| 摘要 |
PURPOSE:To prevent the rapid level fluctuation of a line to be clamped from exerting any effect on a circuit by clamping a voltage level of the line to be clamped to a shift average value when the voltage level is fluctuated in excess of the voltage shift average value. CONSTITUTION:When the voltage to be clamped of the line 15 to be clamped is inputted to an averaging circuit 11, an average value voltage is obtained and inputted to a level shift circuit 12. The circuit 12 outputs a shift average voltage shifting the said average voltage by a prescribed value to a level shift circuit output line 17. A level comparator 13 compares the voltage to be clamped with the shift average voltage and when the former exceeds the latter, an interruption signal is outputted to an interruption signal line 18 during that period only. The switch circuit 14 is operated by the interruption signal to clamp the line 15 to the shift average voltage. Thus, the affect of the rapid level fluctuation of the line 15 to be exerted on the circuitry is prevented. |
