【LED臺燈電(dian)路(lu)圖(tu)】led充電(dian)臺燈電(dian)路(lu)圖(tu) LED臺燈工作原(yuan)理

一、簡易LED臺燈電路

先找一臺廢棄的熒光管臺燈，除去(qu)燈管及燈座(zuo)中(zhong)的(de)(de)電(dian)(dian)(dian)(dian)路(lu)板;準備兩塊(kuai)(kuai)敷銅板，一塊(kuai)(kuai)裝(zhuang)串接(jie)的(de)(de)88只發(fa)光(guang)管，一塊(kuai)(kuai)裝(zhuang)整(zheng)流(liu)(liu)濾波(bo)電(dian)(dian)(dian)(dian)路(lu)元件(jian)，尺寸依實(shi)際情況而定;采用全波(bo)倍壓(ya)(ya)(ya)整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)(整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)的(de)(de)作用是(shi)將交(jiao)(jiao)(jiao)流(liu)(liu)降(jiang)壓(ya)(ya)(ya)電(dian)(dian)(dian)(dian)路(lu)輸出的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)較低的(de)(de)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)轉換成單向(xiang)脈動性直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)，這就是(shi)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)的(de)(de)整(zheng)流(liu)(liu)過(guo)程，整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)主要由(you)整(zheng)流(liu)(liu)二(er)極管組(zu)成。經過(guo)整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)之后的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)已經不是(shi)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，而是(shi)一種含有直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)和(he)交(jiao)(jiao)(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)混(hun)合電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，習慣(guan)上(shang)稱(cheng)單向(xiang)脈動性直(zhi)流(liu)(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)。)為(wei)發(fa)光(guang)管供電(dian)(dian)(dian)(dian)(如附圖(tu))。兩只0.68uF電(dian)(dian)(dian)(dian)容(rong)既是(shi)全波(bo)倍壓(ya)(ya)(ya)整(zheng)流(liu)(liu)電(dian)(dian)(dian)(dian)路(lu)元件(jian)，又有限流(liu)(liu)作用。電(dian)(dian)(dian)(dian)容(rong)選(xuan)耐(nai)壓(ya)(ya)(ya)400V以上(shang)的(de)(de)，電(dian)(dian)(dian)(dian)阻用0.25W的(de)(de)。由(you)于電(dian)(dian)(dian)(dian)路(lu)簡單，電(dian)(dian)(dian)(dian)路(lu)板用刀(dao)刻而成，管腳(jiao)位置鉆Φlmm焊接(jie)孔。

元件焊好(hao)后(hou)(hou)，先用(yong)15kΩ/5W電(dian)(dian)阻(zu)作假負載，測試整(zheng)流(liu)電(dian)(dian)路(lu)，電(dian)(dian)阻(zu)上應(ying)(ying)有280V左右的(de)直流(liu)電(dian)(dian)壓，此(ci)時除電(dian)(dian)阻(zu)外，其他元件不(bu)應(ying)(ying)發(fa)熱(re)。一切正常后(hou)(hou)接人燈(deng)(deng)板(ban)，通電(dian)(dian)后(hou)(hou)，88只(zhi)發(fa)光(guang)管應(ying)(ying)正常發(fa)光(guang)。最后(hou)(hou)，將(jiang)電(dian)(dian)源板(ban)和燈(deng)(deng)板(ban)分別固定在(zai)底座和燈(deng)(deng)罩上。該臺燈(deng)(deng)亮度不(bu)及(ji)原燈(deng)(deng)，且(qie)照亮面積偏小，但看書寫字尚(shang)可(ke)，點亮一段時間后(hou)(hou)燈(deng)(deng)板(ban)溫(wen)度升高，但比熒(ying)光(guang)燈(deng)(deng)管溫(wen)度低得多(duo)。測量負載回路(lu)電(dian)(dian)流(liu)約18mA，燈(deng)(deng)板(ban)兩端電(dian)(dian)壓約280V，計(ji)算其功耗約5W。

制(zhi)作時要(yao)注意，焊接(jie)不得有虛焊，LED要(yao)逐只測(ce)試且極性不得焊錯;電源進線要(yao)加裝電流小于200mA的保險管;斷(duan)電后(hou)電容元件(jian)有高壓要(yao)注意安(an)全;電路(lu)不可(ke)(ke)斷(duan)開負載(zai)，否則600V左(zuo)右的電壓可(ke)(ke)能損壞元件(jian)。

二、LED臺燈工作原理

遵循安全第一的(de)(de)民用(yong)電(dian)(dian)器的(de)(de)設(she)計(ji)理念(nian)，LED 光(guang)(guang)源(yuan)是(shi)(shi)(shi)一種低電(dian)(dian)壓(ya)(ya)直(zhi)流(liu)恒流(liu)源(yuan)的(de)(de)發光(guang)(guang)器件(jian)，不(bu)能用(yong)100-220V 的(de)(de)交(jiao)(jiao)流(liu)高壓(ya)(ya)電(dian)(dian)直(zhi)接(jie)點亮，因(yin)此(ci)，LED 臺燈(deng)方(fang)案設(she)計(ji)思路，首先(xian)要(yao)(yao)(yao)將高壓(ya)(ya)的(de)(de)交(jiao)(jiao)流(liu)電(dian)(dian)變(bian)換(huan)成低壓(ya)(ya)的(de)(de)直(zhi)流(liu)恒流(liu)源(yuan)，才能點亮LED 光(guang)(guang)源(yuan)。使(shi)(shi)用(yong)最(zui)經濟有效的(de)(de)方(fang)法降壓(ya)(ya)和(he)進行交(jiao)(jiao)直(zhi)流(liu)變(bian)換(huan)是(shi)(shi)(shi)設(she)計(ji)的(de)(de)首要(yao)(yao)(yao)考慮，今便攜式電(dian)(dian)產(chan)品使(shi)(shi)用(yong)交(jiao)(jiao)流(liu)電(dian)(dian)源(yuan)的(de)(de)交(jiao)(jiao)直(zhi)流(liu)降壓(ya)(ya)變(bian)換(huan)器--適配(pei)器（Adapter）就成了既經濟實惠(hui)、又現成、好用(yong)的(de)(de)首選(xuan)。適配(pei)器的(de)(de)輸出(chu)電(dian)(dian)壓(ya)(ya)要(yao)(yao)(yao)求(qiu)穩定在DC12V，輸出(chu)電(dian)(dian)流(liu)要(yao)(yao)(yao)根據LED 的(de)(de)光(guang)(guang)源(yuan)的(de)(de)功率來選(xuan)擇，一般(ban)要(yao)(yao)(yao)給予30%的(de)(de)余(yu)量，以(yi)3X1W 的(de)(de)白(bai)光(guang)(guang)LED 光(guang)(guang)源(yuan)為(wei)(wei)例，1W 的(de)(de)白(bai)光(guang)(guang)LED 的(de)(de)標準工作電(dian)(dian)流(liu)應為(wei)(wei)350mA，因(yin)而3 個LED 光(guang)(guang)源(yuan)串聯其(qi)電(dian)(dian)路需要(yao)(yao)(yao)的(de)(de)電(dian)(dian)流(liu)也(ye)是(shi)(shi)(shi)350mA，考慮到延(yan)長LED 壽命和(he)降低光(guang)(guang)衰，可(ke)以(yi)設(she)計(ji)為(wei)(wei)300mA--330mA，不(bu)會明顯的(de)(de)影(ying)響LED 發光(guang)(guang)的(de)(de)亮度，所以(yi)適配(pei)器的(de)(de)輸出(chu)電(dian)(dian)流(liu)應選(xuan)750mA--1A 的(de)(de)。

LED 臺(tai)(tai)燈(deng)一(yi)種簡(jian)潔實(shi)用的(de)(de)(de)方案如(ru)圖1 所示。AC220V 經由適配(pei)器(qi)在(zai)燈(deng)具外的(de)(de)(de)安全(quan)降壓變(bian)換，向LED 臺(tai)(tai)燈(deng)提供穩(wen)定(ding)的(de)(de)(de)12V 直流(liu)電(dian)(dian)源(yuan)，在(zai)臺(tai)(tai)燈(deng)底座殼內安置恒(heng)流(liu)源(yuan)電(dian)(dian)源(yuan)板，將直流(liu)電(dian)(dian)壓變(bian)換成(cheng)穩(wen)定(ding)的(de)(de)(de)直流(liu)恒(heng)流(liu)源(yuan)，以滿足LED 光源(yuan)發光的(de)(de)(de)技術要求。在(zai)直流(liu)恒(heng)流(liu)源(yuan)前(qian)可加一(yi)電(dian)(dian)源(yuan)開(kai)(kai)關(guan)，以便在(zai)臺(tai)(tai)燈(deng)不用時(shi)(shi)可關(guan)斷直流(liu)電(dian)(dian)源(yuan)，但不能關(guan)斷220V 交流(liu)電(dian)(dian)源(yuan)，因此真的(de)(de)(de)不用時(shi)(shi)應(ying)從墻(qiang)上取下適配(pei)器(qi)的(de)(de)(de)電(dian)(dian)源(yuan)插(cha)頭，這也是這個實(shi)用方案的(de)(de)(de)唯一(yi)“缺(que)點(dian)”。如(ru)不想(xiang)采用機械(xie)開(kai)(kai)關(guan)，和想(xiang)要一(yi)個更有創意(yi)的(de)(de)(de)賣點(dian)，可選用電(dian)(dian)子觸摸(mo)(mo)開(kai)(kai)關(guan)，如(ru)手指輕點(dian)可實(shi)現臺(tai)(tai)燈(deng)的(de)(de)(de)開(kai)(kai)->全(quan)亮、半暗、關(guan)；由于電(dian)(dian)子技術的(de)(de)(de)快速進步(bu)，電(dian)(dian)子觸摸(mo)(mo)開(kai)(kai)關(guan)如(ru)今(jin)已是一(yi)個低成(cheng)本的(de)(de)(de)器(qi)件。