INDEPENDENT BIAS CIRCUIT TO VOLTAGE CHARACTERISTIC OF OUTPUTDEVICE FOR APPLYING BIAS TO AMPLIFIER OF AB CLASS OPERATION

摘要

A Class AB amplifier circuit includes bias circuitry for biasing the output transistor into partial conduction independent of the base-to- emitter voltage of the transistor. The bias circuitry is a simple circuit loop including the output transistor and forms the remainder of the amplifier circuit which can be fabricated in monolithic integrated circuit form. The loop comprises a differential amplifier for providing a substantially constant offset voltage across a pair of terminals between which is connected a current biasing component. The current biasing component is connected in series with the output transistor to produce a small quiescent current to flow therethrough, the value of which is independent of the transistor's characteristics.