反激式开关电源 理工科毕业设计(论文)外文翻译

1、华南理工大学本科生毕业设计（论文）翻译英文原文名single chip switching power supply design based on top247y中文译名 基于top247y的反激式单片开关电源研制 学 院 华南理工大学 专业班级 电气工程及其自动化学生姓名 学生学号 指导教师 填写日期 2014.1.25 英文原文版出处： the world of power supply in 2005 fifth 译文成绩： 指导教师（导师组长）签名： 译文：摘要：单片开关电源具有高集成度、高性价比、最简外围电路、最佳性能指标等特点引起了越来越多人的重视。目前，随着单片开关电源模块的应

2、用，中、小功率开关电源正朝着短、小、轻、薄的方向发展。可广泛用于仪器仪表、计算机、家用电器（如彩电、dvd、数码像机）、自动控制等领域，为新型高效节能电源的推广与普及奠定了基础。开发各种通用型、精密型及特种单片开关电源模块，能够大大提高我国开关电源产品的科技水平和在国内外市场上的竞争能力，创造出巨大的经济效益与社会效益。关键字：topswitch 开关电源 单片一：单片开关电源的发展概况自从人类进入电的社会，电源就诞生了，电源已是各种电子设备必不可少的重要组成部分。它直接决定了整个系统的质量、安全性等多个指标。随着科技飞速般的发展，开关电源以其特有的优势高稳定性、高性价比、低损耗、高效率，已经

3、在市场中占领了一席之地。开关电源的发展方向是高频、高可靠、低耗、低噪声、抗干扰和模块化。目前，随着单片开关电源集成电路的应用，开关电源正朝着短、小、轻、薄的方向阳发展。上世纪末，是开关电源的一个重大转折时期，单片开关电源产生了。从那时开始，它变广泛的应用于通信、计算机、银行通信、航天等各种不同的领域之中。它的发展潜力与对未来社会的影响都将会颇深，从而，世界各国也争相的大力投入资金去发展相关科技。在此背景下，最近几年的科技成果非常喜人，国外许多著名的芯片厂家推出了一大批单片开关电源集成电路，更为新型开关电源的推广与普及奠定了良好的基础。90年代中、后期，随着集成电路的发展，出现了各种类型的单片开

4、关电源集成电路。它将开关电源中的脉宽控制器、功率输出级、保护电路等集成在一个芯片中，能构成高效率无须工频变压器的隔离式开关电源。比较有代表性的荷兰philips公司2000年研制的tea1520系列开关电源，美国onsemi公司19982002年先后开发的ncp1050、ncp1000系列单片开关电源，美国motorola公司1999年推出的mc33370系列五端开关电源，美国pi公司于1994年最先推出了topswitch系列第一代产品，被人们誉为“顶级开关电源”，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、，随后又推出了topswitch-gx系列，并做为主流产品加以推广。本文以topswitch-gx系列中的top247y为例具体阐述其性能特点和典型设计应用。二：topswitch-gx系列六端开关电源芯片特点设计一台单端反激式离线开关电源，涉及到电气工程的许多方面：模拟电路和数字电路的结构，双极管和mos功率管器件的特征，磁性材料的考虑，热温升的散发，过流和过压的安全防护，控制回路的稳定性能等。这就提出了一个巨大的挑战：它的设计涉及到需要综合协调的许多可变因素。正是由于topswitch的高度集成化，才使得这项设计任务被大大地简化。因为它有效的缩减了设计变数项目，并且建立了ic内部回路的稳定

6、性，所以发展成为一种简单的逐步设计方法，使之容易遵循参照，并指引读者从topswitch的设计流程图中，快速的得到较满意的结果。在优化最佳数据和信息的过程中，可利用关键的基本工作数据作为设计指南，例如一些方程式和导向图标等。在以上三者之间，它们提供了前后相互参照的内容，让读者能开阔思路，在给定的阶段执行有关程序，实现最佳参数，这有利于深入理解和进一步优化数据。由于topswitch器件电路的高度集成化，过去设计这类电源的一些争论，均在芯片中得到解决。只有少量需要调节的器件留在ic外面加以安排，这就能维持它的基本电路结构不变。有关反馈变换器要求的特殊应用，例如恒定电流输出、恒定功率输出等，详见有

7、关文献。对于用topswitch的反馈电路，只需在基本的变换器电路结构上增加一些改进措施，因为它们都设置在ic外围。有四种不同的反馈电路形式可供选用，其中两种反馈回路是受光耦器件控制的。另外两种反馈回路是偏置绕组只接阻容（或再串二极管）加到ic。这取决于开关电源对输出电压和输出电流的要求指标。1 topswitch-gx内部主要由控制电压源、带隙基准电压源、频率抖动振荡器、脉宽调制器、并联调整器/误差比较器、门驱动级和输出级、高压功率开关管(mosfet)、偏置电路、过流保护电路、过压、欠压检测及保护电路、过热保护电路、上电复位电路、软启动电路、轻载时自动降低开关频率电路、停止逻辑、开启电压为

8、1v的电压比较器组成。通过高频变压器使输出端和电网实现隔离，使之具有体积小、效率高、安全可靠的特点。2 输入交流电压范围很宽，可以是固定230vac15%，或者宽范围85-265vac，但在宽范围输入情况下，最大输入功率降低40%左右。输入信号的频率范围为47-440hz。3 开关频率典型值为132k，在轻载时可以工作在半频工作模式，最大占空比可达80%，电源效率80%左右，最大可达到90%。4 topswitch-gx有六个引出端，它们分别是控制端c、线路检测端l、极限电流设定端x、源极s、开关频率选择端f、漏级d。控制端c具有多项功能：(1)该端电压vc为片内并联调整器和门驱动级提供偏压，

9、(2)通过控制该端的电流来调整占空比，(3)作为电源支路与自动重启动/补偿电容的连接点，通过外接旁路电容来决定自动重启动的频率，并对控制回路进行补偿。5topswitch工作原理通过反馈电流ic来调节占空比，从而实现稳压。比如说，当由于某种原因导致电源的输出电压vo降低时，则将经过光耦反馈电路使icdvo，从而实现vo的稳定。6 能有效的降低开关电源所产生的电磁干扰(emi)。7 外围电路简单，成本低廉，外部只需要接整流滤波器、高频变压器、漏级钳位保护电路、反馈电路和输出电路。这样能增加电路可靠性和降低成本。三：典型设计基于top247y的24v/72w的单片反激式开关电源如图1所示。图1：2

10、4v、72w的开关电源输入端为110v交流，经过电磁干扰滤波器(emi)(c1,t1),再经过由d1/d2和c2/c3组成的倍压整流电路至高频变压器的原边。r1/r2为均衡电阻，可以平衡c2/c3上的电压，避免某一电容因压降过高而被击穿。在top247y导通期间，高频变压器的原边下端为负，由同名端可知此时副边储能，并不向外输出能量。当top247y截止时间，副边才可以向外输出能量。所以此电路拓扑为一反激拓扑。在高频变压器的初级，必须加保护电路，这样才能吸收由于漏感产生的高压，图中超快恢复二极管d3和瞬态电压抑制器vs(p6ke200)以及rc组成的snubber电路可以将尖峰电压钳位到安全值。

11、线路检测端l来实现过电压/欠电压保护；电压前馈（当电网电压过低时用来降低最大占空比）。次级电压经过d4 c6 l1 c8整流滤波后，获得+24v、3a的稳压输出。为减小整流管的损耗，d4采用mbr1060型10a/60v肖特基二极管。c5和r6并联在d4两端，能防止d4在高频开关状态下产生自激振荡（振铃）,r11作为空载情况下的假负载。提高轻载时的负载调整率。改变高频变压器的变比或者r8，r9的比值，可以改变输出直流电压的大小。由可调式精密并联稳压器tl431构成外部误差放大器，它与线形光耦cny17-2组成了光耦反馈电路。其稳压原理是当输出电压vo发生波动时，经r8、r9分压后得到的取样电压

12、就与tl431中的2.5v基准电压进行比较，产生外部误差电压u， 再通过光耦使ic产生相应的变化，并以此调节输出占空比，达到稳压目的。反馈绕组电压经过d5和c7整流滤波后，产生12v的反馈电压，经过cny17-2给top247y的控制端提供偏压。c9是旁路电容，它与r10构成控制环路的补偿电路并设定自动重启动频率。四：设计要点器件选择：1 首先要根据功率要求和效率要求选择合适的topswitch管。2 二极管(d3,d4)选择方面要选择超快恢复二极管，如果输出电压较低，d4可选用反向耐压较低的肖特基管可更好的提高系统的效率。3 应选用电流传输比(ctr)能线性变化的光耦，如cny17-2，pc

13、817a，nec2501，6n137等，不宜使用如4n25、4n35等普通光耦，后者线性度差，将造成失真而影响开关电源的稳压性能。高频变压器设计高频变压器设计的好坏是整个系统成功与否的关键，可以先利用pi公司提供的pi expert软件来进行初步设计，然后再在此基础上进行修正设计。与正激电路中变压器设计不同的是反激变压器磁芯要留有合适的气隙。根据系统频率要求(130k)选择高频铁氧体的磁芯，在满足功率容量的同时要改善饶组饶制方法尽量减少原边漏感。本电源设计中，原边漏感做到了10uh以下。较好的满足了系统的要求。五: 结束语在信息和数字时代，所有电子设备都需要有一个稳定可靠的电源来提供能量。因此

14、开关电源的发展对于国家的发展与建设有及其重要的作用。经过几十年的发展，开关电源方面的技术已经有了长足的发展。为了小型化，高效率可靠的开关电源，全世界的工程师做出了不懈的努力。电力电子技术是重要的支撑科技，据美国总统科学和技术顾问委员会提出，国家关键性的科技领域有七个方面：能源、环保、资讯与通信、生命科学、材料和交通。每一领域无一不和电力电子有关，都在起着重要作用，而开关电源是其中的一个重要方面，有着深远的美好前景。可以预计，关电源频率要高，这样动态响应才能快，配合高速微处理器工作是必须的；也是减小体积的重要途径电路集成和系统集成及封装工艺等问题是开关电源发展的方向。单片开关电源是一项颇有前景和

15、影响力的新产品。本文以目前主流topswitch-gx系列中的典型芯片top247y为例给出了具体的设计。对于单片开关电源设计具有普遍意义。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