| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To raise a rewrite frequency in all erase unit areas even when each erase unit area has a different rewrite frequency. <P>SOLUTION: A flash EEPROM 100 has a trimming value storage area 130 for storing a trimming value corresponding to each erase unit area 120 included in a memory cell array 110. When performing erasing and writing to an erase unit area 120, a regulator circuit 150 changes a voltage boosted by a booster circuit 140 to a level according a trimming value for the erase unit area 120. When erase and rewrite frequency increases and an abnormality is detected by a read-out determination circuit 170, the trimming value is updated to a voltage to raise a voltage outputted from the regulator circuit 150. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
