| 摘要 |
PURPOSE:To allow an output to rise and fall quickly by constituting an element corresponding to the pull-down resistance of an emitter follower with a variable impedance element like an FET. CONSTITUTION:A pnp transistor TR QEF is used as a TR for emitter follower, and the element corresponding to the pull-down resistance is constituted with a MOS TR QPD whose impedance is varied according as the TR QEF is turned on and off. By this constitution, the output of a signal line rises quickly in case of the change of the output to the high level because the TR QEF has a very low impedance and the TR QPD has a high impedance. In case of the change of the output to the low level, the output potential falls quickly because the TR QPD is set to a low resistance state and the electric charge of the signal line is discharged quickly through the TR QPD. |
