Non-contacting RF-ID card for wide voltage range input

摘要

A battery-free non-contacting information card of a relatively simple arrangement which prevents an IC chip or the like from being destroyed by an excess voltage. This non-contacting information card includes a resonance circuit (3) for receiving a carrier signal (e.g., FSK signal) modulated on the basis of information supplied from a card reader/writer (2), an information processing system (5), (6), (7) for obtaining information from the carrier signal and a rectifier system (13) for obtaining a voltage by rectifying the carrier signal, wherein the non-contacting information card can be operated by the voltage obtained at the output side of the rectifier circuit (13). The resonance circuit (3) includes a variable capacitive element (3d). A resonance frequency of the resonance circuit (3) is varied by varying the capacity value of the variable capacitive element (3d) in response to the voltage value obtained at the output side of the rectifier circuit (13) to thereby make the voltage value obtained at the output side of the rectifier circuit (13) substantially constant.