反激式開關電源 理工科畢業(yè)設計(論文)外文翻譯

1、華南理工大學本科生畢業(yè)設計（論文）翻譯英文原文名single chip switching power supply design based on top247y中文譯名 基于top247y的反激式單片開關電源研制 學 院 華南理工大學 專業(yè)班級 電氣工程及其自動化學生姓名 學生學號 指導教師 填寫日期 2014.1.25 英文原文版出處： the world of power supply in 2005 fifth 譯文成績： 指導教師（導師組長）簽名： 譯文：摘要：單片開關電源具有高集成度、高性價比、最簡外圍電路、最佳性能指標等特點引起了越來越多人的重視。目前，隨著單片開關電源模塊的應

2、用，中、小功率開關電源正朝著短、小、輕、薄的方向發(fā)展?？蓮V泛用于儀器儀表、計算機、家用電器（如彩電、dvd、數(shù)碼像機）、自動控制等領域，為新型高效節(jié)能電源的推廣與普及奠定了基礎。開發(fā)各種通用型、精密型及特種單片開關電源模塊，能夠大大提高我國開關電源產品的科技水平和在國內外市場上的競爭能力，創(chuàng)造出巨大的經濟效益與社會效益。關鍵字：topswitch 開關電源 單片一：單片開關電源的發(fā)展概況自從人類進入電的社會，電源就誕生了，電源已是各種電子設備必不可少的重要組成部分。它直接決定了整個系統(tǒng)的質量、安全性等多個指標。隨著科技飛速般的發(fā)展，開關電源以其特有的優(yōu)勢高穩(wěn)定性、高性價比、低損耗、高效率，已經

3、在市場中占領了一席之地。開關電源的發(fā)展方向是高頻、高可靠、低耗、低噪聲、抗干擾和模塊化。目前，隨著單片開關電源集成電路的應用，開關電源正朝著短、小、輕、薄的方向陽發(fā)展。上世紀末，是開關電源的一個重大轉折時期，單片開關電源產生了。從那時開始，它變廣泛的應用于通信、計算機、銀行通信、航天等各種不同的領域之中。它的發(fā)展?jié)摿εc對未來社會的影響都將會頗深，從而，世界各國也爭相的大力投入資金去發(fā)展相關科技。在此背景下，最近幾年的科技成果非常喜人，國外許多著名的芯片廠家推出了一大批單片開關電源集成電路，更為新型開關電源的推廣與普及奠定了良好的基礎。90年代中、后期，隨著集成電路的發(fā)展，出現(xiàn)了各種類型的單片開

4、關電源集成電路。它將開關電源中的脈寬控制器、功率輸出級、保護電路等集成在一個芯片中，能構成高效率無須工頻變壓器的隔離式開關電源。比較有代表性的荷蘭philips公司2000年研制的tea1520系列開關電源，美國onsemi公司19982002年先后開發(fā)的ncp1050、ncp1000系列單片開關電源，美國motorola公司1999年推出的mc33370系列五端開關電源，美國pi公司于1994年最先推出了topswitch系列第一代產品，被人們譽為“頂級開關電源”，1997年推出了topswitch-系列，1998年推出了tinyswitch系列，2000年推出了topswitch-fx系列

5、，隨后又推出了topswitch-gx系列，并做為主流產品加以推廣。本文以topswitch-gx系列中的top247y為例具體闡述其性能特點和典型設計應用。二：topswitch-gx系列六端開關電源芯片特點設計一臺單端反激式離線開關電源，涉及到電氣工程的許多方面：模擬電路和數(shù)字電路的結構，雙極管和mos功率管器件的特征，磁性材料的考慮，熱溫升的散發(fā)，過流和過壓的安全防護，控制回路的穩(wěn)定性能等。這就提出了一個巨大的挑戰(zhàn)：它的設計涉及到需要綜合協(xié)調的許多可變因素。正是由于topswitch的高度集成化，才使得這項設計任務被大大地簡化。因為它有效的縮減了設計變數(shù)項目，并且建立了ic內部回路的穩(wěn)定

6、性，所以發(fā)展成為一種簡單的逐步設計方法，使之容易遵循參照，并指引讀者從topswitch的設計流程圖中，快速的得到較滿意的結果。在優(yōu)化最佳數(shù)據(jù)和信息的過程中，可利用關鍵的基本工作數(shù)據(jù)作為設計指南，例如一些方程式和導向圖標等。在以上三者之間，它們提供了前后相互參照的內容，讓讀者能開闊思路，在給定的階段執(zhí)行有關程序，實現(xiàn)最佳參數(shù)，這有利于深入理解和進一步優(yōu)化數(shù)據(jù)。由于topswitch器件電路的高度集成化，過去設計這類電源的一些爭論，均在芯片中得到解決。只有少量需要調節(jié)的器件留在ic外面加以安排，這就能維持它的基本電路結構不變。有關反饋變換器要求的特殊應用，例如恒定電流輸出、恒定功率輸出等，詳見有

7、關文獻。對于用topswitch的反饋電路，只需在基本的變換器電路結構上增加一些改進措施，因為它們都設置在ic外圍。有四種不同的反饋電路形式可供選用，其中兩種反饋回路是受光耦器件控制的。另外兩種反饋回路是偏置繞組只接阻容（或再串二極管）加到ic。這取決于開關電源對輸出電壓和輸出電流的要求指標。1 topswitch-gx內部主要由控制電壓源、帶隙基準電壓源、頻率抖動振蕩器、脈寬調制器、并聯(lián)調整器/誤差比較器、門驅動級和輸出級、高壓功率開關管(mosfet)、偏置電路、過流保護電路、過壓、欠壓檢測及保護電路、過熱保護電路、上電復位電路、軟啟動電路、輕載時自動降低開關頻率電路、停止邏輯、開啟電壓為

8、1v的電壓比較器組成。通過高頻變壓器使輸出端和電網實現(xiàn)隔離，使之具有體積小、效率高、安全可靠的特點。2 輸入交流電壓范圍很寬，可以是固定230vac15%，或者寬范圍85-265vac，但在寬范圍輸入情況下，最大輸入功率降低40%左右。輸入信號的頻率范圍為47-440hz。3 開關頻率典型值為132k，在輕載時可以工作在半頻工作模式，最大占空比可達80%，電源效率80%左右，最大可達到90%。4 topswitch-gx有六個引出端，它們分別是控制端c、線路檢測端l、極限電流設定端x、源極s、開關頻率選擇端f、漏級d。控制端c具有多項功能：(1)該端電壓vc為片內并聯(lián)調整器和門驅動級提供偏壓，

9、(2)通過控制該端的電流來調整占空比，(3)作為電源支路與自動重啟動/補償電容的連接點，通過外接旁路電容來決定自動重啟動的頻率，并對控制回路進行補償。5topswitch工作原理通過反饋電流ic來調節(jié)占空比，從而實現(xiàn)穩(wěn)壓。比如說，當由于某種原因導致電源的輸出電壓vo降低時，則將經過光耦反饋電路使icdvo，從而實現(xiàn)vo的穩(wěn)定。6 能有效的降低開關電源所產生的電磁干擾(emi)。7 外圍電路簡單，成本低廉，外部只需要接整流濾波器、高頻變壓器、漏級鉗位保護電路、反饋電路和輸出電路。這樣能增加電路可靠性和降低成本。三：典型設計基于top247y的24v/72w的單片反激式開關電源如圖1所示。圖1：2

10、4v、72w的開關電源輸入端為110v交流，經過電磁干擾濾波器(emi)(c1,t1),再經過由d1/d2和c2/c3組成的倍壓整流電路至高頻變壓器的原邊。r1/r2為均衡電阻，可以平衡c2/c3上的電壓，避免某一電容因壓降過高而被擊穿。在top247y導通期間，高頻變壓器的原邊下端為負，由同名端可知此時副邊儲能，并不向外輸出能量。當top247y截止時間，副邊才可以向外輸出能量。所以此電路拓撲為一反激拓撲。在高頻變壓器的初級，必須加保護電路，這樣才能吸收由于漏感產生的高壓，圖中超快恢復二極管d3和瞬態(tài)電壓抑制器vs(p6ke200)以及rc組成的snubber電路可以將尖峰電壓鉗位到安全值。

11、線路檢測端l來實現(xiàn)過電壓/欠電壓保護；電壓前饋（當電網電壓過低時用來降低最大占空比）。次級電壓經過d4 c6 l1 c8整流濾波后，獲得+24v、3a的穩(wěn)壓輸出。為減小整流管的損耗，d4采用mbr1060型10a/60v肖特基二極管。c5和r6并聯(lián)在d4兩端，能防止d4在高頻開關狀態(tài)下產生自激振蕩（振鈴）,r11作為空載情況下的假負載。提高輕載時的負載調整率。改變高頻變壓器的變比或者r8，r9的比值，可以改變輸出直流電壓的大小。由可調式精密并聯(lián)穩(wěn)壓器tl431構成外部誤差放大器，它與線形光耦cny17-2組成了光耦反饋電路。其穩(wěn)壓原理是當輸出電壓vo發(fā)生波動時，經r8、r9分壓后得到的取樣電壓

12、就與tl431中的2.5v基準電壓進行比較，產生外部誤差電壓u， 再通過光耦使ic產生相應的變化，并以此調節(jié)輸出占空比，達到穩(wěn)壓目的。反饋繞組電壓經過d5和c7整流濾波后，產生12v的反饋電壓，經過cny17-2給top247y的控制端提供偏壓。c9是旁路電容，它與r10構成控制環(huán)路的補償電路并設定自動重啟動頻率。四：設計要點器件選擇：1 首先要根據(jù)功率要求和效率要求選擇合適的topswitch管。2 二極管(d3,d4)選擇方面要選擇超快恢復二極管，如果輸出電壓較低，d4可選用反向耐壓較低的肖特基管可更好的提高系統(tǒng)的效率。3 應選用電流傳輸比(ctr)能線性變化的光耦，如cny17-2，pc

13、817a，nec2501，6n137等，不宜使用如4n25、4n35等普通光耦，后者線性度差，將造成失真而影響開關電源的穩(wěn)壓性能。高頻變壓器設計高頻變壓器設計的好壞是整個系統(tǒng)成功與否的關鍵，可以先利用pi公司提供的pi expert軟件來進行初步設計，然后再在此基礎上進行修正設計。與正激電路中變壓器設計不同的是反激變壓器磁芯要留有合適的氣隙。根據(jù)系統(tǒng)頻率要求(130k)選擇高頻鐵氧體的磁芯，在滿足功率容量的同時要改善饒組饒制方法盡量減少原邊漏感。本電源設計中，原邊漏感做到了10uh以下。較好的滿足了系統(tǒng)的要求。五: 結束語在信息和數(shù)字時代，所有電子設備都需要有一個穩(wěn)定可靠的電源來提供能量。因此

14、開關電源的發(fā)展對于國家的發(fā)展與建設有及其重要的作用。經過幾十年的發(fā)展，開關電源方面的技術已經有了長足的發(fā)展。為了小型化，高效率可靠的開關電源，全世界的工程師做出了不懈的努力。電力電子技術是重要的支撐科技，據(jù)美國總統(tǒng)科學和技術顧問委員會提出，國家關鍵性的科技領域有七個方面：能源、環(huán)保、資訊與通信、生命科學、材料和交通。每一領域無一不和電力電子有關，都在起著重要作用，而開關電源是其中的一個重要方面，有著深遠的美好前景。可以預計，關電源頻率要高，這樣動態(tài)響應才能快，配合高速微處理器工作是必須的；也是減小體積的重要途徑電路集成和系統(tǒng)集成及封裝工藝等問題是開關電源發(fā)展的方向。單片開關電源是一項頗有前景和

15、影響力的新產品。本文以目前主流topswitch-gx系列中的典型芯片top247y為例給出了具體的設計。對于單片開關電源設計具有普遍意義。single chip switching power supply design based on top247yabstract: single chip switching power supply with high integration, high performance price ratio, the most simple peripheral circuit, best performance index has attracted m

16、ore and more attention. at present, with the application of single chip switching power supply module, medium, small power switch power supply is moving in the short, small, light, thin direction. can be widely used in instrumentation, computer, household electrical appliances (such as color tv, dvd

17、, digital camera), automatic control and other areas, for the promotion and popularization of new energy efficient power laid the foundation. development of a variety of general type, precision type and special type single chip switching power supply module, can greatly improve the switching power s

18、upply products, the level of science and technology in domestic and international market competition ability, create the enormous economic benefits and social benefits.keywords: topswitch switching power supply chipone: the development of single-chip switching power supplysince human beings entered

19、the electric power society, was born, the power supply has been is an indispensable part in all kinds of electronic devices. it directly determines the qua. it directly determines the quality, safety and the whole system of multiple index. with the rapid development of science and technology like, s

20、witching power supply with its peculiar advantage - - high stability, high cost, low loss, high efficiency, now occupy a space for one person in the market. switching power supply is the development direction of high frequency, high reliability, low power, low noise, interference and modular. at pre

21、sent, with the application of monolithic integrated circuit switching power supply, switching power supply is moving in the short, small, light, thin direction yang development. at the end of the last century, is an important turning point in the switching power supply, switching power supply produc

22、es. since then, it becomes widely used in communication, computer, communication, aerospace and other banks in various fields. effect of its development potential and future society will be quite deep, thus, countries of the world are vying to vigorously invested to develop science and technology. u

23、nder this background, scientific and technological achievements in recent years is very gratifying, and many famous foreign manufacturers introduced a large number of monolithic integrated circuit switching power supply, the new switching power supply more promotion and popularization and laid a goo

24、d foundation.in the late 90s, along with the development of integrated circuit, the monolithic integrated circuit switching power supply of various types of. it will switch power supply of pulse width controller, power output stage, protection circuit in a single chip, isolated switching power suppl

25、y can form high efficiency without transformer. the representative of holland philips company in 2000 to develop the tea1520 series switching power supply, american onsemi company 19982002 has developed ncp1050, ncp1000 series single chip switching power supply, usa motorola company in 1999 launched

26、 the mc33370 series of five terminal switch power supply, america pi company in 1994 launched the first topswitch series is the first generation product, was hailed as a top switch power, the 1997 launch of the topswitch- ii series, launched in 1998 2000 launched tinyswitch series, topswitch-fx seri

27、es, then introduced the topswitch-gx series, and promoted as a mainstream product. based on the topswitch-gx series top247y for example to explain its characteristics and typical design application.two: topswitch-gx series of six terminal switch power supply chip characteristicsdesign of a single en

28、d flyback off-line switching power supply, involving many aspects of electrical engineering: structural simulation circuit and digital circuit, characteristics of bipolar transistor and mos power tube device, magnetic materials, heat temperature, overcurrent and overvoltage protection control circui

29、t, stable performance etc. this presents a great challenge: its design involves many variables to the comprehensive coordination. it is due to the highly integrated topswitch, which makes the design task is greatly simplified. because it effectively reduces the design variables and the establishment

30、 of the project, the stability of ic internal loop, so become a step by step design method is simple, making it easy to follow the reference, and guide readers from the design flow chart of topswitch, fast to get satisfactory result.in the process of optimal data and information, can be used as basi

31、c data of the key design guidelines, such as some equations and guide icons. between the three above, they provide before and after the mutual reference content, so the reader can broaden thinking, the implementation of the relevant procedures in a given period, to achieve the best parameters, it is

32、 helpful to understand and optimize the data. due to the highly integrated topswitch device circuits, some debates of the past design of this kind of power supply, can be solved in the chip. only a small amount of need adjustment device in ic outside to arrange, which can maintain the basic circuit

33、structure of the invariant.feedback on the special converter application requirements, such as constant current output, constant power output, see the relevant documents. the feedback circuit with topswitch, only need to add some improvement measures in the converter circuit basic structure, because

34、 they are all arranged on the periphery of the ic. there are four different feedback forms are available, including two kinds of feedback loop is controlled by optocoupler. two other kinds of feedback loop is bias winding only connecting rc (or on) to ic. depending on the power switch on the output

35、of voltage and current requirements.1 internal topswitch-gx mainly consists of a control voltage source, bandgap voltage reference, oscillator frequency jitter, pulse width modulator, shunt regulator / error comparator, gate drive and output, high voltage power switch (mosfet), bias circuit, over-cu

36、rrent protection circuit, an overvoltage, undervoltage detection and protection circuit, overheat protection circuit, a power on reset circuit, soft start circuit, light load automatically reduce the switching frequency circuit, logic, threshold voltage 1v voltage comparator. through the high freque

37、ncy transformer output end and the grid to realize the isolation, which has the characteristics of small volume, high efficiency, safe and reliable.2 ac input voltage range is very wide, can be either fixed 230vac 15%, or a wide range 85-265vac, but in a wide range of input conditions, the maximum i

38、nput power is reduced by about 40%. the frequency range of the input signal is 47-440hz.3 switch frequency is typically 132k, can work in the half frequency mode at light loads, the maximum duty cycle is 80%, power supply efficiency about 80%, the maximum can reach 90%.4 topswitch-gx six terminal, t

39、hey are the control end c, line detection end l, current limit set end x, the source s, the switch frequency choice is f, the drain d. the control end c has multiple functions: (1) the voltage vc bias supply for internal shunt regulator and gate drive level, (2) the duty cycle is adjusted by the end

40、 of the current, (3) as a power supply branch and automatic restart / connection point compensation capacitor, an external bypass. capacity to decide automatically restart frequency, and to compensate the control loop.5 the working principle of topswitch through the feedback current ic to adjust the

41、 duty cycle, to achieve a constant voltage. for example, when for some reason causes the output voltage vo supply reduction, will be through the optocoupler feedback circuit to make the low ic d vo , so as to realize the stable vo.6 can reduce the electromagnetic interference of switching power supp

42、ly produces effective (emi).7 peripheral circuit is simple, low cost, external only need rectifier filter, high frequency transformer, drain clamp protection circuit, feedback circuit and the output circuit. this can increase the reliability of the circuit and reduce the cost of.three: the typical d

43、esignmonolithic top247y 24v/72w flyback switching power supply as shown in figure 1 based on.switching power supply 1:24v, 72wthe input for the 110v ac, through emi filter (emi) (c1, t1), and then after the primary side is composed of d1/d2 and c2/c3 voltage doubler rectifier circuit and high freque

44、ncy transformer. r1/r2 balanced resistance, voltage balance on the c2/c3, to avoid a capacitance due to pressure drop and high breakdown. during the top247y conduction, the lower end of primary side of the high-frequency transformer is negative, by the same name end that the secondary storage, not o

45、utput energy. when the top247y deadline, side can output energy. so this circuit topology for a flyback topology. in the high frequency transformer primary, must add the protection circuit, so it can absorb high pressure leakage caused by ultra fast recovery diode, fig. d3 and vs transient voltage s

46、uppressor (p6ke200) snubber circuit and rc composition can spike voltage clamp to a safe value. end l detection circuit to realize voltage / under voltage protection; voltage feedforward (used to reduce the maximum duty cycle when the grid voltage is too low). after the d4 c6 l1 c8 secondary voltage

47、 is rectified and filtered to obtain stable output, +24v, 3a. in order to reduce the loss of the rectifier tube, d4 uses mbr1060 10a/60v schottky barrier diode. c5 and r6 are connected in parallel in the d4 ends, can prevent d4 in high frequency switch generates self-excited oscillation state (zhen

48、ling), r11 as the no-load condition false load. to improve load rate during light load adjustment. change the high-frequency transformer or r8, r9 ratio, can change the size of the output dc voltage. the adjustable precision shunt regulator tl431 external error amplifier and linear optocoupler cny17

49、-2, it formed the optocoupler feedback circuit. the voltage stabilizing principle is when the vo output voltage fluctuates, the sampling voltage by r8, partial pressure of r9 is obtained after it was compared with 2.5v reference voltage of tl431, external error voltage delta u, again through the opt

50、ocoupler ic have changed, and to regulate the output duty ratio, reach the purpose of regulation. feedback winding voltage through d5 and c7 rectifier and filter, produces the feedback voltage 12v, through the cny17-2 to the control end of the top247y bias supply. c9 is a bypass capacitor, it and r1

51、0 compensation circuit control loop and set the automatic restart frequency.four: design pointsdevice selection:1 according to the first power requirements and efficiency requires the selection of suitable topswitch tube.2 diodes (d3, d4) the choice to choose the ultrafast recovery diode, if the out

52、put voltage is low, the efficiency of d4 can use reverse voltage low schottky tube system can be improved better.3 should use the current transfer ratio (ctr). linear change, such as cny17-2, pc817a, nec2501, 6n137, 4n25, 4n35 should not be used as ordinary optical coupler, the linear degree differe

53、nce, will cause distortion and voltage switching power supply.design of high frequency transformerquality of the high-frequency transformer design is the key to the success of the system, can come to the preliminary design using pis pi expert software, and then to correct the design based on. and th

54、e design of transformer excitation circuit is different core flyback transformer should have appropriate air gaps. according to the system frequency (130k) choosing core high-frequency ferrite, while satisfying power capacity to improve rao rao system group method to reduce the primary leakage induc

55、tance. the design of power supply, primary leakage inductance done below 10uh. better to meet the system requirements.five: conclusionin the information and digital era, all electronic equipment are required to have a stable and reliable power supply to provide energy. the development of the switching power supply for national development and construction has an important rol