The purpose of this application note is to show an example of how a digital potentiometer can be used in thefeedback loop of a step-up DC-DC converter to provide calibration and/or adjustment of the output voltage.The example circuit uses a MAX5025 step-up DC-DC converter (capable of generating up to 36V,120mWmax) in conjunction with a DS1845, 256 position, NV digital potentiometer. For this example, the desiredoutput voltage is 32V, which is generated from an input supply of 5V. The output voltage can be adjusted in35mV increments (near 32V) and span a range wide enough to account for resistance, potentiometer and DCDCconverter tolerances (27.6V to 36.7V).
Radio Frequency Integrated Circuit Design
I enjoyed reading this book for a number of reasons. One reason is that itaddresses high-speed analog design in the context of microwave issues. This isan advanced-level book, which should follow courses in basic circuits andtransmission lines. Most analog integrated circuit designers in the past workedon applications at low enough frequency that microwave issues did not arise.As a consequence, they were adept at lumped parameter circuits and often notcomfortable with circuits where waves travel in space. However, in order todesign radio frequency (RF) communications integrated circuits (IC) in thegigahertz range, one must deal with transmission lines at chip interfaces andwhere interconnections on chip are far apart. Also, impedance matching isaddressed, which is a topic that arises most often in microwave circuits. In mycareer, there has been a gap in comprehension between analog low-frequencydesigners and microwave designers. Often, similar issues were dealt with in twodifferent languages. Although this book is more firmly based in lumped-elementanalog circuit design, it is nice to see that microwave knowledge is brought inwhere necessary.Too many analog circuit books in the past have concentrated first on thecircuit side rather than on basic theory behind their application in communications.The circuits usually used have evolved through experience, without asatisfying intellectual theme in describing them. Why a given circuit works bestcan be subtle, and often these circuits are chosen only through experience. Forthis reason, I am happy that the book begins first with topics that require anintellectual approach—noise, linearity and filtering, and technology issues. Iam particularly happy with how linearity is introduced (power series). In therest of the book it is then shown, with specific circuits and numerical examples,how linearity and noise issues arise.
In a recent discussion with a system designer, the requirementfor his power supply was to regulate 1.5Vand deliver up to 40A of current to a load that consistedof four FPGAs. This is up to 60W of power that must bedelivered in a small area with the lowest height profi lepossible to allow a steady fl ow of air for cooling. Thepower supply had to be surface mountable and operateat high enough effi ciency to minimize heat dissipation.He also demanded the simplest possible solution so histime could be dedicated to the more complex tasks. Asidefrom precise electrical performance, this solution had toremovethe heat generated during DC to DC conversionquickly so that the circuit and the ICs in the vicinity do notoverheat. Such a solution requires an innovative designto meet these criteria:
介紹了基于單片機(jī)航空交流電參數(shù)測(cè)試儀的系統(tǒng)設(shè)計(jì)。以Silicon Labs公司的C8051F005單片機(jī)為核心設(shè)計(jì)出數(shù)據(jù)采集板,通過(guò)RS-232串口與上位機(jī)通訊。運(yùn)用Lab Windows/CVI編寫(xiě)的上位機(jī)軟件實(shí)現(xiàn)信號(hào)的檢測(cè)以及波形和數(shù)據(jù)的顯示,給出了測(cè)試儀硬件電路的組成和軟件流程圖。本系統(tǒng)具有硬件結(jié)構(gòu)簡(jiǎn)單、容易實(shí)現(xiàn)和成本低等特點(diǎn),在實(shí)際應(yīng)用中其穩(wěn)定性、精確性均能滿足客戶要求。
Abstract:
The design of aeronautics AC parameters tester based on the single-chip is introduced.The core component of data acquisition board is C8051F005 single chip of Silicon Labs Company,and communication with PC through RS-232. The signal processing software programmed with LabWindows/CVI can be used successfully to fulfill inspection of signal and display of the waveform and data. The hardware and software configuration of test instrument are provided.The hardware of the system is simple, and can be easily realized.The stability and precision of the measurement instrument are enough to meet the requirements.
基于變頻調(diào)速的水平連鑄機(jī)拉坯輥速度控制系統(tǒng)Frequency Inverter Based Drawing RollerS peedC ontrolSy stem ofHorizontal Continuous Casting MachineA 偉劉沖旅巴(南 華 大 學(xué)電氣工程學(xué)院,衡陽(yáng)421001)摘要拉坯輥速度控制是水平連鑄工藝的關(guān)鍵技術(shù)之一,采用變頻器實(shí)現(xiàn)水平連鑄機(jī)拉坯輥速度程序控制,由信號(hào)發(fā)生裝置給變頻器提供程控信號(hào)。現(xiàn)場(chǎng)應(yīng)用表明該控制系統(tǒng)速度響應(yīng)快,控制精度高,滿足了水平連鑄生產(chǎn)的需要。關(guān)鍵詞水平連鑄拉坯輥速度程序控制變頻器Absh'act Speedc ontorlof dr awingor leris on eo fth ek eyte chnologiesfo rho rizontalco ntinuousca stingm achine.Fo rth ispu rpose,fr equencyco nverterisad optedfo rdr awingor lersp eedp rogrammablec ontorlof ho rizontalco ntinuousca stingm achine,th ep rogrammableco ntorlsi gnalto fr equencyc onverteris provided場(chǎng)a signal generator. The results of application show that the response of system is rapid and the control accuracy is high enough to meet thedemand of production of horizontal continuous casting.Keywords Horizontalco ntinuousc asting Drawingor ler Speedp rogrammablec ontrol Ferquencyin verter
隨著 現(xiàn) 代 化工業(yè)生產(chǎn)對(duì)鋼材需求量的日益增加,連鑄生產(chǎn)能力已經(jīng)成為衡量一個(gè)國(guó)家冶金工業(yè)發(fā)展水平的重要指標(biāo)之一。近十幾年來(lái),水平連鑄由于具有投資少、鑄坯直、見(jiàn)效快等多方面的優(yōu)點(diǎn),國(guó)內(nèi)許多鋼鐵企業(yè)利用水平連鑄機(jī)來(lái)澆鑄特種合金鋼,發(fā)揮了其獨(dú)特的優(yōu)勢(shì)并取得了較好的經(jīng)濟(jì)效益〔1,2)0采用 水 平 連鑄機(jī)澆鑄特種合金鋼時(shí),由于拉坯機(jī)是水平連鑄系統(tǒng)中的關(guān)鍵設(shè)備之一,拉坯機(jī)及其控制性能的好壞直接影響著連鑄坯的質(zhì)量,因此,連鑄的拉坯技術(shù)便成為整個(gè)水平連鑄技術(shù)的核心。由于鋼的冶煉過(guò)程是在高溫下進(jìn)行的,鋼水溫度的變化又容易影響鑄坯的質(zhì)量和成材率,因此,如何能在高溫環(huán)境下控制好與鑄坯速度相關(guān)的參數(shù)(拉、推程量,中停時(shí)間和拉坯頻率等)對(duì)于確保連鑄作業(yè)的進(jìn)一步高效化,延長(zhǎng)系統(tǒng)的連續(xù)作業(yè)時(shí)間十分關(guān)鍵。因此,拉坯輥速度控制技術(shù)是連鑄生產(chǎn)過(guò)程控制領(lǐng)域中的關(guān)鍵技術(shù)之- [31
Accurate measurement of the third order intercept pointfor low distortion IC products such as the LT5514 requirescertain precautions to be observed in the test setup andtesting procedure. The LT5514 linearity performance ishigh enough to push the test equipment and test set-up totheir limits. A method for accurate measurement of thirdorder intermodulation products, IM3, with standard testequipment is outlined below.It is also important to correctly interpret the LT5514specification with respect to ROUT, and the impact ofdemo-board transmission-line termination loss whenevaluating the linearity performance, as explained in theLT5514 Datasheet and in Note 1 of this document.
Java Clock is a FREE Java applet used to display a clock on your Web pages. You can display either analog or digital clock. The full source code of this applet is also available (visit my home page to download it). You may use this applet on your Web pages WITHOUT paying me fee or royalty as long as credit is given (a link to my home page is enough).
In this book, we aim to give you an introduction to a wide variety of topics important to you as a developer using UNIX. The word Beginning in the title refers more to the content than to your skill level. We ve structured the book to help you learn more about what UNIX has to offer, however much experience you have already. UNIX programming is a large field and we aim to cover enough about a wide range of topics to give you a good beginning in each subject.
This book isn t for uber-programmers who already have all the answers. If you think that J2EE does everything that you need it to do and you can make it sing, this book is not for you. Believe me, there are already enough books out there for you.
* Function:
* 1. Replace the first oldstr with newstr in srcstr
* Arguments:
* IN :
* srcstr
* oldstr
* newstr
* OUT :
* srcstr
* Return:
* 1. If find and replace one oldstr with newstr in srcstr , return 1
* 2. If find no oldstr in srcstr , return 0
* 3. If error (malloc return NULL) return -1
* Notes:
* 1. srcstr should be large size enough.