一种基于遗传算法的VDSM IC电源网格动态IR-drop分析新方法

提出了一种用于超深亚微米集成电路电源网格IR-drop验证的新方法.该方法以遗传算法为基础,与已有的分析方法相比,该方法兼具静态IR-drop分析法和动态IR-drop分析法的优点,适用于包含大型组合模块的超大规模集成电路,可主动寻找电路中最大IR-drop.通过对ISCAS85电路实现的验证,发现了静态分析法不能发现的芯片边缘IR-drop问题.实验结果验证了该方法的正确性与有效性.     

大规模SoC的电源网络设计

介绍了适用于SoC的电源网络设计方法。通过优化power pad的数目与布局,合理设计power ring和power grid的宽度,有效降低了电源网络上的EM和IR-drop。保证了电源网络分配的可靠性,实现了一种So C的电源网络设计。     

晶上系统电源分配网络建模及IR-drop研究

为预测和评估晶上系统电性能，提出了一种结合电磁和分析模拟的晶上系统电源分配网络（PDN）建模方法。该方法将PDN结构划分为单独组件，用电磁工具和公式计算提取无源电阻、电感、电容参数后，按组件位置组装成等效电路模型。通过与三维全波仿真自阻抗曲线比较对模型进行了验证，并基于模型，用ADS研究了模组位置排布、垂直互连密度、芯片功耗及去耦电容对电压降（IR-drop）的影响。结果表明：模型自阻抗曲线与三维全波仿真基本吻合；在一定范围内，合理排布模组位置、增加垂直互连密度、减少芯片功耗、使用较大去耦电容能降低IR-drop，为晶上系统设计和制造提供了参考。     

评估真实环境下的电源分配网络

引言在数字化时代,集成电路(1C)的使用在嵌入式设计中越来越普遍。集成电路芯片通常安装在印刷电路板(PCB)上,由电源分布网络(PDN)供电。使用每个集成电路芯片时,都必须考虑到它对电源分布网络的影响。大多数集成电路芯片只在改变状态时消耗电流,这种不规律的用电给PDN带来了很大失真,产生电源完整性的问题。电源分布网络出问题,会对其它电路产生干扰,增加噪声,进而导致信噪比降低,影响集成电路芯片     

深亚微米SOC电源网络设计与优化

针对传统电源网络设计对芯片会产生大量冗余的情况,提出一种采取模块限定布局确定优化范围,应用电源网络线宽优化释放绕线空间的非均匀阶梯型电源网络。与传统相比,此方法不但可以有效减小芯片面积与信号线总长度,而且对芯片功耗也具有优化作用。基于SMIC 0.18μm Eflash 1P4M工艺,采用Synopsys IC Compiler完成设计。芯片经流片验证,优化后版图面积减小8.69%,功耗降低4.04%。这种适用性广泛优化设计方法对电源网络设计具有一定参考价值。     

多负载电源分配网络的去耦分析

传统的利用单端口自阻抗指导电源分配网络设计方法(FDTI),主要适用于一个电源/地平面只有一个负载芯片的情况,对现阶段多负载芯片的复杂电源分配网络已不再适用。文中通过全波仿真软件SI-wave提取每个负载芯片的多输入叠加阻抗,用以指导多负载芯片复杂电源分配网络的设计。利用矢量拟合算法拟合多输入叠加阻抗曲线的有理函数,将该有理函数导入相关电容器选择算法中得到每个芯片的去耦方案。实验结果表明,将选出的去耦电容添加到电源/地平面后,芯片电源端口处的噪声在容许的5%范围内。     

电源管理市场

在绝大多数情况下,电源管理芯片(PMIC)或电源管理单元(PMU)为一个复杂的器件供电,如一个应用处理器.     

双阈值电压与电源门控设计优化流程方案

双阈值电压和电源门控设计流程可同时管理泄漏功率与电路性能。使用双阈值电压门限(VTH)的设计优化方法与流程可以在高度自动化的情况下达到功率和时序两方面的优异结果。这种双VTH方法对VDSM(极深亚微米)芯片非常     

一种ADC电源方案设计与电源完整性分析

为合理利用机箱空间、减少电源芯片使用数量,提出了一种20片模数转换器(Analog-to-Digital Converter,ADC)芯片供电方案,既可减小不同频段ADC芯片因输入相同电源造成信号干扰的可能,也可减少低压差线性稳压器(Low Dropout Linear Regulator,LDO)的使用数量,充分利用电源芯片的供电能力,大大降低了模块开发成本。与传统电源方案相比,该方案中电源芯片使用数量减少一半,电源布局面积缩小60%。同时通过仿真可提前识别出其中一路LDO芯片输出的2.5 V电压在到达ADC芯片时未能达到ADC芯片输入的最小电压要求。结合静态压降公式提出3种优化方法,均可达到ADC芯片输入的最小电压要求。采用第2种优化方法,回板实测结果显示3个芯片接收到的电源电压差值为0.3 V,与仿真结果一致。     

深亚微米下芯片电源网络的设计和验证

随着芯片集成度的逐渐提高，芯片单位面积所消耗的功耗也越来越大，因此，可靠的电源网络设计和验证已成为芯片设计成败的关键因素之一。在以往。集成电路（IC）设计工程师往往根据经验来设计电源网络，但工艺到0．18um，这往往会引起芯片功能失效。根据这个问题。本文首先介绍电压降（IR-Drop）和电子迁移率（Electro-migration）现象和对芯片性能的影响；其次，提出一种有效的电源网络设计和验证方法，并在芯片的物理设计初期对电源网络作可靠性估计；最后，经过椭圆曲线加密芯片（ECC＆RSA）的流片，表明采用该方法设计的芯片，工作情况良好。     

Compact physical IR-drop models for chip/package co-design of gigascale integration (GSI)

The supply voltage decrease and power density increase of future GSI chips demand accurate models for the IR-drop. Compact physical IR-drop models of on-chip power/ground distribution networks are derived for two generic types of packages. In the early stages of design, these models enable accurate estimates of all required power/ground grid interconnect dimensions and chip pad counts that are needed for power distribution. The models also quantify the tradeoff between on-chip interconnect dimensions and the number of I/O pads required for power distribution and therefore enable rigorous chip/package co-design. Comparison with SPICE simulations show less than 1% and 5% error for the wire-bond package and the flip-chip package, respectively.     

Decreased Effectiveness of On-Chip Decoupling Capacitance in High-Frequency Operation

This paper shows the decreased effectiveness of on-chip decoupling capacitance in high-frequency operation. On-chip decoupling capacitance is often used to decrease the variation of the propagation delay caused by power/ground noise, i.e., dynamic IR-drop and/or delta-I noise. However, it is shown in this paper that decoupling capacitance is only effective for coping with dynamic IR-drop if the recharging time between switching events is sufficient. In other words, the effectiveness of decoupling capacitance for dynamic IR-drop in high-frequency operation is less than that of a fully-charged decoupling capacitor. The recharging time and the effectiveness of a decoupling capacitor depend on the propagation delay of the average circuit path which is used to determine the total switching current of a given macro/chip and clock cycle time. If the propagation delay of the critical paths is approximately equal to that of the average circuit path, then it is shown in this paper that adding decoupling capacitance never improves the maximum frequency of the system due to dynamic IR-drop limitations. On the other hand, if the propagation delay of the critical paths is larger than that of the average circuit path, then the maximum frequency is improved by adding decoupling capacitance. In both cases, a new metric, called the apparent capacitance, can be used to help make correct decisions about decoupling capacitance planning.     

室内分布系统有源设备质量性能的测试与分析

针对室分系统日益重要的网络环境,重点选取了武汉市四个指标恶劣、干扰严重的小室分系统进行有源设备质量性能的检测。通过检测,发现了有源设备质量与网络性能之间的关系,采取了替换设备的方式提升网络质量,并给出了有源设备测试指标的修正建议。     

Supporting bursty traffic with bandwidth guarantee in WDM distribution networks

This paper presents new research results of the DARPA-funded ONRAMP consortium on the next generation Internet to study efficient WDM-based network architectures and protocols for supporting broadband services in regional access networks. In particular, we present new efficient scheduling algorithms for bandwidth sharing in WDM distribution networks. The current ONRAMP distribution network architecture has a tree topology with each leaf node (e.g., a router or workstation) sharing access to the root node of the tree, which corresponds to an access node in the feeder network. Our model allows a leaf node to use one or more fixed-tuned or tunable transceivers; moreover, different leaf nodes can support different subsets of wavelengths depending on their expected traffic volumes. An important goal of ONRAMP is to support bandwidth-on-demand services with QoS guarantee over WDM. As a first step toward this goal, we have developed several fast scheduling algorithms for flexible bandwidth reservations in a WDM distribution network. The scheduling algorithms can provably guarantee any bandwidth reservations pattern that does not overbook network resources, i.e., bandwidth reservation (throughput) up to 100% network capacity can be supported.     

基于复杂网络理论的校友网络研究

在某高校校友会网站的开发建设中,引入复杂网络机制,借鉴城市公共交通网络的space P和space L方法,构建了校友网络,分析了其平均路径长度、聚类系数和度分布等基本网络统计特性,并借用数学期望的思想,对构建的校友网络方法进行了验证。由分析结果可知,校友网络是一个具有指数型度分布的小世界网络;校友网络是由一些关键节点（主席、副主席和班长和团支书等）连接起来的,应该切实保障这类节点的桥梁作用;space P方法构造的校友网络比space L方法构造的校友网络更加合理,更能反映真实的校友关系。     

General criterion for decomposition of exact blocking computationin circuit-switched networks

The criterion for the decomposition of the computation of blocking probabilities in circuit-switched networks is given. As the criterion does not depend on the network topology or the traffic distribution, more efficient decomposition can be obtained accordingly     

Low Capture Switching Activity Test Generation for Reducing IR-Drop in At-Speed Scan Testing

At-speed scan testing, based on ATPG and ATE, is indispensable to guarantee timing-related test quality in the DSM era. However, at-speed scan testing may incur yield loss due to excessive IR-drop caused by high test (shift & capture) switching activity. This paper discusses the mechanism of circuit malfunction due to IR-drop, and summarizes general approaches to reducing switching activity, by which highlights the problem of current solutions, i.e. only reducing switching activity for one capture while the widely used at-speed scan testing based on the launch-off-capture scheme uses two captures. This paper then proposes a novel X-filling method, called double-capture (DC) X-filling, for generating test vectors with low and balanced capture switching activity for two captures. Applicable to dynamic & static compaction in any ATPG system, DC X-filling can reduce IR-drop, and thus yield loss, without any circuit/clock modification, timing/circuit overhead, fault coverage loss, and additional design effort.

配网台区三相不平衡分析及治理方法探究

配网台区三相不平衡的现象日益严重,对电网的安全稳定运行提出了新的挑战,为了提高电网对于三相不平衡问题的治理水平,提升配电网终端的电能质量,介绍了配网台区三相不平衡现象产生的原因以及具体危害,提出了一种基于SVPWM算法的SVG装置,通过实例验证该装置对于三相不平衡现象具有较好的治理效果。     

网际组态软件在配电系统在线监测中的应用

针对配电系统现状,为提高电力用户用电安全性,设计了一款基于网际组态软件的配电系统在线监测服务平台,对配电系统的运行状况进行在线监测,用户可通过远程客户端查看配电系统的运行状况和报警信息,实现远程控制,为促进配电系统更加经济高效地运行提供了数据支持。