Patent ID: 7441711

Claim:
An IC card, comprising: an antenna for receiving alternate current superposed with an information signal; a rectifier circuit for receiving the alternate current received by said antenna and outputting rectifier voltage to obtain a direct power supply; a voltage controlling circuit for receiving the rectifier voltage outputted from said rectifier circuit and outputting an operating voltage which is a voltage difference between a first potential and a second potential; an internal circuit to which said operating voltage is supplied; and an operating current detector circuit for detecting current supplied by said operating voltage and outputting a detection signal indicating whether or not the current is higher than a predetermined current value, wherein said internal circuit is adapted to reset an internal state and to operate when receiving said detection signal at power on, wherein said voltage controlling circuit includes: a voltage comparator circuit which compares said operating voltage and a predetermined reference voltage; and a voltage controlling current source controlled by an output of said voltage comparator circuit, and said operating current detector circuit detects current passing through said voltage controlling current source and outputs said detection signal, wherein said voltage controlling circuit controls a voltage value of said operating voltage by subtracting the current supplied to the internal circuit from the current passing through said voltage controlling current source when said detection signal is named enable and said internal circuit starts to operate.