| 摘要 |
PURPOSE:To prevent the precharge from being brought into a power supply potential by using a bootstrap circuit so as to boost a gate potential of a transistor (Tr) to be precharged to a level near twice the power supply potential thereby avoiding the effect of the threshold value of the TR. CONSTITUTION:A gate electrode of a Tr2 to be precharged is driven by a bootstrap circuit comprising a Tr1 and a capacitor Cs, and a potential boosted up to 2Vcc (Vcc is a power supply potential) is fed to the gate when the Tr2 is turned on. Thus, up to the level of the power supply Vcc is charged to a load capacitor CL and even when the power supply potential is increased momentarily, when the level is restored to the potential Vcc, since the precharge potential of the load capacitor CL is discharged till the Vcc level, the potential at the start of discharge is made constant and the time required for the discharge is made always constant. |
