| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize a highly reliable high capacity nonvolastile memory in which corruption of data due to transition with time of threshold voltage of a memory cell can be avoided. SOLUTION: The memory 10 comprises more than one, e.g. six, memory chips 11-16, a refresh function block 17, a clock function block 18, and a battery 19 wherein the refresh function block measures the time elapsed after final writing for each memory chip or memory sector. The elapsed time thus measured is compared with a preset limit charge holding time and when the limit charge holding time is reached, each memory chip or memory sector is rewritten. Consequently, corruption of stored data incident to elapse of time can be avoided resulting in a highly reliable nonvolatile memory having significantly enhanced capacity.</p> |
