Design And Realization Of CMOS Audio Power Amplifier

Audio power amplifier is an important part of power integrated circuits which is widely used in consumer electronic products. Audio power amplifiers have driven for low cost and high performance. Majority of conventional power amplifiers are designed using bipolar technology on the basis of well-known merits of bipolar transistors. Although CMOS technology offers low cost alternatively, they suffer major problems such as large size in output transistors, stabilities on driving low resistive at high bandwidth, noise and so forth.Considering output voltage range and common-mode noise rejection, we adopt bridge structure of series form. Audio power amplifier includes input stage,output stage,reference biasing current module,thermal shut down module,mode switching and outside controlling module,"POP" rejection circuits module. In a 0.5μm CMOS technology the simulated result shows that the open-loop gain is 60 dB, the phase margin is up to 65°, the PSRR is 68dB , the unity gain-bandwidth is 3 MHz, the quiescent supply current is 10mA and realized 2.5W rated power into a 40 load.This paper at first introduces classifies of power amplifiers and their principles,virtues and flags. Then it detailed introduces CMOS AB class power amplifier, and presents total circuits,layout designs and simulations. Finally, it supplies system application circuits and complete the chip test work of audio power amplifier.