共查询到20条相似文献,搜索用时 46 毫秒
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Tony Armstrong 《电子设计应用》2007,(3):113-114
大多数嵌入式系统都是通过48V背板供电的。这个电压通常要降为更低的12V或5V中间电压,以向系统内的电路板供电。然而,在这些电路板上,大多数电路都要求供电电压范围在0.8V~3.3V,电流范围为几十mA至几十A。因此,需要负载点(POL)DC/DC转换器对12V或5V降压,以获得所需的电压和电流值。 相似文献
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分布式供电体制(distributed-power architectures,DPA)的盛行,极大地促进了集成DC/DC变换器的发展。本文主要讲述了DC/DC变换器在评测、对比和选型时的需要注意的问题,以协助DPA设计人员在市场上挑选出合适的产品。功率、输入和输出首先要考虑的是输入电压、额定功率以及输出电压的大小和种类。根据额定功率的大小,DC/DC变换器通常可分为超低功率(1W以下)、小功率(1~9W)、中功率(10~150W)和大功率(150W以上)等类别。大多数变换器的输入电压是12V或24V,对于那些要求输入电压可变或者输入电压不标准的场合,可以选用具有宽电源输… 相似文献
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1AX641/642/643简介MAX641/642/643是美国MAXIM公司生产的升压型DC -DC变换器 ,它具有较宽的输入/输出范围 ,其中输入电压范围为3~12V ,输出电压范围为5~50V ;工作温度范围为 -55~125℃ ;在输出电压方面 ,该系列产品具有5、12、15V等多种输出可供用户任意选择。MAX641/642/643系列DC -DC的功耗电流小于135μA ,而同时其转换效率却高达80 %。当MAX641/642/643单独构成DC/DC变换器时 ,其输出功率为5mW ,如果外加MOSFET功率开关管 ,其输出功率可扩展到10W。MAX641/642/643具有DIP8和SO8两种封装形式 ,其内部原理框图如… 相似文献
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Tony Armstrong 《今日电子》2008,(8)
大多数嵌入式系统都是由48V背板供电的。这个电压通常要降至较低的24V、12V或5V的中间总线电压,以向系统内的电路板支架供电。然而,这些电路板上的大多数分支电路或集成电路要求在低于1~3.3V的电压范围内工作,电流范围为数十mA至数十A。因此,需要负载点(POL)DC/DC转换器将24V、12V或5V电压轨降至这些分支电路或集成电路所需的电压和电流值。 相似文献
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Tony Armstrong 《中国集成电路》2007,16(3):89-92
1、背景大多数嵌入式系统都是由48V背板供电的。这个电压通常要降至较低的12V或5V中间电压,以向系统内的电路板支架供电。然而,这些电路板上的大多数分支电路或集成电路所要求的供电电压范围为0.8V至3.3V,供电电流范围为数十毫安至数十安培。结果,需要负载点(POL)DC/DC转换器将12V或5V电压降低至这些分支电路或集成电路所需的电压和电流值。 相似文献
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This paper proposes a novel zero-voltage-switching (ZVS) current-tripler dc/dc converter. Compared to the conventional phase-shifted ZVS full-bridge dc/dc converter with current-doubler rectifier, the proposed current-tripler dc/dc converter reduces the synchronous rectifier (SR) conduction loss as well as the transformer winding loss. Furthermore, the proposed transformer structure is very compact, and thus the power density of the converter could be greatly increased. Analysis and experimental results show that the proposed topology offers great advantages when the converter output current goes higher and the voltage goes lower, as demanded by future microprocessors and telecommunications systems. A 48-V/1.0-V, 100-A, 300-kHz prototype is implemented, and the experimental results show that it can achieve 87% efficiency at full load. 相似文献
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要从单个正极性输入产生双极性(正和负)输出的常见方法是采用变压器.虽然这种设计比较简单,但变压器本身会带来体积问题.把一个变压器装入一台要求减小电路占用面积和高度的设备中,这是具有挑战性的.图1所示电路可以从由3V~10V输入产生±5V输出,适用于没有地方安装变压器的设备.该电路所用的一种结构,能在DC/DC变换器处于关机模式时切断两个输出,这样就使处于关机(待机)模式时的静态电流很小. 相似文献
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最近推出的各种集成式降压DC/DC变换器均已采取对外接低侧MOSFET同步整流器的电压降采样的方法,无需高侧电流检测电阻器。这种拓扑节省了检测电阻器的成本和印制电路板的空间,也适当提高了电路效率。但是,MOSFET的导通电阻与温度有很大的相关性,它决定了限流大 相似文献
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Although conventional transformers are ac, a device that may be termed a dc transformer has been constructed by using superconductors. To provide an understanding of how such a transformer would operate, some of the properties of type I and type II superconductors are reviewed. Since the dc transformer under discussion is constructed from thin superconducting films, the main emphasis is on these structures; the concept of flux motion is also explained. The result of the work described is a device in which a direct current or voltage can be transformed, and in which it is possible to extract power from the secondary circuit. 相似文献
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Jim Williams 《电子设计技术》2006,13(8):96-96,98
使用JFET的自偏置特性可以建立一个DC/DC转换器,它能用太阳能电池、热电偶和单级燃料电池等电源工作,这些电源电压都低于600 mV,有的甚至低至300 mV。 相似文献
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Ralph Raiola 《今日电子》2004,(10):38-38
DC/DC转换器制造商C&DTechnologies公司(位于美国亚利桑那州图森)开发的PositionPerfect引脚技术消除了元件在组装时发生移动的可能性,从而使无引线SMTDC/DC转换器的机械安装整体性和精确性均有所提高。与传统技术相比,此项技术还能够使转换器引脚提供更高的电流,从而确保将满载的额定电流输送至主PC电路板上。该技术运用了SMT互连,这种SMT互连采用了由高速自动模锻工艺固定在转换器上的独特铜柱。在模锻处理之后进行的修剪形成了极端平整的表面,从而确保了引脚的共面误差小于0.004英寸,并且消除了元件的移动。将引脚固定在转换器… 相似文献
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Since 1900 most of our power has been supplied by alternating current, but the high-voltage electron tubes and the rectifying equipment developed during the last decade have revived our interest in direct current. Because geographical factors have made most of our present-day dc cables submarine, we find that we are beset by the same problems that were involved with their historical antecedents? transatlantic telegraph, and later telephone, cables. Mechanical problems arise because of the complex structure of a cable, and because of all of the stresses to which it is subjected. There is also the problem of electrical stress. A comparison of the various types of cable shows that rugged, lightweight equipment is desirable, and that taped insulation insures reliability. 相似文献
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The failure of dc/dc converters can directly result in electronic systems working unconventionally or significant downtime. To pre-determine time to failure and generate substantial safety and cost benefits, it is necessary to assess the extent of deviation of dc/dc converters from its expected state of health in real time and predict time to failure in advance. This paper presents a novel prognostic method for predicting the time to failure of dc/dc converters. The process involves identifying precursor parameters, determining prognostic of failure, and determining a criterion for predicting time to failure. The output voltage is used as a precursor parameter and directly monitored when the converter with a given load periodically operates at different temperature stresses. The phenomenon that the differences of output voltages collected at different temperature stresses begin to increase with a large (or small) fluctuation is detected in collected output voltages. This phenomenon is identified as a prognostic of failure. A percentage of the initial difference is used as the criterion for predicting time to failure. A case study is given to illustrate the procedure that how to monitor output voltages, detect prognostic and predict time to failure. The results show the health state could be assessed in real time and the time to failure could be predicted in advance. Furthermore, the deviation of the predicted time to failure from the actual time to failure could meet the demand of a considered acceptable range in engineering practice. 相似文献