Impinj, Inc.

Synopsys, Inc.

Other

Trw Limited

Virage Logic Corporation

John D Hyde

Christopher J Diorio

Theron Stanford

Jay A Kuhn

Ronald A Oliver

Harley K Heinrich

Charles J T Peach

Alberto Pesavento

Kurt Eugene Sundstrom

Shailendra Srinivas

Scott A Cooper

Vadim Gutnik

Amita Patil

Todd E Humes

Matthew Robshaw

Tan Mau Wu

Omer Onen

Charles Peach

Terry D Hass

Chad A Lindhorst

Frédéric J Bernard

Robert M Glidden

Dennis Kiyoshi Hara

Jaskarn Johal

Miguel E Figueroa

David D Dressler

Andrew Edward Horch

Carver A Mead

Ronald Lee Koepp

Donald Glen Heflinger

David Kaplan

Kaila Raby

Troy N Gilliland

Ronald E Paulsen

Phillip D Hayashida

Vincent A Giagni, Sr

Amir Sarajedini

Vincent Giagni

An RFID IC may operate at a relatively low clock frequency while impedance matching to an antenna is being tuned to increase the amount of power that the IC can extract from an incident RF wave. A tuning circuit tunes the impedance matching by adjusting a variable impedance coupling the IC and the antenna. The IC may power-up with a low clock frequency or reduce its current clock frequency to a lower clock frequency prior to tuning or during the tuning process, and may increase its clock frequency upon completion of tuning or during the tuning process.

RFID tag clock frequency reduction during tuning

Embodiments are directed to rectifiers using a single bias current or bias current path to bias multiple rectifying elements. A rectifier that has multiple rectifier stages coupled together serially includes a bias current path coupled to each of the rectifier stages. Thee bias current path is configured to simultaneously bias rectifying elements in each of the rectifier stages by using a bias current to bias a first rectifying element and reusing the bias current to bias other rectifying elements.

RFID tag rectifiers with bias current reuse

RFID ICs sense and indicate changes in their surrounding environment, such as changes in temperature, humidity, chemical presence, RF signals, and similar. An RFID IC indicates when a significant environmental change has occurred, for example by adjusting the value of a flag, writing data to memory, transmitting a message to an external entity, exiting a sleep state, and/or responding repeatedly to an inventorying reader. In some cases, RFID IC actively notifies an external entity that a significant environmental change has been sensed. For example, RFID IC may alert the external entity by participating in a special inventory process meant for RFID ICs sending environmental change. The RFID IC may alert the external entity by interjecting itself into an inventory round, re-participating in an inventory round, refraining from entering a sleep state after inventorying, and/or adjusting timing of a scheduled reply to communicate with an RFID reader ahead of schedule.

Environment-based RFID IC behavior

Backflow in rectifiers may be reduced via biasing. Upon determining that backflow within a rectifier is likely, one or more rectifying elements in the rectifier may be debiased, via analog or digital means. The debiased rectifying elements become less conductive or nonconductive, thereby reducing or preventing backflow. The determination of backflow likelihood may be performed based on a signal to be backscattered or the amplitude-modulated envelope of an incident RF wave, and may be digital or analog in nature.

Rectifier backflow reduction via biasing

Embodiments are directed to rectifiers using a single bias current or bias current path to bias multiple rectifying elements. A rectifier that has multiple rectifier stages coupled together serially includes a bias current path coupled to each of the rectifier stages. The bias current path is configured to simultaneously bias rectifying elements in each of the rectifier stages by using a bias current to bias a first rectifying element and reusing the bias current to bias other rectifying elements.

Embodiments are directed to mitigating power-based impedance changes in Radio Frequency Identification (RFID) tags. The intrinsic impedance of components in an RFID tag front-end may change as incident RF power on the tag changes, causing the input impedance of the front-end to change and altering the RF properties of the RFID tag. A number of approaches can be used to mitigate input impedance variations due to power variations. One approach involves adjusting the operating point of one or more components in the RFID tag front-end to change their intrinsic impedances so as to counteract or mitigate the RF-power-based input impedance variation.

Impedance-change mitigation in RFID tags

A level shifter circuit configured to convert a digital input signal with a first high logic level to a digital output signal having a second high logic level substantially higher than the first high logic level is provided. The level shifter circuit may include a PMOS latch circuit configured to receive the digital input signal and having first and second latch outputs and a current mirror circuit having a mirror input and a mirror output. The mirror input may be at least partly gated by a switch having a control input. The mirror output may be coupled to the first latch output. The control input may be coupled to the first or second latch outputs, and the digital output signal is provided from the first and/or second latch outputs.

Level shifter circuit with self-gated transition amplifier

Growing community of inventors

Corvallis, OR, United States of America

John D Hyde