Non-inverting buffer circuit device and semiconductor memory circuit

Abstract

A non-inverting buffer circuit device suited for an input buffer circuit of a semiconductor memory is provided so that the number of logic gate stages can be reduced to realize a high speed operation. The circuit is designed in such a way that an MOS transistor at an input stage drives a bipolar transistor at an output stage to produce an output. An n-channel MOS transistor and a p-channel MOS transistor connected in parallel between the base and the collector of the bipolar transistor are on/off controlled by an inverted signal of the input digital signal and a non-inverted signal thereof, respectively. In another aspect, the input buffer circuit includes an inverted signal outputting circuit, and a non-inverted signal outputting circuit in the set mode the input signal in the non-inverted state and outputting in the reset mode the signal at the prescribed potential. The inverted signal outputting circuit includes a bipolar transistor producing an output signal at its collector potential, a first switching circuit for controlling supply of a collector current to the bipolar transistor, an n-channel MOS transistor, connected in parallel between the base and the collector of the bipolar transistor, for supplying a base current to the bipolar transistor in accordance with the input signal, and a second switching circuit for controlling supply of the base current to the bipolar transistor, wherein the first switching circuit and the second switching circuit are selectively on-off controlled.