DRIVING APPARATUS OF A BOOTSTRAPPING CMOS

摘要

PURPOSE: A driving apparatus of a bootstrapping CMOS(Complementary Metal Oxide Semiconductor) is provided to prevent an operating speed at a low voltage from letting down by pull-up and pull-down operations. CONSTITUTION: In a driving apparatus, when a logic high signal is inputted from an external input terminal(IN), a second PMOS(M7) turns off and a second NMOS(M8) turns on. A fourth NMOS(M2) turns off because the low voltage is applied to a gate of the fourth NMOS(M2) via the second NMOS(M8). The voltage difference between the terminals of a second capacitor(Cn) becomes minus Vdd, a first PMOS(M3) turns off and a first NMOS(M4) turns on. Therefore a gate of a fourth PMOS(M1) is connected to one end of a first capacitor(Cp) via the NMOS(M4) and boosted to minus Vd. Thereby the fourth PMOS(M1) turns on and an external output terminal(OUT) is rapidly charged to a highly charged state via the fourth PMOS(M1). When a logic low signal is inputted from the external input terminal(IN), the first NMOS(M7) turns off and the first PMOS(M3) turns on whereby a third NMOS(M5) turns on. Therefore the fourth PMOS(M1) comes to turn off by applying the ground voltage to the gate of the fourth PMOS(M1) and the minus Vdd is developed across the first capacitor(Cp). When the second NMOS(M8) turns off and the second PMOS(M7) turns on, a fourth PMOS(M6) turns on. Therefore the fourth NMOS(M2) is boosted to 2 times Vdd by the second capacitor(Cn) and the fourth PMOS(M6). Finally the external output terminal(OUT) is rapidly discharged via the fourth NMOS(M2).