三(san)(san)端(duan)稳(wen)压(ya)管(guan)-三(san)(san)端(duan)稳(wen)压(ya)管(guan)7812中文(wen)资(zi)料及稳(wen)压(ya)电源电路(lu)图(tu) 引脚图(tu)-KIA MOS管(guan)
信(xin)息(xi)来源:本站 日(ri)期:2018-10-15
用78/79系(xi)列(lie)三端稳压(ya)器IC来(lai)组成(cheng)稳压(ya)电(dian)(dian)源所需的(de)外围元件极少(shao),电(dian)(dian)路内部还有(you)过(guo)流(liu)、过(guo)热及调整管的(de)保护电(dian)(dian)路,使用起(qi)来(lai)可靠、方便,而且价格便宜。该系(xi)列(lie)集成(cheng)稳压(ya)IC型号中的(de)78或79后面的(de)数字代表该三端集成(cheng)稳压(ya)电(dian)(dian)路的(de)输出电(dian)(dian)压(ya),如7806表示输出电(dian)(dian)压(ya)为正6V,7909表示输出电(dian)(dian)压(ya)为角(jiao)9V。
因(yin)为三端固定集成(cheng)稳压(ya)(ya)电(dian)路的(de)使用(yong)方便,电(dian)子制(zhi)作(zuo)中经常采用(yong)。最大(da)输出电(dian)滴l. 5A,Ⅻ78Ⅱ系列输出电(dian)压(ya)(ya)分别为5V 6V 8V 9V IOV 12V 15V 18V 24V.
三(san)端(duan)稳(wen)(wen)压(ya)(ya)器集(ji)成(cheng)(cheng)电(dian)路(lu)(lu)7812。电(dian)子产(chan)品中(zhong)(zhong),常见(jian)的(de)(de)三(san)端(duan)稳(wen)(wen)压(ya)(ya)集(ji)成(cheng)(cheng)电(dian)路(lu)(lu)有(you)正电(dian)压(ya)(ya)输(shu)(shu)(shu)出(chu)的(de)(de)78××系列(lie)和负电(dian)压(ya)(ya)输(shu)(shu)(shu)出(chu)的(de)(de)79××系列(lie)三(san)端(duan)稳(wen)(wen)压(ya)(ya)器。顾名思义,三(san)端(duan)IC是指(zhi)这(zhei)种稳(wen)(wen)压(ya)(ya)用的(de)(de)集(ji)成(cheng)(cheng)电(dian)路(lu)(lu),只(zhi)有(you)三(san)条引脚输(shu)(shu)(shu)出(chu),分别是输(shu)(shu)(shu)入端(duan)、接地端(duan)和输(shu)(shu)(shu)出(chu)端(duan)。它(ta)的(de)(de)样子像是普通的(de)(de)三(san)极管,TO- 220的(de)(de)标准封装,也有(you)9013样子的(de)(de)T0-92封装。KIA有(you)很多封装供客户(hu)选择,在(zai)以下的(de)(de)附(fu)件中(zhong)(zhong)仅(jin)显(xian)示(shi)一个,
注:点击图片是7812详细资料
三端(duan)稳(wen)压(ya)管7812集(ji)成电(dian)路使用时要求输入电(dian)压(ya)比输出(chu)电(dian)压(ya)值至少大(da)2V以上,即|U1|-|U2|>=2V,但也不宜过(guo)大(da)。另外(wai)还有自地端(duan)流过(guo)的(de)静态电(dian)流IQ=8mA。
W7812为(wei)三(san)端固(gu)定(ding)正(zheng)12V输入(ru)的集(ji)成(cheng)稳(wen)压器(qi),7812引(yin)脚(jiao)图(tu)如下图(tu)所示.7812主要(yao)参数有:输出(chu)直流电压?U0=+12V,输出(chu)电流?L:0.1A,M:0.5A,电压调(diao)整(zheng)率?10mV/V,输出(chu)电阻?R0=0.15Ω,输入(ru)电压UI的范(fan)围15~17V?。因(yin)为(wei)一(yi)般UI要(yao)比?U0大(da)3~5V?,才能保证集(ji)成(cheng)稳(wen)压器(qi)工作在线性区。
三端稳压管(guan)7812典型(xing)应用电路图:
78XX系列三端稳(wen)压(ya)(ya)(ya)器集成(cheng)稳(wen)压(ya)(ya)(ya)器的典型应用电(dian)路图,是一(yi)个(ge)输(shu)出正(zheng)5v直流电(dian)压(ya)(ya)(ya)的稳(wen)压(ya)(ya)(ya)电(dian)源电(dian)路。IC采(cai)集成(cheng)稳(wen)压(ya)(ya)(ya)器7812,CI、C2分(fen)别为输(shu)入端和输(shu)端滤波(bo)电(dian)容,RL为负载电(dian)阻。当输(shu)出电(dian)流较(jiao)大时,三端稳(wen)压(ya)(ya)(ya)管7812应配上散(san)热板。
为提(ti)高输(shu)出(chu)电(dian)压(ya)(ya)的应(ying)用电(dian)路。稳(wen)压(ya)(ya)二襁(qiang)管(guan)VDI串(chuan)接在78XX稳(wen)压(ya)(ya)器2脚与(yu)地之间(jian),可使输(shu)出(chu)电(dian)压(ya)(ya)Uo得到一(yi)定的提(ti)高,输(shu)出(chu)电(dian)压(ya)(ya)Uo为78XX稳(wen)压(ya)(ya)器输(shu)出(chu)电(dian)压(ya)(ya)与(yu)稳(wen)压(ya)(ya)二极管(guan)VC稳(wen)压(ya)(ya)值之和。VD2是输(shu)出(chu)保(bao)护二极管(guan),一(yi)旦(dan)输(shu)出(chu)电(dian)压(ya)(ya)低于(yu)VDI稳(wen)压(ya)(ya)值时,VD2导通,将输(shu)出(chu)电(dian)流旁路,保(bao)护7800稳(wen)压(ya)(ya)器输(shu)出(chu)级不被损(sun)坏。
为输(shu)出(chu)(chu)电(dian)压(ya)(ya)(ya)(ya)可在(zai)一定(ding)范围内调(diao)节的(de)应用电(dian)路。由于(yu)(yu)R1、RP电(dian)阻网络(luo)的(de)作用,使(shi)得(de)输(shu)出(chu)(chu)电(dian)压(ya)(ya)(ya)(ya)被提(ti)高(gao),提(ti)高(gao)的(de)幅度取(qu)决于(yu)(yu)RP与R1的(de)比(bi)值。调(diao)节电(dian)位器RP,即可一定(ding)范围内调(diao)节输(shu)出(chu)(chu)电(dian)压(ya)(ya)(ya)(ya)。当lP=O时(shi),输(shu)出(chu)(chu)电(dian)压(ya)(ya)(ya)(ya)Uo等于(yu)(yu)78XX稳压(ya)(ya)(ya)(ya)器输(shu)出(chu)(chu)电(dian)压(ya)(ya)(ya)(ya):当RP逐步增大时(shi),Uo也随之逐步提(ti)高(gao)。
为(wei)扩(kuo)大(da)输出(chu)电流的(de)应用(yong)电路。VT2为(wei)外(wai)接(jie)扩(kuo)流率管,VTI为(wei)推动管,二者为(wei)达林(lin)顿连(lian)接(jie)。R1为(wei)偏置电阻。该(gai)电路最大(da)输出(chu)电流取决于VT2的(de)参数。
用三端稳(wen)压(ya)(ya)(ya)管(guan)(guan)(guan)7812三端稳(wen)压(ya)(ya)(ya)器(qi)(qi)设(she)(she)(she)(she)计(ji)一款(kuan)最大(da)1A输(shu)出电(dian)流(liu)的(de)(de)(de)稳(wen)压(ya)(ya)(ya)器(qi)(qi)很简单,但当输(shu)出电(dian)流(liu)高于1A时(shi),就会出现许多问题。为提(ti)(ti)供(gong)大(da)输(shu)出电(dian)流(liu),稳(wen)压(ya)(ya)(ya)器(qi)(qi)通常使用并(bing)联的(de)(de)(de)功(gong)(gong)(gong)率晶体管(guan)(guan)(guan)。这些功(gong)(gong)(gong)率晶体管(guan)(guan)(guan)的(de)(de)(de)工(gong)作(zuo)点( operating point )很难设(she)(she)(she)(she)计(ji)。因(yin)为晶体管(guan)(guan)(guan)的(de)(de)(de)集极(ji)和射极(ji)需要(yao)必不可(ke)少的(de)(de)(de)功(gong)(gong)(gong)率电(dian)阻(zu)来设(she)(she)(she)(she)计(ji)直流(liu)工(gong)作(zuo)点,而功(gong)(gong)(gong)率晶体管(guan)(guan)(guan)和功(gong)(gong)(gong)率电(dian)阻(zu)都要(yao)消耗很大(da)功(gong)(gong)(gong)率,因(yin)此设(she)(she)(she)(she)计(ji)中要(yao)加散热措施(shi)。本设(she)(she)(she)(she)计(ji)实例是(shi)一个可(ke)提(ti)(ti)供(gong)大(da)输(shu)出电(dian)流(liu)的(de)(de)(de)简单稳(wen)压(ya)(ya)(ya)器(qi)(qi)。基本的(de)(de)(de)构想是(shi)并(bing)联多个三端稳(wen)压(ya)(ya)(ya)器(qi)(qi)。每只7812稳(wen)压(ya)(ya)(ya)器(qi)(qi)能提(ti)(ti)供(gong)1A电(dian)流(liu),并(bing)且有5 、 6 、 8 、 9 、 12 、 15 、 18和24V多种(zhong)电(dian)压(ya)(ya)(ya)版本。本文以7812为例.
图(tu)1 显示两只并联(lian)的7812
图(tu)2 用20只(zhi)7812将图(tu)1中电路的输(shu)出(chu)能力提升至(zhi)20A
两(liang)只三端稳压(ya)(ya)管(guan)7812独立工作,每只提供(gong)最(zui)大1A电(dian)(dian)流(liu)(liu)。 D1和(he)D2完成两(liang)只稳压(ya)(ya)器(qi)的(de)(de)(de)隔离。输出电(dian)(dian)压(ya)(ya)为(wei)稳压(ya)(ya)器(qi)的(de)(de)(de)标(biao)称(cheng)输出电(dian)(dian)压(ya)(ya)减(jian)去(qu)二极(ji)(ji)管(guan)压(ya)(ya)降: VOUT=VREG – VD 。在COM端接地(0V)情况下(xia),稳压(ya)(ya)器(qi)的(de)(de)(de)输出电(dian)(dian)压(ya)(ya)为(wei)VOUT 。若要将图(tu)1中的(de)(de)(de)输出电(dian)(dian)压(ya)(ya)提高(gao)到与(yu)三端稳压(ya)(ya)器(qi)标(biao)称(cheng)值一(yi)(yi)(yi)致, COM端电(dian)(dian)位必须(xu)比接地高(gao)出一(yi)(yi)(yi)个(ge)二极(ji)(ji)管(guan)压(ya)(ya)降。 C 、 C1和(he)C2为(wei)滤波电(dian)(dian)容。图(tu)2显示了一(yi)(yi)(yi)个(ge)使(shi)用20只7812 ,可(ke)提供(gong)20A电(dian)(dian)流(liu)(liu)的(de)(de)(de)稳压(ya)(ya)器(qi)。所(suo)有(you)的(de)(de)(de)二极(ji)(ji)管(guan)均为(wei)1N4007 。 C=47000 μ F ,所(suo)有(you)带(dai)编(bian)号的(de)(de)(de)电(dian)(dian)容均为(wei)4700μF 。 7812均固定到一(yi)(yi)(yi)个(ge)散热片上,并用一(yi)(yi)(yi)个(ge)小风扇降温。采用这(zhei)种设计概念,可(ke)以将电(dian)(dian)路的(de)(de)(de)输出电(dian)(dian)流(liu)(liu)扩(kuo)充(chong)至数百安培。
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