INTEGRATED CIRCUITS WITH PERSISTENT DATA STORAGE

• US 20150122898A1
• Filed: 01/16/2015
• Published: 05/07/2015
• Est. Priority Date: 05/31/2001
• Status: Active Grant

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Align Technology Incorporated
• Inventors: Carrender, Curtis L., Stewart, Roger G., Rolin, John H., Gilbert, Ronald
• Granted Patent: US 9,406,012 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• 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 19/07381 with deactivation or otherwise incapacitation of at least a part of the circuit upon detected tampering
• CPC Class Codes: G06K 7/10019 resolving collision on the communication channels between simultaneously or concurrently interrogated record carriers. collision between the communication channels used by wireless communication devices, where the solution is not particularly adapted for RFIDs or the like, H04W74/08

Abstract

The circuitry introduced in this invention selectively slows down the functioning of an electronic circuit maintaining a particular state for a prolonged period of time. This circuitry is used not only to achieve the desired effect in maintaining security from electronic thieves trying to circumvent codes but also in other applications such as enabling a circuit to continue to function in the event of a brief loss of power. For example, in an RFID system, if a reader is frequency hopping, a tag loses power for as long as about 400 milliseconds when the reader changes to other frequencies. In a preferred embodiment, the disclosed circuitry is used in conjunction with a destruct sequence.

Claims

1. A method for a radio frequency identification (RFID) tag comprising:

receiving a first code transmitted by an RFID reader, the first code generated by an XOR calculation;

comparing a second code within the tag to the first code;

if the first code and second code do not match, muting by the tag; and

if the first code and second code match, transmitting by the tag a third code to the RFID reader.