Power switching unit of a portable telephone capable of monitoring and controlling a battery supply voltage thereof

摘要

A power switching unit of a portable telephone which has a function of storing data such as telephone numbers and operates with a battery. The unit comprises a battery for supplying power to a radio unit and a control unit which contains a data storage function and controls operation of the radio unit, first voltage monitor means for monitoring a supply voltage of the battery to output a first voltage drop signal when the supply voltage falls below a first predetermined value, and communication disconnection means for stopping power supply to the radio unit upon reception of the first voltage drop signal. The power switching unit of the portable telephone further includes voltage adjustment means for adjusting voltage suppled to the control unit from the battery to a predetermined operating voltage of the control unit for supplying it to the control unit.