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.
上傳時間： 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成比例關系。根據設備有所不同，比例帶一般為2～10％(溫度控制)。但是，僅僅是P 控制的話，會產生下面將提到的off set (穩態誤差)，所以一般加上積分控制(I)，以消除穩態誤差。
上傳時間： 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.
上傳時間： 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.
上傳時間： 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.
上傳時間： 2013-11-10
上傳用戶：diets
光伏發電是未來新能源發電重要方向之一，而光伏變流器是光伏發電系統的核心。介紹一種基于微網理念的光伏變流器設計。以該變流器為核心的光伏發電系統可以看做一個小型的微網系統。該系統能根據外部電網情況，工作于并網模式和離網模式。介紹了該系統的各個組成部件的設計以及變流器主電路部分器件的選型。最后，由實驗樣機進行測試。試驗結果驗證了電路拓撲結構及控制方案的可行性，也說明了系統參數設計方法的正確性。 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
上傳時間： 2014-12-24
上傳用戶：Shaikh
歐姆龍plc編程軟件CX-Programmer使用手冊 第一章安裝和啟動 1. 安裝 1-1. 安裝CX-Programmer 1-2. 在線注冊 2. 打開新工程和設置設備型號 3. 打開新工程和設置設備型號 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.創建程序 5-1.常開接點的輸入 5-2.線圈的輸入 5-3.符號注釋的編輯 5-4.條注釋的輸入 5-5.常閉接點的輸入 5-6.元素注釋的輸入 5-7.上升沿微分接點的輸入 5-8.下降沿微分接點的輸入 5-9.向上垂線的輸入 5-10.向下垂線的輸入 5-11.高級指令的輸入1 - 字符串的輸入 5-12.高級指令的輸入1 - 有用的功能 5-13.輔助繼電器的輸入- 1.0 秒時鐘脈沖位 5-14.高級指令的輸入2 – 微分指令的輸入 5-15.或邏輯的條輸入 5-16.高級指令的輸入3 – 通過功能號來輸入 5-17.定時器指令的輸入 5-18.計數器指令的輸入 5-19.條的編輯…復制和粘貼 5-20. END指令的輸入 第二章在線/調試 1. 程序錯誤檢查(編譯) 2. 進入在線 3. 監視 4. 監視- 2 同時監視程序中多處位置 5. 監視- 3 以十六進制數監視 6. 監視- 4 查看窗口 7. 監視- 5 查看窗口的當前值修改和二進制數監視 8. 查看窗口的有用功能 9. 監視- 6 監視窗口- 2 10.監視- 7 以短條形式顯示 11.監視- 8 微分監視 12.強制為On/Off 13.強制-on/off 位的顯示列表 14.修改定時器的設定值 15.修改定時器的當前值 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 通過注釋的關鍵字來查找 19.查找功能- 4 進入條注釋 20.查找功能- 5 查找位地址 21.在線編輯 實用的功能 相關資料： 歐姆龍PLC編程軟件CX-Programmer7.1 簡體中文版
上傳時間： 2013-10-25
上傳用戶：84425894
數字控制的交流調速系統所選用的微處理器、功率器件及產生PWM波的方法是影響交流調速系統性能好壞的直接因素。在介紹了正弦脈寬調制(SPWM)技術的基礎上，設計了一種以8098單片機作為控制器，以智能功率模塊IPM為開關器件的變頻調速系統。通過軟件編程，產生正弦脈沖寬度調制波形來控制絕緣柵雙極晶體管的導通和關斷，從而達到控制異步電動機轉速的目的。實驗結果表明，該系統可調頻率調電壓，穩定度高，調速范圍寬，具有較強的實用價值 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.
上傳時間： 2013-11-14
上傳用戶：ynwbosss
針對煤礦井下調度及緊急救援系統的需求，以DTMF編解碼模塊為核心，設計了具有自動撥號功能的新型電話系統。該系統利用MT8880對DTMF信號的編解碼功能實現一鍵撥號和遠程設置，通過檢測振鈴和忙音信號，完成自動摘機和掛機過程，配合AGC等外圍電路達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.
上傳時間： 2014-11-18
上傳用戶：ly1994
