| 摘要 |
<p>PURPOSE:To economize power and exchange a battery, and to use the battery efficiently by detecting the fluctuation of voltage with the lapse of time and estimating the residual capacity of the battery. CONSTITUTION:Voltage VDD by which the whole is operated by a voltage control 7 is generated by a battery 6 in a main power supply. The voltage of the battery 6 is converted into a digital value by an A/D converter 9, and voltage is processed by a CPU 8 on the basis of the digital value. A time clock module 11 counts time, and time is investigated and compared every time, thus determining the time elapsed. The time and a detecting voltage value are stored in a RAM 10, and the RAM 10 and the moduel 11 continue to be supplied with supply voltage by a battery for backup even when the power supply control 7 interrupts the supply of currents. When the CPU 8 rewrites the value of a D/A converter 17 and load 19 is given currents through an amplifier 18 regarding output currents, the CPU 8 changes a current value in response to a voltage value.</p> |
