Radio frequency data communications device

• US 6,774,685 B2
• Filed: 04/03/2000
• Issued: 08/10/2004
• Est. Priority Date: 05/13/1996
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Tuttle, John R., Rotzoll, Robert R., Lowrey, Tyler, Yu, Shu-Sun, Devereaux, Kevin M., Ovard, David K., Tuttle, Mark E., Higgins, Brian P., Pax, George E., OʼToole, James E.
• Primary Examiner(s): LAM, TUAN THIEU
• Application Number:
  US09/542,406
• Publication Number:
  US 20010050580A1
• Time in Patent Office: 1,590 Days
• Field of Search: 327/147, 327/149, 327/150, 327/155, 327/156, 327/158, 327/159, 331/57, 331/34, 331/15, 331/17
• US Class Current: 327/156
• 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 19/07758 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: 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. An apparatus for determining when frequency lock occurs relative to a desired frequency, the apparatus comprising:

a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies depending on a voltage applied to the voltage controlled oscillator;

circuitry configured to apply the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;

first circuitry configured to increase the voltage applied to the voltage controlled oscillator using one or more steps of a first size;

said first circuitry configured to further increase the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;

second circuitry configured to decrease the voltage applied to the voltage controlled oscillator using one or more steps of a third size smaller than the first size;

said second circuitry configured to further increase the voltage applied to the voltage controlled oscillator after decreasing the voltage; and

said first circuitry configured to further provide a signal indicating that lock has occurred in response to the increase.

2. An apparatus for determining when frequency lock occurs relative to a desired frequency in accordance with claim 1 wherein the voltage controlled oscillator has a control node, and wherein the voltage controlled oscillator oscillates at a frequency responsive to the voltage applied to the control node.

3. A method of determining when frequency lock occurs relative to a desired frequency, the method comprising:

providing a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies responsive to a voltage applied to the voltage controlled oscillator;

applying the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;

increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;

decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;

increasing the voltage applied to the voltage controlled oscillator after the decreasing and indicating that lock has occurred.

4. An apparatus for determining when frequency lock occurs relative to a desired frequency, the apparatus comprising:

a phase lock loop including a voltage controlled oscillator configured to oscillate at a frequency which varies responsive to a voltage applied to the voltage controlled oscillator;

means for applying the voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;

means for increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;

means for decreasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size;

means for increasing the voltage applied to the voltage controlled oscillator after the decreasing and means for indicating that lock has occurred responsive to the increasing after the decreasing.

5. A method of determining when a phase lock loop achieves frequency lock relative to a desired frequency, the phase lock loop including a voltage controlled oscillator having a control node and oscillating at a frequency responsive to the voltage applied to the control node, the method comprising:

adjusting the voltage on the control node in a first direction beyond the voltage that results in a lock;

subsequent to the adjusting in the first direction, adjusting the voltage on the control node in a second direction, opposite the first direction, overshooting the voltage that results in a lock;

subsequent to the adjusting in the second direction, adjusting the voltage on the control node in the first direction; and

providing a signal, indicating that frequency lock has been achieved, in response to the adjusting in the first direction after the adjusting in the second direction.

6. A method in accordance with claim 5 wherein the first mentioned adjusting in the first direction comprises using steps.

7. A method in accordance with claim 6 wherein the adjusting in the second direction using steps smaller than the steps used in the first adjusting.

8. A method of determining when frequency lock occurs relative to a desired frequency, the method comprising:

providing a phase lock loop including a voltage controlled oscillator that oscillates at a frequency responsive to voltage applied to the voltage controlled oscillator;

applying a voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;

first increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;

second increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size, beyond the voltage appropriate for a lock;

decreasing the voltage applied to the voltage controlled oscillator, after the second increasing, using one or more steps of a third size smaller than the first size beyond the voltage appropriate for a lock;

increasing the voltage applied to the voltage controlled oscillator after the decreasing and providing a signal indicating that lock has occurred.

9. A method in accordance with claim 8 wherein the phase lock loop tracks a timing signal.

10. A method in accordance with claim 8 wherein the voltage controlled oscillator has a control node, and wherein the voltage controlled oscillator oscillates at a frequency responsive to the voltage applied to the control node.

11. A method of determining when a phase lock loop achieves frequency lock relative to a desired frequency, the phase lock loop including a voltage controlled oscillator having a control node and oscillating at a frequency responsive to the voltage applied to the control node, the method comprising:

increasing the voltage applied to the control node to a voltage above the voltage that results in the phase lock loop tracking the desired frequency;

decreasing the voltage applied to the control node to a voltage below the voltage that results in the phase lock loop tracking the desired frequency; and

increasing the voltage applied to the control node and indicating that frequency lock has been achieved in response to the increasing after the decreasing.

12. A method in accordance with claim 11 wherein the first mentioned increasing of the voltage applied to the control node comprises increasing in steps the voltage applied to the control node.

13. A method in accordance with claim 12 wherein the decreasing of the voltage applied to the control node comprises decreasing the voltage applied to the control node using steps smaller than the steps used in the first mentioned increasing of the voltage applied to the control node.

14. A method in accordance with claim 12 wherein the second mentioned increasing of the voltage applied to the control node comprises increasing the voltage applied to the control node using a step smaller than the steps used in the first mentioned increasing of the voltage applied to the control node.

15. A method of determining when frequency lock occurs relative to a desired frequency, in a communication system, the method comprising:

receiving a reference timing signal via radio frequency;

providing a phase lock loop including a voltage controlled oscillator that oscillates at a frequency responsive to voltage applied to the voltage controlled oscillator, the phase lock loop being configured to track the reference timing signal;

applying a voltage to the voltage controlled oscillator to produce a frequency of oscillation less than the desired frequency;

first increasing the voltage applied to the voltage controlled oscillator using one or more steps of a first size;

second increasing the voltage applied to the voltage controlled oscillator using one or more steps of a second size smaller than the first size, beyond the voltage appropriate for a lock;

decreasing the voltage applied to the voltage controlled oscillator, after the second increasing, using one or more steps of a third size smaller than the first size beyond the voltage appropriate for a lock;

increasing the voltage applied to the voltage controlled oscillator after the decreasing and providing a signal indicating that lock has occurred.

16. A method in accordance with claim 15 wherein the voltage controlled oscillator has a control node, and wherein the voltage controlled oscillator oscillates at a frequency responsive to the voltage applied to the control node.