基极电流补偿曲率校正的0.13μm CMOS带隙基准源

带隙基准是各种模拟/数模混合集成电路中的基础性组成部件,其温度稳定性是决定整体电路性能的重要因素之一。使用级联三极管的带隙基准结构能够有效的降低运算放大器输入失调对基准电路稳定性的影响。但是在CMOS工艺中,由于三极管器件的放大倍数值较小,“发射极-基极”电流对集电极电流的分流作用较为显著,致使基准电压输出存在较大的温度漂移。针对这个问题,提出了一种自适应的基极电流补偿的技术,能够有效的提高级联三级管的带隙基准电路中输出基准电压的温度稳定性,实现基准电压的温度响应曲线的曲率校正。基于0.13μm CMOS工艺的实现结果表明,输出基准电压的温度稳定性可达到6.2ppm/℃（-40℃～125℃）,输出基准电压1.238V。     

CMOS带隙基准源研究现状

带隙基准源是集成电路中的重要单元,输出不随温度、电源电压变化的基准电压或电流.简单介绍了CMOS带隙基准源的基本工作原理;指出了限制其性能的主要因素;分析了低电源电压、低功耗、高精度和高PSRR四种类型的CMOS带隙基准源.     

一种新型CMOS带隙基准电压源

传统带隙基准源电路采用PNP型三极管来产生ΔVbe,此结构使运放输入失调电压直接影响输出电压的精度。文章在对传统CMOS带隙电压基准源电路原理的分析基础上,提出了一种综合了一阶温度补偿和双极型带隙基准电路结构优点的高性能带隙基准电压源。采用NPN型三极管产生ΔVbe,消除了运放失调电压影响。该电路结构简洁,电源抑制比高。整个电路采用SMIC 0.18μmCMOS工艺实现。通过Cadence模拟软件进行仿真,带隙基准的输出电压为1.24V,在-40℃~120℃温度范围内其温度系数为30×10-6/℃,电源抑制比(PSRR)为-88 dB,电压拉偏特性为31.2×10-6/V。     

一种阵列式版图布局的低温度系数CMOS带隙基准电压源

设计了一款低温度系数的自偏置CMOS带隙基准电压源电路,分析了输出基准电压与关键器件的温度依存关系,实现了低温度系数的电压输出。后端物理设计采用多指栅晶体管阵列结构进行对称式版图布局,以压缩版图面积。基于65 nm/3.3 V CMOS RF器件模型,在Cadence IC设计平台进行原理图和电路版图设计,并对输出参考电压的精度、温度系数、电源抑制比(PSRR)和功耗特性进行了仿真分析和对比。结果表明,在3.3 V电源和27℃室温条件下,输出基准电压的平均值为765.7 mV,功耗为0.75μW;在温度为-55~125℃时,温度系数为6.85×10~(-6)/℃。此外,输出基准电压受电源纹波的影响较小,1 kHz时的PSRR为-65.3 dB。     

一种带2阶温度补偿的负反馈箝位CMOS基准电压源

根据带隙基准电压源工作原理,设计了一种带2阶温度补偿的负反馈箝位CMOS基准电压源。不同于带放大电路的带隙基准电压源,该基准电压源不会受到失调的影响,采用的负反馈箝位技术使电路输出更稳定。加入了高阶补偿电路,改善了带隙基准电压源的温漂特性。电路输出阻抗的增大有效提高了电源抑制比。基于0.18 μm CMOS 工艺,采用Cadence Spectre软件对该电路进行了仿真,电源电压为2 V,在-40 ℃~110 ℃温度范围内温度系数为4.199 ×10-6/℃,输出基准电压为1.308 V,低频下电源抑制比为78.66 dB,功耗为120 μW,总输出噪声为0.12 mV/Hz。     

一种带曲率补偿的低功耗带隙基准设计

为了改善传统带隙基准中运放输入失调影响电压精度和无运放带隙基准电源抑制差的问题,设计了一款基于0.35μm BCD工艺的自偏置无运放带隙基准电路。提出的带隙基准源区别于传统运放箝位,通过负反馈网络输出稳定的基准电压,使其不再受运算放大器输入失调电压的影响;在负反馈环路与共源共栅电流镜的共同作用下,增强了输出基准的抗干扰能力,使得电源抑制能力得到了保证;同时采用指数曲率补偿技术,使得所设计的带隙基准源在宽电压范围内有良好的温度特性;且采用自偏置的方式,降低了静态电流。仿真结果表明,在5 V电源电压下,输出带隙基准电压为1.271 V,在-40～150℃工作温度范围内,温度系数为5.46×10^-6/℃,电源抑制比为-87 dB@DC,静态电流仅为2.3μA。该设计尤其适用于低功耗电源管理芯片。     

带2阶温度补偿的多输出带隙基准电压源

基于传统带隙基准的原理,通过优化电路结构,消除双极晶体管基极．发射极电压中的非线性项,设计了一种带2阶补偿的多输出带隙基准电压源。整个电路采用CSMC0．5μmCMOS工艺模型进行仿真。Spectre仿真结果表明,在-55～125℃的温度范围内,带隙基准电压源的温度系数为3．1ppm／℃,在5V电源电压下,输出基准电压为1．2994V;带隙基准电压源的电源抑制比在低频时为84．5dB;在5v电源电压下,可以同时输出0—5V多个基准电压。     

一种低温漂输出可调带隙基准电压源的设计

带隙基准电压源是利用PN结电压的负温度系数和不同电流密度下两个PN结电压差的正温度系数电压相互补偿,而使输出电压达到很低的温度漂移。带隙电压基准具有低温度系数、高电源抑制比、低基准电压以及长期稳定性等优点。根据带隙基准电压源理论,在传统CMOS带隙电压源电路结构的基础上,采用一级温度补偿、电流反馈等技术,设计出了一种高精度、输出可调的带隙电压基准源。该电路具有精度高,输出电压可调,稳定性好,易于实现的特点。     

一个低压高阶曲率补偿的CMOS带隙基准电压源的设计

运用带隙基准的基本原理,采用0.6μm的CMOS工艺,对一个低压高阶曲率补偿的高性能CMOS带隙基准电压源进行研究,并结合所提出电路给出了高阶曲率补偿的数学表达式。Cadence软件仿真结果显示:电源电压最低可为1.2 V,在-20~100℃温度范围内,输出电压为0.6 V,温度系数为9.1 ppm/℃,即基准输出电压随温度变化不超过±0.1%。低频(f=1 kHz)时PSRR为-78 dB。在室温电源电压为1.2 V时总功耗约为38μW。整个带隙基准电压源具有良好的综合性能。     

振动能量拾取MEMS压电式微能源研究

设计并制作了一种"四悬臂梁-中心质量块"结构的振动能量拾取微机电系统(MEMS)压电式微能源,实现了环境振动能量向电能的转换。首先利用溶胶-凝胶工艺完成锆钛酸铅(PbZrxTi1-xO3,PZT)压电薄膜的异质集成制备;然后通过MEMS工艺和引线键合技术进行器件基础结构的集成制造;最后借助振动测试系统对该器件的各项输出性能进行测试。测试结果表明,8Hz谐振频率工作状态下,该压电式微能源器件的输出电压峰-峰值随着加速度激励的增加呈线性增大,当加速度激励为10 m/s2时,该能量采集器件的输出电压峰-峰值为82.4mV。在器件两端加载2.0 MΩ的负载时,器件输出功率密度达最大值(为2.074 3μW/cm3)。     

Simulation and optimization on the squeeze-film damping of a novel high-g accelerometer

The damping characteristics of a packaged high-g accelerometer have been investigated in this paper. Firstly, a multi-segments-plates-approximate (MSPA) model on curved surface damping suitable for this component has been established to obtain the relationship between the parallel-shift-distance (PSD) of curved stop and the damping of component. Subsequently, not only the effect of the PSD of curved protection but also the impact of the characteristics of damping media on the dynamic shock response of the component has been studied with ANSYS FEM technology. Results show that the dynamic output responses of component were in reality the superposition of both the forced vibration under acceleration shock and the vibration of cantilever in its inherent frequency. With the increase of PSD, the inherent frequency vibration became outstanding in output response and both the peak output voltage and displacement of beam end increased linearly whereas its corresponding time decreased nonlinearly. The effects of damping media on the dynamic response characteristics of the component were attributed to the difference of viscosity coefficient of damping medium. Under the same other conditions, with increment of viscosity coefficient, the output response curve become smoother except for lower peak voltage. Therefore, the PSD of curved stop should be controlled between 0.5 and 0.65 μm during the fabrication of chip and if the PSD was about 0.5 μm, air would be the most suitable damping media in the packaging of the component.     

Investigation and simulation on the dynamic shock response performance of packaged high-g MEMS accelerometer versus the impurity concentration of the piezoresistor

To enhance the stability of packaged high-g MEMS accelerometers with double cantilevers positioned asymmetrically, the dynamic shock responses of components versus impurity concentration of piezoresistors at various working temperatures have been probed by using Finite Element Method (FEM). Results indicate that the dynamic output responses of component are actually the superposition of the forced vibrations with dynamic shock and those of cantilevers in their eigenfrequency. The dynamic responses of components are sensitive to the working temperature. With the increase of working temperature, the inherent frequency vibrations of the cantilevers are depressed gradually. Moreover, the larger the difference between the working temperature and reference temperature, the more obvious the impurity effect of piezoresistors is. The difference between the peak output voltage of response under 1 × 10¹⁸ cm⁻³ and that under 1 × 10²¹ cm⁻³ varies greatly from −2.2146 mV at T = 0 °C to 8.6609 mV at T = 100 °C, of course, is partly due to the characteristic variation of damping media under various working temperatures. Therefore, to improve the stability of component and further weaken the impurity concentration effect and the temperature effect of piezoresistors on the performance of components, it is necessary to increase the impurity concentration of piezoresistors and keep the components working at relatively lower temperature only if the electro-performance of component is satisfied.     

变截面悬臂梁压电俘能器动力学特性分析

提出一种变截面悬臂梁压电俘能器结构,通过有限元仿真分析其振动特性和输出电压,有利于提高发电性能。该俘能器结构固定端为等截面梁,自由端为变截面梁,压电层粘贴在悬臂梁根部等截面梁表面,改变悬臂梁自由端与固定端的宽度比,得到多种不同形式的变截面悬臂梁。对比分析了三角形梁、矩形梁和具有不同宽度比梯形梁的固有频率、应力和应变分布及简谐激励输出电压响应。结果表明,三角形梁固有频率较大,输出电压最大,同时分析了不同变截面段长度对输出电压的影响。该文还分析了具有相同一阶频率、不同宽度比俘能器的输出电压,表明三角形结构单位体积压电层输出电压最大。对比分析了基体层上根部粘贴压电片和全部粘贴压电片的输出电压特性。结果表明,前者输出电压较大,发电性能更好。     

自调谐全方向振动能量收集装置的设计及优化

为解决现有振动能量收集装置单方向收集及收集效率低等问题,该文设计了一种自调谐全方向振动能量收集装置,通过多场耦合方式改变装置的振动特性,提高能量转换效率。建立了装置横向和纵向振动模型,分析了横向和纵向振动的动力学特性。利用有限元分析对结构参数进行优化,得到结构参数与谐振频率的关系。最后,搭建实验平台。通过实验表明,能量收集装置的谐振频率随组合悬臂梁宽度和厚度的增大而增大,当选取组合悬臂梁宽10mm、厚1mm,外界激振力1.5N时,谐振频率为16.47Hz,峰值电压为9.67V,且在各个方向均能产生有效输出电压。     

A Branched Beam-Based Vibration Energy Harvester

In this paper, a strategy to utilize a branched beam system to improve the frequency response characteristic of vibration energy harvesting is demonstrated. A basic unit of the device consists of several branch beams with proof mass at their ends and one main cantilever beam with a piezoelectric component at its root and proof mass at its end. The device can utilize the resonance of the branch beams and main beam to generate multiple output voltage peaks, providing a better frequency response characteristic than that of the conventional piezoelectric vibration energy harvester. Multiple branch structure and multiple basic units with similar structures can be connected to generate more output voltage peaks in the frequency response characteristic. Only one piezoelectric component is needed in the device, which makes it competitive in the management of harvested electric energy.     

Analytical modeling of piezoelectric vibration-induced micro power generator

In this article, a novel piezoelectric cantilever bimorph micro transducer electro-mechanical energy conversion model is proposed. Based on the curvature basis approach, the relationship between the deduced voltage and the mechanical strain induced piezoelectric polarization is formulated. In addition to the working equation for piezoelectric sensors, the damping effect is included to enable the resonance frequency, the maximum induced voltage at the resonance, the conversion energy density and the dimensions of the piezoelectric micro power generator to be analytically estimated. The analytical model shows that the vibration-induced voltage is proportional to the excitation frequency and the width of the device but is inversely proportional to the length of the cantilever beam and the damping factor. To verify the theoretical analysis, two micro transducer clusters are fabricated. The experimental results demonstrate that the maximum output voltage coincides with the energy conversion analytical model.     

考虑疲劳寿命的压电悬臂梁结构优化设计方法

提出了一种插入式的压电悬臂梁结构,通过将其末端质量块转化成等效惯性力和惯性力矩,得出了求解其固有频率的理论公式。在此基础上,设计了一系列一阶固有频率相同、长宽比不同的压电悬臂梁。通过ANSYS模态分析发现,理论计算和仿真结果的误差均在5%以内,证明了这种求解压电悬臂梁固有频率方法的可行性。通过瞬态分析得出,随着长宽比的增大,压电悬臂梁的输出电压及压电层的最大应力随长宽比呈近似线性关系增大,这种线性关系对于压电悬臂梁的性能预测很有意义。最后通过疲劳分析软件nCode DesignLife,求解出了各压电悬臂梁的疲劳寿命,并以此为依据,选取了最优的结构设计方案。为压电悬臂梁的结构优化设计建立了一种新的、相对完整的方法。     

带异形孔的双稳态压电能量采集器研究

针对传统线性压电悬臂梁能量采集器共振频率高、偏离共振频率时输出电压快速下降的问题,该文设计了一种悬臂梁基板上带异形孔的新型双稳态能量采集器。建立该能量采集器的理论模型,并制作了实验样机,研究了该能量采集器在外界不同正弦激振频率下,磁间距对其输出电压和工作频带的影响。结果表明,随着磁极对间距减小,带异形孔结构的双稳态能量采集器的双稳态效应先增强再减弱,由此确定最佳磁极对间距为12 mm,谐振频率为18 Hz,最大输出均方根电压达到12.01 V,采集器有效工作频率为15.5～22.5 Hz,工作带宽达到7 Hz,带异形孔的双稳态能量采集器具有更宽的采集频带,在低频振动环境下具有更高的输出电压响应。     

基于ANSYS的压电微悬臂双梁的有限元分析

提出一种新型的对偶子式的压电微悬臂双梁,采用简化的等效器件建立数学分析模型,利用ANSYS对这种对偶子微悬臂梁进行模拟仿真分析,得出微悬臂梁的振型、固有频率及其在受外加负载时的形变和电压输出。同时分析微悬臂梁的几何尺寸对它们的影响,以便更好地指导实际工艺。     

BaTiO_3压电薄膜的制备及其性能研究

利用旋涂技术,在聚二甲基硅氧烷(PDMS)混合液中掺入不同质量分数(30%,50%,70%)的钛酸钡(BaTiO_3)纳米颗粒,并将混合物均匀涂在洁净的硅片表面进行旋涂处理;加热固化制得压电薄膜,并对压电薄膜进行极化处理,分别运用扫描电子显微镜(SEM),X线衍射(XRD)仪分析薄膜表面和BaTiO_3粉末。实验结果表明,薄膜内部BaTiO_3分布相对均匀,且其中BaTiO_3纳米颗粒为四方相。设计振动能量采集测试系统测试分析薄膜的输出开路电压和供电能力,分别用单悬臂梁振动和激振器敲击的形式对压电薄膜的输出特性进行研究。压电薄膜的输出电压峰-峰值与BaTiO_3的质量分数具有高度的一致性,在w(BaTiO_3)=70%时,输出电压最高,对应的峰-峰值为3.50V。