Patent ID: 8478224

Claim:
A mobile communication terminal device comprising: a noncontact proximity communication unit carrying out noncontact proximity communication; a wireless communication unit carrying out wireless communication longer in communication distance than the noncontact proximity communication and input/output control for this wireless communication; a security controller utilized in security processing for the noncontact proximity communication unit and the wireless communication unit; and a battery, wherein the noncontact proximity communication unit receives electromagnetic field power from a carrier in the battery and operates and supplies the received power to the security controller, wherein the security controller determines whether or not voltage from power supplied from the noncontact proximity communication unit has reached a specified level and, when it is determined that the specified level has not been reached, carries out control so as to reduce the electricity consumption of the security controller, wherein the security controller includes a clock control circuit generating a synchronous clock signal for internal operation, and wherein when it is determined that the specified level has not been reached, the clock control circuit reduces the frequency of the synchronous clock signal as compared with when it is determined the specified level has been reached.