| 摘要 |
<p>PURPOSE:To increase the operating time of a device to a single charging operation of a battery for a GPS receiver which can be driven by a battery by reducing the power consumption of a CPU. CONSTITUTION:A frequency divider 3, a selector 5, etc., are provided so that the frequency of a CPU driving clock signal can be changed with the setting of an output port 4 of a CPU 1. A battery voltage minitoring circuit 6 is added to monitor the voltage of a battery 7. When the battery voltage drops less than a level set previously, a lock signal of the frequency lower than that outputted from the divider 3 is selected as the CPU driving clock signal by an instruction of the CPU 1. In such a constitution, the power consumption of the CPU 1 is reduced.</p> |
