红外焦平面探测器的读出电路

红外焦平面阵列是现代红外成像系统的关键元件 ,不论是混合式还是单片式红外焦平面阵列 ,都采用读出电路来实现信号的多路传输以减少阵列输出信号线的数目。论述了读出电路在焦平面信号传输中的作用 ;讨论了用于实现红外焦平面阵列读出电路的一些实施技术 ;提出了红外焦平面阵列读出电路今后的研究方向     

基于金属氧化物薄膜晶体管的高速行集成驱动电路

本文提出了一种基于非晶铟锌氧化物薄膜晶体管的高速行集成驱动电路,该电路采用输入级复用的驱动结构,一级输入级驱动三级输出级,不仅减少电路输入级2/3晶体管的数量,实现AMOLED或AMLCD显示屏的窄边框显示,而且输入级的工作频率是输出级的1/3,该结构适用于高速驱动电路.电路内部产生了三次电容耦合效应,每一次电容耦合效应都可以提高相应节点的电压,保证了信号完整传输.输出级采用了一个二极管接法的薄膜晶体管,该薄膜晶体管连接了输出级的控制信号和上拉薄膜晶体管的栅极,利用的每一级输出级输出时所产生的电容耦合效应,增加上拉薄膜晶体管的栅极电压,有效地提高电路输出能力和工作速度.仿真表明电路能够输出脉宽达到4μs速度.最后成功地制作了10级行集成驱动电路,包括10级输入级电路和30级输出级电路,负载为R=10k?和C=100pF,实验结果验证,该电路满足4k×8k显示屏在120 Hz刷新频率下的驱动需求.     

一款2 G/s采样率20 GHz带宽主从式跟踪保持电路设计研究

设计了一款全差分、20 GHz带宽主从式跟踪保持芯片(MS-THA)。该芯片采样率为2 G/s,工作带宽大于20 GHz,采用0.13μm SiGe BiCMOS工艺实现。该芯片采用传统的开关发射极跟随器(SEF)作为跟踪保持核心电路,Cherryhooper电路作为输入缓冲和输出缓冲的带宽增强核心电路,并利用交叉反馈电容抑制馈通。为了验证上述电路的有效性,设计了一个单级THA电路,测试结果为MS-THA电路提供了足够的支持。在单电源+3.3 V供电、输入直流电平为0 V,2 G/s采样率以及-3 dBm输入信号功率条件下,获得的单端输出无杂散动态范围小于-23.5 dB,总功耗约为300 mW。     

高帧频384×288长波数字红外焦平面探测器

高帧频红外焦平面探测器在红外武器系统、光谱成像和高速测温中有着重要应用.目前,我国高帧频红外焦平面技术还比较落后,这严重制约着我国高端红外武器装备、光谱成像技术、高速测温仪器的发展.针对高帧频红外成像应用,设计并流片加工了一款384×288面阵、像元间距为25 μm的数字读出电路,与长波HgCdTe红外探测器芯片进行倒装互连,形成混合探测器芯片,并封装于金属真空杜瓦中,再配置斯特林制冷机,成功研制出了高帧频384×288长波数字红外探测器组件.经测试,所研制器件最高帧频达到1012 Hz,噪声等效温差(NETD)为16.8 mK,动态范围达到95.2 dB.采用所研制器件成功捕捉到了打火机点火瞬间的红外图像,该图像清晰呈现了火焰产生、迸出的过程,获得了良好的成像效果.     

积分时间对红外焦平面成像系统的影响

结合电容反馈互导放大结构读出电路,理论上分析了积分时间与红外成像系统输出信号之间的关系,在电路参数固定的情况下得出：输出电压的变化和积分时间的变化成正比。以电子数法分析了积分时间与噪声及比探测率之间的关系,推导出积分时间、噪声和比探测率之间的非线性关系。分析了积分时间变化对非均匀性的影响,并通过试验对其变化趋势和影响效果进行了验证。说明了积分时间选取对红外焦平面成像系统设计的重要性。     

非制冷红外探测器读出电路的非均匀性研究

对于长线列的非制冷红外探测器组件, 不同探测元之间的非均匀性是衡量电路设计的关键指标. 为了实现长线列非制冷红外探测器的高性能读出, 本文设计了一种基于电流镜方式的非制冷红外探测器160线列读出电路, 电路由电流镜输入模块、电容负反馈互导放大器模块及相关双采样输出模块组成. 电路采用0.5 μm工艺制作完成. 通过合理设置电路中MOS管的参数和布局电流镜版图, 电路的非均匀性有了明显地改善. 通过测试, 电路的非均匀性小于1%, 器件总功耗约为100 mW, 并具有良好的低噪声特性, 输出噪声小于1 mV, 输出摆幅大于2 V. 该电路与160线列非制冷红外探测器互连后, 能较好地完成红外信号的读出, 在积分时间为20 μups的情况下, 器件的响应为0.294 mV/Ω, 整体性能良好. 该电路的研制对超长线列的非制冷红外冷探测器读出电路研制奠定了重要的技术基础.     

基于锁相放大原理的微弱光信号检测系统设计

为了解决强噪声背景下微弱光信号检测难的问题,介绍了一种基于锁相放大原理的微弱光信号检测系统。系统采用对1 550nm的DFB激光进行调制的方法产生前级信号,利用PIN光电二极管产生的电流信号作为原始信号,经过前级放大、锁相放大及低通滤波电路还原调制信号。系统采用OPA124作为前级运放,AD630作为锁相放大器,参考信号和调制信号均由DDS芯片AD9850产生。滤波电路、移相电路和调制电路均采用高精度运放OP07来设计。实验结果表明,该系统具有很高的线性度,灵敏度为4.51V/V,精度大于0.05%,是一种高精度、高实用性的微弱光信号检测系统。     

塑料闪烁体阵列探测器读出ASIC中峰值保持电路的设计

塑料闪烁体阵列探测器(PSD,简称塑闪阵列探测器)的输出信号经过前置放大器和滤波成形电路后输出准高斯波形,利用峰值保持电路可对准高斯波形信号的峰值进行采样和保持,以便后续的电子学系统对其进行进一步的分析。本工作采用180 nm CMOS工艺设计并实现了一款峰值保持电路ASIC芯片,每通道主要由跨导放大器(OTA)、电流镜和充电电容三部分电路组成。实验室电子学功能和性能测试结果表明:峰值保持电路功能良好;输入动态范围为33~940 mV,非线性误差优于0.8%,下垂速率好于8.6 μV/μs,峰值探测延迟时间小于35 ns,芯片单通道静态功耗为825 μW,达到设计要求。     

超导量子干涉器件读出电路中匹配变压器的传输特性研究

在磁通调制超导量子干涉器件(SQUID)的读出电路中, 匹配变压器具有放大信号和阻抗匹配的功能, 是实现SQUID低噪声读出的关键元件. 利用模拟SQUID电路对匹配变压器进行性能测试, 研究了不同绕制匝数变压器的传输特性, 确定最佳绕制匝数比. 在变压器拾取SQUID电压信号的耦合网络中, 研究了不同电容对变压器传输特性的影响, 实现了变压器耦合网络参数的匹配和优化. 室温下匝数比为1:20的匹配变压器在匹配电容C=1μF时, 输出源电压增益为21.2, 带宽范围可达到210 kHz. 最后在基于磁通调制式DC SQUID读出电路中, 对匹配变压器的工作性能进行了评估与验证. 关键词： 超导量子干涉器件读出电路 匹配变压器 低噪声 传输特性     

基于FPGA的红外焦平面信息获取系统设计

基于红外焦平面探测器的红外遥感技术是实现多通道和高空间分辨率的重要手段,而随着焦平面探测器中探测单元的增加探测数据也急剧增加,研究基于FPGA的高速并行处理技术对解决红外探测领域多通道高速信息获取有重要意义。以FPGA作为控制器件,设计了16通道,数字分辨率为16bit的ADC采集方案,实现对32×32元的红外焦平面探测器数据并行获取,并设计了数据宽度为16bit的数据输出接口,用来完成采样数据的上传功能。实验结果表明该方案设计简洁,数据上传速度控制灵活,可以满足焦平面探测器的信号获取与传输。     

High-speed CMOS readout integrated circuit for large-scale and high-resolution microbolometer array

A new CMOS readout integrated circuit (ROIC) for microbolometric focal plane array (FPA) is proposed in this paper. By applying multiple-module parallel working technique, the pixel readout speed of the CMOS ROIC can reach 10 MHz, which is very suitable for large-scale microbolometer array. The CMOS ROIC of each parallel working module consists of three major parts: direct injection (DI) input circuits, column-shared integrating circuits, and common noise-suppressing circuits. The readout structure of the ROIC is simple because of the DI input, shared and common circuits, and this makes the ROIC satisfy the requirements of small-pixel microbolometric FPA. Furthermore, the voltage signals from different working modules can be output according to a certain order through a high-speed output circuit. An experimental readout chip based on the proposed ROIC has been designed and fabricated to verify its readout function and performance. The measurement results of the experimental readout chip have successfully proved that the proposed CMOS ROIC can be applied to high-speed, low-noise, large-scale and high-resolution microbolometric FPA.     

High performance two-color one megapixel CMOS ROIC for QWIP detectors

FLIR Systems, Inc. has designed and fabricated the ISC0501 CMOS readout integrated circuit (ROIC) for quantum well infrared photodetectors (QWIPs). The ISC0501 is a two-color 1024 × 1024 format array with a 30 μm pixel pitch. The ROIC contains a separate analog signal path for each wavelength band. Separate signal paths allow the two-colors to have optimized detector biases, integration times, offsets and gains. This architecture also allows both colors to simultaneously sample a scene and readout the pixel data. This paper will describe the interface, design and features of the ROIC as well as a summary of the characterization test results. A sample image is included from a focal plane array (FPA) built by the Jet Propulsion Laboratory (JPL) using the ISC0501 ROIC with QWIP detectors designed by JPL.     

单晶热释电探测器混合集成制造方法研究

在比较几种探测器集成制造方法的基础上,提出采用各向异性导电膜作为电信号互联的手段,实现热释电探测器与信号处理电路的混合集成,从而演示了一种兼容性良好的集成化多传感器制造方法.对单晶钽酸锂热释电探测器采取机械研磨减薄获得其薄膜,利用3M的5552R各向异性导电膜,实现了探测器与信号读出电路的互联.对探测器的测试表明:机械研磨减薄获得的钽酸锂薄膜表现出与晶体接近的热释电特性,探测器表现出良好的绝热性质和动态响应特性.     

Investigation of high sensitivity radio-frequency readout circuit based on AlGaN/GaN high electron mobility transistor

An Al Ga N/Ga N high electron mobility transistor(HEMT) device is prepared by using a semiconductor nanofabrication process. A reflective radio-frequency(RF) readout circuit is designed and the HEMT device is assembled in an RF circuit through a coplanar waveguide transmission line. A gate capacitor of the HEMT and a surface-mounted inductor on the transmission line are formed to generate LC resonance. By tuning the gate voltage V g, the variations of gate capacitance and conductance of the HEMT are reflected sensitively from the resonance frequency and the magnitude of the RF reflection signal. The aim of the designed RF readout setup is to develop a highly sensitive HEMT-based detector.     

A new circuit model of HgCdTe photodiode for SPICE simulation of integrated IRFPA

We propose a novel sub circuit model to simulate HgCdTe infrared photodiodes in a circuit simulator, like PSPICE. We have used two diodes of opposite polarity in parallel to represent the forward biased and the reverse biased behavior of an HgCdTe photodiode separately. We also connected a resistor in parallel with them to represent the ohmic shunt and a constant current source to represent photocurrent. We show that by adjusting the parameters in standard diode models and the resistor and current values, we could actually fit the measured data of our various HgCdTe photodiodes having different characteristics. This is a very efficient model that can be used for simulation of readout integrated circuit (ROIC) for HgCdTe IR photodiode arrays. This model also allows circuit level Monte Carlo simulation on a complete IRFPA at a single circuit simulator platform to estimate the non-uniformity for given processes of HgCdTe device fabrication and Si ROIC fabrication.     

Non-ideal effects of MOS capacitor in a switched capacitor waveform recorder ASIC

SCAs(Switched Capacitor Arrays) have a wide range of uses, especially in high energy physics, nuclear science and astrophysics experiments. This paper presents a method of using a MOS capacitor as a sampling capacitor to gain larger capacitance with small capacitor area in SCA design. It studies the non-ideal effects of the MOS capacitor and comes up with ways to reduce these adverse effects. A prototype SCA ASIC which uses a MOS capacitor to store the samples has been designed and tested to verify this method. The SCA integrates 32 channels and each has 64 cells and a readout amplifier. The stored voltage is converted to a pair of differential currents( 4m A max) and multiplexed to the output. All the functionalities have been verified. The power consumption is less than 2 m W/ch. The INL of all the cells in one channel are better than 0.39%. The equivalent input noise of the SCA has been tested to be 2.2 m V with 625 k Hz full-scale sine wave as input, sampling at 40 MSPS(Mega-samples per Second) and reading out at 5 MHz. The effective resolution is 8.8 bits considering 1 V dynamic range. The maximum sampling rate reaches up to 50 MSPS and readout rate of 15 MHz to keep noise smaller than 2.5 m V. The test results validate the feasibility of the MOS capacitor.     

Detector and readout performance goals for quantum well and strained layer superlattice focal plane arrays imaging under tactical and strategic backgrounds

Advancements in III–V semiconductor based, Quantum-well infrared photodetector (QWIP) and Type-II Strained-Layer Superlattice detector (T2SLS) technologies have yielded highly uniform, large-format long-wavelength infrared (LWIR) QWIP FPAs and high quantum efficiency (QE), small format, LWIR T2SLS FPAs. In this article, we have analyzed the QWIP and T2SLS detector level performance requirements and readout integrated circuit (ROIC) noise levels for several staring array long-wavelength infrared (LWIR) imaging applications at various background levels. As a result of lower absorption QE and less than unity photoconductive gain, QWIP FPAs are appropriate for high background tactical applications. However, if the application restricts the integration time, QWIP FPA performance may be limited by the read noise of the ROIC. Rapid progress in T2SLS detector material has already demonstrated LWIR detectors with sufficient performance for tactical applications and potential for strategic applications. However, significant research is needed to suppress surface leakage currents in order to reproduce performances at pixel levels of T2SLS FPAs.     

An equivalent circuit model of a novel photodetector

An equivalent circuit model of a novel photodetector (PD) is proposed in this article. We use this model to describe the relation between the bias voltage and current (I–V), also the bias voltage and capacitance(C–V) of this kind of novel PD. The circuit model could optimize the structure of the circuit and could be linked with the readout circuit. According to the comparison between the simulation result and the experimental result by circuit testing, we could find they are in good agreement, which proving the correctness of the equivalent circuit model. The signification of this equivalent circuit model is to design an optimal readout circuit (ROIC) for the novel PD.     

一种新型双间隙输出腔的理论和实验研究

从双间隙分离腔的色散关系式出发,通过数值计算求出了分离腔中IM010模对应的谐振频率,并给出了腔内轴向电场的分布图,证实了分离腔中存在着电场反相的π模场。因此,可以将其用作电场反相的双间隙输出腔,来实现双间障提取。并用2.5维粒子模拟程序——卡拉特（KARAT）程序对这种分离腔输出回路进行了粒子模拟和优化设计。通过详细的冷测和调试实验,研制出了中心频率为3.74GHz、QL值为7.8的低QL值双间隙输出腔。