The Design And Research Of Digital Audio Amplifier

Audio power amplifier is an important part of PIC (Power Integrated circuits) which is widely used in consumer electronic products, and China is the most important market of consumer products and the biggest world manufacture center of the consumer products. We launch a reach on audio power amplifier.Traditional analog audio amplifier can be very linear but suffers from poor energy efficiency. With improvement of Integrated Circuits, An audio amplifier of small size and high efficiency can cater to the needs of a market comprising mobile phone,computer multimedia, flat panel TV,Portable computer. Class D audio Power amplifier, which works in switching mode, has advantage of high efficiency and Thus becomes one of the most Promising audio amplifier solutions.This paper examines the design and implementation of a digital audio amplifier based on sigma-delta modulator. Its input is digital audio sources and it can directly amplify digital signals without D/A circuit which is a must in traditional class D amplifier. This Paper at first introduce The Comparison of analog audio amplifier and digital audio amplifier, and then detailed description the Principle of the different sound power amplifier and explain the advantages of digital audio amplifier. Then it presents the principle of sigma-delta incremental modulation and research the detailed theoretical analysis of the Key Technique, thus give the stability system of sigma-delta incremental modulation. Finally, Analysis and Simulation of Internal Circuit of the system though the Hspice simulator at Cadence software. Including operational amplifier, integrator circuit, comparator circuit, filter circuit and Voltage Reference. At last, from carefully simulation of the whole circuits, the SFDR of the sigma-delta modulator system is 72dB, and the THD is less than 0.05%. So we could know the system is stable, and excellent performance was achieved, The simulation results shows that it reach the expected objective.