随笔分类 - Circuit
摘要：The LM27313 switching regulator is a current-mode boost converter with a fixed operating frequency of 1.6 MHz.The use of the SOT-23 package, made possible by the minimal losses of the 800 mA switch, and small inductors and capacitors result in extremely high power density. The 30V internal switch ma
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posted @ 2013-08-25 18:16
IAmAProgrammer
摘要：http://bbs.kechuang.org/read-kc-tid-9837-page-e.html摘要：本文介绍了一种性价比高、功能丰富的程控开关电源的设计，对基于LM2576控制核心的升、降压电路设计、切换及恒流输出电路进行了详细介绍。性能测试结果验证了本设计的有效性及实用性。关键词：开关电源;多功能;LM2576引言随着电源技术的飞速发展，开关电源以其功耗小、体积小、重量轻等优点得到了广泛的应用。目前开关电源也正在朝着集成化与多功能化的方向发展。本文以大学生电子设计竞赛为背景，介绍一种性价比高、功能较强的实用开关电源设计方案。竞赛内容为设计具有单路恒压输出功能的开关电源，输出电压范围
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posted @ 2013-08-25 00:02
IAmAProgrammer
摘要：http://www.electronic-products-design.com/geek-area/electronics/mosfets/using-mosfets-as-general-switchesUsing this back to back arrangement of P Chan...
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posted @ 2013-08-24 17:38
IAmAProgrammer
摘要：双向可控硅工作原理与特点从理论上来讲，双向可控硅可以说是有两个反向并列的单向可控硅组成，理解单向可控硅的工作原理是理解双向可控硅工作原理的基础单向可控硅单向可控硅也叫晶闸管，其组成结构图如图1-a所示，可以分割成四个硅区P、N、P、N和A、K、G三个接线极。把图一按图1-b 所示切成两半，就很容易理解成如图1-c所示由一个PNP三极管和一个NPN三极管为主组成一个单向可控硅管。在图1-c的基础上接通电源控制电路如图2所示，当阳极-阴极（A-K）接上正向电压V后，只要栅极G接通触发电源Vg，三极管Q2就会正向导通，开通瞬间Q1只是类似于接在Q1集电极的一个负载与电源正极接通，随后Q1也在Q2的拉
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posted @ 2013-08-24 12:43
IAmAProgrammer
摘要：http://www.elecfans.com/dianlutu/protect/2009102499242.html采用CW136构成的过压保护电路图中是采用CW136构成的过压保护电路，当电子设备的供电电压由于某种原因超过额定电压值时，使CW136正负极间达到5V，呈现低阻抗状态，立即触发晶闸管导通，短路电流瞬间即可将熔断丝熔断，从而切断电源，实现电子设备的过压保护。它是由一个P-N-P-N四层 (4 layers) 半导体构成的，中间形成了三个PN结。晶闸管导通条件为：加正向电压且门极有触发电流晶闸管在工作过程中，它的阳极（A）和阴极（K）与电源和负载连接，组成晶闸管的主电路，晶闸管的门
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posted @ 2013-08-24 09:34
IAmAProgrammer
摘要：MB506 ULTRA HIGH FREQUENCY PRESCALERThe Fujitsu MB506 is a high frequency, up to 2.4GHz, prescaler used with afrequency synthesizer to form a Phase Locked Loop (PLL). It will divide the inputfrequency by the modulus of 128 or 256 and the output level is 1.6V peak to peakon ECL level.Operation in the
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posted @ 2013-08-04 22:38
IAmAProgrammer
摘要：http://www.ti.com/lit/an/spraa88a/spraa88a.pdfhttp://www.ti.com/litv/zip/spraa88aThe high-resolution PWM on the TMS320F280x DSP family has been used to implement a digital-to-analog converter with the addition of an external analog low-pass filter. Such an approach can offer a lower-cost alternative
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posted @ 2013-08-03 21:13
IAmAProgrammer
摘要：http://bbs.ednchina.com/BLOG_ARTICLE_18577.HTM电感是储能元件，而磁珠是能量转换（消耗）器件。电感多用于电源滤波回路，侧重于抑止传导性干扰；磁珠多用于信号回路，主要用于EMI方面。磁珠用来吸收超高频信号，象一些RF电路，PLL，振荡电路，含超高频存储器电路（DDR,SDRAM,AMBUS等）都需要在电源输入部分加磁珠，而电感是一种储能元件，用在LC振荡电路、中低频的滤波电路等，其应用频率范围很少超过50MHz。1.片式电感：在电子设备的PCB板电路中会大量使用感性元件和EMI滤波器元件。这些元件包括片式电感和片式磁珠，以下就这两种器件的特点进行描述并
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posted @ 2013-07-24 00:26
IAmAProgrammer
摘要：IC开短路测试(open_short_test),编程器测试接触不良、开短路用的该是这个原理http://kitebee.gnway.net/forum.php?mod=viewthread&tid=69654IC开短路测试(open_short_test)又叫continuity test 或contact test,它是一种非常快速发现芯片的各个引脚间的是否有短路，及在芯片封装时是否missing bond wires.通常都会被放测试程序的最前面.它还能发现测试时接触是否良好，探针卡或测试座是否有问题.开短路测试的测试原理比较简单，分open_short_to_VDD 测试和op
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posted @ 2013-07-22 14:51
IAmAProgrammer
摘要：http://www.ideyi.org/article/11-05/2575971305526398.html?sort=2068_2073_2092_0MP1593制作的DC-DC稳压电源，这款DC-DC稳压电源的体积很小，但它能提供2A 甚至最高达3A 的输出电流，并且其性能指标非常好，下面就...
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posted @ 2013-07-22 10:58
IAmAProgrammer
摘要：http://www.amobbs.com/thread-3293203-1-1.html首先必须要了解电感的一些特性:电磁转换与磁储能.其它所有参数都是由这两个特性引出来的.电感回路通电瞬间断电瞬间相信有初中文化是坛友们都知道,一个电池对一个线圈通电,这是个电磁铁.不论你是否科盲,你一定会奇怪,这有什么值得分析的呢?有!我们要分析它通电和断电的瞬间发生了什么.线圈(以后叫作"电感"了)有一个特性---电磁转换,电可以变成磁,磁也可以变回电.当通电瞬间,电会变为磁并以磁的形式储存在电感内.而断电瞬磁会变成电,从电感中释放出来.现在我们看看下图,断电瞬间发生了什么:前面我说过
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posted @ 2013-07-17 14:06
IAmAProgrammer
摘要：http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011794In many applications, a DC/DC Converter is used to produce...
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posted @ 2013-07-17 01:24
IAmAProgrammer
摘要：http://analogtalk.com/?p=534http://analogtalk.com/?p=551Posted byAnalogAdvocateon April 09, 2010Design,GeneralIn today’s highly competitive electronics environment, designers are constantly looking for ways to reduce overall system costs. One of the most commonly asked questions that analog speciali
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posted @ 2013-07-16 23:16
IAmAProgrammer
摘要：http://www.edn.com/design/analog/4337128/Make-a-DAC-with-a-microcontroller-s-PWM-timerMany embedded-microcontroller applications require generation of analog signals. An integrated or stand-alone DAC fills the role. However, you can often use PWM signals for generating the required analog signals. Y
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posted @ 2013-07-16 22:46
IAmAProgrammer
摘要：http://pdfserv.maximintegrated.com/en/an/AN818.pdfhttp://www.maximintegrated.com/app-notes/index.mvp/id/818Digital Adjustment of DC-DC Converter Output Voltage in Portable ApplicationsAbstract:This tutorial discusses methods for digitally adjusting the output voltage of a DC-DC converter. The digita
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posted @ 2013-07-16 22:34
IAmAProgrammer
摘要：http://www.freelabs.com/~whitis/electronics/jtag/One of the big issues in making a JTAG pod is level translation. The state of level translation ICs leaves a LOT to be desired. You would think that there would be a lot of chips that you could apply 1.2-5V power and logic on port A and 1.2-5V (or 0V)
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posted @ 2013-07-16 15:48
IAmAProgrammer
摘要：http://www.ethernut.de/en/hardware/turtelizer/Introducing Turtelizer 2OverviewTurtelizer 2 had been developed to provide JTAG Flash programming and debugging of ARM based boards via USB. Typical target boards areEthernut 3, theElektor Internet RadioorEthernut 5. However, as the hardware is based on
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posted @ 2013-07-16 15:17
IAmAProgrammer
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