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(yi)動(dong)DVD機(ji)，受其體積限制，外接(jie)電池電壓(ya)大(da)多為9V左右，但其液晶(jing)(jing)屏(ping)(ping)驅動(dong)部分(fen)，需要多組不同的(de)電壓(ya)，因(yin)此移(yi)動(dong)DVD機(ji)液晶(jing)(jing)屏(ping)(ping)驅動(dong)部分(fen)的(de)供電電路相對較為復雜，故障率也較高。附圖(tu)為新科(ke)SDP1710型移(yi)動(dong)DVD機(ji)液晶(jing)(jing)屏(ping)(ping)驅動(dong)部分(fen)電路圖(tu)。

此電(dian)(dian)路(lu)為液晶(jing)屏驅動供電(dian)(dian)電(dian)(dian)路(lu)（又稱二(er)次升(sheng)(sheng)壓(ya)(ya)電(dian)(dian)路(lu)）。因(yin)彩(cai)色TFT顯示屏播放(fang)視頻圖(tu)像時，要求有快(kuai)速響應(ying)時間(jian)，對(dui)于控(kong)制電(dian)(dian)路(lu)，意味著要加上更高(gao)的驅動電(dian)(dian)壓(ya)(ya)；TFT屏的非晶(jing)薄膜(mo)晶(jing)體(ti)管的閾值電(dian)(dian)壓(ya)(ya)較(jiao)高(gao)，輸入的信號(hao)有的高(gao)達20V。而此電(dian)(dian)壓(ya)(ya)作為便捷式產品，一般難以達到要求，故需要通過升(sheng)(sheng)壓(ya)(ya)電(dian)(dian)路(lu)來變(bian)換。

由N106五端5V穩(wen)壓集成電(dian)(dian)(dian)路③腳輸(shu)出5V電(dian)(dian)(dian)壓，此電(dian)(dian)(dian)壓作(zuo)為整個液晶屏驅(qu)動的輸(shu)入(ru)電(dian)(dian)(dian)壓（不包括CCFL共(gong)電(dian)(dian)(dian)）。一路供升壓電(dian)(dian)(dian)路；一路供N112（PU5100）脈寬調制集成電(dian)(dian)(dian)路。

N112的③腳(jiao)加(jia)上5V電(dian)壓，經內部(bu)穩壓，恒(heng)流(liu)得到1.25V的基(ji)準電(dian)壓，由(you)⑨腳(jiao)輸(shu)出。12腳(jiao)外掛(gua)C174為定時電(dian)容。R151為定時電(dian)阻，其值決(jue)定N112的工作頻率，①、11腳(jiao)輸(shu)入的正負(fu)反饋(kui)電(dian)壓，經N112內部(bu)誤差放大、PWM比較(jiao)等，由(you)④腳(jiao)輸(shu)出受控脈沖信號，經R143控制(zhi)VD122（BR）開關管(guan)。

當(dang)VD122導(dao)通時，對(dui)(dui)L137蓄(xu)積(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)。而(er)(er)(er)VD122截止(zhi)時，L137電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)經(jing)(jing)V123二(er)極管（MI）對(dui)(dui)C182充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并供負載能(neng)量(liang)(liang)(liang)，周(zhou)而(er)(er)(er)復始。V1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓值(zhi)為(wei)-14V，調節(jie)N112①腳(jiao)(jiao)(jiao)外接(jie)反(fan)饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)R140阻(zu)值(zhi)可(ke)改變其輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓值(zhi)；⑩腳(jiao)(jiao)(jiao)基準電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，與來自15腳(jiao)(jiao)(jiao)的(de)(de)反(fan)饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓經(jing)(jing)N112內部(bu)誤(wu)(wu)差放大，PWM比較(jiao)等(deng)，經(jing)(jing)⑤腳(jiao)(jiao)(jiao)輸(shu)出(chu)一(yi)個(ge)受控(kong)的(de)(de)脈(mo)沖信(xin)號(hao)，經(jing)(jing)R146控(kong)制VD127（IR）開(kai)關管，當(dang)VD127導(dao)通時，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流從L131電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感經(jing)(jing)集電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極到發射極形成(cheng)(cheng)回路，從而(er)(er)(er)在L13l中(zhong)(zhong)蓄(xu)積(ji)能(neng)量(liang)(liang)(liang)。而(er)(er)(er)VD127截止(zhi)時，L131電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)(de)能(neng)量(liang)(liang)(liang)經(jing)(jing)VD128（MI）對(dui)(dui)C181電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并供負載能(neng)量(liang)(liang)(liang)周(zhou)而(er)(er)(er)復始工(gong)作(zuo)。V2電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓值(zhi)為(wei)13.6V，調節(jie)R144阻(zu)值(zhi)可(ke)改變其輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓值(zhi)；由(you)⑩腳(jiao)(jiao)(jiao)輸(shu)入的(de)(de)基準電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，與來自14腳(jiao)(jiao)(jiao)的(de)(de)反(fan)饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓經(jing)(jing)N112內部(bu)誤(wu)(wu)差放大，PWM比較(jiao)等(deng)。經(jing)(jing)⑥腳(jiao)(jiao)(jiao)輸(shu)出(chu)一(yi)個(ge)受控(kong)的(de)(de)脈(mo)沖信(xin)號(hao)，經(jing)(jing)R145控(kong)制VD125（IR）開(kai)關管，當(dang)VD125導(dao)通時，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流從L132電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感經(jing)(jing)集電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極到發射極形成(cheng)(cheng)回路，從而(er)(er)(er)在L132電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)蓄(xu)積(ji)能(neng)量(liang)(liang)(liang)，VD125截止(zhi)時L132電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)(de)能(neng)量(liang)(liang)(liang)經(jing)(jing)VD126二(er)極管（MI）對(dui)(dui)C124電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并供負載能(neng)量(liang)(liang)(liang)周(zhou)而(er)(er)(er)復始工(gong)作(zuo)。V3電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓值(zhi)為(wei)7.5V，調節(jie)14腳(jiao)(jiao)(jiao)外接(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)R152阻(zu)值(zhi)，可(ke)改變其輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓值(zhi)。V1、V2、V3電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓主要作(zuo)為(wei)方波放大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源。