带使能端及保护电路的LDO设计

设计了一种带有使能端以及保护电路的低压差线性稳压器(LDO)。这种基于传统结构、带有使能端的LDO可在系统电路不工作时被关断,以减小电路功耗。使能信号可由数字模块输出。该LDO带有过流保护、短路保护以及过温保护电路,在过流、过温以及短路时能受到保护,避免电路被损坏。基于CSMC 0.5 μm单阱工艺完成电路设计,输入电压为5 V,输出电压为3 V,最大输出电流为100 mA,输出瞬态电压最大变化为4.26 mV。     

单相AC-DC变换电路设计及试验

该单相AC-DC变换电路以有源功率因数控制器UCC28019为核心,STM32F103做主控芯片,采用主控芯片片上DAC调节UCC28019电压误差放大器反馈端,控制输出电压稳定输出;设计功率因数测量电路、输出保护电路、功率因数调整电路等电路模块。经测试,系统输入电压为24 V时,输出2 A电流时可稳定输出36 V电压,负载调整率为0.02%,电压调整率为0.028%,功率因数测量最大误差为0.02,过流保护动作电流为2.54 A,交流输入侧功率因数校正后最高达99.9%,转换效率达96.7%,功率因数在0.8¹.0稳定可调。     

低功率场射频能量收集电路的仿真与验证

该文设计了一种低功率场射频能量收集电路,可收集中心频率为915 MHz的射频信号,并提供对外直流电源输出。该电路由阻抗匹配电路、倍压整流电路和电能存储电路组成。该文基于ADS仿真软件对电路进行设计,并对其性能进行检验,搭建了硬件电路进行实验验证。实验结果表明,当输入射频功率大于-5 dBm,整流倍压电路的负载电阻为10 kΩ时,输出电压高于0.8 V,空载时输出电压高于4.39 V;当输入功率为10 dBm,整流倍压电路的负载电阻为10 kΩ时,输出电压高达3.6 V,空载时输出电压高达7.7 V。为提高倍压整流电路输出电压,设计了谐振电路对倍压整流电路进行改进优化,并对其进行仿真实验验证。仿真实验结果表明,加入谐振回路的倍压整流电路的输出电压是传统倍压整流电路输出电压的2.5倍。该射频整流电路可用于无线传感器等低功耗电子设备的电能无线供应。     

低压差可调稳压器SM3941

<正> SM3941是一种低压差、低功耗、多功能的降压稳压器,它的特点是:能输出1A电流,其典型的压差为0.5V,输出电压可从+5V调到+20V。当输入与输出电压差大于3V、输出电流在1A时,其静态电流为30mA。 SM3941内部有短路保护、超温保护、电池反接保护、输入电压瞬间突变保护、输入电压瞬间超压保护电路。 SM3941为TO—220塑料封装,管脚排列如图1所示,特性参数如附表所列。现介绍几种应用电路。     

输电线路架空地线取电系统电源变换模块仿真设计

本文为输电线路架空地线取电系统设计出配套的电源变换模块,并对模块电路进行了仿真分析。该电源变换模块可以实现9~100V交流输入到12V直流输出的转换。通过设计整流电路、搭建电路模型、分析电路的输入输出特性,从而得到相对稳定的直流电压源。通过设计电压变换电路将整流电路输出的直流电压进行转换,得到系统所需的12V直流电压,文中优化了电路控制信号脉冲占空比,得到了不同输入电压情况下的最优脉冲占空比,拟合出最优占空比随输入电压变化曲线。     

驱动式DC-DC变换器设计

为了对直流电压进行变换,采用DC-DC技术,设计输出电压可调的直流电压变换器。变换器包括驱动式方波电路、功率管组成的调整电路、比较采样电路和滤波电路。在multisim软件环境下进行仿真,并在实际电路进行测试,获得的结果满足设计要求。实验证明,升压变换器可实现输入5 V直流电压,输出12 V直流电压;降压变换器可实现输入12 V直流电压,输出5 V直流电压;具有良好的直流变换功能。     

一种低失调运算放大器的设计

基于Bipolar工艺设计,结合激光修调技术,实现一种四通道、低失调、低功耗、高增益的运算放大器。电路整体结构包含：基准偏置电路、差分输入及偏置补偿电路、中间级电路、输出及过流保护电路。输入级选择差分输入结构,采用输入偏置补偿设计,降低了输入失调电压和偏置电流;中间级采用射随器结构,结合密勒补偿电容及零点电阻,提高电路的稳定性;输出级采用B类的输出结构,结合过流保护设计,增加电路的安全性。电路封装后测试：输入失调电压10μV,输入偏置电流0.5nA,大信号电压增益130 dB,电源电流2.4mA,增益带宽积1.5MHz,噪声电压7.34nV/√Hz。     

一种有源电压限位电路的设计

本文提出了一种新颖的电压限位电路。该电路该采用电压跟随器FOLLOWER和模拟二选一选择器结构,其中的比较器采用PNP双极型三极管,从而使输出更精确地跟随输入。与传统电压限压电路相比,该电路在设定的电压范围内,输出电压能更好地跟随输入电压变化,在输出端误差小,设定的电压范围以外,电路输出能固定在某一特定值。本电路基于0.35 um BCD工艺,对所设计电路进行了仿真验证。仿真结果表明,当下限阈值VTH-设定在0.5V,上限阈值VTH+设定在2V,输入电压VIN输入范围在0~3V内时,输出电压精确跟随VIN的变化而变化。     

一种低失调CMOS轨到轨运算放大器研究

基于CMOS工艺设计了一款轨到轨运算放大器,整体电路包括偏置电路、输入级、输出级以及ESD保护电路。电路中的输入级使用了一种全新的架构,通过一对耗尽型NMOS管作为输入管,实现轨到轨输入,同时在输入级采用了共源共栅结构,能够提供较高的共模输入范围和增益;在输出级,为了得到满摆幅输出而采用了AB类输出级;同时ESD保护电路采用传统的GGMOS电路,耐压大于2 kV。经过仿真后可知,电路的输入偏置电流为150 fA,在负载为100 kΩ的情况下,输出最高和最低电压可达距电源轨和地轨的20 mV范围内,当电源电压为5 V时能获得80 dB的CMRR和120 dB的增益,相位裕度约为50°,单位增益带宽约为1.5 MHz。     

一款高精度低功耗电压基准的设计与实现

设计了一款高输出电压情况下的高精度低功耗电压基准电路.电路采用了比例采样负反馈结构达到较高和可控的输出电压,并利用曲率补偿电路极大地减小了输出电压的温度系数.针对较宽输入电压范围内的超低线性调整率规格,给出了多级带隙级联的电路结构.针对功耗和超低负载调整率的问题,电路采用了基于运算放大器的限流模式和内置大尺寸横向扩散金属氧化物半导体(LDMOS)晶体管的设计.该电路在CSMC 0.25 μm高压BCD工艺条件下进行设计、仿真和流片,测试结果表明,该电压基准输出电压为3.3V,温度系数为19.4×10-6/℃,线性调整率为5.6 μV/V,负载调整率为23.3 μV/V,工作电流为45 μA.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.