| 摘要 |
PURPOSE:To miniaturize a data non-volatilizing mechanism and to reduce the capacity of a backup power source by dividing a power source into two and always supplying power to a semiconductor memory part by one of them. CONSTITUTION:When the power-off indication is inputted, a power control means 7 controls a first power source part 5 to turn off this part 5, but the means 7 does not turn off a second power source part 6 to continue the power supply. A non-volatilization control means 4 is started to save data from a semiconductor memory part 1 to a non-volatile storage part 3, and thereafter, the second power source part 6 is kept turned on to continue the power supply to the semiconductor memory part 1, and stored data is held. Consequently, it is unnecessary to restore data at the time of power-on. Since data is saved in the non-volatile storage part 3 at the time of the occurrence of trouble in the second power source part 6 or the like, it is unnecessary to save data at a high speed, and the constitution of a data transfer circuit in the non- volatilization control means 4 can be minimized. Thus, the data non-volatilizing mechanism is miniaturized and the capacity of a battery for power backup is reduced. |
