Microprocessor based control circuits for Class-A amplifier

Abstract

The class-A amplifier is widely used in the audio-visual engineering. It has a less complex, less distortion and more linear when compare to the other class of amplifier. It means that the class-A amplifier has a high quality of audio signal, but the drawback is very inefficient. Most of the energy turns to heat. Therefore, the cost of operation is high because of the power consumption of class-A amplifier is higher than the other class with same output power. Another drawback is the components will decay due to the temperature of working condition is always high. The amplifier becomes unstable at last. Although the class-A amplifier has so many disadvantages, it still has a lot of people pay attention on it because of the high quality of audio signal. Nowadays, the most expensive audio amplifier is class-A. It always matches with a good quality of speaker to provide an ideal audio sound. Because of their value, series of protection and compensation actions are needed to protect and extend the live of class-A amplifier and speaker. This project aims to design a microprocessor based circuit to protect the amplifier by control the working condition and the I/O of the amplifier and speaker. All the protections are target on the disadvantages and abnormal situations of the class-A amplifier. The most important is the circuit board is cheap relative to amplifier and speaker.