Patent ID: 6487100
Filing Date: 2002-11-26
Classification: G06K

Abstract:
A contactless electronic device comprising:an antenna for receiving a signal and electric power; a power supply circuit for producing an internal voltage from the electric power received by said antenna; an inner circuit operated by said internal voltage produced by said power supply circuit to make processing of the signal received by said antenna and preservation of data; and a communication circuit operated by said internal voltage produced by said power supply circuit to make reception and transmission of a signal through said antenna; said power supply circuit including: first and second input terminals applied with an AC voltage produced by said antenna; a first rectification transistor having a drain (or collector) terminal connected to said second input terminal and gate (or base) and drain (or collector) connected through first resistor means and for supplying a rectified current between said first and second input terminals; a first voltage controlled current source for producing a current in accordance with a control voltage to supply said current to said first resistor means; and first voltage detection means for producing said control voltage so that a rectified voltage obtained on the side of said source (or emitter) terminal of said first rectification transistor is equal to a predetermined reference voltage.