| 摘要 |
<p>PURPOSE:To prevent nonselection leakage and to reduce writing malfunctions by adding a back bias circuit to an EPROM or a semiconductor device in which an EPROM is placed in mixture, and forming a circuit for applying a back bias at the time of writing the EPROM. CONSTITUTION:A negative potential generator 2, a back bias switching circuit 3 for generating a back bias only at the time of writing in an EPROM, and a back bias potential controller 4 are added to the EPROM or a semiconductor device in which an EPROM is placed in mixture. The controller 4 has a DMOS 4a, a resistor 4b. An L is input to an inverter 4c if an absolute value of a negative potential is a predetermined value or less, the generator 2 is operated. If the absolute value of the negative potential becomes excessively large, an H is input to stop generation of the negative potential. Thus, the back bias potential of suitable value necessary at the time of writing is supplied, nonselection leakage is suppressed, and writing malfunctions are reduced.</p> |
