This thesis presents a doubly cascaded power amplifier for high fidelity audio application. Cascaded amplifier is composed of two independent analog-amplifiers. The one is a class A amplifier with high fidelity and the other is a class B amplifier with high efficiency. So the cascaded amplifier realizes high fidelity and high efficiency simultaneously.
The previous cascaded amplifier was used inductor to merge two analog amplifiers. Inductor plus voltage amplifier is voltage-controlled-current-source. Also OTA is voltage-controlled-current-source. Thus this thesis replaces inductor plus voltage amplifier with OTA at the previous structure.
A cascaded audio amplifier using OTA is designed for 130W rated output power at 6Ω load. This thesis deals with the design procedure of the 130W cascaded amplifier using OTA.
Also, this thesis presents the newly proposed cascaded audio amplifier which is composed of two voltage amplifiers. In other words, the one is a independent voltage source with high fidelity and the other is a dependent voltage source with high efficiency.
Experimental results shows that 130W cascaded audio amplifier attains the 76.5% efficiency at 130W output power and achieves the 0.0065%THD(Total Harmonic Distortion).
