| 摘要 |
<p>PROBLEM TO BE SOLVED: To set desired energizing time by accommodating variations in the holding time of a backup power supply unit caused by variations in current consumption of a storage element in the backup power supply unit with a capacitor. SOLUTION: Stable current is ensured, and required and sufficient current can be run through a RAM 12 by increasing the capacitance of an electric double layer capacitor 230 so as to be a current value extremely larger than a current value required and sufficient for the RAM 142, and connecting a discharging resistor 232 to the electric double layer capacitor 230 parallelly to discharge most of the whole current. A current value ARAM running through the RAM 142 can be almost ignored by increasing the current ARES/ARAM, thus it is possible to compute the energizing time to the RAM 142 only by setting the value of resistance of the discharging resistor 232 independent of the power consumption of the RAM 142.</p> |
