高精度差动式电容传感器信号处理电路的研究

介绍了一种具有高精度的差动式电容传感顺的信号处理电路,该电路是基于张弛振荡器的,由积分器、微分器和比较器组成,最后对该接口电路的性能进行了分析。     

一种新型结构的湿度传感器

本文提出了一种以聚酰亚胺为介质膜的电容式湿度传感器.它的工作原理是,在不同的湿度环境下,聚酰亚胺—水系统介电常数改变引起传感器电容的变化.该传感器具有工艺简单、体积小、灵敏度高、响应快等优点.该文介绍了它的结构、制造工艺和试验结果.     

一种实用的压力传感器测量电路

介绍了扩散硅压力变送器这种实用电阻有源惠斯登全电桥传感器电路，定性分析了其电路原理，定量分析了零点／量程的调整及迁移、输出信号反馈方式等技术措施和性能。     

一种湿度传感器接口电路的分析与改进

介绍了一种本实验室开发的集成湿度传感器，它实现了湿敏电容和接口电路在一块芯片上的集成。重点分析了它的接口电路，基于施密特触发器构建，实现电、容值与频率值的转换。对样片进行了测试，电容值与湿度值近似为线性关系；但是，输出波形的占空比与理论值有较大的偏差。通过分析，给出了测试结果发生偏差的原因。最后，对施密特触发器的参数进行优化，重新对电路的结构进行了设计，实现了与实验室第二代湿度传感器的集成。     

一种温度电容混合传感器的接口电路

基于NXP 0.16 μm CMOS工艺,设计并实现了一种温度、电容混合传感器的接口电路。温度传感器的前端基于双极型晶体管的温度依赖特性,将温度信息转换为与温度有关的电压信息;电容传感器的前端基于开关电容电路,将电容值转换为与电容有关的电荷。两个传感器共用一个2阶Δ-Σ模数转换器,以减小芯片面积。测试结果表明,在-55 ℃~125 ℃范围内,温度传感器的准确度达到0.2 ℃(3σ);在0~3.8 pF的范围内,电容传感器每一次测量的FOM值可达0.76 pJ。整个芯片面积为0.2 mm²,供电电压为1.8 V,电流为4.6 μA。     

一种具有温度补偿的低功耗张弛振荡器

提出了一种具有温度补偿和数字修调的低功耗CMOS张弛振荡器。基于阈值电压和偏置电流的匹配技术实现输出频率的1阶温度补偿,保证输出频率在大温度范围内的高稳定性。采用数字修调技术,校正工艺偏差引起的频率偏差。因此,该振荡器的输出频率对温度、电源电压和工艺偏差不敏感。振荡器采用0.18 μm CMOS工艺进行设计,使用Cadence进行仿真验证。结果表明,在1.8 V电源电压下,消耗电流为400 nA;在－40 ℃~125 ℃温度范围内,输出频率变化小于±1%;在1.5~2.5 V电源电压变化范围内,频率偏差小于1%。     

一种高精度测量微小电容的电路

提出了一种高精度、低成本的电容的测量方法。该方法采用差动式直流充电法测量微小电容,具有功耗低、体积小、分辨率高、刷新率高的特点。同时详细阐述了测量电路的基本原理、具体实现,并且通过测量固定电容验证了电路的性能。     

一种线性化有源电桥在测温中的应用

介绍了用热电阻作感温元件,设计一种有源线性化测量桥路,分析了此测量桥路的测温优点,并给出了实用的测温现象连接方式。     

具有较大测量范围的激光线扫描三维测量机

文章就线结构光三维轮廓测量方法及其实用化做了深入的分析和研究。研制的光刀中心位置获取电路,提高了测量速度;采用双CCD 补偿算法来提高系统的测量精度;用最小二乘拟合结构参数的方法来标定光刀在高度方向和轴向的物象相对坐标关系,解决了测量中的标定问题;对物体的分段与分层测量极大地扩展了测量范围。实验结果表明,所开发的线扫描测量机具有较大的测量范围,较高的精度和测量速度,具有很高的实用价值     

像素内两次曝光组合的宽动态范围CMOS图像传感器

提出了一种基于五管有源像素的宽动态范围CMOS图像传感器（CIS）,在像素内部的浮动节点处进行长曝光时间信号和短曝光时间信号的组合。通过优化像素操作,光电响应曲线得到了压缩,获得了宽动态范围图像。设计的CMOS图像传感器采用0.18μm CIS工艺进行了流片,测试结果表明在两次曝光时间分别为2.4ms和70ns,30帧每秒的帧频条件下,传感器的动态范围达到80dB,满足安防监视系统的应用需求。     

变间隙自感式传感器线性度和量程关系的探讨

简要分析了一类非线性传感器的输出特性,在此基础上,运用最佳一致逼近理论,导出了线性度和量程之间的关系式,并进行了实例计算和MATLAB仿真,同时与传统方法所得结果做了比较。结果表明,当输入值相对变化量为0.1时,非线性误差由原来的10%降为1.25%;而当非线性误差给定为1%时,输入的相对变化量由0.01增加为0.08,即量程是原来的8倍。     

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.     

New ISFET interface circuit design with temperature compensation

An integrated and new interface circuit with temperature compensation has been developed to enhance the ISFET readout circuit stability. The bridge-type floating source circuit suitable for sensor array processing has been proposed to maintain reliable constant drain-source voltage and constant drain current (CVCC) conditions for measuring the threshold voltage variation of ISFET due to the corresponding hydrogen ion concentration in the buffer solution. The proposed circuitry applied to Si₃N₄ and Al₂O₃-gate ISFETs demonstrate a variation of the drain current less than 0.1 μA and drain-source voltage less than 1 mV for the buffer solutions with the pH value changed from 2 to 12. In addition, the scaling circuitry with the V_T temperature correction unit (extractor) and LABVIEW software are used to compensate the ISFET thermal characteristics. Experimental results show that the temperature dependence of the Si₃N₄-gate ISFET sensor improved from 8 mV/°C to less than 0.8 mV/°C.     

Cobalt oxide nanosheet humidity sensor integrated with circuit on chip

The work studies a micro humidity sensor integrated with a seven-stage ring oscillator circuit-on-a-chip fabricated by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The structure of the humidity sensor consists of interdigitated electrodes and a sensing film. The sensing film is cobalt oxide nanosheet that is prepared by a precipitation-oxidation method. The sensor, which is a capacitive type, changes in capacitance when the sensing film adsorbs or desorbs water vapor. The ring oscillator circuit is employed to convert the capacitance of the sensor into the oscillation frequency output. The post-process of the sensor includes etching the sacrificial oxide layer and coating the sensing film on the interdigitated electrodes.     

一种新型大动态范围CMOS图像传感器

提出了一种具有新型像素结构的大动态范围CMOS图像传感器,通过调整单个像素的积分时间来自适应不同的局部光照情况,从而有效提高动态范围。设计了一种低延时、低功耗、结构简单的新型pixel级电压比较器及基于可逆计数器的时间-电压编码电路。采用0.6μm DPDM标准数字CMOS工艺参数对大动态范围像素单元电路进行仿真,积分电容电压Vcint与光电流呈良好的线性关系,其动态范围可达126dB。在3.3V供电电压下,单个像元功耗为2.1μW。     

一种0.18μm CMOS工艺的低功耗神经信号测量电路

针对神经信号测量系统的功耗和增益问题,提出一种增益可调的低功耗16通道神经信号测量以及刺激系统。该系统电路的放大级由16个前置放大器、1个多路转换器以及2个宽频后置放大器组成。系统包含1个逻辑控制单元,用于从缓冲器中获取实测结果,同时也可以控制电路的偏置电流、高通转折频率、后置放大器增益以及刺激电流强度。可将所有通道配置为输出,利用双极电流脉冲刺激神经元。提出的系统电路是采用低成本0.18 μm IC工艺制成。实际测试结果显示,相比其他类似结构电路,提出电路的功率消耗最低,仅为1.31到1.48 mW,可调增益最高可达76.2dB,数据传输速率可达3.5Mbps。     

A wide dynamic range CMOS image sensor with pulse-frequency-modulation and in-pixel amplification

This paper briefly examines the pros and cons of CMOS pulse-frequency-modulation (PFM) digital pixel sensors. A pulse-frequency-modulation digital pixel sensor with in-pixel amplification is proposed to improve the resolution of the pixel sensor at low illumination. The proposed PFM digital pixel sensor offers the characteristics of a reduced integration time when the level of illumination is low with the fill factor comparable to that of PFM digital pixel sensors without in-pixel amplification. The proposed digital image sensor has been designed in TSMC- 1.8 V CMOS technology and validated using Spectre from Cadence Design Systems with BSIM3V3 device models. Simulation results demonstrate that the dynamic range of the proposed PFM digital pixel sensor with in-pixel amplification is 20 dB larger as compared with that of PFM digital pixel sensors without in-pixel amplification. The increased dynamic range is obtained in the low illumination condition where PFM digital pixel sensors without in-pixel amplification cease the operation due to the low photo current.     

带校准系数的数字温湿度传感器及其应用

介绍基于新型湿度传感器HIH4000及数字温度传感器DSISB20开发的新型数字温温度传感器．它所具有的可靠性、准确性、稳定性、自带校准系数等性能是传统传感器无法达到的。并给出实际的应用电路。     

A wide speed range and high precision position and velocity measurements chip with serial peripheral interface

This paper presents a VLSI chip, with a serial peripheral interface (SPI), that obtains position and velocity measurements from incremental optical encoder feedback. It combines period and frequency countings to provide velocity estimates with good dynamic behavior over a wide speed range (10 Hz-50 MHz). By sensing the velocity of the encoder, it reserves the computational power of a supervisory microcontroller, and subsequently enhances the performance of the total system. It is compact with lower power consumption when compared to traditional FPGA implementations. Although designed for use in the control unit of a medical robot with 34-axes and tight space and power constraints, it can be readily used in other applications. It is implemented in a 2P3 M 0.5 μm CMOS process and consumes 4.82 mW power with active area of 0.45 mm².