| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the power consumption as a whole and prolong the battery life of a power source part by providing a voltage converting means which converts the voltage value for the power source of an interface means and signals from the voltage of the power source part to a specific voltage. SOLUTION: For example, a 3V output voltage is used for the IC interface part 16 of the portable terminal device 1 for IC cards and a battery 17 as the power source part. A voltage converting circuit 15 consists of a converter, a buffer circuit and power source input from the battery 17, and the converter is applied with a CNT signal and boosts the source voltage +3V from the battery to +5V to generate a VCC signal (source voltage) to the IC card 5 of an IC card I/F part 16. The total power consumption is reducible by lowering the voltage of the power source part and then lowering the operating voltage to a low voltage (e.g. 3V), and generating a specific voltage (e.g. 5V) for the IC card from the low voltage by the voltage converting means.</p> |
