Patent Number: 6,167,236

Title: Damping modulation circuit for a full-duplex transponder

Abstract: An improved damping modulation circuit (140) for a transponder (14) receives energy transmitted from a transmitter/receiver antenna (16) to produce a unique recognition signal in the transponder. The improved damping modulation circuit (140) includes a high fieldstrength circuit (152, 160, 174) that protects full-duplex transponder (14) from over-voltage through the use of voltage limiters (132), while still providing power to transponder (14). Low fieldstrength circuit (152) activates only minimal circuitry to provide the highest possible amount of power to full-duplex transponder (14). Medium fieldstrength circuit (152, 160) increases the fieldstrength in full-duplex transponder (14) for establishing a sufficient amount of current flow for proper modulation using only a medium amount of transponder (14) circuit elements.

Inventors: Kaiser; Ulrich (Warstein, DE), Steinhagen; Wolfgang (Mauern, DE)

Assignee: Texas Instruments Deutschland, GmbH

International Classification: G06K 19/07 (20060101); H04B 005/00 ()

Expiration Date: 12/26/2017