一种用于传感器模拟前端的可编程增益放大器  

A programmable gain amplifier for analog front-end of a sensor

作　　者：王程 张加宏[1,2] 刘祖韬 邹循成 WANG Cheng;ZHANG Jiahong;LIU Zutao;ZOU Xuncheng(School of Integrated Circuits,Nanjing University of Information Science and Technology,Nanjing 210044,China;Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology,Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学集成电路学院,江苏南京210044 [2]南京信息工程大学江苏省大气环境与装备技术协同创新中心,江苏南京210044

出　　处：《电子元件与材料》2024年第2期230-237,245,共9页Electronic Components And Materials

基　　金：国家重点研发计划(2022YFB3205902,2022YFB3205903)。

摘　　要：基于华虹0.18μm CMOS工艺设计了一款用于传感器模拟前端的可编程增益放大器(PGA),其整体采用全差分结构来抑制传感器输出的共模噪声、直流分量以及供电电源的输出噪声。该电路由仪表放大结构轨对轨输入级、轨对轨自动调零全差分运算放大器、数字控制电路以及直流分量消除电路这四个部分构成,同时采用连续时间自动调零校准技术来降低其输入失调电压。PGA的放大倍数为5 bit调节,共12个档位,分别为1,2,4,8,…,1024,2048倍。在3.3 V电源电压下,PGA输入输出摆幅为0.2~3.1 V。在输入500 mV的直流分量条件下,在-40~125℃的温度范围内,可将直流分量抑制到47.6μV。通过Virtuoso软件进行电路设计、版图绘制以及仿真验证,后仿真结果表明,在进行100次蒙特卡罗仿真下,电源抑制比和共模抑制比在1 kHz处的平均值分别约为110.3 dB和116.1 dB,输入失调电压的1σ值约为21.3μV。Based on the Huahong 0.18μm CMOS process,a programmable gain amplifier(PGA)was designed for the analog front end of a sensor.A fully differential structure was adopted to suppress the common mode noise of the sensor output,the DC component and the noise of the power supply.The circuit was composed of four parts,namely,a rail-to-rail input stage of an instrument amplifier structure,a rail-to-rail auto-zero fully differential operational amplifier,a digital control circuit,and a DC component elimination circuit.Meanwhile,continuous time auto-zero stabilization technology was used to reduce its input offset voltage.The amplification factor of the PGA is 5 bit adjustable with a total of 12 gears,which amplify 1,2,4,8,…,1024,2048 times respectively.The input and output swing of the PGA is between 0.2 V and 3.1 V at 3.3 V power supply.At 500 mV DC input,the DC component can be suppressed to 47.6μV from-40℃to 125℃.The circuit design,layout drawing and simulation verification were carried out through Virtuoso software.Monte Carlo simulations show that the average power supply rejection ratio and the common mode rejection ratio at 1 kHz are about 110.3 dB and 116.1 dB respectively,and the 1σvalue of the input offset voltage is about 21.3μV.

关 键 词：可编程增益放大器 输入输出范围 自动调零校准 电源抑制比 共模抑制比 

分 类 号：TN722.7[电子电信—电路与系统]