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高效同相的降压-升压DC/DC转换器的控制方法 总被引:1,自引:0,他引:1
采用一种四开关拓扑结构的降压-升压DC/DC转换器控制方法,能使转换器在输入电压高于、低于或等于输出电压的情况下操作,实现降压、降压-升压、升压3种模式自动并且平稳地转换,提供一种可在所有操作模式进行连续转换的功能。具有效率高、外围器件少、同相输出的优点。经HSPICE仿真,采用Hynix0.5μm 5V CMOS工艺,在输入电压2.5-5.5V、输出电压3.3V、频率1MHz时,效率高达95%以上。是输出电压处于电池电压范围内的单节锂离子电池、多节碱性电池或NiMH电池应用的理想选择,解决了在便携式电子设备电源设计过程中所遇到的问题。 相似文献
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《仪表技术与传感器》2018,(12)
设计了一款基于0. 18μm CMOS工艺带失调校准的高速高精度两级采样保持电路。该电路选择开环双通道时间交织的采样保持架构,提高了整体采样保持电路的速率。通过采用高精度失调校准电路、改进的级间缓冲器以及栅压自举开关等来提高采样保持电路的精度。电路仿真结果表明,在电源电压为2 V,采样时钟为1. 6 GHz,输入信号频率为382. 8 MHz,第一级和第二级保持电容分别为0. 9 f F和0. 6 f F时,该电路的无杂散动态范围(SFDR)为85. 8 d B,总谐波失真(THD)为-81. 7 dB,有效位数(ENOB)为12. 6 Bits。 相似文献
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基于USB2.0及GPIF的CMOS图像传感器视频实时采集系统 总被引:2,自引:0,他引:2
应用Hynix Semiconductor Inc.的HV7131R CMOS图像传感器为光电成像器件,通过USB2.0控制器cv7c8013以通用可编程接口GPIF MASTER模式实现与传感器的无缝连接,在isochronous传输方式下采用Auto-In(自动打包)工作机制实现了串行总线对图像系统数据的实时传输。设计了结构简单、高效的适用于高速图像采集的硬件系统.并编写了基于多线程技术的软件系统。阐述了CMOS图像传感器的一般特征,详细介绍了RGBCMOS图像传感器芯片HV7131R的性能、特点及工作原理。并对GPIF的原理、应用做了详细说明。 相似文献
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本文介绍一个通用机床主传动计算机辅助设计系统,以计算机为工具,CAD技术为手段,采用Visual c 6.0实现多个设计模块的集成,在输入原始参数后即可获得最佳主传动系统设计。 相似文献
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超声波流量计高分辨率A/D转换电路设计与实现 总被引:1,自引:0,他引:1
针对高精度时差法超声波流量计的时间差信号采集问题,采用一款双通道12位低功耗单片CMOS模拟数字转换器ADC12DL040芯片设计并实现了超声波流量计ns级时间差的高分辨率数据采集,给出了A/D芯片外围引脚电路设计,软件流程图和关键代码,实现了400 kHz输入频率,8 MHz采样频率的超声波时间差高分辨率实时采样. 相似文献
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利用TSMC0.18μm CMOS工艺设计了一块LDD(Laser DiodeDriver)电路,该LDD设计工作频率为15Gb/s,电路采用直接耦合的两级差分放大器结构,其中运用并联峰化技术和放大器直接耦合技术以扩展带宽,后仿真结果显示该电路可工作在15Gb/s,输出电压双端峰峰值可达3.3V。 相似文献
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本文选择了硝酸、王水、逆王水,进行碳钢、低合金钢溶样条件试验,以谱线强度为指标,溶解酸种类、溶解酸浓度、溶解酸用量、定容酸用量等四因素为变化条件,各因素中有三水平,即按正交实验表L_9(3~4)进行试验,编制计算程序,快速、科学地优选出最佳溶样条件—30ml NHO_3(1+5v/v)和3ml HCl,ICP-AES法同时测定铝、砷、铬、钴、铜、磷、锰、钼、镍、硅、锡、钛和钒13种元素。为确定测试方法的重复性(r)和再现性(R)而进行精密度试验。精密度数据是由10个实验室对7个样品作试验确定的。方法的回收率为94%-105%。精密度在8%以内。 相似文献
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采用ICP-AES法测定GH3128合金中硅、锰、钨、钼、铬、钛、铝、铁、锆等多种合金元素。系统研究了各元素4条分析谱线的光谱干扰情况,根据光谱干扰研究结果和分析谱线的灵敏度、信背比以及等效离子浓度等进行了分析线的选择。采用柠檬酸络合钨,基体匹配法消除共存元素干扰,效果良好。 相似文献
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Mott scattering factors are needed for the quantitative interpretation of elastic scattering phenomena in electron spectroscopy and microscopy. The inelastic mean free path of electrons has been deduced from the elastic peak intensity. The theoretical approach is based on the effective elastic cross section derived from the differential elastic cross sections. In the present work they are calculated using the partial wave expansion method, supplying as well the Mott scattering factors. Tabulated data are presented for a number of elements and 500–3000 eV electrons in steps of 2° or 5° of the scattering angle θ. The effective and total elastic scattering cross sections are also presented. 相似文献
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石油焦中Fe、Ni、V、Na、Si、Ti的ICP-AES测定 总被引:1,自引:0,他引:1
本文提出用ICP-AES法直接测定石油焦中Fe、Ni、V、Na、Si、Ti含量,该测试方法能满足我厂石油焦中金属元素的检测,测定结果的准确度和精密度均满足分析要求。 相似文献
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《仪器科学与技术》2013,41(4):439-440
ABSTRACT This paper presents some results of experimental research addressing the influence of different thermal insulation fillings on dynamic properties of industrial resistance temperature probes, based on a thin-film platinum resistance temperature detector. The experiments were carried out with four jacket thin-film resistance temperature probes, all having identical protection tube geometry, yet differing in the thermal insulation filling materials. Further, a comparison between transient response characteristics in water established experimentally and those based on simulations with electric–thermal analogy, is given. The results of these analyses can be applied to enhance the dynamic response of temperature measurement made by temperature probes in water. 相似文献
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Isaac GH Thompson J Williams S Fisher J 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2006,220(2):119-133
When first introduced, total hip replacements offered pain relief and improved mobility in elderly patients. The success of this procedure in terms of long-term durability and restoration of function has led to its use in younger, more active patients. This has resulted in a commensurate increase in patient expectation regarding longevity and the degree to which function and lifestyle is restored. The bearing surface is a key feature of the performance of replacement joints. It is generally accepted that excessive amounts of wear debris preclude their long-term survivorship and hence there is an ongoing requirement for bearing surfaces which minimize debris generation. The purpose of this paper is to review the factors which affect the performance of so-called metal-on-metal bearings, to compare their performance with that of the other commonly used contemporary alternatives, metal and ceramic articulating against highly cross-linked polyethylene, and ceramic-on-ceramic, and finally to consider the potential solutions offered by new developments such as ceramic-on-metal and coatings applied to metal-on-metal bearings. 相似文献