A semiconductor integrated circuit has a rectifying circuit, a switched capacitor, a switched-capacitor drive circuit, a demodulator, and an internal circuit. The switched capacitor executes series charging and parallel discharging to/from a plurality of capacitors using an output rectified voltage. When the current driving performance at the time of supplying a power source voltage is set to a high state, so that a receiving operation in a card is executed reliably even at a long communication distance. Transmission signal data from a card is supplied to a switched-capacitor current driving performance increase disable circuit, and the current driving performance at the time of supplying the power source voltage in the switched capacitor is changed to be low. The change is detected as a magnetic field change in an antenna by an apparatus.