移動DVD液晶屏驅動電路供電原理分析 移動DVD是如何供電的

原理分析

移動DVD機(ji)，受其(qi)(qi)體積(ji)限(xian)制，外接電(dian)(dian)池電(dian)(dian)壓大多為(wei)9V左(zuo)右(you)，但其(qi)(qi)液晶(jing)屏驅動部(bu)分，需要(yao)多組(zu)不(bu)同的電(dian)(dian)壓，因此移動DVD機(ji)液晶(jing)屏驅動部(bu)分的供電(dian)(dian)電(dian)(dian)路相對較為(wei)復雜，故障率(lv)也較高(gao)。附圖(tu)為(wei)新科SDP1710型移動DVD機(ji)液晶(jing)屏驅動部(bu)分電(dian)(dian)路圖(tu)。

此電路(lu)(lu)(lu)為液晶屏驅動(dong)(dong)供電電路(lu)(lu)(lu)（又稱二次(ci)升壓電路(lu)(lu)(lu)）。因彩色TFT顯示屏播放視(shi)頻(pin)圖像時(shi)，要求(qiu)有快速響(xiang)應時(shi)間，對于控制電路(lu)(lu)(lu)，意(yi)味著要加上更(geng)高的(de)驅動(dong)(dong)電壓；TFT屏的(de)非(fei)晶薄膜晶體管的(de)閾(yu)值電壓較高，輸入的(de)信(xin)號有的(de)高達(da)(da)20V。而此電壓作(zuo)為便捷式產(chan)品，一般難以達(da)(da)到要求(qiu)，故需要通過升壓電路(lu)(lu)(lu)來變換。

由N106五端5V穩壓(ya)(ya)(ya)集(ji)成電路(lu)③腳輸出5V電壓(ya)(ya)(ya)，此電壓(ya)(ya)(ya)作為整個液晶屏驅動的輸入(ru)電壓(ya)(ya)(ya)（不(bu)包括(kuo)CCFL共(gong)電）。一路(lu)供升(sheng)壓(ya)(ya)(ya)電路(lu)；一路(lu)供N112（PU5100）脈寬調制集(ji)成電路(lu)。

N112的(de)③腳(jiao)加上5V電壓，經內部(bu)穩壓，恒(heng)流得到1.25V的(de)基準電壓，由(you)⑨腳(jiao)輸出(chu)。12腳(jiao)外掛(gua)C174為定(ding)時電容。R151為定(ding)時電阻，其(qi)值決定(ding)N112的(de)工作頻率，①、11腳(jiao)輸入(ru)的(de)正(zheng)負(fu)反饋電壓，經N112內部(bu)誤(wu)差放大、PWM比較(jiao)等(deng)，由(you)④腳(jiao)輸出(chu)受控脈沖信號，經R143控制VD122（BR）開關管(guan)。

當VD122導通時，對(dui)L137蓄(xu)積電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)。而(er)VD122截(jie)止(zhi)(zhi)時，L137電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)中(zhong)(zhong)(zhong)的(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)經(jing)(jing)(jing)V123二(er)(er)極(ji)管(guan)(guan)(guan)（MI）對(dui)C182充電(dian)(dian)(dian)(dian)(dian)，并供(gong)負(fu)載能(neng)量(liang)(liang)，周(zhou)(zhou)而(er)復(fu)始。V1電(dian)(dian)(dian)(dian)(dian)壓(ya)值(zhi)(zhi)(zhi)為(wei)(wei)-14V，調(diao)節(jie)N112①腳(jiao)(jiao)(jiao)外接(jie)反(fan)饋(kui)(kui)電(dian)(dian)(dian)(dian)(dian)阻R140阻值(zhi)(zhi)(zhi)可(ke)(ke)改變(bian)其(qi)輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)值(zhi)(zhi)(zhi)；⑩腳(jiao)(jiao)(jiao)基準(zhun)電(dian)(dian)(dian)(dian)(dian)壓(ya)，與來(lai)(lai)自(zi)15腳(jiao)(jiao)(jiao)的(de)反(fan)饋(kui)(kui)電(dian)(dian)(dian)(dian)(dian)壓(ya)經(jing)(jing)(jing)N112內部(bu)(bu)誤(wu)差放(fang)大，PWM比(bi)(bi)較等，經(jing)(jing)(jing)⑤腳(jiao)(jiao)(jiao)輸出(chu)一(yi)個受控的(de)脈沖信號(hao)，經(jing)(jing)(jing)R146控制VD127（IR）開關(guan)管(guan)(guan)(guan)，當VD127導通時，電(dian)(dian)(dian)(dian)(dian)流從(cong)L131電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)經(jing)(jing)(jing)集電(dian)(dian)(dian)(dian)(dian)極(ji)到(dao)發射極(ji)形(xing)成(cheng)(cheng)回路(lu)，從(cong)而(er)在L13l中(zhong)(zhong)(zhong)蓄(xu)積能(neng)量(liang)(liang)。而(er)VD127截(jie)止(zhi)(zhi)時，L131電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)中(zhong)(zhong)(zhong)的(de)能(neng)量(liang)(liang)經(jing)(jing)(jing)VD128（MI）對(dui)C181電(dian)(dian)(dian)(dian)(dian)容充電(dian)(dian)(dian)(dian)(dian)，并供(gong)負(fu)載能(neng)量(liang)(liang)周(zhou)(zhou)而(er)復(fu)始工作(zuo)。V2電(dian)(dian)(dian)(dian)(dian)壓(ya)值(zhi)(zhi)(zhi)為(wei)(wei)13.6V，調(diao)節(jie)R144阻值(zhi)(zhi)(zhi)可(ke)(ke)改變(bian)其(qi)輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)值(zhi)(zhi)(zhi)；由⑩腳(jiao)(jiao)(jiao)輸入的(de)基準(zhun)電(dian)(dian)(dian)(dian)(dian)壓(ya)，與來(lai)(lai)自(zi)14腳(jiao)(jiao)(jiao)的(de)反(fan)饋(kui)(kui)電(dian)(dian)(dian)(dian)(dian)壓(ya)經(jing)(jing)(jing)N112內部(bu)(bu)誤(wu)差放(fang)大，PWM比(bi)(bi)較等。經(jing)(jing)(jing)⑥腳(jiao)(jiao)(jiao)輸出(chu)一(yi)個受控的(de)脈沖信號(hao)，經(jing)(jing)(jing)R145控制VD125（IR）開關(guan)管(guan)(guan)(guan)，當VD125導通時，電(dian)(dian)(dian)(dian)(dian)流從(cong)L132電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)經(jing)(jing)(jing)集電(dian)(dian)(dian)(dian)(dian)極(ji)到(dao)發射極(ji)形(xing)成(cheng)(cheng)回路(lu)，從(cong)而(er)在L132電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)中(zhong)(zhong)(zhong)蓄(xu)積能(neng)量(liang)(liang)，VD125截(jie)止(zhi)(zhi)時L132電(dian)(dian)(dian)(dian)(dian)感(gan)(gan)中(zhong)(zhong)(zhong)的(de)能(neng)量(liang)(liang)經(jing)(jing)(jing)VD126二(er)(er)極(ji)管(guan)(guan)(guan)（MI）對(dui)C124電(dian)(dian)(dian)(dian)(dian)容充電(dian)(dian)(dian)(dian)(dian)，并供(gong)負(fu)載能(neng)量(liang)(liang)周(zhou)(zhou)而(er)復(fu)始工作(zuo)。V3電(dian)(dian)(dian)(dian)(dian)壓(ya)值(zhi)(zhi)(zhi)為(wei)(wei)7.5V，調(diao)節(jie)14腳(jiao)(jiao)(jiao)外接(jie)電(dian)(dian)(dian)(dian)(dian)阻R152阻值(zhi)(zhi)(zhi)，可(ke)(ke)改變(bian)其(qi)輸出(chu)電(dian)(dian)(dian)(dian)(dian)壓(ya)值(zhi)(zhi)(zhi)。V1、V2、V3電(dian)(dian)(dian)(dian)(dian)壓(ya)主要作(zuo)為(wei)(wei)方波放(fang)大電(dian)(dian)(dian)(dian)(dian)路(lu)供(gong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源(yuan)。