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)(yi)動(dong)DVD機(ji)(ji)，受其(qi)體積限制，外接電(dian)池電(dian)壓大多為(wei)(wei)9V左右(you)，但其(qi)液(ye)(ye)晶屏驅動(dong)部分，需要多組不同的(de)電(dian)壓，因(yin)此移(yi)(yi)動(dong)DVD機(ji)(ji)液(ye)(ye)晶屏驅動(dong)部分的(de)供電(dian)電(dian)路相對較(jiao)為(wei)(wei)復雜(za)，故(gu)障率也(ye)較(jiao)高。附(fu)圖為(wei)(wei)新(xin)科(ke)SDP1710型移(yi)(yi)動(dong)DVD機(ji)(ji)液(ye)(ye)晶屏驅動(dong)部分電(dian)路圖。

此電(dian)路(lu)為液(ye)晶屏驅動(dong)供電(dian)電(dian)路(lu)（又稱二次升壓電(dian)路(lu)）。因彩色TFT顯示屏播(bo)放視頻(pin)圖像時，要求有快(kuai)速響應時間，對于控制電(dian)路(lu)，意(yi)味著(zhu)要加上更高(gao)的驅動(dong)電(dian)壓；TFT屏的非晶薄膜晶體管的閾值電(dian)壓較高(gao)，輸入(ru)的信(xin)號有的高(gao)達20V。而(er)此電(dian)壓作為便(bian)捷(jie)式產品，一(yi)般難(nan)以達到要求，故(gu)需要通過升壓電(dian)路(lu)來變換。

由(you)N106五(wu)端5V穩壓(ya)集成電(dian)路(lu)③腳輸(shu)出(chu)5V電(dian)壓(ya)，此電(dian)壓(ya)作為整個液晶屏(ping)驅動的輸(shu)入電(dian)壓(ya)（不包括CCFL共電(dian)）。一路(lu)供升壓(ya)電(dian)路(lu)；一路(lu)供N112（PU5100）脈(mo)寬調制(zhi)集成電(dian)路(lu)。

N112的(de)③腳加上5V電壓(ya)(ya)，經內部穩壓(ya)(ya)，恒流得到(dao)1.25V的(de)基準電壓(ya)(ya)，由⑨腳輸(shu)出。12腳外掛C174為(wei)(wei)定(ding)(ding)時電容。R151為(wei)(wei)定(ding)(ding)時電阻，其(qi)值決定(ding)(ding)N112的(de)工作頻率，①、11腳輸(shu)入的(de)正負反(fan)饋電壓(ya)(ya)，經N112內部誤差(cha)放(fang)大、PWM比(bi)較等，由④腳輸(shu)出受控脈沖信號(hao)，經R143控制VD122（BR）開關管。

當(dang)VD122導(dao)通時(shi)，對(dui)L137蓄(xu)積電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)。而(er)(er)(er)VD122截止(zhi)時(shi)，L137電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)經V123二(er)極(ji)(ji)管(guan)(guan)（MI）對(dui)C182充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并供負(fu)載(zai)能(neng)(neng)量(liang)(liang)，周而(er)(er)(er)復始。V1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)值為(wei)-14V，調節(jie)N112①腳(jiao)(jiao)(jiao)外接(jie)反饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)R140阻(zu)(zu)值可改(gai)變(bian)(bian)其(qi)輸出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)值；⑩腳(jiao)(jiao)(jiao)基準電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)，與來自(zi)15腳(jiao)(jiao)(jiao)的(de)(de)(de)反饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)經N112內部誤(wu)差(cha)放(fang)大(da)(da)，PWM比(bi)較等，經⑤腳(jiao)(jiao)(jiao)輸出一個(ge)受控的(de)(de)(de)脈沖信(xin)號，經R146控制VD127（IR）開關管(guan)(guan)，當(dang)VD127導(dao)通時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)從L131電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感經集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)到發射(she)極(ji)(ji)形成回(hui)路，從而(er)(er)(er)在L13l中(zhong)蓄(xu)積能(neng)(neng)量(liang)(liang)。而(er)(er)(er)VD127截止(zhi)時(shi)，L131電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)的(de)(de)(de)能(neng)(neng)量(liang)(liang)經VD128（MI）對(dui)C181電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并供負(fu)載(zai)能(neng)(neng)量(liang)(liang)周而(er)(er)(er)復始工(gong)(gong)作。V2電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)值為(wei)13.6V，調節(jie)R144阻(zu)(zu)值可改(gai)變(bian)(bian)其(qi)輸出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)值；由⑩腳(jiao)(jiao)(jiao)輸入的(de)(de)(de)基準電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)，與來自(zi)14腳(jiao)(jiao)(jiao)的(de)(de)(de)反饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)經N112內部誤(wu)差(cha)放(fang)大(da)(da)，PWM比(bi)較等。經⑥腳(jiao)(jiao)(jiao)輸出一個(ge)受控的(de)(de)(de)脈沖信(xin)號，經R145控制VD125（IR）開關管(guan)(guan)，當(dang)VD125導(dao)通時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)從L132電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感經集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)到發射(she)極(ji)(ji)形成回(hui)路，從而(er)(er)(er)在L132電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)蓄(xu)積能(neng)(neng)量(liang)(liang)，VD125截止(zhi)時(shi)L132電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)的(de)(de)(de)能(neng)(neng)量(liang)(liang)經VD126二(er)極(ji)(ji)管(guan)(guan)（MI）對(dui)C124電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并供負(fu)載(zai)能(neng)(neng)量(liang)(liang)周而(er)(er)(er)復始工(gong)(gong)作。V3電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)值為(wei)7.5V，調節(jie)14腳(jiao)(jiao)(jiao)外接(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)R152阻(zu)(zu)值，可改(gai)變(bian)(bian)其(qi)輸出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)值。V1、V2、V3電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)主要(yao)作為(wei)方(fang)波(bo)放(fang)大(da)(da)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。