一种用于电容式MEMS麦克风的读出电路

在分析电容式MEMS麦克风工作原理的基础上,提出了一种用于电容式MEMS麦克风的读出电路.该读出电路包括低极点频率的高通滤波器和低噪声单位增益缓冲器,高通滤波器用来读出MEMS麦克风在声压作用下产生的小信号,单位增益缓冲器用来隔离高通滤波器和后续信号处理电路,并提供较大的驱动能力.仿真结果表明,当电源电压在1.2～3.6V之间时,读出电路都可以正常工作,且静态电流小于60 μA,等效输入噪声为5.2 μV,电压增益大于-1.56 dB(83.6％).由于消除了失调电压的影响,电路可以处理幅度范围为50 μV～200 mV的小信号(参考X-FAB 0.35 μm CMOS工艺).     

宽动态范围读出电路研究

为提高光电探测器的读出性能,设计的电容互阻放大器(CTIA)注入效率大于99%,线性度达99.84%。相关双采样电路(CDS)采用不同控制时序,读出电路可以工作在噪声抑制模式和两次采样模式。噪声抑制模式时读出电路平均噪声为0.91 mV,动态范围为66.85 dB,两次采样模式平均噪声为5.82 mV,动态范围扩展到90.82 dB。     

一种高灵敏度大动态范围读出电路

为读出光电探测器微弱的响应电流,设计了一种增益自动可调列放大器,提高了读出电路的灵敏度和动态范围,读出电路的动态范围提高了24dB,读出电路功耗为230μW,满足探测器读出要求。读出电路的输出信号可以根据应用要求分别采用线性法和非线性法重建。     

混成红外探测器列阵与改善动态范围的CMOS读出电路

美国专利US7551059 (2009年6月23日授权)本发明提供一种混成图像传感器,它包括一个CMOS读出电路和一个红外探测器列阵。CMOS读出电路通过铟柱焊接与红外探测器列阵的至少一个探测器连接。CMOS读出电路包括两个放大器电路,这     

一种基于VCO量化的MEMS加速度计接口电路

采用0.18 μm CMOS工艺,设计了一种基于VCO量化的电容式MEMS加速度计接口电路。电路基于VCO实现量化,可直接输出数字信号,克服了传统模拟力反馈的非线性问题,且不需要ADC或额外的比较器电路,大大降低了电路的复杂性。仿真结果表明,该接口电路系统噪声基底为18 μg·Hz-1/2,最大非线性误差为0.57%,电路功耗为6.7 mW,输入带宽和检测范围分别为2.5 kHz和±1.0 g。该接口电路达到较好的性能。     

一种高灵敏度大动态范围的红外焦平面异形读出电路的设计

针对短波红外焦平面探测器高灵敏度、大动态范围的发展需求,设计了一款新型的红外焦平面异形读出电路。传统的像元只使用一种输入级,难以兼顾高灵敏度和大动态范围,而在该设计中包含的组合像元使用了CTIA和大动态范围两种输入级,兼顾了其优点。具体布局为每2×2个CTIA输入级模块阵列中间,含有1个直接注入模式/对数模式可切换的大动态范围输入级模块。工作模式有两种,第一种为CTIA输入级模块和直接注入模式的大动态范围输入级模块同时工作;第二种为CTIA输入级模块和对数模式的大动态范围输入级模块同时工作。基于0.18μm 3.3V标准CMOS工艺,绘制了CTIA输入级阵列规模为320×256,像元中心距为15μm的异形电路像元阵列版图。仿真结果表明,异形电路像元通过小积分电容实现了高灵敏度,通过对数光响应输出实现了大动态范围。     

MEMS高精度电容读出电路的单芯片集成研究

MEMS电容式传感器的迅速发展为后续集成化读出电路的设计提出了巨大挑战.系统地分析了制约微传感器高精度电容读出电路设计的主要因素,回顾了目前主要的几种读出电路结构,阐述了这些电路的基本原理,并对影响电路分辨率的主要设计参数进行了分析和对比,最后探讨了电容式读出电路设计的发展趋势.     

MEMS电容式加速度计的动态特性分析

针对梳齿电容形式的微机械加速度计,对其工作原理和动态性能进行了分析。该微结构的质量块由4个折叠梁支撑,采用梳齿结构形成差分检测电容用于检测质量块的位移。通过理论推导得到了结构的质量、刚度和阻尼的计算公式。组成梳齿结构的两平行极板间的气体在极板运动时产生两种作用力:阻尼力和弹性力,运动频率较低时阻尼力为主要表现形式,高频时弹性力则占主要因素。针对一组特定的结构参数,对气体压强分别为100Pa和0.1MPa时微机械加速度计的频率响应特性进行了分析,当气体压强太小时,会造成系统带宽的降低,而当气体压强较高时,系统的动态特性表现良好,并在电容极板间隙约为3μm时,系统的动态特性达到最优。     

一种用于红外读出电路的低温SAR ADC

本文提出了一种用于低温红外读出系统的连续逼近模数转换器（SAR ADC）电路。为了在很宽的温度范围内保证电路的性能,ADC中采用了一种温度补偿时域比较器结构。该比较器可在从室温到77K的极端工作温度条件下,实现稳定的性能和极低的功耗。该转换器采用标准的 0.35 μm CMOS 工艺制造,在77K的温度下,其最大微分非线性（DNL）和积分非线性（INL）分别为0.64LSB和0.59LSB。在采样率为200kS/s时可实现9.3bit的有效位数。在3.3V的电源电压下其功耗为0.23mW,占用的芯片面积为0.8*0.3 mm2。     

97dB动态范围、带温度补偿的MEMS电容传感器读出电路

This paper presents a charge-sensitive-amplifier(CSA)based readout circuit for capacitive microelectro-mechanical-system(MEMS)sensors.A continuous-time(CT)readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the readout circuits.An operational trans-conductance amplifier(OTA)structure with an auxiliary common-mode-feedback-OTA is proposed in the fully differential CSA to suppress the chopper modulation induced disturbance at the OTA input terminal.An analog temperature compensation method is proposed,which adjusts the chopper signal amplitude with temperature variation to compensate the temperature drift of the CSA readout sensitivity.The chip is designed and implemented in a 0.35 m CMOS process and is 2.1 2.1 mm2in area.The measurement shows that the readout circuitachieves0.9aF/√Hz capacitive resolution,97dBd ynamic range in 100Hz signal bandwidth,and 0.8mV/fF sensitivity with a temperature drift of 35 ppm/℃ after optimized compensation.     

新型双向电容式MEMS加速度计特性分析

文章研究了一新型的栅形条电容MEMS加速度计,通过新型结构设计降低了传感器的机械噪声和电子噪声。用软件ANSOFT-Maxwell对栅形条电容的宽度、厚度及叠加宽度对检测电容的影响进行了分析。用深度离子刻蚀工艺和硅-玻璃键合工艺制作了传感器,初步测试结果表明其在X和Y方向的灵敏度分别为0.53pF/g 、0.49pF/g。制作的栅形条谐振子在大气下的品质因子达到514,说明栅形条结构可大大降低机械噪声。     

Characteristics of a novel biaxial capacitive MEMS accelerometer

A novel MEMS accelerometer with grid strip capacitors is developed.The mechanical and electrical noise can be reduced greatly for the novel structure design.ANSOFT-Maxwell software was used to analyze the fringing electric field of the grid strip structure and its effects on the designed accelerometer.The effects of the width,thickness and overlapping width of the grid strip on the sensing capacitance are analyzed by using the ANSOFT-Maxwell software.The results show that the parameters have little effect on the characteristics of the presented accelerometer.The designed accelerometer was fabricated based on deep RIE and silicon-glass bonding processes.The preliminary tested sensitivities are 0.53 pF/g and 0.49 pF/g in the x and y axis directions,respectively.A resonator with grid strip structure was also fabricated whose tested quality factor is 514 in air,which proves that the grid strip structure can reduce mechanical noise.     

环境振动测量电容式加速度传感器设计

设计了一种用于环境振动测量的高分辨率电容式加速度传感器 ,通过适当减小质量块的质量 ,不改变敏感电容的大小 ,降低了实现加速度传感器闭环控制对多晶硅固定电极刚度的要求 ,采用简单的加工工艺 ,多晶硅固定电极刚度就能满足加速度传感器闭环控制的需要。通过在传感器的三层电极上都刻蚀阻尼孔 ,减小阻尼 ,提高传感器的品质因子 ,传感器能提供 μ犂级的分辨率     

针对电容型MEMS读出电路噪声与失调的优化

This paper presents a high precision CMOS readout circuit for a capacitive MEMS gyroscope. A continuous time topology is employed as well as the chopper noise cancelling technique. A detailed analysis of the noise and mismatch of the capacitive readout circuit is given. The analysis and measurement results have shown that thermal noise dominates in the proposed circuit, and several approaches should be used for both noise and mismatch optimization. The circuit chip operates under a single 5 V supply, and has a measured capacitance resolution of 0.2 aF/√Hz. With such a readout circuit, the gyroscope can accurately measure the angular rate with a sensitivity of 15.3 mV/°/s.     

Noise and mismatch optimization for capacitive MEMS readout

This paper presents a high precision CMOS readout circuit for a capacitive MEMS gyroscope. A continuous time topology is employed as well as the chopper noise cancelling technique. A detailed analysis of the noise and mismatch of the capacitive readout circuit is given. The analysis and measurement results have shown that thermal noise dominates in the proposed circuit, and several approaches should be used for both noise and mismatch optimization. The circuit chip operates under a single 5 V supply, and has a measured capacitance resolution of 0.2 aF/√Hz. With such a readout circuit, the gyroscope can accurately measure the angular rate with a sensitivity of 15.3 mV/°/s.     

MEMS加速度计静态温度模型的辨识

在研究了当前国内外各种温度补偿方法的基础上,提出了逐步线性回归分析的方法,将零位和比例因子拟合,得到了MEMS加速度计静态温度模型系数随温度变化的规律,建立了全温范围内加速度计的分段温度模型。应用该模型进行温度补偿后,使模型辨识精度得到很大的提高。     

Low-voltage CMOS current-mode exponential circuit with 70 dB output dynamic range

The paper proposes new accurate exponential circuits, having a multitude of practical applications in analog signal processing. The original method for obtaining the exponential function is based on the utilization of new superior-order approximation functions. The accuracy of the proposed structures is excellent and the output dynamic range is strongly extended as a result of the fourth-order approximation and of the independence of implemented function on technological errors and on temperature variations (the best original proposed architecture of the exponential generator has an output dynamic range of 70 dB for an approximation error smaller than ±1 dB). The exponential circuits are designed for implementing in 0.18 µm CMOS technology, having a low-voltage operation (a minimal supply voltage of 1 V). The power consumptions of the proposed exponential circuits are smaller than 0.08 mW, for a supply voltage of 1 V. As application of the new exponential circuit, a dB-linear VGA circuit with high output dynamic range will be presented. The new computational structures have the possibility of generating any continuous mathematical function, presenting also an increased modularity and controllability and reduced design costs per implemented function.     

数字闭环石英挠性加速度计信号检测技术

数字闭环石英挠性加速度计可以有效地解决传统模拟式加速度计在模数转换中引起的精度损失问题,而数字式加速度计的精度主要取决于差动电容检测环节。阐述了数字式加速度计的工作原理,重点设计了差动电容检测方法,利用单载波调制与数字自相关解调技术构建完整的数字式加速度计信号检测方案。搭建数字式加速度计原理样机,对其进行0 g/1 g稳定性测试,得到数字式加速度计0 g/1 g零偏稳定性分别为17.595 0 g、19.363 7 g、20.715 3 g。测试结果表明,当前的数字式加速度计精度达到了模拟式加速度计精度量级,有效验证了该方案的可行性及正确性。     

高灵敏度、大动态范围光电接收电路设计与实现

无人机载的激光半主动导引头具有机动灵活、打击范围广、命中精度高等优点,在制导武器领域里占有重要的地位。为提高光电接收系统的灵敏度、动态范围和抗杂散光性能,通过对基于四象限雪崩光电二极管(QAPD)光电接收系统的分析,设计了前端信号调理电路与后端信号处理电路。试验结果表明,系统灵敏度达到了100nW,动态范围为45dB,峰值跟踪最大误差比例是1.06,在杂散光环境下可以工作正常,实现了闭环控制。研究结果对光电接收电路的设计具有一定的应用价值。