| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic semiconductor storage device which attains lower power consumption and suppresses increase in chip area by reducing a standby power supply current. SOLUTION: A word line corresponding to a row address accessed during a normal operation is stored in a RAM 101. When entring self refresh, data in a memory cell connected to the word line corresponding to the row address accessed during the normal operation is read out and a check bit is added to the read data by an encoder 115, and the resultant data is written into a check bit area. As initialization processing for the first self refresh entry after power is turned on, a data holding time of the memory cell is checked for each word line, a set value of a refresh cycle of a word line is determined based on the check result, the refresh cycle for each word line is set by writing the set value into the RAM 101. When an error is detected during the refresh operation, the error is corrected by an error correction circuit. COPYRIGHT: (C)2008,JPO&INPIT
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