| 摘要 |
<p>PURPOSE:To keep a fixed amount of electrons after a writing mode and to increase the integration density of an EEPROM, by providing a voltage detecting circuit which shows the amount of electrons of a memory cell and feeding the output of the voltage detecting circuit to a writing system. CONSTITUTION:A voltage detecting circuit 6 for a node A is provided and the output of this circuit 6 is supplied to the gate of a transistor TR7 which is set in parallel to a TR5 which performs writing control. In a writing mode the level of a node C is raised up to the voltage VPP by a writing control signal. Then the voltage of a high level is applied to the node A for control of the terminal of a memory cell 1. When the amount of electrons of the memory cell 1 has a change, the impedance of the cell 1 has a change. Thus the impedance including a Y gate 2 connected in series to the cell 1 has a change and then the voltage of the node A has a change. The conditions are set so that a TR conducts by the voltage of the node B when the voltage of the node A reaches a desired level. Thus a writing action is stopped automatically.</p> |
