传感器模拟前端低噪声可变增益放大器的设计  

Design of a low-noise variable gain amplifier for the analog front-end of the sensor

作　　者：宿芷若 陈雪峰 李志远[1] SU Zhiruo;CHEN Xuefeng;LI Zhiyuan(College of Electronic Engineering,Heilongjiang University,Harbin 150080,China)

机构地区：[1]黑龙江大学电子工程学院,哈尔滨150080

出　　处：《黑龙江大学自然科学学报》2024年第6期731-742,共12页Journal of Natural Science of Heilongjiang University

基　　金：黑龙江省自然科学基金资助项目(TD2021F001)。

摘　　要：传感器在汽车、通信和医疗等行业作为与外界物理世界连接的接口,有着极为重要且广泛的应用。针对传感器模拟前端所要处理的信号微弱且幅值随机的问题,基于中芯国际集成电路制造有限公司(Semiconductor manufacturing international corporation,SMIC)0.18μm互补金属氧化物半导体(Complementary metal oxide semiconductor,CMOS)工艺,设计了一款传感器模拟前端低噪声可变增益放大器。该设计以双运放结构的仪表放大器为核心电路,通过斩波电路及滤波器改善了噪声特性,通过调整反馈网络中金属氧化物半导体场效应晶体管(Metal-oxide-semiconductor field-effect transistor,MOSFET)的阻值,实现了可变增益的调节。前仿真结果表明,所设计的两级差分放大器开环增益81.16 dB,为反馈网络的引入提供了基础。在整体电路设计及仿真分析的基础上,完成了可变增益放大器整体电路的版图设计、验证及后仿真。后仿真结果表明,整体电路可实现的增益为6.38~24.76 dB,当V g为0 V时,在频率10000 Hz时,等效输入噪声功率谱密度为15.7 nV/sqrt(Hz),带宽1~10000Hz输入参考噪声为1.57μV rms。该电路所获得的低噪声及可变增益特性对改善传感器模拟前端电路的信号处理质量将起到重要的作用。Sensors in automotive,communications,medical and other industries as an interface to connect with the external physical world,have extremely important and wide range of applications.The low-noise variable-gain amplifier is designed based on the Semiconductor manufacturing international corporation(SMIC)0.18μm Complementary metal oxide semiconductor(CMOS)process for the weak and variable amplitude signals of the sensor analog front-end circuit.An dual-op amp instrumentation amplifier is designed in this design,in which the noise characteristics is improved by chopper-stabilized circuits and filters,and the variable gain adjustment is performed by adjusting the resistance value of the Metel-oxide-semiconductor field-effect transistor(MOSFET)resistor in the feedback network.The simulation results indicate that the open-loop gain of the designed two-stage differential amplifier is 81.16 dB,providing a basis for the introduction of feedback networks.Based on the overall circuit design and simulation analysis,the layout design,verification,and post simulation of the variable gain amplifier’s overall circuit are completed.The post-simulation results show that the achievable gain range of the overall circuit is 6.38~24.76 dB,and when the V g is 0 V,the equivalent input noise power spectral density is 15.7 nV/sqrt(Hz)at 10000 Hz,and the input referred noise is 1.57μV rms in the bandwidth of 1~10000 Hz.The low noise variable gain characteristics obtained by this design will play an important role in improving the signal processing quality of sensor analog front-end circuits.

关 键 词：可变增益放大器 低噪声 仪表放大器 斩波调制 

分 类 号：TN402[电子电信—微电子学与固体电子学]