一种适用于准谐振AC/DC控制芯片的波谷检测电路

设计了一种适用于准谐振反激式AC/DC(交流/直流)控制芯片的波谷电压检测电路.根据反激式变换器辅助绕组电压的特点,在一个开关周期内对辅助绕组电压采用三种不同的处理方式.电路实现了以下功能:检测变压器消磁完成的时间点,然后控制检测电路进行波谷检测;在功率开关管漏极电压斜率士0.09的范围内,检测到电压波谷;对母线输入电压和输出电压进行过压检测.Cadence specter S仿真结果显示,实现了以上功能.将检测电路用于准谐振AC/DC控制芯片,功能实现良好.     

基于Saber的反激式开关电源的仿真研究

反激式开关电源因成本低、外围元器件少、可宽电压范围输入能耗小、支持多组输出而备受欢迎,但因输出电压纹波大而严重影响其工作性能。从反激式开关电源的工作原理出发,采用反激式开关电源输出端增加输出滤波电路的方法,解决反激式开关电源输出电压纹波大的问题。运用Saber仿真软件分别对普通反激式开关电源和增加 输出滤波电路的反激式开关电源进行建模和仿真。试验仿真对比表明,通过该方法可改善反激式开关电源的输出电压纹波,提高了反激式开关电源的工作性能。     

多路输出单端反激式开关电源设计

在阐述了基于TOPSwitch系列芯片设计的单片反激式开关电源原理的基础上，详细介绍了一种用于智能仪表小功率多输出AC／DC开关电源的设计方法。该电源主电路采用反激式电路，应用反馈手段和脉冲调制技术实现多路电压的稳定输出。最后，给出了实验结果。试验表明，该电源具有良好的性能。     

可编程带温度补偿的限流电路设计

介绍一种为反激式DC-DC开关电源设计的限流电路,通过限流对芯片工作的模式切换进行控制,同时为芯片提供过流保护。首先,如果连接在外部限流引脚的限流电阻Rx不变,内部限流电路采用温度补偿技术使得限流值随温度的变化最小。其次,通过调节限流电阻Rx的阻值,使芯片的参考限流值控制在初始限流值的30%~100%之间。最后,分别介绍了限流设定和限流比较模块电路的设计方法和工作原理,实现了通过限流电路对开关电源工作模式的判别和控制。最后,给出了相应的TSMC 0.5 um工艺下的仿真结果,并对仿真结果进行分析。     

基于FSCQ系列准谐振反激式电源设计

介绍了准谐振反激式开关电源电路的基本工作原理,并对其工作过程进行了详细的分析。文中采用Fairchild公司的FSCQ系列新型开关控制器设计了单管反激式准谐振电源,并给出了实验波形。实验证明,此设计使开关管可以实现零电压关断和基本实现零电压开通,提高了电源的效率,降低了电磁干扰,同时简化了电路。     

电流模式反激变换器中功率限制电路的设计

讨论电流模式反激变换器的工作原理与优点,重点分析反激变换器中的过功率保护模块的功能与实现方式。提出在过功率保护电路中利用斜坡电压取代传统的固定电压,以达到不同输入电压下的恒定功率限制。基于CMOS工艺设计了相应的斜坡电压产生电路,该电路结构简单,可广泛适用于各类反激开关电源控制电路。最后并对电路进行了仿真。     

多路输出反激式开关电源设计研究

三相变频器逆变环节IGBT的稳定可靠性,很大程度上依赖于其驱动模块供电电源性能。全面分析了多路输出反激式开关电源的设计流程和关键要点,重点分析了反激变压器和电压反馈电路的设计计算方法,给出了用于优化反射电压的匝比调整具体计算公式。基于UC3842电源控制芯片完成了4路输出反激式开关电源设计实例,为该类电源设计提供了理论指导和实际样例参考。通过Saber仿真软件验证了设计实例的可行性,并根据所设计电路制作了样机,进行了关键性能测试。实验结果表明所设计电路输出电压稳定,纹波小,达到了设计要求。     

CR6853在反激式开关电源电路中的应用

结合蓄电池检测系统的课题,根据已设计出的AC - DC转换电源,研究CR6853在反激式开关电源中的应用.介绍了CR6853的结构、功能和单端反激式开关电源的原理及DC - DC变换的主电路和控制电路及其功能的实现.由调试和测试结果表明,基于CR6853的开关电源输出稳定可靠,输入电压的变化范围较广,响应速度较快,结构简单,体积小,造价低廉,实用性强,可以给蓄电池检测系统提供稳定的直流电源.     

小功率宽范围输入开关电源的设计与实现

基于TinySwith系列芯片,详细介绍了一款定时计数单元供电的开关电源的设计方法,该电路在宽范围输入电压范围内,采用单端反激式拓扑电路,利用光藕反馈和脉冲宽度调制技术实现电压稳定输出。     

基于UC3843反激式开关电源的设计

单端反激开关电源具有输出纹波小、输出稳定、体积小、重量轻、效率高以及良好的动态响应性能等许多优点,被广泛应用在小功率开关电源的设计中。文中首先对UC3843芯片做了简单的介绍,描述了其在电路中的主要功能;设计了电路原理图,并对电路原理图进行了简单介绍;再根据反激式开关电源电路设计公式详细介绍了各部分参数,最后给出了电路的测试结果。实验表明,该开关电源输出电压平稳,性能稳定。     

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.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.