiving an input signal to be amplified, the inputs respectively including coupling capacitors, the amplifier including a differential amplifier having inputs respectively connected to the first and second inputs through the coupling capacitors, and having an output;

engaging first selectively engageable resistances between the voltage source and respective inputs of the differential amplifier;

engaging second selectively engageable resistances between the voltage source and respective inputs of the differential amplifier, the second resistances respectively having smaller values than the first mentioned resistances, the second resistances being engaged then disengaged in response to the integrated circuit switching from the sleep mode to the receiver on mode; and

performing a plurality of tests using the wake-up timer circuit, each test including counting data transition pulses, and making the determination in response to the plurality of tests.

40. The method of claim 39, further comprising switching the integrated circuit to a microprocessor on mode from the receiver on mode when the integrated circuit determines that the signal received by the receiver is a radio frequency command from the interrogation device, more power being consumed in the microprocessor on mode than in the receiver on mode.

41. The method of claim 39, further comprising:

turning on transistors forming the first selectively engageable resistances in response to switching the integrated circuit between the sleep mode and the receiver on mode;

waiting for a predetermined interval; and

turning off the transistors forming the first selectively engageable resistances while maintaining the receiver on mode.

42. The method of claim 39, further comprising:

turning on transistors forming the first selectively engageable resistance in response to switching the integrated circuit between the sleep mode and the receiver on mode;

waiting for a predetermined interval; and

turning off transistors forming the first selectively engageable resistances but not transistors forming the second selectively engageable receives while maintaining the receiver on mode.

43. The method of claim 39, further comprising:

turning on p-type transistors forming the first selectively engagable resistances in response to switching to the receiver on mode;

waiting for a predetermined interval; and

turning off the p-type transistors forming the first selectively engagable resistances while maintaining the receiver on mode.

44. The method of claim 39, further comprising:

turning on p-type transistors forming the first selectively engageable resistances in response to switching to the receiver on mode;

waiting for a predetermined interval; and

turning off the p-type transistors forming the first selectively engagable resistances but not p-type transistors forming the second selectively engagable resistances while maintaining the receiver on mode.

45. The method of claim 39, further comprising transmitting a signal identifying the device from the transmitter to the interrogator in response to commands from the microprocessor.