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)(dong)DVD機(ji)，受(shou)其體積限制，外接電池(chi)電壓大多(duo)為(wei)9V左右，但其液晶屏驅動(dong)(dong)部(bu)分，需要(yao)多(duo)組(zu)不同(tong)的(de)電壓，因此移(yi)(yi)動(dong)(dong)DVD機(ji)液晶屏驅動(dong)(dong)部(bu)分的(de)供電電路相對較(jiao)為(wei)復雜(za)，故障(zhang)率也較(jiao)高(gao)。附圖為(wei)新(xin)科(ke)SDP1710型(xing)移(yi)(yi)動(dong)(dong)DVD機(ji)液晶屏驅動(dong)(dong)部(bu)分電路圖。

此電(dian)(dian)(dian)路(lu)為液(ye)晶屏驅動供(gong)電(dian)(dian)(dian)電(dian)(dian)(dian)路(lu)（又(you)稱二次升壓電(dian)(dian)(dian)路(lu)）。因(yin)彩色TFT顯示屏播(bo)放視頻(pin)圖像時，要(yao)求有快(kuai)速響應時間(jian)，對于控制電(dian)(dian)(dian)路(lu)，意味(wei)著要(yao)加上更高的驅動電(dian)(dian)(dian)壓；TFT屏的非(fei)晶薄(bo)膜晶體管的閾值電(dian)(dian)(dian)壓較高，輸入的信號有的高達(da)20V。而(er)此電(dian)(dian)(dian)壓作(zuo)為便捷(jie)式產品，一般難以(yi)達(da)到要(yao)求，故需要(yao)通過升壓電(dian)(dian)(dian)路(lu)來(lai)變換。

由(you)N106五端5V穩(wen)壓(ya)(ya)集成電(dian)路③腳輸(shu)(shu)出5V電(dian)壓(ya)(ya)，此電(dian)壓(ya)(ya)作(zuo)為整個液晶屏驅動的輸(shu)(shu)入電(dian)壓(ya)(ya)（不包括(kuo)CCFL共電(dian)）。一(yi)路供升壓(ya)(ya)電(dian)路；一(yi)路供N112（PU5100）脈(mo)寬調制集成電(dian)路。

N112的③腳(jiao)(jiao)加上5V電壓(ya)，經內部(bu)穩壓(ya)，恒(heng)流得到(dao)1.25V的基準電壓(ya)，由(you)⑨腳(jiao)(jiao)輸(shu)出。12腳(jiao)(jiao)外掛C174為定(ding)時電容。R151為定(ding)時電阻，其值決定(ding)N112的工作頻率，①、11腳(jiao)(jiao)輸(shu)入的正負(fu)反饋電壓(ya)，經N112內部(bu)誤差放大、PWM比較等，由(you)④腳(jiao)(jiao)輸(shu)出受控脈(mo)沖信(xin)號，經R143控制VD122（BR）開關管。

當VD122導通(tong)(tong)時(shi)，對(dui)L137蓄積電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)。而(er)(er)(er)VD122截止(zhi)時(shi)，L137電(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)電(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)經(jing)(jing)(jing)(jing)(jing)V123二極管（MI）對(dui)C182充(chong)電(dian)(dian)(dian)(dian)(dian)，并(bing)供負載能(neng)(neng)(neng)量(liang)(liang)(liang)，周而(er)(er)(er)復始(shi)(shi)。V1電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值(zhi)為(wei)(wei)-14V，調(diao)節N112①腳(jiao)外接反饋電(dian)(dian)(dian)(dian)(dian)阻R140阻值(zhi)可改變其(qi)(qi)輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值(zhi)；⑩腳(jiao)基(ji)(ji)準(zhun)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，與(yu)來自15腳(jiao)的(de)反饋電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)經(jing)(jing)(jing)(jing)(jing)N112內(nei)部誤差(cha)放大，PWM比較(jiao)等，經(jing)(jing)(jing)(jing)(jing)⑤腳(jiao)輸(shu)(shu)出一個(ge)受(shou)控(kong)(kong)的(de)脈沖信號(hao)，經(jing)(jing)(jing)(jing)(jing)R146控(kong)(kong)制VD127（IR）開關管，當VD127導通(tong)(tong)時(shi)，電(dian)(dian)(dian)(dian)(dian)流從(cong)(cong)L131電(dian)(dian)(dian)(dian)(dian)感經(jing)(jing)(jing)(jing)(jing)集(ji)電(dian)(dian)(dian)(dian)(dian)極到發(fa)射(she)極形成回(hui)路(lu)(lu)，從(cong)(cong)而(er)(er)(er)在(zai)L13l中(zhong)(zhong)蓄積能(neng)(neng)(neng)量(liang)(liang)(liang)。而(er)(er)(er)VD127截止(zhi)時(shi)，L131電(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)能(neng)(neng)(neng)量(liang)(liang)(liang)經(jing)(jing)(jing)(jing)(jing)VD128（MI）對(dui)C181電(dian)(dian)(dian)(dian)(dian)容(rong)充(chong)電(dian)(dian)(dian)(dian)(dian)，并(bing)供負載能(neng)(neng)(neng)量(liang)(liang)(liang)周而(er)(er)(er)復始(shi)(shi)工作(zuo)。V2電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值(zhi)為(wei)(wei)13.6V，調(diao)節R144阻值(zhi)可改變其(qi)(qi)輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值(zhi)；由⑩腳(jiao)輸(shu)(shu)入的(de)基(ji)(ji)準(zhun)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，與(yu)來自14腳(jiao)的(de)反饋電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)經(jing)(jing)(jing)(jing)(jing)N112內(nei)部誤差(cha)放大，PWM比較(jiao)等。經(jing)(jing)(jing)(jing)(jing)⑥腳(jiao)輸(shu)(shu)出一個(ge)受(shou)控(kong)(kong)的(de)脈沖信號(hao)，經(jing)(jing)(jing)(jing)(jing)R145控(kong)(kong)制VD125（IR）開關管，當VD125導通(tong)(tong)時(shi)，電(dian)(dian)(dian)(dian)(dian)流從(cong)(cong)L132電(dian)(dian)(dian)(dian)(dian)感經(jing)(jing)(jing)(jing)(jing)集(ji)電(dian)(dian)(dian)(dian)(dian)極到發(fa)射(she)極形成回(hui)路(lu)(lu)，從(cong)(cong)而(er)(er)(er)在(zai)L132電(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)蓄積能(neng)(neng)(neng)量(liang)(liang)(liang)，VD125截止(zhi)時(shi)L132電(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)能(neng)(neng)(neng)量(liang)(liang)(liang)經(jing)(jing)(jing)(jing)(jing)VD126二極管（MI）對(dui)C124電(dian)(dian)(dian)(dian)(dian)容(rong)充(chong)電(dian)(dian)(dian)(dian)(dian)，并(bing)供負載能(neng)(neng)(neng)量(liang)(liang)(liang)周而(er)(er)(er)復始(shi)(shi)工作(zuo)。V3電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值(zhi)為(wei)(wei)7.5V，調(diao)節14腳(jiao)外接電(dian)(dian)(dian)(dian)(dian)阻R152阻值(zhi)，可改變其(qi)(qi)輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值(zhi)。V1、V2、V3電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)主要(yao)作(zuo)為(wei)(wei)方波(bo)放大電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)供電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源。