共查询到20条相似文献,搜索用时 78 毫秒
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Steve Mannas 《电子设计应用》2009,(6)
固态过流保护IC,比如USB和卡槽的电源开关,提供了一种简单、可靠的引脚保护方法,通常可在过载、生产测试或用户使用不当而发生短路时提供有效的系统保护。设计中如果忽视存储在寄生电感中的能量,这些开关可能产生过压,甚至被损坏。这些电源开关能实现的保护能力并非没有限制,本文主要讨论了这些限制因素。 相似文献
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Adrian Mikolajczak 《电子产品世界》2003,(20):65-68
在通用串行总线(USB)技术规范中,要求为USB电源管理提供电流限制和电源开关功能,而且提出自复式聚合物正温度系数(PPTC)器件和固态开关可以作为可行的过电流保护方案。与保险丝相似的是,PPTC器件有助于保护电路免受过电流的损坏,但它与保险丝的不同之外在于,在电路断电以及故障消除的情况下,PPTC器件可自行复位。除了这项自复功能以外,PPTC器件在USB应用中拥有很多关键性设计优表1 USB1. 可以按多端口共享或单个端口基础上进行设计2. 双模式集线器可以用作双电源集线器或总线供电集线器。点,其中包括低阻值、快速断开时间、低… 相似文献
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本文阐述了过流保护电路的原理和特性曲线,分析了常用的DC/DC变换器过流保护电路的原理和存在的缺陷,提出了一种精确、稳定的减流型过流保护电路,介绍了其设计方法。 相似文献
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广泛使用的低成本电源管理芯片或直流电源模块通常并未集成输出均流控制功能,因此不能直接并联输出使用。而使用特殊的电源管理芯片或是额外的均流控制电路会提高电源电路的复杂程度,造成电路成本的提高。针对此应用场景,提出了一种具有主动均流功能的双路电源开关,作为负载开关或电源多路复用器应用于电路之中,利用开关电流的方法均分输出电流,在几乎不增加电路成本的同时对两路电源进行均流。阐述了所提双路电源开关的工作原理与参数设计方法,并通过仿真与实验证明了所提方法的正确性与可行性。 相似文献
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一种新型的基于LDO的过流保护电路设计 总被引:1,自引:0,他引:1
设计了一种基于低压差线形稳压器的Foldback过流保护电路。该Foldback过流保护电路的静态电流不超过0.94μA,极大地提高了电流利用率。该芯片采用TSMC0.6um、BiCMOS工艺生产制造。 相似文献
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分别针对矩阵变换器的整流级和逆变级IGBT的过流现象进行了讨论,提出了一种新的集中式过流保护电路的设计方式。该方式可确保IGBT在短路情况下及时被关断,从而安全稳定地运行。试验结果表明:新的集中式过流保护电路具有经济、准确、快速的特点。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
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. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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《中国通信》2014,(7)
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 相似文献