開關(guān)電源外文翻譯

1、<p>　　西安科技大學(xué)高新學(xué)院</p><p><b>　　畢業(yè)設(shè)計(jì)（論文）</b></p><p><b>　　外文翻譯</b></p><p>　　學(xué)生姓名： 蘇曉磊 </p><p>　　院（系）： 機(jī)電信息學(xué)院 </p><

2、;p>　　專業(yè)班級(jí)： 電氣0804 </p><p>　　指導(dǎo)教師： 魯堅(jiān)丘 </p><p>　　完成日期： 2011年12月14日 </p><p><b>　　譯文</b></p><p><b>　　開關(guān)電源</b></p>

3、<p>　　高頻開關(guān)電源由以下幾個(gè)部分組成：</p><p>　　主電路從交流電網(wǎng)輸入、直流輸出的全過程，包括輸入濾波器,其作用是將電網(wǎng)存在的雜波過濾，同時(shí)也阻礙本機(jī)產(chǎn)生的雜波反饋到公共電網(wǎng)。整流與濾波：將電網(wǎng)交流電源直接整流為較平滑的直流電，以供下一級(jí)變換。逆變：將整流后的直流電變?yōu)楦哳l交流電，這是高頻開關(guān)電源的核心部分，頻率越高，體積、重量與輸出功率之比越小。還有輸出整流與濾波：根據(jù)負(fù)載需要，提供穩(wěn)

4、定可靠的直流電源。</p><p>　　控制電路一方面從輸出端取樣，經(jīng)與設(shè)定標(biāo)準(zhǔn)進(jìn)行比較，然后去控制逆變器，改變其頻率或脈寬，達(dá)到輸出穩(wěn)定，另一方面，根據(jù)測(cè)試電路提供的資料，經(jīng)保護(hù)電路鑒別，提供控制電路對(duì)整機(jī)進(jìn)行各種保護(hù)措施。除了提供保護(hù)電路中正在運(yùn)行中各種參數(shù)外，還提供各種顯示儀表資料。輔助電源提供所有單一電路的不同要求電源。</p><p>　　改變開關(guān)接通時(shí)間和工作周期的比例，電壓的

5、平均值也隨之改變，因此，隨著負(fù)載及輸入電源電壓的變化自動(dòng)調(diào)整和的比例便能使輸出電壓維持不變。改變接通時(shí)間和工作周期比例亦即改變脈沖的占空比，這種方法稱為“時(shí)間比率控制”。</p><p>　　按控制原理，有三種方式：</p><p><b>　　1、脈沖寬度調(diào)制</b></p><p>　　開關(guān)周期恒定，通過改變脈沖寬度來改變占空比的方式。&l

6、t;/p><p><b>　　2、脈沖頻率調(diào)制</b></p><p>　　導(dǎo)通脈沖寬度恒定，通過改變開關(guān)工作頻率來改變占空比的方式。</p><p><b>　　3、混合調(diào)制</b></p><p>　　導(dǎo)通脈沖寬度和開關(guān)工作頻率均不固定，彼此都能改變的方式，它是以上二種方式的混合。</p>

7、;<p>　　脈寬調(diào)調(diào)制集成芯片發(fā)明于1975 年,促進(jìn)了開關(guān)電源的發(fā)展并引領(lǐng)當(dāng)今數(shù)十億美元的電源控制芯片產(chǎn)業(yè)。</p><p>　　在過去的幾年中,生產(chǎn)出一系列用于控制開關(guān)電源的集成電路。其中之一——TL494，結(jié)合了以往控制電路中的優(yōu)點(diǎn)。TL494 獨(dú)特的內(nèi)部結(jié)構(gòu)簡(jiǎn)化了許多設(shè)計(jì)上的難題。這份應(yīng)用報(bào)告的目的就是讓讀者對(duì)TL494的特點(diǎn)、電氣特性和應(yīng)用上的局限性有更深入的了解。</p>

8、<p>　　在這份應(yīng)用報(bào)告中,將詳細(xì)研究TL494在開關(guān)電源中的應(yīng)用。通過16引腳雙列直插式封裝的TL494內(nèi)部結(jié)構(gòu)及其特點(diǎn)，可以了解其基本功能。這份對(duì)其各功能模塊的深入透徹研究，將向我們展示其在控制電路中的用途和局限性，還可以對(duì)各功能模塊之間的內(nèi)部聯(lián)系有更深入的理解。此控制電路的一些實(shí)際應(yīng)用證實(shí)了其優(yōu)越性。不過仍存在一些沒有解決的問題。</p><p>　　控制信號(hào)產(chǎn)生于兩個(gè)方面：死區(qū)時(shí)間控制電路和

9、誤差放大器。死區(qū)時(shí)間比較器具有100mV 的輸入補(bǔ)償電壓。當(dāng)輸入端接地，鋸齒波形低于110mV 期間輸出是禁止的。這樣可以產(chǎn)生最小約3%的可調(diào)節(jié)占空比。PWM 比較器與誤差放大器控制信號(hào)進(jìn)行比較。誤差放大器功能之一是檢測(cè)輸出電壓和提供足夠的增益使得輸入端有毫伏級(jí)的誤差時(shí)也能產(chǎn)生足夠幅值的控制信號(hào)來進(jìn)行調(diào)節(jié)控制。誤差放大器還可以用來檢測(cè)輸出電流并限制負(fù)載電流。</p><p>　　一片TL494 芯片集成了脈寬調(diào)制

10、控制器電路的許多功能。基本功能是控制開關(guān)電源，它包括兩個(gè)誤差放大器、一個(gè)片內(nèi)可調(diào)振蕩器、一個(gè)死區(qū)控制比較器、一個(gè)鋸齒波發(fā)生器、一個(gè)2.5V基準(zhǔn)電壓和輸出控制電路。</p><p>　　在其工作在150kHz 時(shí),振蕩周期為6.67 us.由內(nèi)部死區(qū)比較器補(bǔ)償?shù)乃绤^(qū)時(shí)間將產(chǎn)生200 ns的零脈沖。只有當(dāng)比較器的輸入電壓大于振蕩器的比較電壓，則比較器的輸出端將停止輸出管Q1 和Q2。在輸出控制接地的時(shí)候，死區(qū)控制比較

11、器包含有效的120mV輸入偏置能把最小輸出死區(qū)時(shí)間控制在鋸齒波前4%的周期左右。通過在死區(qū)控制輸入加固定電壓增加更多死區(qū)時(shí)間，電壓范圍在0V到3.3V。</p><p>　　TL494是一種固定頻率脈寬調(diào)制型開關(guān)電源集成控制器。輸出脈沖的調(diào)調(diào)制是通過內(nèi)部振蕩器在定時(shí)器件CT 上產(chǎn)生的鋸齒波與另外兩個(gè)控制信號(hào)比較來實(shí)現(xiàn)的。只有在鋸齒波電壓大于控制信號(hào)期間才會(huì)被選通。當(dāng)控制信號(hào)增大，輸入鋸齒波的時(shí)間將減小，因此，輸出

12、脈沖的寬度將減小。</p><p>　　隨著開關(guān)電源技術(shù)的進(jìn)步和發(fā)展，各類類用途的直流電源都傾向于采用開關(guān)電源技術(shù)。開關(guān)電源以其線性電源無法比擬的特點(diǎn)與優(yōu)點(diǎn)已經(jīng)成為電源行業(yè)的主流形式。</p><p><b>　　外文文獻(xiàn)</b></p><p>　　Switch Power Supply</p><p>　　High-

13、frequency switching power supply circuit of high frequency switching power</p><p>　　supply from the following components :</p><p>　　A main circuit from the exchange network input, DC output of t

14、he entire process,</p><p>　　including an import filter , its role is to network the clutter filtration, but also hindered theplane of the clutter feedback to the public grid. Rectifier and filter:They direct

15、 AC powerrectifier for smoother DC, for under a transformation.The inverter:Rectifier the highfrequency alternating current into direct current, high-frequency switching power supply isthe core component of the higher fr

16、equency, size, weight and output ratio smaller. And therectifier output filter : Under load the need </p><p>　　The control circuit while output from the sample, with the set standards, then controlledinverte

17、r, change its frequency or pulse width output achieve stability, on the other hand,according to test data provided by the circuit by circuit protection identification, Controlcircuit for the unit for various protection m

18、easures. In addition to providing detection circuitprotection circuit is running various parameters, but also provide information displayinstruments. The auxiliary power supply circuit</p><p>　　The change sw

19、itch connected to the work cycle time and the ratio of the voltage betweenthe average change also, therefore, With the load and input supply voltage changes andautomatically adjust ratio, it will cause the output voltage

20、 unchanged. Change the access timeand cycle percentage change is the pulse duty cycle. This method, known as "time ratiocontrol" (Time Ratio Control, for the initials TRC).</p><p>　　TRC under contr

21、ol principle, there are three ways : 1. Pulse width modulation (PulseWidth Modulation, acronym for PWM) switching constant cycle by changing the pulse widthto change the duty cycle approaches. 2, pulse frequency modulati

22、on (Pulse FrequencyModulation, acronym for the PFM) conduction pulse width constant by changing theswitching frequency to change the duty cycle approaches. 3, mixed conduction modulationand pulse width switching frequenc

23、y not fixed are, they change the way It is mo</p><p>　　A pulse-width modulation control chip invented in 1975 spurred the development of</p><p>　　switching power supplies,leading to a power cont

24、rol IC industry that today is measured inbillions of dollars.</p><p>　　Over the past few years, a series of monolithic integrated circuits for the control of</p><p>　　switching power supplies ha

25、ve been introduced. One of these, the TL494, combines many ofthe features previously requiring several control circuits. The TL494 simplifies many designproblems with its unique architecture .It is the purpose of this ap

26、plication report to give thereader a thorough understanding of the TL494,its features, its performance characteristics, andits limitations.</p><p>　　In this application report,the TL494 switching power suppl

27、y control is discussed in</p><p>　　detail.A general overview of the device’s architecture presents the primary functions</p><p>　　contained in the 16-pin dual-in-line package and its features. A

28、n in-depth study of each of thedevice’s primary building blocks highlights the versatility and limitations of the control circuitand gives a thorough understanding of their interrelationship. Applying the control circuit

29、 toseveral basic applications demonstrates the circuits’usefulness and outlines some stillunresolved problems.</p><p>　　The control signals are derived from two sources:the dead-time(off-time) control circui

30、tand the error amplifier circuit. The dead-time-control input is compared directly by thedead-time-control comparator.This comparator has a fixed 100-mV offset.With the controlinput biased to ground ,the output is inhibi

31、ted during the portion of time the sawtoothwaveform is below 110mV. This provides a preset dead time of approximately 3%, which isthe minimum dead time that can be programmed. The PWM comparato</p><p>　　The

32、TL494 incorporates all the functions required in the construction of a</p><p>　　pulse-width-modulation(PWM) control circuit on a single chip. Design primarily for</p><p>　　power-supply control ,

33、this device offers the flexibility to tailor the power-supply control</p><p>　　circuitry to a specific application. It contains two error amplifiers , an on-chip adjustable</p><p>　　oscillator ,

34、 a dead-time control(DTC) comparator , a pulse-steering control flip-flop , a 2.5-V,5%-precision regulator , and output-control circuits.</p><p>　　At an operation frequency of 150 kHz ,the period of the osci

35、llator is 6.67 us.The deadtime established by the internal offset of the dead-time comparator yields a blanking pulse of200 ns. The output of the comparator inhibits switching transistors Q1 and Q2 whenever thevoltage at

36、 its input is greater than the ramp voltage of the oscillator. An internal offset of 110mV assures a minimum dead time of 3% with the dead-time-control input grounded.Additional dead time can be imposed by applying a vol

37、</p><p>　　The TL494 is a fixed-frequency pulse-width-modulation(PWM) control circuit.</p><p>　　Modulation of output pulses is accomplished by comparison of the sawtooth waveform,</p><

38、p>　　created by the internal oscillator on the timing capacitor(CT),to either of two control signals.The output stage is enabled during that portion of time when the sawtooth voltage is greater than the control signal

39、s. As the control signals increase ,the period of time the sawtooth input is greater decreases; therefore,the output pulse duration deceases.</p><p>　　With the development and advancement of switch power sup