Abstract: Many digital devices incorporate analog circuits. For instance, microprocessors, applicationspecificintegrated circuits (ASICs), and field-programmable gate arrays (FPGAs) may have internalvoltage references, analog-to-digital converters (ADCs) or digital-to-analog converters (DACs). However,there are challenges when you integrate more analog onto a digital design. As with all things in life, inelectronics we must always trade one parameter for another, with the application dictating the propertrade-off of analog function. In this application note, we examine how the demand for economy of spaceand cost pushes analog circuits onto digital substrates, and what design challenges emerge.
標(biāo)簽： 模擬IC 性能 模擬 數(shù)字化設(shè)計(jì)
上傳時(shí)間： 2013-11-17
上傳用戶：菁菁聆聽
比例控制(P)是一種最簡單的控制方式。其控制器的輸出與輸入誤差信號(hào)成比例關(guān)系。根據(jù)設(shè)備有所不同，比例帶一般為2～10％(溫度控制)。但是，僅僅是P 控制的話，會(huì)產(chǎn)生下面將提到的off set (穩(wěn)態(tài)誤差)，所以一般加上積分控制(I)，以消除穩(wěn)態(tài)誤差。
上傳時(shí)間： 2014-07-21
上傳用戶：frank1234
Handheld designers often grapple with ways to de-bounceand control the on/off pushbutton of portable devices.Traditional de-bounce designs use discrete logic, fl ipflops, resistors and capacitors. Other designs includean onboard microprocessor and discrete comparatorswhich continuously consume battery power. For highvoltage multicell battery applications, a high voltageLDO is needed to drive the low voltage devices. All thisextra circuitry not only increases required board spaceand design complexity, but also drains the battery whenthe handheld device is turned off. Linear Technology addressesthis pushbutton interface challenge with a pairof tiny pushbutton controllers.
標(biāo)簽： 按鍵開關(guān) 控制器 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2013-11-18
上傳用戶：ZJX5201314
Many system designers need an easy way to producea negative 3.3V power supply. In systems that alreadyhave a transformer, one option is to swap out the existingtransformer with one that has an additional secondarywinding. The problem with this solution is that manysystems now use transformers that are standard, offthe-shelf components, and most designers want toavoid replacing a standard, qualifi ed transformer with acustom version. An easier alternative is to produce thelow negative voltage rail by stepping down an existingnegative rail. For example, if the system already employsan off-the-shelf transformer with two secondary windingsto produce ±12V, and a –3.3V rail is needed, a negativebuck converter can produce the –3.3V output from the–12V rail.
標(biāo)簽： 458 DN 降壓轉(zhuǎn)換器 低電壓
上傳時(shí)間： 2013-10-09
上傳用戶：Jerry_Chow
One of the fi rst lessons in a basic electronics coursecovers the symbols for resistors, capacitors, inductors,voltage sources and current sources. Althougheach symbol represents a functional component of areal-world circuit, only some of the symbols have directphysical counterparts. For instance, the three discretepassive devices—resistors, capacitors, inductors—canbe picked off a shelf and placed on a real board muchas their symbolic analogs appear in a basic schematic.Likewise, while voltage sources have no direct 2-terminalanalog, a voltage source can be easily built with an offthe-shelf linear regulator.
上傳時(shí)間： 2013-11-24
上傳用戶：simonpeng
Abstract: As electronic systems take over many of the mechanical functions in a car—ranging from engine timing to steering andbraking—there is a growing concern about fault tolerance. There should not be a single point of failure that would prevent a car fromat least "limping" off the road or making it to the nearest service station. Redundant systems, watchdog timers, and other controlcircuits are used to reroute signals and perform other functions that ensure that a vehicle can safely make it off the road when afailure occurs.
標(biāo)簽： 看門狗定時(shí)器 汽車安全系統(tǒng)
上傳時(shí)間： 2013-11-10
上傳用戶：diets
光伏發(fā)電是未來新能源發(fā)電重要方向之一，而光伏變流器是光伏發(fā)電系統(tǒng)的核心。介紹一種基于微網(wǎng)理念的光伏變流器設(shè)計(jì)。以該變流器為核心的光伏發(fā)電系統(tǒng)可以看做一個(gè)小型的微網(wǎng)系統(tǒng)。該系統(tǒng)能根據(jù)外部電網(wǎng)情況，工作于并網(wǎng)模式和離網(wǎng)模式。介紹了該系統(tǒng)的各個(gè)組成部件的設(shè)計(jì)以及變流器主電路部分器件的選型。最后，由實(shí)驗(yàn)樣機(jī)進(jìn)行測試。試驗(yàn)結(jié)果驗(yàn)證了電路拓?fù)浣Y(jié)構(gòu)及控制方案的可行性，也說明了系統(tǒng)參數(shù)設(shè)計(jì)方法的正確性。 Abstract: Solar Photovoltaic generation is an important direction of new energy power generation in the future，while photovoltaic converter is the core of photovoltaic generation system. This paper deals with a study on photovoltaic inverter based on the concept of microgrid. This paper describes a system whose core component is the photovoltaic inverter，can work on grid-connected mode or run independently according to the external situation. The paper simply describes the main components of the system. At last，the prototype was produced and tested. Test result has proved feasibility of circuit topology structure and controlling scheme and shown correctness of system parameters.Key words: PV inverter； microgrid； off-grid； storage battery
標(biāo)簽： 光伏 變流器 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2014-12-24
上傳用戶：Shaikh
歐姆龍plc編程軟件CX-Programmer使用手冊(cè) 第一章安裝和啟動(dòng) 1. 安裝 1-1. 安裝CX-Programmer 1-2. 在線注冊(cè) 2. 打開新工程和設(shè)置設(shè)備型號(hào) 3. 打開新工程和設(shè)置設(shè)備型號(hào) 4. 主窗口 4-1.兼容SYSWIN軟件的按鍵分配 4-2. 段 4-3.刪除和顯示其他窗口 5.創(chuàng)建程序 5-1.常開接點(diǎn)的輸入 5-2.線圈的輸入 5-3.符號(hào)注釋的編輯 5-4.條注釋的輸入 5-5.常閉接點(diǎn)的輸入 5-6.元素注釋的輸入 5-7.上升沿微分接點(diǎn)的輸入 5-8.下降沿微分接點(diǎn)的輸入 5-9.向上垂線的輸入 5-10.向下垂線的輸入 5-11.高級(jí)指令的輸入1 - 字符串的輸入 5-12.高級(jí)指令的輸入1 - 有用的功能 5-13.輔助繼電器的輸入- 1.0 秒時(shí)鐘脈沖位 5-14.高級(jí)指令的輸入2 – 微分指令的輸入 5-15.或邏輯的條輸入 5-16.高級(jí)指令的輸入3 – 通過功能號(hào)來輸入 5-17.定時(shí)器指令的輸入 5-18.計(jì)數(shù)器指令的輸入 5-19.條的編輯…復(fù)制和粘貼 5-20. END指令的輸入 第二章在線/調(diào)試 1. 程序錯(cuò)誤檢查(編譯) 2. 進(jìn)入在線 3. 監(jiān)視 4. 監(jiān)視- 2 同時(shí)監(jiān)視程序中多處位置 5. 監(jiān)視- 3 以十六進(jìn)制數(shù)監(jiān)視 6. 監(jiān)視- 4 查看窗口 7. 監(jiān)視- 5 查看窗口的當(dāng)前值修改和二進(jìn)制數(shù)監(jiān)視 8. 查看窗口的有用功能 9. 監(jiān)視- 6 監(jiān)視窗口- 2 10.監(jiān)視- 7 以短條形式顯示 11.監(jiān)視- 8 微分監(jiān)視 12.強(qiáng)制為On/Off 13.強(qiáng)制-on/off 位的顯示列表 14.修改定時(shí)器的設(shè)定值 15.修改定時(shí)器的當(dāng)前值 16.查找功能- 1 通過地址引用工具查找 17.查找功能- 2 梯形圖的折回查找 18.查找功能- 3 通過注釋的關(guān)鍵字來查找 19.查找功能- 4 進(jìn)入條注釋 20.查找功能- 5 查找位地址 21.在線編輯 實(shí)用的功能 相關(guān)資料： 歐姆龍PLC編程軟件CX-Programmer7.1 簡體中文版
標(biāo)簽： plc 歐姆龍 使用手冊(cè) 編程軟件
上傳時(shí)間： 2013-10-25
上傳用戶：84425894
數(shù)字控制的交流調(diào)速系統(tǒng)所選用的微處理器、功率器件及產(chǎn)生PWM波的方法是影響交流調(diào)速系統(tǒng)性能好壞的直接因素。在介紹了正弦脈寬調(diào)制(SPWM)技術(shù)的基礎(chǔ)上，設(shè)計(jì)了一種以8098單片機(jī)作為控制器，以智能功率模塊IPM為開關(guān)器件的變頻調(diào)速系統(tǒng)。通過軟件編程，產(chǎn)生正弦脈沖寬度調(diào)制波形來控制絕緣柵雙極晶體管的導(dǎo)通和關(guān)斷，從而達(dá)到控制異步電動(dòng)機(jī)轉(zhuǎn)速的目的。實(shí)驗(yàn)結(jié)果表明，該系統(tǒng)可調(diào)頻率調(diào)電壓，穩(wěn)定度高，調(diào)速范圍寬，具有較強(qiáng)的實(shí)用價(jià)值 Abstract: AC variable speed with digital control systems used microprocessors， power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage， high stability， wide speed range， has a strong practical value.
標(biāo)簽： 8098 SPWM 單片機(jī) 變頻調(diào)速系統(tǒng)
上傳時(shí)間： 2013-11-14
上傳用戶：ynwbosss
針對(duì)煤礦井下調(diào)度及緊急救援系統(tǒng)的需求，以DTMF編解碼模塊為核心，設(shè)計(jì)了具有自動(dòng)撥號(hào)功能的新型電話系統(tǒng)。該系統(tǒng)利用MT8880對(duì)DTMF信號(hào)的編解碼功能實(shí)現(xiàn)一鍵撥號(hào)和遠(yuǎn)程設(shè)置，通過檢測振鈴和忙音信號(hào)，完成自動(dòng)摘機(jī)和掛機(jī)過程，配合AGC等外圍電路達(dá)到話音清晰流暢的效果。 Abstract: To meet the demand for mine scheduling and emergency rescue system， with using DTMF signal codec as the core， a new telephone system was designed with automatic dialing function. In the system， the DTMF signal encoding and decoding function of MT8880 was used to achieve one-touch dialing and remote setting. The circuit detects the ringing and busy signal， and then completes automatic off-hook and hangup. With AGC(Automatic Gain Control) and other peripheral circuits， the voice was regulated to a clear and smooth effect.
標(biāo)簽： 8880 MT 撥號(hào)電話 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2014-11-18
上傳用戶：ly1994
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