Operational amplifying circuit and semiconductor device comprising the same

Abstract

An operational amplifying circuit are provided. The operational amplifying circuit includes a control circuit, pull-up and pull-down transistors, first and second bias circuits, and a bias voltage generating circuit. The control circuit includes first and second input terminals, and is configured to change, when an input voltage transitions to a first level, a voltage level of a pull-up node and a pull-down node to a second level different from the first level. The pull-up transistor provides a power supply voltage to the output terminal. The pull-down transistor connects the output terminal to a ground voltage. The first bias circuit provides a first bias current to the control circuit. The bias voltage generating circuit generates a bias voltage when the voltage level of at least one of the pull-up and pull-down nodes reaches a threshold voltage level, and the second bias circuit provides a second bias current to the control circuit.