| 摘要 |
PROBLEM TO BE SOLVED: To extend the backup time by limiting the region to be backed up to an absolute minimum during a power interruption in the refresh control of a DRAM. SOLUTION: A portion of the region, in which picture information is stored, among the entire region of a DRAM 1 is specified 2 by row addresses. Then, a refresh period 3 is set to the period that is proportional to the reciprocal of the percentage of the refresh range among all row addresses so that refresh operations are executed with a sufficient frequency for a memory holding and the condition of the data is maintained.
|
