基于高性能升压转换器的跨导误差放大器

在分析峰值电流模式升压转换器原理的基础上,设计了一种结构新颖,高精度高性能跨导误差放大器。提出了将具有动态电流自补偿功能的基准电压电路复用为误差放大器输入级的新方法,克服了传统外接基准电压时误差放大器易受干扰和基准电路设计复杂的缺点,提高了误差信号精度和放大器跨导。设计了输出电阻可调电路,简化了补偿网络设计。电路用0.6μmBiCMOS工艺实现,测试表明:3V输入电压,1.2MHz工作频率下,误差放大器开环电压增益57dB,跨导322μS,输入偏置电流小于50nA;升压转换器输出电压15V,输出纹波小于5mV。     

一种基于自举电路的可调恒压恒流源设计

介绍了一种基于自举电路的可调恒压恒流源的设计.解决了使用普通运算放大器调整较高输出电压的问题.在输出电压在较大范围变化时,通过自举的方法保证运算放大器的供电电压不变,并且能够对输出电压和电流进行有效地调整,实现了0~30V的电压输出和0~1A的电流输出.     

高精度低功耗电流采样电路设计

为了实现低功耗高精度电流检测,文中设计了一种基于运算放大器的具有对称结构的电阻采样结构,该结构不仅实现采样电压和采样电流的高线性度,而且能实现对微弱采样信号的可靠检测。设计的电路架构中包含5个电流-电压转换阶段,基于Hspice仿真,设计电路内部匹配电阻网络,以减小输入失调电压对采样的影响,拓展共模输入范围。该采样电路架构通过某0.35μm BCD工艺实现,版图面积仅为0.12 mm2,实测结果证明其工作电流小于1μA,采样电压检测精度高达5 mV,且具有高速响应能力。     

高精度闭环数控恒流源的设计

本文设计的高精度闭环数控恒流源，以单片机为核心，采样实际输出值经A/D转换反馈回单片机，经分析、处理后与预置值进行比较，采用PI调节控制D／A输出的电压值并调整负载电流的大小，形成外部闭环动态的误差调整，消除电路中的静止误差，实现高精度的恒流输出。其中，扩流模块采用达林顿管放大电流，达到2A的恒流输出要求，电源模块采用开关电源的设计方法，电流取样采用具有高稳定性阻值的锰铜电阻比作为取样电阻，最后通过软件分析、校正，最终达到精度高、实时性强、稳定度高、输出范围宽的目的。     

一种大电流高精度双极集成稳压器

介绍了一种大电流高精度双极性集成稳压器的设计原理及电路结构。该输出集成稳压器由基准电压源、比较放大器和调整管等单元组成,其工作原理为负稳压、正跟踪。该电路采用硅双极介质隔离功率IC工艺和芯片级电阻修调技术制作,具有±500mA的大输出电流和-10～+10V±50mV的高精度双极性输出电压,以及小于10mV的高正、负输出电压平衡度。     

高精度宽范围数控电流源模块设计

文章设计并制作了一个高精度宽范围数控电流源模块,该模块由逻辑控制电路、D/A转换电路、压控恒流源电路和电压监测保护电路组成,采用可编程逻辑解析处理器的控制字,经过D/A转换控制压控恒流源电路输出电流,同时输出电流通过采样电阻转换成电压送至A/D转换,并与预设值进行比较,以实现高精度、高量程的电流输出。设计的该电流源模块能够满足高精度航空电机的控制需求,具有控制精度高、输出范围宽,降低了设备的重量和体积等优点。     

大功率高精度直流扫场电流源的设计

大功率高精度直流扫场电流源在一些特殊领域有重要的用途。基于精度要求,扫场电流源由整流滤波、采样放大、比较放大、调整放大、手动基准及自动基准等电路环节构成。为了确保其高精密度,整流滤波环节采用电感滤波,采样环节使用锰铜电阻作为采样电阻,在基准电压环节中采用精密基准电源SW399、通用运放μA741构成的浮动式恒流源以提高基准稳定性,并在误差比较放大环节中采用PI算法以消除稳态误差。试验及安装调试结果表明,此电流源的精度达到了设计要求,运行良好。     

一种高精度数字可调片上振荡器设计

在传统的电路基础上对电流、电压基准电路进行补偿,设计一种高精度数字可调CMOS片上振荡器电路.利用电阻和PNP管相反的温度系数产生的自偏置基准电流电路PTAT,NTAT两路电流,叠加得到一路与温度无关的基准电流上,实现了温度补偿;利用电阻网络补偿工艺产生高PSRR带隙基准电路电压的频率误差;数字修调寄存器粗调电流用以选择频率,微调电阻用以调节精度.经流片测试表明,该振荡器频率2 MHz,4 MHz可选,2 MHz可调精度达±0.1%;4 MHz可调精度达±0.125%.     

基于TL494控制的同步整流BUCK恒流源的设计

为了解决线性恒流源功耗大,输出电流小的缺点,提出了一种基于TL494控制的同步整流BUCK开关恒流源。该恒流源采用PWM控制原理调节主开关管和同步整流管的占空比来实现输出电流从0到20A稳定连续可调。控制器采样输出电压,当输出电压超过预定的10V电压时,主开关管关断,输出电压稳到10V,实现过压保护。另外,给出了电路原理图并进行了样机的制作与测试。测试结果表明,其恒流精度相对误差最大值为0.75%,因此该方案是可行的。     

LED可调光自动控制系统设计

基于低功耗MSP430单片机的特点,提出一个用数字化恒流源来控制LED灯光可调的设计思路。在规定时间内,系统通过对背景光和人体红外信号检测,选择LED需求的亮度,单片机将输出电压数字写入D/A转换器,将D/A输出的电压作为恒流源的输入电压,间接地控制功率管的基极电压使功率管输出不同的电流,实现LED亮度数字可调,从而完成对LED光强度的智能控制。     

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.