| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a refreshing method for semiconductor memory, which can shorten the refreshing time and can suppress the effects on the ordinary data reading and writing during the refreshing operation, furthermore. SOLUTION: A memory array 20 is divided into four sub-arrays 1-4, and a reserve sub-array 5 is provided. The reserve sub-array 5 is set in the erased state beforehand, and four sub-arrays 1-4 are sequentially selected and refreshed. The data of the selected sub-array 1 are copied into the reserve sub-array 5, and the original sub-array 1 is erased. After the copying, address conversion for converting the reserve sub-array 5 into the sub-array 1 and for converting the original sub-array 1 into the reverse sub-array 5 is performed. This operation is sequentially performed from the sub-array 1 to the sub-array 4, and the refreshing of the memory array 20 is completed.</p> |
