| 摘要 |
PURPOSE:To increase the versatility of an integrated circuit, by changing the threshold value of an MOSFET having a floating gate for a storage device with a substrate voltage and using RAM and ROM functions separately. CONSTITUTION:The drain of an MOSFET1 having a floating gate is connected to a data line 7, the source is connected to an information storage capacitor 5 and the gate is to a word line 3 respectively, and the threshold value is changed with a substrate voltage VBG. Because of two threshold voltages to be given, an ROM function is obtained for the write-in of ROM. Further, the write-in for the RAM is made by making the voltage VBG as 0 volt, and the line 6 as 0 volt, respectively, and when the line 6 is made to a high potential through the application of write-in data high level or 0 volt to the line 7 and returned to 0 volt, write-in for the RAM is made. This is similar to the readout, and functions of RAM and ROM are separately used to increase the versatility of an integrated circuit storage device. |
