电容器贮存电荷能力与可靠性

试图探讨铝电解电容器贮存电荷的能力与电容器可靠性之间的关系。用自放电电压的高低来判定电容器的质量。用铝电解电容器常规的三参数(电容量、漏电流、损耗角正切值)检验电容器的可靠性有一定的局限性,而电容器贮存电荷的能力却与电容器的可靠性之间更有直接的关系,实验证明:在其他条件一定的情况下,电容器自放电电压越高,电容器的可靠性越高。     

储能放电用高压大容量铝电解电容器

对储能大电流放电用高压大容量铝电解电容器，要求其漏电流小、等效串联电阻值小、电容量稳定性好、一致性好等。为确保这些特性要求，可通过稳定介质膜性能，研制相应的工作电解液，优配电极片，降低引出条和极片之间的接触电阻等工艺措施达到。对电容器的组合应用，要注意均衡性     

Novel Ceramic Composite Substrates for High-Density and High Reliability Packaging

This paper presents the development and evaluation of a large-area carbon-silicon carbide (C-SiC) based composite board material that has the advantages of organic boards in terms of large-area processability and machinability at potentially low-cost while retaining the high stiffness (> 200 GPa) and Si-matched coefficient of thermal expansion (CTE) (~ 2.5 ppm/degC) of ceramics. Test vehicles were fabricated using C-SiC boards for assessing ultra-fine pitch solder joint reliability without underfill as well as the reliability of high-density wiring with microvias on the board. Finite element reliability models were developed to simulate the thermomechanical behavior of test vehicles. From the finite-element simulations as well as accelerated reliability tests, the high stiffness low-CTE C-SiC boards did not show any premature solder joint fatigue failure or dielectric cracking. Furthermore, the C-SiC boards show minimal via-pad misalignment and support the multilayer buildup structure required to achieve very high wiring density. The modeling and experimental results suggest that the low-cost large-area ceramic matrix composite (C-SiC) has superior thermomechanical properties, and is, therefore, a promising candidate substrate material for the emerging microelectronic systems.     

神光Ⅲ强激光能源模块高储能密度电容器的快速保护

分析了大功率激光脉冲电源高储能密度电容器快速保护的必要性 ,提出了电感和特种熔断器快速保护技术路线 ,介绍了快速保护熔断器设计方法。试验表明 ,所研制的熔断器故障情况下可在四分之一周期时间内快速动作 ,使电容器反向电压不超过 10 %,已成功应用于神光Ⅲ能源模块高储能密度电容器的保护。     

一种用于LCD驱动的高效电荷泵的设计

电荷泵是一种流行的获取高于供电电源的直流电压转换技术.传统的电荷泵电路采用二极管连接的NMOS管级联来获取较高的电压,由于阈值电压的作用,这种电荷泵的提升效率会随着级数的增加而下降.为了提高效率,文中提出了一种提升5倍电压的采用液晶显示器(LCD)驱动的新型电荷泵结构.特别设计了开关管的栅控电路,消除了阈值电压对电压提升效率的影响,并且通过对开关管尺寸和控制时钟的进一步优化,提高了电压转换效率,降低了功耗,特别适合于小尺寸LCD驱动的需要.     

An Alternative Setup for a Base-Station Cellular Antenna

This paper proposes the use of an alternative setup of a cellular base-station antenna with the potential of reducing the cochannel interference. The setup uses a different cell antenna placement strategy where there is one base-station antenna per cell located high at its center. Unlike a traditional base-station antenna radiating in the horizontal direction, the antenna under consideration radiates downward. The beamwidth of the antenna is considered to be wide enough to match the cell diameter. In addition, the radiation pattern beyond the associated beamwidth is assumed to possess a large attenuation. This paper studies the use of the proposed antenna setup by examining the cell geometry and grouping and its effect on the antenna radiation pattern. It is shown that for a sufficiently large attenuation pattern beyond the antenna beamwidth, the corresponding signal-to-interference ratio can be made significantly larger than the one resulting from the traditional antenna setup     

An Optimal Control Method for Buck ConvertersUsing a Practical Capacitor ChargeBalance Technique

A novel control method is presented in this paper which utilizes the concept of capacitor charge balance to achieve optimal dynamic response for Buck converters undergoing a rapid load change. The proposed charge balance method is implemented with analog components and is cheaper and more effective than its digital counterparts since complex arithmetic and sampling delay is eliminated. The proposed controller will consistently cause the Buck converter to recover from an arbitrary load transient with the smallest possible voltage deviation in the shortest possible settling time. Since the controller is nonlinear during transient conditions, it is not limited by bandwidth/switching frequency. Unlike conventional linear controllers, the dynamic response (voltage deviation, settling time) of the proposed controller can be estimated using a set of equations. This greatly simplifies the design process of the output filter. Simulation and experimental results show the functionality of the controller and demonstrate the superior dynamic response over that of a conventional linear controller.      

Magnetic Tape for Data Storage: An Enduring Technology

Magnetic tape as used for data storage is reviewed. Attributes such as bit and track densities, tape cartridge capacities and data rates are discussed in terms of the growth seen over time together with future trends envisioned for tape. Tape has seen almost six orders of magnitude density increase since its introduction as a computer data storage device in the early 1950's with 1 Terabyte native capacity tape cartridges being introduced into the market. The recording methods and technologies used for tape data storage devices are outlined and tapes position in the storage landscape discussed. Most of the world's data is stored and archived on magnetic tape primarily because of its long shelf life and favorable cost factors.      

An Analog Data Storage System for a Reading Machine for Blind Readers

The problem of output for reading machines for the blind is discussed and it is concluded that speech is essential if reading rates greater than 80 words/min are desired. Means for achieving this are considered to be dependent on the design of a cheap compact data store. Assuming that monotonic telephone-quality speech would be acceptable, the minimum storage capacity for normal reading speeds is shown to be 6 × 10-6 bits, if speech synthesis is not used.     

一种新型大驱动、低功耗和高精度的电荷泵电路

提出一种适用于NOR结构快闪存储器应用的,具有大驱动能力、低功耗和高精度特性的电荷泵系统。它通过对八个子电荷泵的并联来提高电荷泵的驱动能力,并采用电容分离法来动态地自洽改变每个子电荷泵的驱动能力,仿真结果表明,在擦除模式、一位编程模式和八位编程模式工作下,其瞬态平均电流分别约为2.5mA、4 mA和12 mA,电荷泵的输出高压精度可达±2.3%以下,达到了节省功耗和提高输出高压精度的目的。     

集成高效率电荷泵的无源电子标签芯片射频前端设计

提出了一种满足ISO/IEC 18000-6C标准的无源超高频RFID(射频识别)标签芯片的射频前端结构,该结构包括高效率电荷泵、解调器、调制器、阻抗匹配网络和ESD保护电路.电荷泵通过阈值补偿原理及精确控制补偿电压有效抑制反向漏电流,消除了传统电荷泵中的阈值损失.芯片经TSMC 0.18 μm CMOS mixed signal工艺流片,实测结果表明,标签最远读距离达7m,写距离为3m,可应用于识别与定位,同时满足HBM 2 000 V的抗静电指标.     

高密度陶瓷倒装焊封装可靠性试验开路后的失效定位

陶瓷材料具有优良的综合特性,被广泛应用于高可靠微电子封装.陶瓷倒装焊封装的特殊结构使得对其进行失效分析相较其他传统封装形式更为困难.针对一款在可靠性试验中发生开路的高密度陶瓷倒装焊封装器件,制定了一套从非破坏性到破坏性的试验方案对其进行分析.通过时域反射计(TDR)测试排除了基板内部失效的可能性,通过X射线(X-ray)检测、超声扫描显微镜(SAM)和光学显微分析初步断定失效位置,并最终通过扫描电子显微镜和X射线能谱仪实现了对该器件的准确的失效定位,确定失效位置为基板端镀Ni层.该失效分析方法对其他陶瓷倒装焊封装的失效检测及分析有一定的借鉴意义.     

As Doping in (Hg,Cd)Te: An Alternative Point of View

Acceptor doping of many II–VI compound semiconductors has proved problematic and doping of epitaxial mercury cadmium telluride (MCT, Hg_1−x Cd _x Te) with arsenic is no exception. High-temperature (>400°C) anneals followed by a lower temperature mercury-rich vacancy-filling anneal are frequently required to activate the dopant. The model frequently used to explain p-type doping with arsenic invokes an amphoteric nature of group V atoms in the II–VI lattice. This requires that group VI substitution with arsenic only occurs under mercury-rich conditions either during growth or the subsequent annealing and involves site switching of the As. However, there are inconsistencies in the amphoteric model and unexplained experimental observations, including arsenic which is 100% active as grown by metalorganic vapor-phase epitaxy (MOVPE). A new model, based on hydrogen passivation of the arsenic, is therefore proposed.     

An Alternative Methodology Based on Spectral Analysis for a Direct Access to Ring Resonator Parameters

An alternative method of ring resonators (RRs) spectral analysis is proposed and demonstrated here. Unlike earlier procedures, the phase information is extracted here from pure spectral intensity data to examine the RR signatures in the time domain. This procedure gives a direct access to all resonator parameters. Also, it is well suited for an automated assessment of dispersive properties of rings in a wide spectral domain.     

低损耗高温型R特性高压电容器瓷料的研制

采用Ｂｉ（３＋）、Ｐｂ（２＋）、Ｍｇ（２＋）与主晶相ＳｒＴｉＯ３固溶，并添加适量的Ｎｂ２Ｏ５、ＳｉＯ２、Ｙ２Ｏ３对ＳｒＴｉＯ３进行改性，研制出εｒ≥２２００，１ｋＨｚ时ｔｇδ≤０．１０×１０（－２），１０ｋＨｚ时ｔｇδ≤０．３０×１０（－２），－２５～＋８５℃｜△Ｃ／Ｃ｜≤１５％，Ｅｂ（ＤＣ）＞９Ｖ／μｍ，Ｒｉ＞１０（１２）Ω，耐高温（可达＋１２５℃），高频性能好的新型介质材料。该瓷料适合制作工作频率高、表面温升低的低损耗、耐高温的高压瓷介电容器。     

SOArTester4RT:一种面向组合服务演化的高效回归测试工具

提出了一中基于有向图关键路径选择的组合服务回归测试方法.通过分析组合服务执行流,识别受影响的执行流,选择适当的回归测试路径,并生成相应的回归测试用例.基于该方法,在SOArWare平台上实现了SOArTester4RT 工具.实例分析和测试结果表明:该工具可以对BPMN的各种控制结构加以分析,产生必需的测试用例,有效提高了组合服务演化后的回归测试效率.