Intermec IP Corporation

International Business Machines Corporation

David E Dieska

Daniel Joseph Friedman

Harley K Heinrich

Kenneth Alan Goldman

Vijay Pillai

The present invention provides an RFID transponder that includes a state holding cell that maintains the present state of the RFID transponder during temporary losses of power. After power is restored to the RFID transponder, the state holding cell restores the present state to the RFID transponder so that transactions with an RFID interrogator can continue without having re-transmit redundant commands. The RFID transponder further comprises an RF front end adapted to receive an interrogating RF signal. An analog circuit is coupled to the RF front end and is adapted to recover analog signals from the received interrogating RF signal. The analog circuit provides state information defining a desired state of the RFID transponder corresponding to the analog signals. A digital state machine is coupled to the analog circuit and adapted to execute at least one command in accordance with the state information. A memory is coupled to the digital state machine and is adapted to store and retrieve digital data responsive to the at least one command executed by the digital state machine. A power capacitor is coupled to the RF front end and derives a voltage rectified from the interrogating RF signal to charge the power capacitor. The power capacitor thereby provides electrical power for the analog circuit, the digital state machine and the memory. The state holding cell is coupled to the analog circuit and the digital state machine and is adapted to maintain the state information during a loss in power provided by the power capacitor due to lapse in receipt of the interrogating RF signal by the RF front end.

Passive RFID tag that retains state after temporary loss of power

A radio frequency identification (RFID) transponder (tag) integrated circuit includes &ldquo;on-chip&rdquo; test circuitry. The test circuitry includes a serially-loaded test register. The test register controls the execution of on-chip tests. Such tests may include the testing of EEPROM circuitry included within the IC, the testing of analog circuitry, or the testing of digital circuitry included within the IC.

Radio frequency identification transponder integrated circuit having a serially loaded test mode register

A Radio Frequency (RF) transponder (tag), method, and system, whereby the tag has a low current tag oscillator, the oscillation frequency of the tag oscillator set by RF signal from a base station.

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Longwood, FL, United States of America

David E Dieska