ASIC Design And Implementation Of Mono Filter-free Stereo Audio Class-D Power Amplifier

The paper is based on the research project"The Theoretical Reach on and Design of High efficiency Low THD Audio Class-D Power Amplifier (PA)"and deals mainly with the design implementation and theoretical study of operating principle of Class-D PA.On the basis of the analysis of operating principles and performance characteristics of various audio PAs, and emphatic description of PWM and operating principle of class-D audio PAs, the design of a class-D stereo audio PA XPD7026, with high power output , low power dissipation and free output filter, is presented in this paper . XPD7026 adopts a novel PWM strategy, which reduces the dependence of class-D PA on output filter by half-wave rectifying PWM signals and taking advantage of full-bridge output. The design of key sub-blocks in class-D, such as OSC, pre-amplifier, integrator and voltage reference is described in detail .Also, a novel band-gap voltage reference as internal voltage supply, which reduces the power dissipation and enhance the efficiency of class-D PA is proposed in this paper. In addition, by introducing a charge pump driver module, the output stage can adopt only NMOS as switch transistors, which saves layout area substantially.The whole circuit is designed on the basis of the 0.6μm BCD process.The simulation and verification are completed by EDA tools such as Cadence etc. According to the simulation results, the function and performance of the whole circuit can meet all the requirements.