Radio frequency identification transponder with electronic circuit enabling/disabling capability

• US 5,874,902 A
• Filed: 07/29/1996
• Issued: 02/23/1999
• Est. Priority Date: 07/29/1996
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Walsh, Brian John Hugh, Friedman, Daniel J., Heinrich, Harley Kent, McAuliffe, Kevin Patrick, Capek, Peter George, Cofino, Thomas Anthony, Sousa, Paul Jorge
• Primary Examiner(s): ZIMMERMAN, BRIAN A
• Application Number:
  US08/681,741
• Time in Patent Office: 939 Days
• Field of Search: 340/825.54, 340/825.49, 340/825.72, 340/825.31, 340/825.52, 340/426, 340/572, 340/573, 342/24
• US Class Current: 340/10.51
• CPC Class Codes: G08B 13/1409 for removal detection of electrical appliances by detecting their physical disconnection from an electrical system, e.g. using a switch incorporated in the plug connector

Abstract

An RF tag has an enable/disable circuit connected to a critical part of an electronic object/circuit, e.g. a computer mother board. The critical part of the circuit is any circuit component and/or connection that can enable and/or disable the electric circuit operation. Signals are sent to the tag to change data in the tag memory which causes the enable/disable tag circuit to control the critical part to enable and disable the electric circuit. A system checks the status of the tag, e.g. the electronic circuit was paid for, before enabling the electronic circuit.

Claims

1. A radio frequency (RF) tag for connection to an external electrical circuit, the RF tag having an antenna for receiving an RF signal to be sent to the RF tag upon authorized transfer of possession of the external circuit, a radio frequency section for demodulating the RF signal to create a demodulated RF signal, and a memory, the tag further comprising:

a logic that puts data in the memory in response to the demodulated RF signal; and

a circuit enabler/disabler that accesses the data in the memory, and enables the external electrical circuit to fully function only when the RF tag has received the RF signal to be sent to the RF tag upon authorized transfer of possession of the external circuit by perturbing a critical part of the external electrical circuit through a connection when the data in the memory satisfies certain conditions.

2. A radio frequency tag capable of being connected to an external electrical circuit, as in claim 1, where the circuit enabler/disabler is capable of enabling and disabling the external circuit by changing a state of a component to perturb the critical part of the external electronic circuit.

3. A radio frequency tag, as in claim 2, where the component includes any one of the following:

a tri-state logic driver, a switch, a transistor, a diode, fusible link, and triac.

4. A radio frequency tag, as in claim 1, where the critical part of the external electrical circuit includes any one of the following:

a ground line, a signal line, a voltage supply line, a clock output line, a connection, an interconnect line, a connection in a semiconductor circuit chip, and a current supply line.

5. A radio frequency tag, as in claim 4, where the component perturbs the critical part by providing a signal to the critical part.

6. A radio frequency tag, as in claim 5, where the signal provided to the critical part is random.

7. A radio frequency tag, as in claim 5, where the signal provided to the critical part is provided at random intervals.

8. A radio frequency tag, as in claim 1, where the enabler/disabler is a logic circuit.

9. A radio frequency tag system, comprising:

an external electrical circuit with a memory bus;

a direct memory access process executing on the external electrical circuit and being capable of enabling and disabling full operation of the external electrical circuit;

an RF tag having an antenna for receiving an RF signal sent to the RF tag upon authorized transfer of possession of the external electrical circuit and further having an RF tag memory containing one or more values that are changed by the RF signal; and

a memory interface connecting the RF tag memory to the memory bus, the external circuit being capable of reading the one or more values across the memory bus, and the direct memory access process enabling the external electrical circuit to function fully only when the RF tag memory contains the one or more values that have been changed by the RF signal.

10. A radio frequency (RF) tagging system comprising:

an external circuit having an external encryptor and an external memory, the external memory storing an external password;

a number generator for generating one or more numbers;

a radio frequency tag, having a tag control logic, a tag memory, and a tag encryption logic, the tag memory containing a tag password, the tag encryption logic encrypting the number with the tag password to created a tag encrypted number;

an external circuit controller on the external circuit, the external circuit controller receiving a tag control signal from the tag control logic and the external circuit controller causing the external encryptor to encrypt the number with the external password to create an external encrypted number;

a comparator that compares the tag encrypted number to the external encrypted number, the comparator causing the external circuit controller to enable the external circuit if the tag encrypted number and the external encrypted number meet criteria and the comparator causing the external circuit controller to disable the external circuit if the tag encrypted number and the external encrypted number do not meet the criteria.

11. A radio frequency system, as in claim 10, where the criteria is that the tag encrypted number and the external encrypted number are equal.

12. A radio frequency (RF) tagging system, comprising:

an external electrical circuit with a critical part, the critical part being capable of enabling and disabling full operation of the external electrical circuit;

an RF tag having an antenna for receiving an RF signal sent to the RF tag upon authorized transfer of possession of the external electrical circuit, a radio frequency section for demodulating the RF signal to create a demodulated RF signal, a memory, and an enabler/disabler, the enabler/disabler producing a perturbation when a value is in the memory; and

a connection connecting the enabler/disabler to the critical part, the perturbation perturbing the critical part when the value is in the memory so that the external circuit is disabled from functioning fully. the value in the memory being changed to another value when the RF signal is received so as to enable the external circuit to function fully.

13. A system, as in claim 12, where the RF signal is sent by a base station.

14. A system, as in claim 13, where the external circuit is enabled when the enabler/disabler ceases to produce the perturbation.

15. A tag, comprising:

an antenna for receiving an RF signal sent to the tag upon authorized transfer of possession of an external circuit;

a fusible link electrically connected to the antenna, the fusible link fusing when the antenna receives the RF signal; and

a connection for connecting the fusible link to the external circuit, the fusible link changing an electrical property when fused, the changed electrical property enabling the external circuit.

16. A method for enabling an external electronic circuit to function fully only upon authorized transfer of possession, comprising the steps of:

sending a predetermined radio frequency signal to a radio frequency tag upon authorized transfer of possession of the external electronic circuit, the radio frequency tag receiving the signal and having a fusible link that fuses upon receipt of the predetermined radio frequency signal and thereby changes an electrical property when the signal is received; and

enabling the external electronic circuit to function fully only when the fusible link is fused through a connection between the external electronic circuit and the fusible link due to the change in the electrical property.

17. A method for enabling an external electronic circuit to function fully only upon authorized transfer of possession, comprising the steps of:

sending a predetermined radio frequency signal to a radio frequency tag only upon authorized transfer of possession of the external electronic circuit;

demodulating the radio frequency signal to obtain one or more values;

writing the one or more values to a tag memory;

accessing the one or more values by an enabling/disabling circuit connected to a critical part of the external electronic circuit, the enabling/disabling circuit being capable of enabling and disabling the external electronic circuit by perturbing a critical part; and

enabling the external electronic circuit to function fully only when the one or more values have been written to the tag memory.

18. A method for enabling an external electronic circuit to function fully only upon authorized transfer of possession, comprising the steps of:

a. sending a predetermined radio frequency signal to a radio frequency tag only upon authorized transfer of possession of the external electronic circuit;

b. demodulating the radio frequency signal to obtain one or more values;

c. writing the one or more values to a tag memory;

d. accessing the one or more values by the external electronic circuit across a memory bus connected to the tag memory; and

enabling the external electronic circuit to function fully only when the one or more values have been written to the tag memory.

19. A method for enabling an external electronic circuit to function fully only upon authorized transfer of possession of the external circuit, comprising the steps of:

providing a tag password to the tag;

providing an external password to the external circuit, either the tag password or the external password being provided upon authorized transfer of possession of the external circuit;

performing a password comparison between the external password and the tag password; and

enabling and disabling the external circuit to function fully in accordance with the password comparison.

20. A method as in claim 19 where the tag password and the external password are encrypted.