INFORMATION COMMUNICATION DEVICE

摘要

An IC card receives a high frequency signal from a reader/writer and rectifies the high frequency signal to generate power. A MOS transistor is connected to the antenna of the reader/writer and the received signal is rectified by the parasitic diode of the MOS transistor. The capacitance accompanying the transistor is added to the capacitance of an input tuning capacitor. By selecting the on/off of the transistor, the capacitance added to that of the tuning capacitor is changed and the input tuning frequency is changed accordingly and the relation between the input tuning frequency and the high frequency of the transmission signal is changed. With the change, the amplitude of the received high frequency signal is changed and hence, the obtained power is also changed.