【作者】 牟在鑫；

【导师】 王松林；

【作者基本信息】 西安电子科技大学 ， 电路与系统， 2008， 硕士

【摘要】 本论文的设计工作来源于西安电子科技大学科研项目“高效低THD音频D类功率放大器的研究与设计”,主要对D类功率放大器的工作原理及性能进行理论研究并设计实现。论文首先分析了各种音频功率放大器的工作原理以及各自的性能特点,重点阐述了D类音频功率放大器的工作原理和脉宽调制方案,并在此基础上设计了一款大功率输出、低功耗、无需输出滤波器的立体声音频D类功率放大器XPD7026。该芯片采用一种新颖的脉宽调制方案,通过对PWM调制信号进行半波整形并利用全桥输出级降低了D类功率放大器对输出滤波器的依赖。文中重点阐述了D类功率放大器的关键子模块设计,如振荡器、前置运算放大器、积分器、PWM比较器以及基准源。特别是文中提出了一种新颖的可以作为片内电源的带隙电压基准,从而降低了D类功率放大器的静态功耗,提高了D类功率放大器的效率。另外,通过引入电荷泵驱动模块使得输出级可以全部采用NMOS晶体管作为开关管,大大节省了芯片面积。整体电路基于某公司0.6μm BCD工艺设计,使用Cadence等EDA软件完成整体电路的前仿真验证。仿真结果表明,电路功能和性能指标均已达到设计要求。更多还原

【Abstract】 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.更多还原