Many complex systems—such as telecom equipment,memory modules, optical systems, networking equipment,servers and base stations—use FPGAs and otherdigital ICs that require multiple voltage rails that muststart up and shut down in a specific order, otherwise theICs can be damaged. The LTC®2924 is a simple andcompact solution to power supply sequencing in a 16-pinSSOP package (see Figures 1 and 2).
A number of conventional solutions have been available forthe design of a DC/DC converter where the output voltageis within the input voltage range—a common scenarioin Li-Ion battery-powered applications—but none werevery attractive until now. Conventional topologies, suchas SEPIC or boost followed by buck, have numerousdisadvantages, including low effi ciency, complex magnetics,polarity inversion and/or circuit complexity/cost. TheLTC®3785 buck-boost controller yields a simple, effi cient,low parts-count, single-converter solution that is easyto implement, thus avoiding the drawbacks associatedwith traditional solutions.
Once relegated to the hinterlands of low cost indicatorlights, the LED is again in the spotlight of the lightingworld. LED lighting is now ubiquitous, from car headlightsto USB-powered lava lamps. Car headlights exemplifyapplications that capitalize on the LED’s clear advantages—unwavering high quality light output, tough-assteelrobustness, inherent high effi ciency—while a USBlava lamp exemplifi es applications where only LEDs work.Despite these clear advantages, their requirement forregulated voltage and current make LED driver circuitsmore complex than the venerable light bulb, but some newdevices are closing the gap. For instance, the LTM®8040μModule™ LED driver integrates all the driver circuitryinto a single package, allowing designers to refocus theirtime and effort on the details of lighting design criticalto a product’s success.
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:
As logic systems get larger and more complex, theirsupply current requirements continue to rise. Systemsrequiring 100A are fairly common. A high current powersupply to meet such requirements usually requires parallelingseveral power regulators to alleviate the thermalstress on the individual power components. A powersupply designer is left with the choice of how to drive theseparalleled regulators: brute-force single-phase or smartPolyPhaseTM.
為了提高傳統(tǒng)溫度控制系統(tǒng)的性能，將PID控制理論與嵌入式系統(tǒng)相結(jié)合，采用瑞薩電子公司的H8S/2166作為核心處理器，AD公司的AD7705以及熱敏電阻溫度傳感器作為溫度檢測單元，利用4×6小鍵盤、LCD顯示器和S1D13305液晶控制器達(dá)到良好的人機(jī)交互，設(shè)計(jì)出了一個(gè)應(yīng)用于化工領(lǐng)域的嵌入式實(shí)時(shí)溫度控制系統(tǒng)。相比于傳統(tǒng)溫度控制系統(tǒng)，該系統(tǒng)提供了更強(qiáng)的計(jì)算能力和可擴(kuò)展能力，采用增量PID控制算法實(shí)現(xiàn)復(fù)雜控制。通過實(shí)驗(yàn)，該系統(tǒng)能達(dá)到0.1 ℃的溫度控制精度以及小于120 s的溫度穩(wěn)定時(shí)間。
Abstract:
In order to improve the performance of conventional temperature control system， combining PID control theory with embedded systems， using the Renesas Electronics Corp. H8S/2166 micro-controller as a core processors， AD7705 and thermistor temperature sensor as a temperature detection unit and 4×6 small keyboard， LCD and S1D13305 LCD controller as a good human-computer interaction， this paper designed an embedded real-time temperature control system which is applied in chemical industry. Compared with conventional temperature control system， this system provides more computing power and extensibility， and adopts PID control algorithm for complex control. Through the experiment， the system can reach temperature control accuracy of 0.1 ℃ and temperature stabilization time of less than 120 seconds.
AVR32801: UC3A3 Schematic Checklist Features • Power circuit • Reset circuit • USB connection • External bus interface • ABDAC sound DAC interface • JTAG and Nexus debug ports • Clocks and crystal oscillators • MMC, SD-card, SDHC, SDIO and CE-ATA interface 1 Introduction A good hardware design comes from a proper schematic. Since UC3A3 devices have a fair number of pins and functions, the schematic for these devices can be large and quite complex. This application note describes a common checklist which should be used when starting and reviewing the schematics for a UC3A3 design.
雖然PIC都是8位的單片機(jī)，但都采用RISC（Reduced Instruction Set Computing）核心結(jié)構(gòu)，這有別于過去一般的CISC(Complex Instruction Set Computing)結(jié)構(gòu)。所謂RISC結(jié)構(gòu)就是采用哈佛雙總線結(jié)構(gòu)，將地址總線與數(shù)據(jù)總線分開，因此在同一個(gè)指令執(zhí)行過程中，數(shù)據(jù)與地址可以同時(shí)傳送，避免了總線處理上的瓶頸。
機(jī)電類比法是一種把機(jī)械量通過一定的計(jì)算等效類比為電量的方法，其在對電子機(jī)械系統(tǒng)的分析中應(yīng)用非常廣泛。它能夠把一個(gè)較復(fù)雜的機(jī)械系統(tǒng)類比為我們熟知的電路系統(tǒng)來進(jìn)行分析，從而使問題的分析得到簡化。本文通過對振弦式傳感器的分析介紹了機(jī)電類比法，并對使用電路進(jìn)行了相關(guān)的分析。 Summary：The electromechanical analogy is assort of analysis which is to analogize the mechanical system by using circuit system , it applied widely in the filed of analysis the electronic-mechanical system. The analysis can take a complex mechanical system analogous to a circuitry that we well-known, which can simplify the problems. In the paper, the electro-mechanical analogy method is briefly introduced by analysis the vibrating wire sensor，and have a correlation analysis about the circuit we used.關(guān)鍵詞： 機(jī)電類比法 振弦式傳感器 頻率 振蕩 反饋Keyword：electro-mechanical analogy method，vibrating wire sensor，frequency, oscillation, feedback
0 引言振弦式傳感器是屬于頻率式傳感器的一種。所謂頻率式傳感器就是能直接將被測量轉(zhuǎn)換為振動(dòng)頻率信號(hào)的傳感器，這類傳感器一般是通過測量振弦、振筒、振梁、振膜等彈性振體或石英晶體諧振器的固有諧振頻率來達(dá)到測量引起諧振頻率變化的被測非電量的目的，其也稱為諧振式傳感器[1]。在分析該類傳感器中，由于其涉及到頻率，就容易讓人聯(lián)想到在電子技術(shù)中接觸到的RLC振蕩電路。因此可以嘗試著用類比的方法使之對應(yīng)起來分析,即機(jī)電類比法分析。
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