Vishay固定输出降压／升压调节器

Vishay Siliconix公司推出降压／升压型调压器，使设计人员可从便携式电子系统电池中获得稳定电压。SiPl759提供3．3V固定输出电压或2．5V～5．5V可变输出电压，其输入电压范围为1．6V～5．5V。这款新型调节器专门用于由电池供电的手持式设备，     

电压不足期间支持电信电源的小电容

本设计实例介绍如何在短暂电压不足期间使电信设备保持正常工作。首先必须了解电信设备专用电源的几个细节。向电信设备馈电的电源的共模电压为-48V,尽管实际电压范围可能是-42．5V— -56V、-40V- -60V,甚至超出这些范围。公共电源——”砖块”DC／DC转换器工作于-36V— -75V范围。当-48V源降至0V并持续10ms时,就会出现电压不足。     

基于WindowsCE6.0的电话系统设计与实现

WindowsCE6．0H入式操作系统新增了对移动通信更强大的支持。这篇文章实现并优化了基于WindowsCE6．0操作系统、Monahans310处理器、SIM300D芯片的电话系统。不同于通常的直接在应用程序中发送AT命令以实现电话功能,此设计基于RIL架构,屏蔽底层设备硬件细节。这篇文章利用TAPI实现电话功能,并引入电话管理层管理电话系统、封装TSP消息,使上层应用和底层硬件设备完全剥离。采用此方案实现的电话系统功能稳定、可移植性高。     

动力监控设备安装中应重点关注的安全问题

随着动力环境集中监控系统的广泛应用,监控工程的不断建设,因忽视安全所带来的隐患也逐渐暴露,并可能导致设备和人身事故的发生。动力环境集中监控系统数据部分主要采用48V直流供电,图像部分采用220V交流供电,因其电压等级不高,在施工和维护时容易因疏忽造成故障或事故发生。文中通过介绍动力监控系统中重要监控设备的正确安装方法,希望引导维护人员重视监控系统安全问题,掌握必要的监控知识和安全常识,使动力环境集中监控系统正常、安全的运行,发挥出其应有的作用。     

计算机不能启动故障检修

有一台计算机平时工作一切正常，突然发生不能启动系统的故障，经重新设置CMOS参数，计算机能正常操作。但隔天开机，计算机仍不能启动系统，无法工作。仍需重新设置CMOS参数才能工作。检查主机板上的CMOS供电电池，电压为3．6V，属正常范围。经分析，故障可能发生在CMOS保持电压的供电电路上。重点检查主机板CMOS供电电路。该电路由3．6V镍搞电池电阻器Rg和一稳压管组成。Rg电阻值标为221Ω稳压管稳压值为3．0V。用万用表电压档测R9两端，一端为3．6V．另一端没有电压。再用万用表电阻挡检测R9的阻值，为无穷大．可以肯定R9失…     

42V电源系统将进入现代汽车新时代

在以节能、环保和安全为中心的现代汽车中,电气设备越来越多,电气负荷越来越大,这就要求汽车电源提供更高的电能,传统的14V电压供电源系统已经捉襟见肘,为此,一种新型42V电源供电源系统即将在汽车上应用。42V电源系统能提供8kW的动力,对汽车电器提供了较大的发展空间。采用42V电源的最重要的意义还在于使产品设计人员从过去许多局限性中解脱出来,为汽车技术的发展提供了充分的想象空间。     

单节锂离子电池监控电路

单节锂离子电池监控电路示于图1。此电路是用超微功率器件LT1496精密运放（工作在1．5μA,最大输入补偿电压475μV,最大输入偏置电流1nA）和LT1634电压基准（工作在1μA,固有精度0．05％,最大温度漂移25ppm／℃）设计的。单节钾离于电池的有效工作范围在4．2V和3V之间。当电压低于3V时其电压下降相当快、低于此电压的系统工作可能不稳定。虽然锂离子电池正被广泛采用,但损坏电池也是很费钱的。本监控电路可以保护电池免于过充电和／或过消耗并且防止电池电压超出其工作范围。电路通过使用电池电压（结点A）的电压分压器来监控理离…     

系统芯片电源管理模块的设计

超深亚微米系统芯片具有规模大，复杂度高，系统时钟频率快的特点。传统的由外部电源直接给芯片供电的方式，由于稳定性等问题往往不能保证芯片正常工作。本文提出了在系统芯片(SOC)中加入电源管理模块，用动态方法对外部电源进行管理的设计思想，达到稳定供电，低电压检测，以及保护随机存储器(RAM)内容等目的。本文给出了电源管理模块的设计方法。电路仿真结果表明当外部电源电压从3．6V降到2．7V时，电源管理模块的输出电压变化为0．2592V。     

LTC3615：4MHz同步降压型稳压器

Linear推出高效率、4MHz同步降压型稳压器LTC3615,该器件采用恒定频率、电流模式架构。低阻抗内部开关使LTC3615能够从每个通道提供3A的连续输出电流,同时其低压差工作提供范围为0．6V至仅比VIN低数mV的输出电压。LTC3615在2．25V至5．5V的输入电压范围内工作,从而适用于单节锂离子应用以及3．3V和5V中间总线系统。其开关频率从400kHz至4MHz是用户可编程的,     

由一起直流系统突发故降解析直流系统配置的重要性

直流电源系统是电力系统的重要设备．在发电厂、变电站中作为继电保护、自动装置、通讯设备、监控系统、信号及事故照明的重要电源。直流电源的故障．直接影响监控系统、继电保护、自动装置等重要设备的正常工作,并造成一系列连锁反应．严重时甚至会造成全站电网设备因失去电源而处于无保护状态,不得不退出运行。因此,直流系统直接关系到电网设备的安全及电网稳定运行。     

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.     

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 rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks