| 摘要 |
PURPOSE:To obtain a stable operation without a reverse flow of current even if a reverse potential different from the conventional one is applied, by not bringing an well layer into contact with a second high potential source. CONSTITUTION:Assuming that a second high-potential point 2 is higher in its potential than a first high potential point 1, an output 7 is on a level of the second high-potential point when a signal d is on a L level, and the output 7 is on a level of the first high potential point when the signal phi is on a H level. However, when the signal phi is on the H level and the output 7 is on the level of the first high-potential point and if the second high-potential point 2 is smaller in its potential than the first high-potential point 1, a current flowing from the high-potential point 1 through a P type diffusion layer 12 and an N well layer 11 is interrupted so as not flow into the second high-potential point because a N<+> diffusion layer has been removed contrary to the conventional technique. Since a well potential of the N well layer 11 is applied through a parasitic diode 17, no hindrance occurs in transistor operations of PMOS 3 and 4. |
