多栅GaAs MESFET开关的结构设计

论述了多栅开关的结构和特点.针对多栅开关器件结构设计中的参数栅栅间距的选取作了分析,确定当栅栅间距等于源漏间距对栅数的平均值时,开关性能最优,并在实验中得到验证.     

多栅GaAs MESFET开关

论述多栅开关的结构和特点。开关设计中需要考虑的一个重要因素是提高开关功率处理能力的同时减小插损 ,多栅开关由于其特殊的结构 ,很好地解决了这一问题。采用多栅结构 ,设计的移动通讯用 DPDT开关在 DC-2 GHz:IL<0 .75 d B,ISO>1 3 d B,VSWR<1 .5 ,P- 1 >1 0 W。开关芯片面积小、成品率高、封装成本低 ,适宜批量生产 ,并已在手机上试装成功。     

GaN功率开关器件的发展与微尺度功率变换(续)

正2.3大栅宽器件大栅宽常关GaN功率开关器件的发展是走向工程应用,2009年报道了栅宽为20 mm的5 A/1 100 V常关GaN功率开关器件在升压变换器中的应用[39],器件特点是,栅下F等离子处理工艺和栅极与源极的双场板结构。栅长为1.5μm,栅漏间距为12μm,栅宽为200μm的小栅宽器件,     

AlGaN/GaN HEMT凹栅槽结构器件的频率特性

采用一系列不同栅长和结构的T型栅器件来研究凹栅槽结构抑制短沟道效应和提高频率特性的作用.随着栅长不断缩短,短沟道效应逐渐明显,栅长从300 nm缩短至100 nm时,亚阈值摆幅逐渐增大,栅对沟道载流子的控制变弱,且器件出现软夹断现象.凹栅槽结构可以降低器件的亚阈值接幅,提高开关比,栅长100 nm常规结构器件的亚阈值摆幅为140 mV/dec,开关比为106,而凹栅槽结构器件的亚阈值摆幅下降为95 mV/dec,开关比增大为107,凹栅槽结构明显抑制了短沟道效应.在漏源电压为20 V时,100 nm栅长的凹栅槽结构器件的截止频率和最高振荡频率达到了65.9和191 GHz,同常规结构相比,分别提高了5.78％和4.49％.由于凹栅槽结构缩短了栅金属到二维电子气(2DEG)沟道的间距,增大了纵横比,所以能够改善器件的频率特性.     

宽带GaAs三栅MESFET开关模型

提出一种三栅MESFET开关的模型--附加栅控开关模型,模型是根据三栅MESFET开关器件的结构,考虑了栅极对微波信号的影响,适用于MMIC开关电路的设计,具有很好的宽带微波特性.器件测试值与模型模拟值吻合较好.     

宽带GaAs三栅MESFET开关模型

提出一种三栅MESFET开关的模型--附加栅控开关模型,模型是根据三栅MESFET开关器件的结构,考虑了栅极对微波信号的影响,适用于MMIC开关电路的设计,具有很好的宽带微波特性.器件测试值与模型模拟值吻合较好.     

提高GaN功率器件开关频率的技术途径

GaN基增强型高速开关器件是提升X波段微系统集成放大器工作效率的核心器件.介绍了凹槽栅结构、F-注入等制作GaN基增强型器件的关键技术,同时分析了场板、介质栅等对器件击穿特性的影响.针对影响GaN基功率器件开关特性的主要因素,重点分析了提高增强型GaN基功率器件开关频率的主要技术途径.减小器件的接触电阻、沟道方块电阻可以降低器件电阻对频率的影响.小栅长器件中栅电容较低,电子的沟道渡越时间较短,也可以提高器件的频率特性.此外,由于GaN基的功率器件频率高,设计应用在GaN器件上的栅驱动电路显得尤为重要.     

GaAs MESFET中的背栅效应

随着集成电路集成度的提高,器件间距不断减小,在GaAs MESFET中产生了一种被称为背栅效应的有害寄生效应。由于器件间距越来越小,某一个器件的电极可能就是另一个器件的背栅,背栅效应影响了集成电路集成度的提高,因此背栅效应在国内外引起了重视。本文介绍了背栅效应及其可能的起因。     

CPU电源电路用沟槽栅MOSFET与e-JFET开关管的功耗对比研究

本文主要针对低压功率开关管的功耗进行了理论分析,并在此基础上分别对两种典型结构的沟槽栅MOSFET和e-JFET在不同工作频率下的功耗分布和总功耗进行了定量的仿真计算和对比。通过研究发现,在一定工作条件下,常闭型e-JFET比目前常用的沟槽栅型MOSFET仅开关功耗就降低约24%,总功耗则降低约30%。将其运用于CPU电源电路中的开关功率管的制造,在高频领域有着极好的应用前景。     

CPU电源电路用沟槽栅MOSFET与e-JFET开关管的功耗对比

本文主要针对低压功率开关管的功耗进行了理论分析，并在此基础上分别对两种典型结构的沟槽栅MOSFET和e—JFET在不同工作频率下的功耗分布和总功耗进行了定量的仿真计算和对比。通过研究发现，在一定工作条件下，常闭型e-JFET比目前常用的沟槽栅型MOSFET仅开关功耗就降低约24％，总功耗则降低约30％。将其运用于CPU电源电路中的开关功率管的制造，在高频领域有着极好的应用前景。     

一种无源软开关技术的研究

开关电源的高频化使得功率开关的损耗加大,采用软开关技术是减小损耗的有效手段。文中提出了一种采用无源器件构成无损耗吸收回路的结构,可以实现PWM开关电源中开关管的零电流开通和零电压关断,而且不会给开关管带来过大的附加电压应力和电流应力。文中对该电路工作原理和能量转移关系进行了分析,给出了关键参数的选取原则。最后利用saber软件对电路进行了仿真。     

Exact and approximate analytical modeling of an FLBM-based all-optical packet switch

This paper develops both exact and approximate models for the analysis of an all-optical packet switch based on a fiber-loop buffer memory (FLBM). The switch structure and operation is based on the fully shared buffer architecture of the Research and Development in Advanced Communications in Europe - ATM Optical Switching (RACE-ATMOS) project , which uses individual wavelengths to store fixed-length packets in the fiber-loop buffer. An exact model of the switch has been developed , which can be used to determine the blocking performance of the switch and obtain both its throughput and packet loss characteristics. It has been used to study the switch performance under different loading conditions and for different values of the key design parameters of the switch. This model is difficult to use for studying large switches of this kind because of computational complexities. To tackle this problem, an approximate queuing model has also been presented, which may be used to study the performance of large switches of this kind. The results obtained by the two methods are compared to confirm that the approximate model works well under typical loading conditions of the switch.     

Design of wavelength converting switches for optical burst switching

Optical burst switching (OBS) is an experimental network technology that enables the construction of very high-capacity routers, using optical data paths and electronic control. In this paper, we study wavelength converting switches using tunable lasers and wavelength grating routers, that are suitable for use in OBS systems and evaluate their performance. We show how the routing problem for these switches can be formulated as a combinatorial puzzle or game, in which the design of the game board corresponds to the pattern of permutation used at the input sections of the switch. We use this to show how the permutation pattern affects the performance of the switch, and to facilitate the design of permutation patterns that yield the best performance. We give upper bounds on the number of different wavelength channels that can be routed through such switches (regardless of the permutation pattern), and show that for 2/spl times/2 switches, there is a simple permutation pattern that achieves these bounds. For larger switches, randomized permutation patterns produce the best results. We study the performance of optical burst switches using wavelength converting switches based on several different permutation patterns. We also present a novel routing algorithm called the most available wavelength assignment and evaluate its benefits in improving the switch throughput. Our results show that for a typical configuration, the switch with the best permutation pattern has more than 87% of the throughput of a fully nonblocking switch.     

一种星地一体的高速星载标签交换机流量控制机制的设计与仿真

为了优化大容量星载交换机的设计,提出了一种星载标签交换技术体制,针对该体制建立了星地一体化卫星网络的队列模型和流量控制机制,根据星载交换机存储资源使用状态调整地面网络设备队列调度权重,降低星载交换机存储资源使用量和丢包率.使用NS2软件仿真分析了长延迟条件下星上缓存队列阈值、星上缓存区容量、地面设备队列调度权重之间的关系.为星载标签交换机和星地一体化网络的设计提供了参考依据.     

Current-controlled switches for HV SoI processes

The paper presents an approach for the design of high-voltage (HV) current-controlled switches. HV switch structures, properties, application possibilities as well as ways of merging these switches into structure of HV signal processing components, are discussed. New HV switch structures are specialized and modified for specific applications. The switch applications include voltage switching with minimized current-load imposed on circuitry attached to input and output side of the proposed switches, as well as current switching with minimal or no current load to the current-mode signal-path, in HV power and smart-power integrated systems, like DC/DC converters or output power stages. The switch structures and modes of operation are introduced, simulated and discussed.     

改进软开关Buck ZCT-PWM开关电路设计及其Pspice仿真

介绍了典型的零电流转换ZCT（Zero Current Transition）PWM直流变换器的基本工作原理,分析了其存在的主开关电流应力大和辅开关硬关断的问题,提出了一种改进型开关电路。对其拓扑结构和工作原理进行了详细分析,设计了电路参数,并对其进行了Pspice仿真。结果证明此改进能够使辅助开关近似零电流关断,提高了变换器的性能。     

High-Speed Digital Switching Technology Using Space-Division-Switch LSI's

NTT is planning a high-speed broad-band switching network that offers high-speed digital and 4 MHz video services. This paper discusses the hardware design of the high-speed space-division digital switching network and requirements for a switch LSI. In addition, the design and measured performance of a 32 × 32 CMOS space-division-switch LSI are described. In this network, video signals are converted into 32 Mbit/s digital signals by band-compression technology. In order to switch such digital signals, space-division switches are more advantageous than time-division switches. This is because time-division switches cannot multiplex many channels at that bit rate. Furthermore, the use of the space-division-switch LSI is the most effective way to miniaturize the switching system.     

定向耦合器热光光开关的设计和特性模拟

对定向耦合器热光光开关的工作原理做了介绍。描述了这种热光光开关的一般设计方法，并且用ＢＰＭ方法（光束传输法）分析了它们的传输特性，提出了几种改善这一光开关波长不敏感特性的方法。     

A Simple Heuristic for Assignment of Cells to Switches in a PCS Network

This work deals with a design problem for a network of Personal Communication Services (PCS). The goal is to assign cells to switches in a PCS Network (PCSN) in an optimum manner so as to minimize the total cost which includes two types of cost, namely handoff cost between two adjacent cells, and cable cost between cells and switches. The design is to be optimized subject to the constraint that the call volume of each switch must not exceed its call handling capacity. In the literature, this problem has been conventionally formulated as an integer programming problem. However, because of the time complexity of the problem, the solution procedures are usually heuristic when the number of cells and switches are more. In this paper, we have proposed an assignment heuristic which is faster and much simpler than the existing algorithms. Despite its simplicity, experimental results show that it performs equally well in terms of solution quality, and, at the same time, it is faster than its predecessors. We present the algorithm as well as comparative results to justify our claim.     

Hybrid circuits for multioctave multiple-throw microwave switches

Single-pole multiple-throw microwave switches may be designed as extremely broad-band multistate low-pass filters. SPDT switch design using p-i-n diodes and high-impedance transmission line is described. Extension of the technique to multiple-throw switches is outlined. Two operating examples of the method, an 18-GHz bandwidth SPDT and a 12-GHz SP4T, are discussed.