POWER TRANSMISSION SYSTEM, IC CARD AND INFORMATION COMMUNICATING SYSTEM USING IC CARD

摘要

PROBLEM TO BE SOLVED: To provide a radio power transmission system, an IC card and an information communicating system using IC card in which power can be fed stably from a reader/writer to the internal circuit of an IC card by radio even when there is a great fluctuation in the distance between the IC card and the reader/writer. SOLUTION: The power transmission system for transmitting power from a reader/writer 1 to an IC card 2 using electromagnetic wave comprises an IC card for converting a transmitted induction power into a DC voltage, detecting the transmitted induction power or a corresponding voltage, and controlling the inductance based on a detected induction voltage or a voltage corresponding to the induced power to produce a desired DC voltage being fed to an internal circuit 29.