| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor storage device which reduces the power consumption of refreshing during a data retention period. SOLUTION: The semiconductor storage device comprises memory cells MC for storing logical data depending on the number of majority carriers in a floating body, a plurality of bit lines BL connected to a plurality of the memory cells, a plurality of word lines WL connected to the plurality of memory cells, sense amplifiers S/A for reading data from the memory cells and writing data into the memory cells, a refresh controller REFC for directing refresh operation by temporarily reading the data from the memory cell to write back the logical data the same as the data into the same memory cell, and refresh timers Tmr1 and Tmr2 which have a refresh interval between successive refresh operations as a first interval for a data reading mode or a data writing mode, and the refresh interval longer than the first interval as a second interval for a data retention mode, respectively. COPYRIGHT: (C)2009,JPO&INPIT
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