硅微陀螺仪高精度数字化相敏解调ASIC  

High-accuracy digitized phase-sensitive demodulation ASIC design for silicon microgyroscope

作　　者：赵阳 夏国明[1] 施芹[1] 裘安萍[1] ZHAO Yang;XIA Guo-ming;SHI Qin;QIU An-ping(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学机械工程学院,江苏南京210094

出　　处：《光学精密工程》2018年第9期2159-2168,共10页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.61701236)

摘　　要：为了抑制相敏解调引入的闪频(1/f)噪声,实现硅微陀螺仪的高精度片上数字化输出,设计了一种基于sigma-delta模数转换器的相敏解调ASIC。首先,提出了一种量化硅微陀螺仪驱动及检测载波信号的低闪频噪声数字化方案,建立了sigma-delta模数转换器的系统级分析模型,并利用Simulink完成了基于谐振器级联前馈(CRFF)结构的三阶sigmadelta模数转换器系统级设计。其次,研究了sigma-delta模数转换器的电路级实现方法,在Cadence IC平台上完成了包括低噪声开关电容积分器、加法器及1bit高速量化器等模块的晶体管级电路设计与验证,并采用AMS 0.35μm工艺进行了流片。实验表明:该sigma-delta模数转换器具有三阶噪声整形功能,在硅微陀螺仪的工作频率处(6.4kHz)量化噪声小于200nV/Hz1/2,等效精度位数为12。硅微陀螺仪数字化输出角度随机游走0.012(°)/h1/2,Allan方差零偏不稳定性为0.34(°)/h,零偏稳定性(1σ)为0.94(°)/h,满足高精度硅微陀螺仪的数字化精度需求,并提高了整表集成度。In order to remove the flicker noise introduced by phase-sensitive demodulation and realize a digitized silicon microgyroscope,a phase-sensitive demodulation Application Specific Integrated Circuit(ASIC)was designed.First,a low flicker noise digitized phase-sensitive demodulation scheme was proposed,and the system level analysis model of a third-order Cascade-Resonator-Feedforward(CRFF)sigma-delta ADC was defined.Then,the circuit level realization method of the sigma-delta ADC was detailed;the low noise switched-cap integrator,the adder and the 1-bit quantizer were designed using Cadence IC design kits.Finally,the proposed phase sensitive demodulation system design was taped out in the AMS 0.35μm process.The experimental results indicate that the proposed ADC has a third-order noise shaping characteristic and its quantization noise floor at 6.4 kHz is below 200 nV/Hz 1/2,which corresponds to 12 bits equivalent accuracy.The digitized silicon microgyroscope has an 0.012(°)/h 1/2 angular random rate and a 0.34(°)/h bias instability,with 1σbias stability of 0.94(°)/h,which satisfies the requirement of high accuracy digitization and improves the integration level of the gyroscope.

关 键 词：硅微陀螺仪 专用集成电路 sigma-delta模数转换 相敏解调 闪频(1/f)噪声 

分 类 号：TN96[电子电信—信号与信息处理] TP212[电子电信—信息与通信工程]