Mobile communication terminal device

A mobile communication terminal device comprising:

• a battery;
• a security controller;
• and
• a noncontact proximity communication unit carrying out noncontact proximity communication,
• wherein the noncontact proximity communication unit receives both electromagnetic field power from noncontact proximity communication and battery power from the battery,
• wherein the noncontact proximity communication unit supplies, as an operating supply power to the security controller, one of the electromagnetic field power and the battery power which is selected depending upon a voltage of the battery,
• wherein when the battery voltage is higher than a predetermined voltage, the noncontact proximity communication unit supplies the electromagnetic field power as the operating supply power to the security controller if the electromagnetic field power is produced, and supplies the battery power as the operating supply power to the security controller if the electromagnetic field power is not produced, and
• wherein when battery voltage is lower than the predetermined voltage, the noncontact proximity communication unit supplies the electromagnetic field power as the operating supply power to the security controller if the electromagnetic field power is produced, and interrupts the supply of the battery power to the security controller.

A mobile communication terminal device comprising:

• a battery;
• a security controller;
• and
• a noncontact proximity communication unit carrying out noncontact proximity communication,
• wherein the noncontact proximity communication unit includes an operating voltage determination and selection circuit having a first terminal that receives a first voltage produced by noncontact proximity communication and a second terminal that receives a battery voltage,
• wherein the operating voltage determination and selection circuit selects one of the first voltage and the battery voltage to be output as an operating supply voltage to the security controller, depending on the battery voltage,
• wherein when the battery voltage is higher than a predetermined voltage, the operating voltage determination and selection circuit outputs the first voltage as the operating supply voltage to the security controller if the first voltage is produced, and outputs the battery voltage as the operating supply voltage to the security controller if the first voltage is not produced, and
• wherein when battery voltage is lower than the predetermined voltage, the operating voltage determination and selection circuit outputs the first voltage as the operating supply voltage to the security controller if the first voltage is produced, and interrupts the supply of the battery voltage to the security controller.