Circuit Composition of Integrated Operational Amplifier:
The integrated operational amplifier is a high-gain direct-coupled amplifier circuit, which is shown in the block diagram in Figure 1.
Figure 1 Operational amplifier block diagram
(1) Input stage Using high-performance differential amplifier circuit, must have a strong rejection of ****-mode signals, the use of double-ended input, double-ended output form.
(2)Intermediate Amplifier Stage Provides high open-loop amplification to ensure the operational accuracy of the op amp. Generally consists of *** emitter multi-stage coupled amplifier circuit.
(3) Output stage Composed of triode or composite tube of both PNP and NPN polarity to provide large output voltage or current.
(4) Bias current source Provides a stable bias current to stabilize the operating point. Generally consists of various constant current source circuits.