用于超低频信号测量的高精度低功耗增量式模数转换器  

Incremental Analog-to-Digital Converter with High Resolution and Low Power for Measurement of Ultra-Low-Frequency Signals

作　　者：陈浩[1] 孙权 张鸿[1] 程军[1] 张瑞智[1] CHEN Hao;SUN Quan;ZHANG Hong;CHENG Jun;ZHANG Ruizhi(School of Mieroeleetronies, Xi＇an Jiaotong University, Xi＇an 710049, China)

机构地区：[1]西安交通大学微电子学院,西安710049

出　　处：《西安交通大学学报》2017年第6期79-85,114,共8页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(61474092);陕西省科技计划资助项目(2014K05-14)

摘　　要：针对超低频信号测量装置对模数转换器(ADC)的高精度、低功耗和小面积要求,提出了一种带有斩波稳零(CHS)和自校准技术的增量式模数转换器(I-ADC)。I-ADC带有复位操作,可避免超低频信号带来的模式噪声。为了尽量降低功耗和芯片面积,I-ADC采用一阶结构,并通过增加一定的转换时间来实现14bit的转换精度。该I-ADC采用斩波稳零技术来消除运放低频噪声和失调对其精度的影响,I-ADC的系统失调则采用上电自校准技术来消除。采用DongBu 0.5μm BCD工艺完成了I-ADC电路及其调制器版图的设计。仿真结果表明:在-156.25~156.25 mV输入范围内,I-ADC转换误差的绝对值最大为21μV,微分非线性误差的绝对值最大为0.12bit,积分非线性误差的绝对值最大为0.21bit,调制器的平均电流消耗仅为20μA;调制器的版图面积仅为150μm×310μm;所设计的I-ADC可满足锂电池电量计等超低频测量系统所需的14bit转换精度,并具有显著的低功耗和小面积优势。An incremental analog-to-digital converter（I-ADC）with chopper stabilization（CHS）and self-calibration techniques is presented to meet the requirements of high resolution,low power consumption and small area for measuring devices of ultra-low-frequency signals.The I-ADC has the function of reset operation to avoid pattern noise caused by ultra-low-frequency signals.A first-order architecture is adopted for the I-ADC to reduce power consumption and chip area,and to achieve 14-bit resolution by increasing certain conversion time.The chopper stabilization technique is employed to eliminate the influence of amplifier＇s low-frequency noise and offset on the I-ADC＇s precision,and power-on self-calibration is employed to eliminate the systematic offset of the I-ADC.The circuit of the I-ADC and the layout of the modulator are designed with the DongBu 0.5μm BCD technology.Simulation results in an input range of-156.25~156.25 mV show that the maximum absolute conversion error of the I-ADC is 21μV,the maximum errors of differential nonlinearity and integral nonlinearity are 0.12 and 0.21 bit,respectively,and the average current consumption of the modulator is only 20μA.The modulator occupies a chip area of only 150μm×310μm.The proposed I-ADC achieves 14 bit resolution,which is required by ultra-low-frequency signal measuring systems,such as lithiumion battery coulometer,and has significant advantages of low power consumption and small area.

关 键 词：超低频 增量式 模数转换器 斩波稳零 自校准 

分 类 号：TN432[电子电信—微电子学与固体电子学]