Push-pull output stage for digital signals with regulated output levels

Abstract

The circuit has a push-pull end stage which acts as an amplifier stage for digital signals. The push-pull end stage has two n-channel MOS transistors which function as source followers and two p-channel MOS transistors which also function as source followers. The gate terminals of the respective n-channel MOS transistors and p-channel MOS transistors are each controlled by an operational amplifier through drivers. A voltage that determines the setpoint value of the high level of the output of the push-pull end stage is present at the non-inverting input of one operational amplifier and a voltage that determines the low level of the output of the push-pull end stage is present at the inverting input of the other operational amplifier. The operational amplifiers interact with feedback elements in such a away that the high level or the low level of the gate voltages of the n-channel and p-channel transistors are controlled at an essentially constant value independently of the operating state of the push-pull end stage.

Dependencies are inferred from the claim text.