Design Of Audio Power Amplifier Based On Bipolar Process

Audio power amplifier is widely used in the field of minimal,intelligent and multimedia systems at present. And it is also in great demand as a typical civilian industry product all the time. Therefore, the research on audio power amplifier is important and of great significance.Base on the principle and performance analysis of audio power integrated circuit, a system structure of audio power amplifier is designed in this paper. The system is divided into many parts according to the designing goal, including differential input stage, middle amplifier, negative feed-back, bandwidth compensation circuit, reference, thermal protection circuit, over-current protection, input range limited block etc. The principle of every block is analyzed and discussed in detail firstly, and then the circuit of the system is realized in transistor level.The whole circuit of the audio amplifier is simulated in Hspice based on Episil 1.5μm bipolar model parameter, the simulation results show that the system works very well and get high stability, small harmonic distortion, a maximum output power of 8W.The layout of the chip is also designed by using tools of Virtuoso Layout Editor in Cadence in Episil 1.5μm bipolar process.. In order to get thermal stability, the layout of the audio power amplifier is completed according to the principle of heat symmetry. By using the tools of DIVA and LVS, the layout of the whole circuit is extracted and verified.