| 摘要 |
<p>PURPOSE:To perform fast writing operation and increase the amount of written information by using an internal write-in voltage higher than an external write- in voltage as the power source for a row decoder, and also using a lower internal write-in voltage as the power source for a column decoder. CONSTITUTION:A charge pump type boosting circuit consists of a ring oscillator 11, driver circuit 6d, capacitance 12, and intrinsic type n channel FET13. A voltage higher than the voltage at an external write-in terminal VPP is obtained at the output B of this boosting circuit and applied to the row driver 4 as an internal power source VPP'1 and also inputted to a switching circuit 1 which drives the column decoder. The output of the switching circuit 1 is used as an internal power source VPP'2 to obtain the voltage as high as the voltage at the terminal VPP during writing operation. Further, the internal power source VPP'1 is held at the same voltage with the power source VCC through a depletion type n channel FET14 during reading operation.</p> |
