USB充電器套件制作原理解說

     USB充電器套件，又名MP3MP4充電器，輸入AC160-240V，50/60Hz，額定輸出：DC 5V250mA（標簽貼紙為500mA，如果要長期輸出更大電流，請更換Q1為13003）。MP3和MP4在全國范圍大量流行，不過作為日常用品的充電器由于直接和220V高壓相連，具有故障率較高，容易損壞的特點，特別是買到那些不成熟的產品后，真是苦不看言。最后，受學校老師委托，我們聯系到了一款成熟量產的充電器套件，現在一同給廣大電子愛好者(zhe)分享。

說明：
      為了(le)簡化(hua)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，達到學習目地(di)，圖中(zhong)用(yong)(yong)1歐的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻F1起到保險絲的(de)(de)作用(yong)(yong)，用(yong)(yong)一個二極(ji)(ji)管(guan)D1完(wan)成整流(liu)作用(yong)(yong)。接通(tong)(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)后(hou)，C1會有300V左右(you)的(de)(de)直流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，通(tong)(tong)(tong)過R2給Q1的(de)(de)基(ji)極(ji)(ji)提(ti)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，Q1的(de)(de)發射(she)極(ji)(ji)有R1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻R1，Q1基(ji)極(ji)(ji)得電(dian)(dian)(dian)(dian)(dian)(dian)(dian)后(hou)，會經過T1的(de)(de)（3、4）產生集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，并同時在(zai)T1的(de)(de)（5、6）（1、2）上(shang)產生感(gan)應電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，這兩個次級絕緣的(de)(de)圈(quan)數相(xiang)同的(de)(de)線(xian)圈(quan)，其(qi)中(zhong)T1（1、2）輸(shu)出(chu)由D7整流(liu)、C5濾(lv)(lv)波后(hou)通(tong)(tong)(tong)過USB座(zuo)給負(fu)(fu)載(zai)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)；其(qi)中(zhong)T1（5、6）經D6整流(liu)、C2濾(lv)(lv)波后(hou)通(tong)(tong)(tong)過IC1（實(shi)為4.3V穩壓(ya)(ya)(ya)(ya)管(guan)）、Q2組(zu)成取(qu)(qu)樣(yang)比(bi)(bi)較電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，檢(jian)測輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)高低；其(qi)中(zhong)T1（5、6）、C3、R4還組(zu)成Q1三極(ji)(ji)管(guan)的(de)(de)正反饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，讓Q1工作在(zai)高頻振(zhen)蕩，不停(ting)的(de)(de)給T1（3、4）開關供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。當負(fu)(fu)載(zai)變(bian)(bian)輕或(huo)者(zhe)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)變(bian)(bian)高等(deng)任何原因導(dao)致(zhi)輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)升高時，T1（5、6）、IC1取(qu)(qu)樣(yang)比(bi)(bi)較導(dao)致(zhi)Q2導(dao)通(tong)(tong)(tong)，Q1基(ji)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)減小(xiao)，集(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)減小(xiao)，負(fu)(fu)載(zai)能力變(bian)(bian)小(xiao)，從而導(dao)致(zhi)輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降(jiang)低；當輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降(jiang)低后(hou)，Q2取(qu)(qu)樣(yang)后(hou)又會截止，Q1的(de)(de)負(fu)(fu)載(zai)能力變(bian)(bian)強，輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)又會升高；這樣(yang)起到自動(dong)穩壓(ya)(ya)(ya)(ya)作用(yong)(yong)。

本電路(lu)(lu)雖然(ran)(ran)元(yuan)件少，但是還(huan)設計有過(guo)流(liu)過(guo)載短路(lu)(lu)保護功能(neng)。當(dang)負載過(guo)載或(huo)者短路(lu)(lu)時(shi)，Q1的集電極電流(liu)大(da)(da)增，而Q1的發射極電阻R1會(hui)產生(sheng)較(jiao)高(gao)(gao)的壓降，這個過(guo)載或(huo)者短路(lu)(lu)產生(sheng)的高(gao)(gao)電壓會(hui)經過(guo)R3讓Q2飽(bao)和導通，從(cong)而讓Q1截止停止輸出(chu)(chu)防止過(guo)載損(sun)壞。因此，改(gai)變R1的大(da)(da)小(xiao)(xiao)，可(ke)以改(gai)變負載能(neng)力，如(ru)果(guo)要(yao)(yao)求輸出(chu)(chu)電流(liu)小(xiao)(xiao)，例(li)如(ru)只需要(yao)(yao)輸出(chu)(chu)5V100MA，可(ke)以將R1阻值改(gai)大(da)(da)。當(dang)然(ran)(ran)，如(ru)果(guo)需要(yao)(yao)輸出(chu)(chu)5V500MA的話，就(jiu)需要(yao)(yao)將R1適當(dang)改(gai)小(xiao)(xiao)。注(zhu)意(yi)：R1改(gai)小(xiao)(xiao)會(hui)增加(jia)燒(shao)壞Q1的可(ke)能(neng)性，如(ru)果(guo)需要(yao)(yao)大(da)(da)電流(liu)輸出(chu)(chu)，建議更(geng)換13003、13007中大(da)(da)功率管。

C4、R5、D5起(qi)什么作(zuo)用呢？T1變壓器是電感(gan)元(yuan)件(jian)，Q1工作(zuo)在開(kai)關狀態(tai)，當(dang)Q1截止時，會(hui)(hui)(hui)(hui)在集電極(ji)感(gan)應出很高(gao)的電壓，這(zhe)(zhe)個電壓可(ke)(ke)(ke)能高(gao)達1000伏以(yi)上(shang)，這(zhe)(zhe)會(hui)(hui)(hui)(hui)使Q1擊穿(chuan)損(sun)壞(huai)(huai)，現在有(you)了高(gao)速(su)開(kai)關管D5，這(zhe)(zhe)個電壓可(ke)(ke)(ke)以(yi)給C4充(chong)電，吸收這(zhe)(zhe)個高(gao)壓，C4充(chong)電后可(ke)(ke)(ke)以(yi)立即通過R5放電，這(zhe)(zhe)樣Q1不會(hui)(hui)(hui)(hui)因(yin)集電極(ji)的高(gao)電壓擊穿(chuan)損(sun)壞(huai)(huai)了，因(yin)此，這(zhe)(zhe)三個元(yuan)件(jian)如有(you)開(kai)關或者(zhe)損(sun)壞(huai)(huai)，Q1是非常(chang)危險的，分(fen)分(fen)秒秒都(dou)可(ke)(ke)(ke)能會(hui)(hui)(hui)(hui)損(sun)壞(huai)(huai)。

給的大家收到貨后(hou)，先熟悉一下電路原理(li)圖，分(fen)析(xi)一下原理(li)，再(zai)(zai)測量一下各(ge)元件，最后(hou)再(zai)(zai)小心來(lai)裝配。

安裝注意事項：

       安裝之(zhi)前請不要(yao)急于(yu)動手(shou)，應先查閱相關的技術資料以及(ji)本(ben)說明(ming)，然(ran)后對(dui)照原理圖，了解(jie)印刷電路板、元(yuan)件清單(dan)，并分清各元(yuan)件，了解(jie)各元(yuan)件的特點、作用、功能(neng)，同時(shi)核(he)對(dui)元(yuan)件數量。

注：
      Z1、D2、D3、D4，IC1本(ben)種組(zu)裝沒有配備(bei)，電路(lu)板(ban)是設計的(de)多用(yong)途的(de)，本(ben)套件只(zhi)用(yong)到半(ban)波整流，只(zhi)有一個1N4007整流，請(qing)大家不要(yao)自己多裝其它的(de)二極管，參考(kao)圖(tu)中(zhong)樣板(ban)做就行(xing)了，樣板(ban)已(yi)經測試過(guo)是OK的(de)，在工廠(chang)做過(guo)的(de)朋友就知道，工廠(chang)都是按照(zhao)樣板(ban)生產的(de)。

正確插入(ru)元件，按照從低到高、從小到大的順利安裝，極性要符合規定。對于(yu)手工安裝，元件應分批安裝。如此板(ban)先電阻(zu)→二極管→三(san)極管→電容→變壓器→USB座

1、Q1、Q2千萬不(bu)(bu)要裝錯，Q1應選用耐壓500V以上具有開關(guan)特性的(de)(de)管子，Q2耐壓幾十伏就行了，Q2適合(he)選放大特性好(hao)的(de)(de)管子，這兩種管子的(de)(de)管腳排列可(ke)能會不(bu)(bu)同常規，請以測量為準(zhun)。

2、IC1、D6請千萬不要裝錯(cuo)，同樣是(shi)(shi)玻璃封裝的(de)二(er)極(ji)管，一(yi)個是(shi)(shi)4.3V的(de)穩壓(ya)二(er)極(ji)管，一(yi)個普通二(er)極(ji)管，其中IC1只是(shi)(shi)PCB板(ban)上(shang)的(de)符號，二(er)極(ji)管只占用兩個PCB元件孔。

3、1N4007、FR107、1N5819請不裝錯，1N4007是低(di)(di)頻二(er)(er)極(ji)管(guan)(guan)，FR107是高頻高壓(ya)二(er)(er)極(ji)管(guan)(guan)，1N5819是低(di)(di)電(dian)壓(ya)高頻肖特基二(er)(er)極(ji)管(guan)(guan)，都(dou)是不能裝錯位置的(de)。（代換(huan)關系：FR107可以代替1N4007，反之則(ze)不行；而1N5819則(ze)不能用其它(ta)二(er)(er)極(ji)管(guan)(guan)代替，1N5819的(de)導(dao)通電(dian)壓(ya)很低(di)(di)，相(xiang)當于鍺(zang)管(guan)(guan)的(de)導(dao)通電(dian)壓(ya)，因此，低(di)(di)電(dian)壓(ya)整流效(xiao)率很高，如果一定要(yao)用其它(ta)二(er)(er)極(ji)管(guan)(guan)代替，則(ze)出(chu)輸出(chu)功率下載，發熱嚴重，效(xiao)率變低(di)(di)。）

記住：FR104(7)是高頻輸出整流二極管，1N4007才是電源整流二極管。
通電測試線路板：
       仔細檢查線(xian)(xian)路板(ban)(ban)安裝無(wu)誤后，要(yao)通電(dian)試(shi)板(ban)(ban)時，可以在PCB板(ban)(ban)直接焊一個220V插頭線(xian)(xian)，為了(le)安全起見，請大家(jia)先在電(dian)源串聯一個10W的白熾燈泡，以防止短路或者接錯(cuo)，千萬(wan)注(zhu)意(yi)安全，還有，元件一不小(xiao)心就燒(shao)壞(huai)了(le)，燒(shao)壞(huai)了(le)需要(yao)再買(mai)才行。如果安裝無(wu)誤，用萬(wan)用表可以測得USB

1腳和4腳應有5V的電(dian)壓輸(shu)出，電(dian)源指示(shi)燈(deng)亮，確認電(dian)路板裝配無誤。