| 摘要 |
<p>PURPOSE:To perform assured writing in a short time by setting the reference input potential of a differential sense amplifier at a level higher by a prescribed value than the reference input voltage of a normal read-out mode when a write verify mode is read out in a writing mode. CONSTITUTION:A transistor (TR) 27 is connected between the gate of a dummy memory TR171 and a joint spot, and the TR of a program voltage detecting circuit 26 is selected so that a threshold value is equal to about 10V as a whole. In other words, the voltage of about 2V is generated at a point (c) if the voltage higher than 10V is impressed to a program power supply terminal 25. Thus the TR27 is turned on for a while. The potential of the point (c) is set at 0V with the 10V input voltage, and therefore the TR27 is turned off. In such a way, the TR27 is off in a normal reading mode. As a result, the 3V voltage is obtained at an output point (b) for the reference signal generating circuit. Then the TR27 is turned on for a while when the write verify mode is read out in a writing mode, and the 3.5V voltage is obtained at the point (b).</p> |
