DCDC变换电流型控制电路设计规范.doc

【精品文档】如有侵权，请联系网站删除，仅供学习与交流DCDC变换电流型控制电路设计规范规范编码： TS-C020201003版 本：V1.0密 级：机密安圣电气研究管理部执笔人:成功、高拥兵页 数：共 14 页 DC/DC变换电流型控制电路设计规范2001 年08月01 日发布 2001年08月01日实施深 圳 市 安 圣 电 气 有 限 公 司前言本规范于 2001年08月01日首次发布。本规范起草单位：二次/工业电源研究部、研究管理部技术管理处本规范执笔人：高拥兵本规范主要起草人： 高拥兵 成功本规范标准化审查人：林攀本规范批准人：李其祥本规范修改记录：更 改 信 息 登 记 表规范名称: DC/DC变换电流型控制电路设计规范 规范编码: TS-C020201003版本更改原因更改说明更改人更改时间目 录摘要.5缩写词/关键词/解释.51.来源.52.适用范围.53.规范满足的技术指标（特征指标）.54.详细电路图.55.工作原理简介.66.设计、调试要点.87.局部PCB版图（可选项）.108.附录.11附录1.元器件明细表.11附录2.斜坡补偿公式的推导.14摘要 本规范介绍了一种DC/DC变换电流型控制电路，该电路使用3843控制芯片和PWM控制技术，完成输出稳压反馈控制功能。缩写词/关键词/解释 DC/DC 直流/直流变换 PWM Pulse Width Modulation，脉宽调制 电流型控制1.来源本规范中的电路来源于SAI4271Z电源中的SAI4271C1单板，已经在SAI4271Z中得到批量使用验证，与之相关的外围单元电路有谐振嵌钳位正激变换主电路、控制保护电路等。2.适用范围 该电路适用于低压直流输入（100Vdc），工作占空比大于0.5的DC/DC电源，实现输出稳压控制功能。3.规范满足的技术指标（特征指标） 本规范中电路能达到的技术指标：输入电压：4060Vdc输出电压：2529Vdc输出电流：65A最大工作占空比：0.70整机工作效率：87.5%4.详细电路图 电路原理图如图1所示，输入输出接口定义如下表所示。分类名 称符号共地点规 格输入接口原边辅助电源Vcc1GND115V副边辅助电源1Vcc2GND215V副边辅助电源1-5VGND2-5V电压反馈信号Vo2GND2原边电流采样信号IsenseGND1副边限流信号I-limitGND2保护信号PROTECTGND2高电平有效输出接口控制信号PWM1GND13843输出控制信号内部接口基准信号2Vref2GND15V基准， 3843提供基准信号3Vref3GND2输出电压基准图1 电路原理图5.工作原理简介电流型控制具有电路形式简单，动态响应速度快，能够实现逐波限流等优点，在开关电源变换器的控制电路中得到了广泛的应用。图2所示为电流型控制基本原理框图。利用输出电压采样信号Vo与参考基准信号Vref经过带PID调节的误差放大器比较放大后得到电流参考信号Iref，Iref 再与主开关管电流采样信号比较后产生驱动脉冲去驱动主开关管。由于直接采样功率管的电流信号作为占空比控制信号，因此可以实现功率管的逐波限流，有利于提高电路工作的可靠性；同时由于功率管的电流信号直接反映了输入电压的前馈量和负载大小，因此可以获得较好的动态响应。图2 电流型控制原理框图具体电路的工作原理简述如下：如图1所示，输出电压信号Vo2经过分压后与基准信号Vref3进行误差比较放大，放大后的误差信号再经过三极管2V1进行功率放大并驱动光耦2IS1，将该误差信号传递到原边控制芯片3843的1脚补偿端，也即3843内部电流比较器的反相输入，作为电流基准信号；同时检测功率管的电流信号Isense作为电流比较器的同相端输入，比较后经RS触发器和或门及图腾柱输出级得到DC/DC变换占空比控制信号PWM1。3843的2脚电压反馈端直接接地，未利用芯片内部的误差放大器，内部误差放大器的工作状态为正偏饱和输出。3843的4脚为内部晶振外接阻容器件的端口，阻容的取值决定开关频率和最大工作占空比的大小，电容值越大，死区时间也越长。PROTECT为保护信号，当它为高电平时光耦2IS2被驱动导通，光耦再驱动三极管2V4，将UC3843的第一脚拉低，从而达到封锁UC3843第六脚的驱动脉冲输出的目的，保护电路同时也拉低副边误差放大器的输出。I-limit为副边输出限流控制信号，通过二极管2D11直接拉低误差放大器的输出而生效。在定频峰值电流型控制方式下，当工作占空比大于0.5时，控制环存在无条件的不稳定性，可以通过引入一定程度的斜波补偿来解决该问题。斜坡补偿的幅度由电流反馈信号的斜率和最大工作占空比决定，要保证电路工作在最大占空比时，电流反馈信号与斜坡补偿信号叠加后，其上升的斜率大于下降的斜率的绝对值，具体推导过程见附录。因为： (1)在(1)式中，m1是主开关电流折算到副边的电流上升斜率，m2是折算到副边的电流下降斜率。那么可以推导出（详见附录）折算到副边的斜坡补偿斜率应满足：特别地，取km2时可以使电路在一个开关周期内将干扰引起的电流扰动减小为零。实际电路中3843的3脚电流反馈端接收的信号由三部分组成：电流反馈信号，斜坡补偿信号和直流偏置信号。直流偏置信号的作用主要是保证当1脚电平被拉低时，3脚电平高于电流比较器反相端输入电平，从而可靠封锁输出脉冲，电路中通过电阻2R41接3843的5V基准电压上拉来实现，2R41取值为5.6K，直流偏置量约0.11V，保护状态下3843驱动脉冲可被可靠封锁。6.设计、调试要点6.1 外接RC振荡器参数3843的4脚外接RC振荡器的参数决定控制信号的工作频率和最大占空比，具体的选值原则见相关的器件手册说明。在本电路中的取值为R=2R44=1.2K，C=2C31+2C32+2C33=10+2.2+2.2=14.4nF，对应振荡频率为80K，最大占空比约0.72。6.2 电流采样反馈滤波为抑制功率器件开关噪声在电流采样信号上的干扰，防止控制电路误动作，一般在电流采样反馈信号上加一个RC滤波处理。RC滤波参数选择的原则是一方面既要有效滤除开关噪声，另一方面又不能影响电流信号的波形，以免因滤波时间常数过大而使采样电流信号崎变，影响控制性能。本电路中RC滤波参数为200并390，330pF。6.3 3843-1脚下拉电阻R48选取在类似的采用外部运放作为电压环误差放大器的电路中，一般将3843的2脚（电压反馈端）直接接地，这样3843内部的运放就处于正偏饱和输出状态，需保证电阻R48可以可靠下拉运放输出端1脚电压。按3843器件手册参数，该运放输出电流为0.8mA，吸收电流为6mA，设下拉电压为1V，则该电阻阻值需小于（1/0.8）=1.25K。同时该电阻阻值对于反馈光耦2IS1的工作点也有影响。设满载时1脚最高电压为4V，光耦的电流传输比为200%400%，降额系数为0.8，副边电压环误差放大器的最高输出电压为13V，2R15阻值为2.4K，2R54阻值为4.7K，2V1为MMBT4401LT1，为满足光耦的最小电流传输比要求，则有：实际取值为620。6.4 原边电流采样斜坡补偿设计令DMAX70%，f80KHz，Vomax=29V，输出滤波电感Lo=15uH。则有： (2)在(2)式中，m1是主开关电流折算到副边的电流上升斜率，m2是折算到副边的电流下降斜率。那么可以推导出（详见附录）折算到副边的斜坡补偿斜率应满足： (3)特别地，取km2时可以使电路在一个开关周期内完全将干扰引起的电流扰动减小为零。将副边的电流斜坡补偿再折算到原边控制电路电流采样回路对应电压斜坡补偿量值为：上式中，k是折算到副边的斜坡补偿斜率，是副边比原边匝比，是电流互感器的互感系数，Ri是接在电流互感器副边的电流采样电阻，是电流采样回路里的电阻网络构成的等效分压系数，该系数由主管峰值电流、电流互感系数、UC3843原边限流电平（约1V）等因素决定。那么对于开关频率f80kHz，占空比D=0.7的开关信号，斜坡补偿信号应在tDT处至少补偿。考虑器件参数的离散性，保留一定余量，实际补偿量值取为0.2V。电路中利用3843三角波振荡信号通过2V3，2R53，2R43，2C21实现，参数见附录1中所示。6.5 副边误差放大器设计为了使变换器的输出具有较好的稳态精度和动态响应性能，通常需要对主电路的控制特性进行补偿，这一般通过误差放大器的设计来实现。本电路中副边误差放大器动态小信号传递函数可由下式来表示：由上式中可知，该误差放大器的传递函数中包含两个零点和两个极点，电路中参数取值为：R40=20K，R42=51，R45=20K，R49=200，R50=1.8K，C18=10n，C14=1500p，其对应的零极点频率分别为： ， ， ，。经测试，采用该参数时电源额定状态下的带宽为3.2K，相位余量为82度，增益余量为15dB，满足工作稳定性要求，高低温状态均能稳定工作。电路中C14能够影响零极点作用的幅值，同时影响一个零点的位置，增大C14能够加强积分作用，降低环路增益，但过大地增大C14将使零点位置前移，在中低频段就会抵消零极点的作用。 C14需要根据实验确定，原则上，在稳定的前提下尽可能减小C14。再来看C18，C18 对输出中的小信号成分 VO2作了微分处理，也就是说引入C18能够加快调节器对输出变化的反应，但是由于引入微分环节，也可能带来环路不稳定。 C18同时影响到了一个零点和极点，其零点在横标的位置始终在其极点横坐标（波特图）之前，减小R50R49的数值能够拉开C18影响的零点和极点的距离（波特图），也就是增加中频增益和带宽（当R50保持不变，减小R49时能够提高中频增益和带宽），在中频补偿零极点的影响。实际产品主电路的小信号传递函数，与拓朴原理，器件参数和材质，PCB走线等均有关系，其精确的数学模型很难得到，在工程设计上也无此必要。所以如上所述，只是提供了关键的电容电阻调节的方法和原则，设计中需要根据具体电路情况和相关指标要求通过实验调试最终确定器件参数，并经过高低温运行测试，防止电路因器件参数漂移而进入不稳定工作状态。6.6 保护电路设计在二次电源的应用中发现，在采用MOTOROLA公司的2843控制芯片，利用下拉1脚的方式来实现保护时，如果1脚电压被拉的过低，2843的6脚输出驱动脉冲并不能完全关死，无法实现正常保护功能。经过物料品质部的分析和实验验证，当1脚电压被拉到0.21.2V范围内时，能够实现可靠关断。在本规范电路中，利用PNP管下拉1脚来实现保护，保护时1脚电压约为0.7V左右。如果采用NPN三极管或光耦的输出端来实现保护的话，需要在支路中串入二极管或电阻来适当控制1脚下拉电压。7.控制板PCB（可选项）.精品文档.DC/DC变换电流型控制电路设计规范8. 附录附录1.元器件明细表元件位置序号MRPII编码MRPII描述厂家型号第二供应商及型号第三供应商及型号2C1208070059片状电容器100V330pF±5%NPO-0805AUX08051A331JAT2AKEMET/C0805C331J1GAC-7800MURATA/GRM40C0G331J100PT2C15、2C2608010030铝电容器25V-47uF ±20%5*11-85NCCSME25VB47MNICHICON江海2C16,2C17,2C21,2C22,2C25,2C29,2C3408070018片状电容器50V0.1uF±10%X7R-0805AUX08055C104KAT2AMURATATAIYO YUDEN2C18,2C20,2C3208070045片状电容器50V0.01uF±10%X7R-0805AUX08055C103KAT2AMURATAKEMET2C2308010168铝电容器50V-10uF ±20%5*11-105NCCKMG50VB10MNICHICON江海2C3008010040铝电容器25V-100uF 6.3*15-105NCCLXV35VB100M6.3*15NICHICON2C31,2C33,2C1408070477片状电容器50V2200pF±10%X7R-0603AUX06035C103KAT2AMURATAKEMET2C3608010153铝电容器25V-330uF 10*12.5-105NCCKMG25VB330MNICHICON/UVZ1E331MPH2D1115010040开关二极管/70V/0.2A/6ns/共阳/SOT-23ONBAW56LT1乐山无线电厂INFINEON2D1215010041开关二极管/70V/0.2A/6ns/共阴/SOT-23FSCBAV70MOTOROLASIEMENS2IS2,2IS139100052光耦单路三极管输出无基极ISOCOMPS2501-1*94/SMLITEON/LTV-816S(C)厦门华联/HPC922-2(H)2R3807090199片状电阻器1/10W-392±10805风华RC-05K3920FTKYOCERAPHYCOMP2R49,2R3907090196片状电阻器1/10W-200±10805风华RC-05K201FTKYOCERAPHYCOMP2R45,2R4007090458片状电阻器1/10W-20k±10805风华RC-05K203FTKYOCERAPHYCOMP2R4107090132片状电阻器1/10W-5.6k±50805风华RC-05K562FTKYOCERAPHYCOMP2R4207090424片状电阻器1/10W-51.1±10805风华RC-05K51R1FTPHYCOMP2R53,2R4307090330片状电阻器1/10W-470±10805风华RC-05K471FTPHYCOMP2R4407090285片状电阻器1/10W-1.21k±10805风华RC-05K1211FTKYOCERAPHYCOMP2R5007090171片状电阻器1/10W-1.8k±10805风华RC-05K182JTKYOCERAPHYCOMP2R5407090534片状电阻器1/10W-4.7k±10805风华RC-05K4701FTKYOCERA2R5507090459片状电阻器1/10W-10±10805风华RC-05K100FTKYOCERAPHYCOMP2R6707090394片状电阻器1/10W-3.01k±10805风华RC-05K3011FTKYOCERAPHYCOMP2R6307090327片状电阻器1/10W-7.5k±10805风华RC-05K7501FTPHYCOMP2U339110096PWM控制芯片3843ONUC2843BD1ST/UC3843BD12U439080011运放LM358低噪声双运放SOIC8NSLM358MX2V315050072PNP三极管40V/0.6A/350mW/SOT-23ONMMBT4403LT1PHILIPS/PMBT44032V415050026NPN三极管40V/0.6A/350mW/SOT-23ONMMBT4401LT1乐山无线电厂/MMBT4401LT1PHILIPS/PMBT44012Z339110200电压调整器TL431ACD-1%-SOP8STTL431ACDTI/TL431ACD（分页）附录2. 斜坡补偿公式的推导有两个假设:1、电路工作在恒频方式。 2、相对于开关频率，电路扰动是“较缓慢地”。设m1是折算到电流采样回路的主开关电流上升斜率，m2是折算到电流采样回路的副边整流滤波电感电流的下降斜率的绝对值。稳定工作占空比为D(>0.5)，斜坡补偿斜率为k。电路稳定工作时有：m1 D=m2 (1-D)。并约定稳定工作时开关导通瞬间电流采样值为纵坐标零点。假设在某个开关周期出现了扰动，主开关导通期延长了，那么到该开关周期结束时，电流采样等效坐标值为（。第二个周期主开关的导通期为：所以到第二个周期主开关关断时，电流采样的等效值为：只要第二个周期结束时，电流采样等效坐标值的绝对值小于前一个周期，那么扰动引起的误差将最终趋近于零。解不等式：，可得：特别地，取k=m2时，在第二个开关周期，就可以使扰动减小为零。结论：斜坡补偿斜率只要大于电流采样下降与上升斜率差值的一半，就能保证电路能自恢复。而当斜坡补偿斜率等于电流采样下降斜率时，电路有最快的自恢复能力。（英文版 ） easily blame, to prevent the broken window effect. Supervise the leading cadres to play an exemplary role, take the lead in the strict implementation of the < code > and < rule >, lead to safeguard the solemnity and authority of the party discipline, ensure that the party discipline and the laws and regulations for implementation in place. Throughout the discipline in the daily supervision and management, strengthen supervision and inspection, from the thorough investigation of violations of discipline behavior. Strengthen to key areas, key departments and key projects as well as the masses reflect the concentration of the units and departments for supervision. - strengthening supervision, discipline inspection and supervision of cadres to set an example for compliance with the < code > and < rule > is a man must be hexyl, blacksmith needs its own hardware. Discipline inspection organs as the executor of the party discipline, and supervisor of the defenders, for its supervision must be more strictly, discipline inspection and supervision of cadres to firmly establish the awareness of Party Constitution, sense of discipline and rules consciousness, politics loyalty, sense obey. Action speak Ji Ordinance to set an example of the regulations of the rule of law, strengthen supervision and accept the supervision of the firmness and consciousness, do comply with < > and < >. To firmly establish the discipline must first be disciplined, the supervisor will be subject to the supervision of "concept, and consciously safeguard and implement party compasses party, take the lead in practicing" three strict real strict, so loyal, clean, play. To be good at learning, the Constitution and the < code > as morality, politics and brought to fruition; to implement < >, do not want to, dare not, not with disciplinary ruler to supervision; to discipline a ruler, often the control inspection, and consciously in the ideological red line to draw the row Ming Good accumulation is indeed the bottom line, so that the heart has fear, said to have quit, the line has ended. Attached: indifferent to heart, calmly to the table in our life, there are many unpredictable things will happen, some good, some bad things, we cannot control is powerless to stop, but with time, you will find in life sometimes turns out to be not good, some bad things finally turned out to be a good thing, but then we muddy however did not know, this is the life teach us things. 1, life can be complex, can also be simple. Want simple life of precipitation, to have enough time to reflect, to make Become more perfect. Life is the most important thing is not to win, but the struggle; not to have conquered, but to have fought well. 2, the plain is the background of life. Live a plain life, give up on themselves is not a coward, but the wise answers; not disillusioned after the heart, such as ashes, but experience the storm after the enlightenment; not unrewarding perfunctorily, but calm attitude of life of unrestrained self-confidence. Plain living, there is no noise noisy, no earthly troubles, more did not fill in the discontent of desire, some just a calm, a calm. 3, memory of heart will not good things to erase the, life is a When no movie, pain is a beginning, the struggle is a kind of process, death is a kind of ending. Give up this giving up is the helpless, do not give up the abandoned, do not give up this giving up is ignorance, do not give up should not give up is persistent. 4, a thing figured is heaven, think impassability is hell. Since the living, to live better. Sometimes we because of too narrow-minded, too care around the chores and penny wise and pound foolish, not worth the candle. Some things to attract trouble and worry, completely depends on how we look at and deal with it. Don't always take everything back to things, and don't get into a blind alley, don't want to face, don't be narrow-minded. Poke to care, is a kind of open-minded, a free and easy. 5, I am not afraid of others behind me a knife, I afraid to look back and see stab me, is my intention to treat people; I am not afraid of the truth to tell the best friend, I'm afraid he turned to it as a joke to tell don't 6, when we are in a positive frame of mind, you will find many good things; and when we are in a negative state of mind, you will find many depressed things; life happy and worry, all is you of life attitude, optimistic, good luck; loss of sink, Eritrea company. When you are in adversity, may wish to change a point of view to think everything over to the good Think, because good mentality decided the fate of the! 7, people are tired, rest; heart tired, calm. Grow up, mature, this society read. Tired and sad, squat down, to their a hug. Because the world no one can sympathize with you, have mercy on you. You cry, tears is your own; you pain, no one can understand. Then you only tears to smile. 8, each people have youth,Each youth are a story, the life of the world never gets easier, I want what, wish the world all know, as has been the same; now want anything, for fear that others know, or like to lose the same. 9, the heart move, everything in the world is followed by birth, Rangrang, important thing is often the most difficult to open one's mouth, because words will reduce its importance; to let strangers people care about your life in the good things, the original is not easy 10, do not blame, do not laugh at who, also don't envy who. Like a person is a kind of feeling, not like a person is true. The truth is easy to explain, I feel Is unspeakable. The best travel life is that you in a strange place found a long lost touched. 11, happy life not in the bustling in, and in the peace of mind; no matter how many grievances, how uncomfortable, and ultimately to heal themselves or their own, others may got you to comfort, but never know your heart is how wanjianchuanxin. 12, ma'am, like a movie, learn to appreciate, learn to be grateful, learn tolerance, and goodness, helping others. Instead of accusing the society, as into one; and an exception is better to give than to what 13, don't envy him A sum o