xuduojiduanqingkuangzhongdeyizhongshizhushuchuzhongfuzai
，erweiwenyaraozuwanquankongfuzai。bianyaqicijiraozushangchuxianderenhedianyazhenlingtongchangdouyoushuchuzhengliuqilaifengzhijiance，congershiweiwenyashuchudianyajidazengjia。zhezhongqingkuangxia
，shuchudianyashengzhiliangbeiqiedingdianyabingbuxianjian。zheduiyuwufachengshougenggaodianyahuozhemeiyousuishirangzuixiaofuzaixiaohaolounengliangderenhexiayoufuzailaishuo，zhedoushizainanxingde。

 

有you幾ji款kuan解jie決jue方fang案an可ke以yi補bu救jiu這zhe種zhong無wu負fu載zai過guo壓ya狀zhuang態tai。最zui簡jian單dan的de方fang法fa是shi以yi電dian阻zu的de形xing式shi給gei未wei穩wen壓ya輸shu出chu添tian加jia一yi個ge預yu負fu載zai。這zhe樣yang會hui使shi輸shu出chu具ju有you負fu載zai，讓rang其qi足zu夠gou消xiao耗hao漏lou能neng量liang，並bing將jiang輸shu出chu電dian壓ya降jiang至zhi一yi個ge可ke以yi接jie受shou的de電dian平ping。不bu幸xing的de是shi，這zhe種zhong負fu載zai會hui始shi終zhong出chu現xian，從cong而er帶dai來lai一yi般ban被bei認ren為wei是shi不bu可ke接jie受shou的de效xiao率lv損sun失shi。

 

第二種選項是隻給未穩壓輸出添加一個齊納二極管。在包括典型的 5% 或 10% zujianrongxianyihou，erjiguandianyaedingzhideshedingbixugaoyuedingshuchudianya。zhejiuyiweizhe，zaishuchudianyashengzhizugougaoyiqian，gaierjiguanjiangbuhuidaodianhuoxiaohaogonglv。jinguanzhekanlaiqihaoxiangshiyizhonglixiangdejiejuefangan，danrengrancunzaiyixieqianzaiwenti。yidanqinaerjiguandaodian
，qizukangbianjidaxiajiang，duidianliudedianzuzuoyongbiandejihumeiyou。jinruerjiguandedianliuyijiqineixiaohaodegonglv
，junyoujishengdianluzujianjueding，yincinanyikongzhi。gaogonghaozhuanhuanqikenenghuixiqudadianliu，congerhuirongyihuihuaiqinaerjiguan。yinci，tianjiayigexiaoxingqinaerjiguanyaomaofengxian，bingqiehennanjisuangonghao。

 

lingyizhongxuanzeshishiyongyigehuanchongqilaixiaohaolounengliang。xiangbishiyongyigeyufuzaidianzu，zheyangzuoyibanhuixiaohaogengduodegonglv，bingqiebunengshizhongtigongwendingdeshuchuwufuzaijiangya。

 

軟ruan鉗qian位wei電dian路lu由you一yi個ge與yu齊qi納na二er極ji管guan串chuan聯lian的de電dian阻zu器qi組zu成cheng，是shi一yi款kuan很hen好hao的de折zhe中zhong方fang案an。它ta可ke以yi將jiang未wei穩wen壓ya輸shu出chu電dian壓ya控kong製zhi在zai一yi定ding水shui平ping，其qi低di於yu未wei鉗qian製zhi輸shu出chu電dian壓ya但dan高gao於yu單dan獨du使shi用yong齊qi納na二er極ji管guan的de電dian壓ya水shui平ping。要yao確que定ding電dian阻zu的de值zhi，需xu要yao利li用yong足zu夠gou的de電dian流liu讓rang輸shu出chu負fu載zai，以yi將jiang高gao輸shu出chu電dian壓ya降jiang至zhi理li想xiang安an全quan水shui平ping。圖tu 1 顯示了一個理想無負載輸出電壓為 7.4V 的(de)例(li)子(zi)。該(gai)電(dian)壓(ya)減(jian)去(qu)齊(qi)納(na)二(er)極(ji)管(guan)的(de)額(e)定(ding)電(dian)壓(ya)，所(suo)得(de)結(jie)果(guo)再(zai)除(chu)以(yi)預(yu)負(fu)載(zai)電(dian)流(liu)，可(ke)得(de)到(dao)串(chuan)聯(lian)電(dian)阻(zu)器(qi)的(de)值(zhi)。這(zhe)種(zhong)電(dian)路(lu)的(de)好(hao)處(chu)是(shi)其(qi)並(bing)不(bu)消(xiao)耗(hao)運(yun)行(xing)中(zhong)常(chang)見(jian)的(de)負(fu)載(zai)功(gong)率(lv)。在(zai)一(yi)些(xie)極(ji)端(duan)交(jiao)叉(cha)負(fu)載(zai)狀(zhuang)態(tai)下(xia)，這(zhe)種(zhong)電(dian)路(lu)將(jiang)"逸出"輸出電壓鉗製到一個更具可預測性的水平。

 

圖 1 電阻齊納二極管為無負載輸出電壓提供軟鉗位控製

 

 

推薦閱讀：