| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic semiconductor storage device which attains low power consumption and deters increase of chip area by reducing standby power supply current. SOLUTION: A word line corresponding to a row address accessed at the time of normal operation is stored in an RAM 101, and at the time of entry to self refresh, data for a memory cell connected to the word line corresponding to the row address accessed during a period for the normal operation is written in a check bit area with the check bit for read data added by an encoder 115. As initialization processing for the self refresh entry for the first time after the power supply is turned on, the data holding time for the memory cell is checked per the word line, a set value for the refresh cycle for the word line is determined based on the check result, a setup for the refresh cycle for every word line is done by writing the set value in the RAM 101. An error is corrected by an error correction circuit at the time of the error detection by refresh operation. COPYRIGHT: (C)2005,JPO&NCIPI
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