| 摘要 |
PURPOSE:To reduce current consumption at the time of waiting for a transmission signal by permitting a DC/DC conversion part to convert output voltage into first and second operation guarantee voltage and to output first voltage at the time of waiting for the transmission signal and second voltage at the time of receiving. CONSTITUTION:A DC/DC converter part 100 converts the output voltage of a battery 101 and a power switch SW124 into first operation guarantee voltage VA or second operation guarantee voltage VB (VB>VA) and supplies it to an internal part. In the waiting state for the call signal, a decoder DEC, CPU 120, LCD 121, ROM 122 and RAM 123 operate by first operation guarantee voltage VA. At the time of writing and reading data of RAM 123, second guarantee voltage VB (larger than first operation voltage VA) is required. Thus, all parts except for a radio part 118 are operated by second guarantee voltage VB. Thus, the converter part 100 outputs voltage VA in the waiting state of the transmission signal by the control of CPU 120, and outputs voltage VB in a reception state. Then, current consumption is reduced at the time of waiting for the signal. |
