| 摘要 |
<p>PURPOSE:To set up the potential of respective common source lines to respective optimum values by dividing the common source lines in every plural memory arrays and connecting a variable impedance means between each common source line and an earth potential point of a circuit. CONSTITUTION:The common source lines CS1-8 are separately connected to the memory arrays M-ARY1-8. When a memory cell for writing exists out of respective memory arrays, the potential of respective common source lines are determined in accordance with writing current formed on the basis of a constant voltage formed by a writing circuit. Therefore, writing current for only one memory cell is always made to flow into the common source lines of the writing memory array and the potential of the common source lines can be set up to their optimum values only by the composite impedance of the MOSFETs Q10, Q11' and the writing current.</p> |
