移动设备应用低THD+N高PSRRD类功率放大器  

A Low THD+Nand High PSRR Class-D Power Amplifier in Mobile Application

作　　者：郑浩 王秋妍 刘延飞 王道平 

机构地区：[1]火箭军工程大学理学院,西安710025

出　　处：《固体电子学研究与进展》2017年第2期134-139,共6页Research & Progress of SSE

基　　金：国家自然科学基金资助项目(61234002;61322405)

摘　　要：介绍了一款可直接由锂电池供电,基于移动全集成CMOSD类功率放大器,该放大器采用非直接反馈结构,通过在反馈环路植入二阶反馈系统,减小高频分量以及消除来自D类放大器输出端的共模干扰,同时高环路增益可获得高电源抑制比以及低THD+N;为节省PCB空间、减少系统成本、提高系统效率,放大器采用全差分"三态"调制技术以实现无滤波器应用。该放大器采用0.35μm数字工艺技术,在电源电压V_(DD)=3.6V、负载电阻为8Ω条件下,输出功率为400mW,THD+N可达0.025%;电源抑制比在217Hz处为78dB;放大器可工作于电源电压范围为2.5~4.2V;放大器芯片面积为0.85mm^2。A fully integrated CMOS class D amplifier that can directly hook up Lithium battery was designed for mobile application. The proposed amplifier adopts non-directly feedback architecture. Through embedding a 2-order low-pass filter, the high frequency component is reduced and the integrator input common disturbance from the class D output is eliminated. And, the obtained high loop gain can result in high PSRR and low THD＋N. Furthermore, a filterless method that can eliminate the external LC filter is employed, which offers great advantages of the smaller PCB space, lower system cost, and higher system efficiency. The prototype class D amplifier, realized in 0. 35m digital technology, achieves a THD＋N of 0. 025% when delivering 400mW power to an 8 load from VDD=3. 6 V. The PSRR of the amplifier is 78dB at 217Hz. In addition, the amplifier can operate in VDD range of 2. 5 to 4. 2V in mobile application. The total area of the amplifier is 0. 85 mm^2.

关 键 词：D类放大器 电源抑制比 总谐波失真 反馈环路 

分 类 号：TN432[电子电信—微电子学与固体电子学]