Radio frequency identification transponder

• US 20060176154A1
• Filed: 04/05/2006
• Published: 08/10/2006
• Est. Priority Date: 02/28/2000
• Status: Active Grant

• Current Assignee: SATO Holdings Corporation
• Original Assignee: Michael John Stanton, Stuart Colin Littlechild
• Inventors: Littlechild, Stuart Colin, Stanton, Michael John
• Granted Patent: US 7,259,654 B2
• Time in Patent Office: Days
• US Class Current: 340/10.500
• 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

Abstract

A radio frequency identification transponder includes a power supply and a dynamic memory array that stores data. When power from the power supply ceases, the data in the dynamic memory array is validly maintained for a predetermined period of time. The dynamic memory array is responsive to an interrogating signal for selectively updating the data. A radio frequency identification transponder includes a signal processor that extracts an identifier from the interrogation signal and is responsive to the identifier and the stored data to determine whether some or all of the identifier is stored in the dynamic memory array.

Claims

1-54. -54. (canceled)

55. A radio-frequency identification (“

RFID”

) transponder for use in an RFID system, the RFID transponder comprising;

a dynamic memory array for storing data;

a first power supply for powering circuitry associated with the RFID transponder, the circuitry comprising the dynamic memory array; and

wherein the RFID transponder is configured such that, when power ceases to be provided to the dynamic memory array by the first power supply, the data in the dynamic memory array is validly maintained therein for a predetermined time period.

56. The RFID transponder as claimed in claim 55, wherein the memory array comprises at least one of:

DRAM;

EEPROM;

FRAM;

RAM;

memory adapted to hold data for a period of time longer than the longest periodic power outage; and

an on-board processer.

57. The RFID transponder of claim 56, wherein the on-board processer comprises at least one of a signal processor, a central processor, and associated memory.

58. The RFID transponder as claimed in claim 55,.wherein the data comprises at least one of:

a date stamp;

a time stamp number representative of a particular time of transmission;

a number representative of the particular orthogonal orientation;

an identifier signal;

an interrogator reference number;

a pseudo-random number or character string;

a mute bit;

an identification number;

configuration information or settings;

temporary data stored in registers;

a PRBS number;

chopper settings;

a coded string to enable discrimination between other RFID transponders;

power mode control;

identity data adapted to determine the order in which the RFID transponder receives an interrogating signal;

the time of provision of the interrogating signal; and

content and timing of transmission signals between devices.

59. The RFID transponder as claimed in claim 55, wherein the memory is further selectively updated with reference to a time stamp.

60. The RFID transponder as claimed in claim 55, comprising a second power supply to power the memory when the power provided by the first power supply ceases.

61. The RFID transponder as claimed in claim 60, wherein the second power supply comprises a capacitor.

62. The RFID transponder according to claim 55, wherein:

the RFID system provides an interrogating signal having an identifier; and

the RFID transponder comprises a receiver for receiving the signal.

63. The RFID transponder according to claim 62, comprising a signal processor responsive to:

a) the receiver for extracting the identifier from the signal; and

b) the identifier and the data for determining whether the identifier is stored in the memory array.

64. The RFID transponder according to claim 55, wherein the power supply is configured to provide power by converting an extemally-applied electromagnetic excitation field into electrical power.

65. The RFID transponder according to claim 55, wherein the first predetermined time period is determined by discharging of the dynamic memory array through stray leakage paths within the dynamic memory array.

66. The RFID transponder according to claim 55, further comprising:

a timer for providing a validity flag in response to an interrogating signal;

wherein the flag is valid if the interrogating signal is received within a second time period;

wherein the flag is invalid if the interrogating signal is received after the second time period; and

wherein the RFID transponder is configured such that the data in the dynamic memory array is maintained in a readable state until at least the expiration of the second time period.

67. The RFID transponder according to claim 66, wherein:

the timer comprises a capacitive cell for storing a charge generated by current from the power supply; and

the timer is configured such that, once power from the power supply ceases to be supplied, the charge in the capacitive cell discharges at a predetermined rate.

68. The RFID transponder according to claim 67, wherein:

the status of the validity flag is based on a voltage generated at a predetermined point in the timer;

the voltage decays as the capacitive cell discharges.

69. The RFID transponder according to claim 68, wherein the voltage is an output voltage of the capacitive cell as the capacitive cell discharges through a load.

70. The RFID transponder according to claim 69, wherein the capacitive cell is a memory cell.

71. The RFID transponder according to claim 70, wherein the memory cell forms part of the dynamic memory array.

72. An RFID system comprising:

an RFID transponder comprising;

a dynamic memory array for storing data;

a first power supply for powering circuitry associated with the RFID transponder, the circuitry comprising the dynamic memory array; and

wherein the RFID transponder is configured such that, when power ceases to be provided to the dynamic memory array by the first power supply, the data in the dynamic memory array is validly maintained therein for a predetermined time period; and

a transponder interrogator for providing an interrogation field and reading data from the RFID transponder.

73. The RFID system according to claim 72, wherein:

the transponder interrogator is configured to sequentially switch an orientation of the interrogation field; and

the second time period is selected to exceed the time that the interrogation field is off during switching of the orientation.

74. A method of storing data in a radio-frequency identification (“

RFID”

) transponder adapted for use in an RFID system, the method comprising the steps of;

storing data in a dynamic memory array of the RFID transponder;

providing a first power supply associated with the dynamic memory array; and

validly maintaining the data in the dynamic memory array for a predetermined time period after power ceases to be provided to the dynamic memory array by the first power supply.

75. The method as claimed in claim 74, further comprising the step of enabling the dynamic memory array to hold data for a period of time longer than a longest periodic power outage.

76. The method as claimed in claim 74, further comprising the step of providing a second power supply to power the dynamic memory array when the power provided by the first power supply ceases.

77. The method as claimed in claim 74, wherein the data comprises at lease one of:

a date stamp;

a time stamp number representative of the particular time of transmission;

a number representative of the particular orthogonal orientation;

an identifier signal;

an interrogator reference number;

a pseudo-random number or character string;

a mute bit;

an identification number;

configuration information or settings;

temporary data stored in registers;

a PRBS number;

chopper settings;

a coded string to enable discrimination between other RFID transponders;

power mode control;

identity data adapted to determine the order in which the RFID transponder receives an interrogating signal;

the time of the provision of the interrogating signal; and

content and timing of transmission signals between devices.

78. The method according to claim 74, further comprising:

the RFID system providing an interrogating signal having an identifier; and

wherein the RFID transponder comprises a receiver for receiving the signal.

79. The method according to claim 78, wherein the RFID transponder comprises a signal processor responsive to:

a) the receiver for extracting the identifier from the signal; and

b) the identifier and the data for determining whether the identifier is stored in the dynamic memory array.