基于TOPSwitch-GX系列的伺服系统多输出开关电源

用TOPSwitch-GX系列单片开关电源中的TOP244Y型电路设计了一种用于交流永磁同步电动机伺服系统的高交叉调整率的单端反激式多输出辅助开关电源.文中介绍TOPSwitch-GX的工作原理和结构特点,重点论述单端反激式多输出开关电源的设计及高频变压器的设计,并对设计的电源进行了试验.试验表明该电源在工作现场能稳定运行并满足系统的需求.     

基于TOP221Y构成的单片开关电源

介绍了基于TOP221Y器件设计实现的单片开关电源,分析了其基本的性能特点和工作原理。阐述了利用反激式单片开关电源芯片TOP221Y构成12V/10W的开关电源实用电路及主要单元电路的设计方法。     

控制电路在多路输出开关电源中的应用

介绍一种采用TOP249Y智能控制集成电路设计的开关电源。介绍TOP249Y的内部结构及工作原理，根据TOP249Y的性能特点给出单端反激式开关电源的设计方法，并对外围电路的设计进行了分析。     

一种新型5 V大功率开关稳压电源

简单介绍了TOP249Y单片开关电源控制电路的内部结构及原理，利用TOP249Y，设计了一种新型5V，大功率开关稳压电源。     

电源

小尺寸的开架式25W开关电源 VLT25开架式开关电源的尺寸为2×4×1英寸。其功率密度已超过3W/in~3。该电源额定功率为25W,有单输出及三输出。单输出的有额定输出5V,输出电流5A;输出电压15V,输出电流为2.1A; 输出电压15V,输出电流1.7A及输出电压24V,输出电流为1.1A。     

基于TOP243Y的单片反激开关电源设计

介绍了一种具有多路输出的单端反激式开关电源的设计方法,给出了利用单片开关电源集成芯片TOP243Y的电源设计实例,对外围输入EMI滤波电路、钳位电路、高频变压器、输出整流滤波电路等部分的设计过程进行了详细的分析和说明,并对设计样机进行组装和调试。     

程控开关稳压电源的设计

引言开关电源是利用现代电力电子技术,控制开关管开通和关断的时间比率,维持稳定输出电压的一种电源。由于拥有较高的效率和较高的功率密度,开关电源在现代电子系统中的使用越来越普及。开关电源高频化、模块化和智能化是其发展方向。其中,步进可调、实时显示是开关电源智能化研究方向之一。本文设计了一种开关电源方案,其技术指标为:输出电压30V至36V可调,最大输出电流2A,有过流保护功能,能对输出电压进行键盘设定和步进调整、步进值1V,并能实时显示输出电压和电流的开关稳压电源。方案论证与比较主控CPU的选择方案一:采用AT89S51单片机进行控制。51单片机外接A/D和D/A比较简单,但是由于51单片机功能简单,对于这种复杂的系统来说做起来比较复杂。     

基于PI Expert的反激式开关电源设计

反激式开关电源具有电路结构简单,安全隔离和输出电压范围较大的特点,因此在电器设备中应用非常广泛。PI Expert是美国Power Integrations公司出品的一款开关电源设计软件,使用PI Expert可以快速设计出可靠的开关电源。本文基于PI Expert设计了一款两路输出(+5V/250mA,+12V/1A)的反激式开关电源,调试结果表明该电源性能良好。     

基于TOP234Y和8051的多路开关电源设计

分析一种采用TOP234Y型多功能单片开关电源与8051型单片机结合设计多路开关电源的方案,同时介绍TOP34Y的内部结构及工作原理,给出该开关电源的主电路及外围电路的设计方法.     

多路输出单端反激电源的设计

设计了一种基于UC2844的多路输出单端反激电源,给出了该电源的具体设计步骤和详细的设计参数及高频变压器的设计方法。实验结果表明了此方法设计的开关电源可以解决工程中的实际需要,是一种性能良好的开关电源。     

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.     

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.     

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.     

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.     

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.     

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.