| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an EEPROM having a multi-level storage system in which a control circuit except a memory cell can be simplified. SOLUTION: A data storage circuit 9 for storing control data deciding control voltage applied in write operation is provided in each bit line BLi, BLi+1 in a multi-level EEPROM, control voltage is applied to a corresponding bit line on the basis of the control data in write, and a read bit line signal is applied selectively to a corresponding bit line on the basis of control data stored in each data storing circuit in read. The data storing circuit comprises first and second sub-data circuits 20, 21 for storing first and second sub-data, detects the write state of a selected memory cell and the logic level of a read signal on a transfer line decided from the second and first sub-data, and changes the first and second sub-data so as to control write when write is sufficient.</p> |
