| 摘要 |
PURPOSE:To eliminate the inconveniences such as a reduction of the punch- through voltage, the fluctuation of threshold voltage, etc., by actuating a transistor with a voltage width smaller than the width of the power supply voltage supplied from outside. CONSTITUTION:The power supply voltage VC and the set voltage V8 are supplied to the drain and the gate of an MOS transistor 9 respectively. Thus the source potential VS of the transistor 9 is constant with V8-VTH (VTH: threshold voltage). At the same time, the source voltage VS is supplied to a differential amplifying circuit 10. As a result, the potential at a circuit point 2 is set equal to the potential VS. Then if the voltage VTH is reduced by the punch- through or short channel effect, the potential VS increases by an amount equivalent to the change of the voltage VTH. And the back gate bias is applied by such amount as to compensate a reduction of the VTH, and thus the VTH is reset to the value obtained before the reduction. As a result, the inconveniences such as a reduction of the punch-through voltage, the fluctuation of VTH, etc. never occur although a function circuit 1 is made minute. |
