| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a noncontact type IC card which highly functionally operates at high communication speed and processing speed at a short communication distance and guarantees minimum operation, even at a long communication distance. SOLUTION: A combination of plural IC elements 30 to 36 and an operation clock are dynamically changed by a transmission/reception control circuit 20. That is, electromagnetic waves from a reader/writer is received, and a power element, a clock element and a data element are extracted. When instruction data included in the extracted data element are power saving power mode change command, a power is supplied only to a CPU 30, an RAM 32, an ROM 33, an EEPREOM 34 and an NDP 36, and the frequency of the operation clock is reduced by half. When the instruction data are normal power mode change command, the power is supplied to all the IC elements 30 to 36, and the frequency of an operation clock is made highest.</p> |
