| 摘要 |
PURPOSE:To permit the use of communicating function and logic function even when the voltage of a main battery lowers, in a portable telephone operated by the battery. CONSTITUTION:A switching means 14 supplies the power supply voltage of a main battery 11 to a logic circuit 15 and a communication circuit 16 normally. When the output voltage of the main battery 11 lowers, a voltage lowness signal is outputted from a voltage monitoring means 13 and the switching means 14 switches the supply of a power from the main battery 11 to a sub-battery 12. Further, the supply of power to the communication circuit 16 is stopped by a power supply cutting means 17 when the power supply is switched from the main battery 11 to the sub-battery 12. |
