| 摘要 |
PURPOSE:To provide the backup device of a semiconductor memory capable of suppressing power consumption to the minimum and extending the holding time of data by backup battery power supply. CONSTITUTION:Plural DRAMs 4-1 to 4-N in which digital-coded data is recorded and switches 5-1 to 5-N which are provided in accordance with each DRAM and turn on/off backup power supply to each semiconductor memory at the time of the fall of the voltage of main power supply 6 are provided. Then, a host CPU 2 to on/off-control the switches 5-1 to 5-N in order to supply the backup power supply to only the DRAM in which the digital-coded data is recorded at the time of the fall of the voltage of the main power supply 6 is provided. |
