| 摘要 |
PURPOSE:To provide a stabilized power supply for always securing the speech quality of a constant level or the like by preventing the S/N of an analog circuit from deteriorating at the supply destination of the stabilized voltage even when the cell voltage is lowered. CONSTITUTION:Stabilized power supply circuit 12 transforms the generated voltage of a cell 11 into a given voltage, and supplies it to a digital circuit 15. A variable type stabilized power supply circuit 13 transforms the generated voltage of the cell 11 into a first given voltage, and supplies it to an analog circuit 16. The digital circuit 15 decreases the outpu voltage of the variable type stabilized power supply circuit 13 to the value of a second given voltage when the generated voltage of the cell 11 detected by a voltage detection circuit 14 is lowered to less than a given value. In this way, even when the cell voltage 11 is lowered, the input/output voltage difference of the variable type stabilized power supply circuit 13 can be held at a given value or higher, thus making it possible to reduce the noise component of the digital circuit 15 in the analog circuit 16 to a level less than a given value. |
