Kontaktlose IC-Karte

摘要

A non-contact IC card has an antenna circuit 16 for receiving and transmitting data via an electromagnetic wave 20, a rectifier 18 and a capacitor 19 providing power for supplying the card by rectification of the received communication signal 20, and a battery 1 which acts as a backup power supply for data stored in a RAM 7 and also powers the card when the received electromagnetic wave 20 is weak. The dual power supply 1, 18, 19 has the advantages of both the prior battery-powered and batteryless types of IC card in achieving long battery and card life and also long communication distance. The battery 1 may be a primary battery with switching between the two power supplies being effected by a diode 2, or by an IC power control chip (14, Figs. 2, 3) which compares the voltage on capacitor 19 with a reference voltage indicative of the card operating voltage. The battery may alternatively be a rechargeable battery charged from the capacitor 19 (Fig. 4). <IMAGE>