多源數碼充電器
充電器(Charger)是(shi)一種為(wei)蓄(xu)電裝置提供能(neng)量的(de)設備,廣泛用于手(shou)機(ji)(ji)、相機(ji)(ji)、MP3、MP4等常(chang)見數(shu)(shu)碼(ma)產(chan)(chan)品。市(shi)場(chang)(chang)上(shang)的(de)產(chan)(chan)品都是(shi)配售充(chong)(chong)(chong)電器,使用市(shi)電充(chong)(chong)(chong)電,但是(shi)有些沒(mei)(mei)有市(shi)電的(de)場(chang)(chang)合或者電源(yuan)插座不(bu)兼容、偏遠地(di)(di)區、旅行中,特別是(shi)沒(mei)(mei)有任(ren)何電源(yuan)情(qing)況下(xia)(xia)不(bu)方便(bian)充(chong)(chong)(chong)電時,設計(ji)的(de)多(duo)源(yuan)數(shu)(shu)碼(ma)充(chong)(chong)(chong)電器可(ke)以(yi)(yi)在(zai)任(ren)何情(qing)況下(xia)(xia)進(jin)行充(chong)(chong)(chong)電:沒(mei)(mei)有市(shi)電,可(ke)以(yi)(yi)用2節1.5 V干電池(chi)(chi)充(chong)(chong)(chong)電,沒(mei)(mei)有干電池(chi)(chi)也可(ke)用3.7 V內部蓄(xu)電池(chi)(chi)充(chong)(chong)(chong)電,即使沒(mei)(mei)有任(ren)何充(chong)(chong)(chong)電設備,也可(ke)以(yi)(yi)用手(shou)壓發電機(ji)(ji)來給數(shu)(shu)碼(ma)產(chan)(chan)品充(chong)(chong)(chong)電。以(yi)(yi)上(shang)介(jie)紹的(de)就(jiu)是(shi)本充(chong)(chong)(chong)電器的(de)特別之(zhi)處(chu),也是(shi)該設計(ji)的(de)特別之(zhi)處(chu):即隨(sui)時隨(sui)地(di)(di)給數(shu)(shu)碼(ma)產(chan)(chan)品充(chong)(chong)(chong)電。
1 設計要求
參照國家有關標準,移動通信手持機充電器應符合如下要求:
1)輸入電壓(ya) 交流充(chong)電器輸入額度交流電壓(ya)范(fan)圍應為100~240 V,容差為±10%。
2)輸出電(dian)(dian)壓 充電(dian)(dian)器的額度輸出電(dian)(dian)壓應(ying)為直流5 V,容差(cha)為±5%。
3)輸出電流(liu) 充電器的額度輸出電流(liu)范(fan)圍應為300~1 800 mA。
4)輸(shu)出波紋(wen) ①輸(shu)出電(dian)流波紋(wen):輸(shu)入(ru)(ru)電(dian)壓(90~264 V)時,模(mo)擬負載上的(de)電(dian)壓范(fan)圍(1.50~4.75 V),輸(shu)出波紋(wen)極限小(xiao)(xiao)于(yu)(yu)等于(yu)(yu)100 mA峰值。②輸(shu)出電(dian)壓波紋(wen):輸(shu)入(ru)(ru)電(dian)壓(90~264 V)時,模(mo)擬負載上的(de)電(dian)壓范(fan)圍(1.50~4.75 V),輸(shu)出波紋(wen)極限小(xiao)(xiao)于(yu)(yu)等于(yu)(yu)200 mV峰值。③短路電(dian)流:輸(shu)入(ru)(ru)電(dian)壓(90~264V)時,負載短路,短路電(dian)流限值小(xiao)(xiao)于(yu)(yu)950 mA。
5)電(dian)(dian)流倒灌 在(zai)任(ren)何情況下,無論充電(dian)(dian)器是否插上電(dian)(dian)源,由手持機測流向充電(dian)(dian)器的電(dian)(dian)流應不大(da)于5 mA。
6)無負載能(neng)量消耗輸(shu)入電壓(100~240 V)時,負載開路,輸(shu)出波紋(wen)極限(xian)小于300 mW。
7)充電器(qi)平(ping)均效(xiao)率 充電器(qi)平(ping)均效(xiao)率應不小(xiao)于50%。
8)干電(dian)池充電(dian)設計要求 充電(dian)電(dian)流(liu)不高于200 mA。
2 系統(tong)整體設計
充電器分(fen)為高壓(ya)(ya)、充電(dian)管理、升壓(ya)(ya)、邏輯控制照明燈、內部蓄電(dian)池、干(gan)電(dian)池、手動按壓(ya)(ya)等功能模(mo)塊。系統整(zheng)體結構框圖如圖1所(suo)示。
2.1 高壓模塊
該(gai)電(dian)(dian)(dian)路(lu)接通(tong)(tong)交流(liu)(liu)220 V經(jing)整流(liu)(liu)橋后(hou),形成直流(liu)(liu)電(dian)(dian)(dian)壓(ya)(ya),經(jing)C1,C2濾波(bo)(bo)后(hou),該(gai)電(dian)(dian)(dian)壓(ya)(ya)經(jing)開(kai)關變壓(ya)(ya)器T1的(de)(de)(de)1,2引(yin)腳(jiao)施加(jia)到(dao)三極(ji)(ji)(ji)管VQ2的(de)(de)(de)C極(ji)(ji)(ji),同時(shi)(shi)該(gai)電(dian)(dian)(dian)壓(ya)(ya)為三極(ji)(ji)(ji)管VQ2的(de)(de)(de)基極(ji)(ji)(ji)(B)提供一(yi)個(ge)正(zheng)向偏置(zhi)電(dian)(dian)(dian)壓(ya)(ya),使(shi)三極(ji)(ji)(ji)管VQ2導(dao)通(tong)(tong)。R4,無極(ji)(ji)(ji)電(dian)(dian)(dian)容(rong)C4和(he)肖(xiao)特基二極(ji)(ji)(ji)管VD3起保護作用(yong)。此時(shi)(shi)振蕩(dang)電(dian)(dian)(dian)路(lu)開(kai)始工作,開(kai)關變壓(ya)(ya)器T1的(de)(de)(de)l,2腳(jiao)中有(you)電(dian)(dian)(dian)流(liu)(liu)通(tong)(tong)過,在變壓(ya)(ya)器T1的(de)(de)(de)3,4腳(jiao)的(de)(de)(de)感應(ying)電(dian)(dian)(dian)壓(ya)(ya)通(tong)(tong)過電(dian)(dian)(dian)阻R12加(jia)到(dao)三極(ji)(ji)(ji)管VQ2的(de)(de)(de)基極(ji)(ji)(ji),使(shi)VQ2的(de)(de)(de)基極(ji)(ji)(ji)導(dao)通(tong)(tong)電(dian)(dian)(dian)流(liu)(liu)加(jia)大(da),迅(xun)速進入(ru)飽和(he)區。當(dang)電(dian)(dian)(dian)流(liu)(liu)大(da)于0.5 A,U2導(dao)通(tong)(tong),把VQ2的(de)(de)(de)基極(ji)(ji)(ji)電(dian)(dian)(dian)壓(ya)(ya)拉低(di),集電(dian)(dian)(dian)極(ji)(ji)(ji)(C)電(dian)(dian)(dian)流(liu)(liu)開(kai)始減(jian)(jian)少(shao),變壓(ya)(ya)器T1的(de)(de)(de)1,2引(yin)腳(jiao)產生的(de)(de)(de)磁通(tong)(tong)量也(ye)開(kai)始減(jian)(jian)少(shao)。VQ3部分為限流(liu)(liu)作用(yong),當(dang)R23,R24增(zeng)(zeng)大(da)時(shi)(shi)電(dian)(dian)(dian)流(liu)(liu)減(jian)(jian)少(shao),減(jian)(jian)少(shao)時(shi)(shi)電(dian)(dian)(dian)流(liu)(liu)增(zeng)(zeng)大(da)。TL431為恒流(liu)(liu)源,輸(shu)出(chu)穩定的(de)(de)(de)電(dian)(dian)(dian)壓(ya)(ya)5 V,使(shi)光耦(ou)工作,這(zhe)樣電(dian)(dian)(dian)路(lu)中才(cai)不斷的(de)(de)(de)產生振蕩(dang)電(dian)(dian)(dian)壓(ya)(ya),在變壓(ya)(ya)器Tl的(de)(de)(de)6引(yin)腳(jiao)感應(ying)出(chu)一(yi)個(ge)5 V的(de)(de)(de)直流(liu)(liu)電(dian)(dian)(dian)壓(ya)(ya),經(jing)二極(ji)(ji)(ji)管VD4整流(liu)(liu)、電(dian)(dian)(dian)容(rong)C4,C5濾波(bo)(bo)后(hou),通(tong)(tong)過標準USB為外部數碼(ma)產品充電(dian)(dian)(dian)。圖(tu)2為高壓(ya)(ya)模(mo)塊電(dian)(dian)(dian)路(lu)圖(tu)。
2.2 充電管理器件BQ2057
此充(chong)電(dian)(dian)器中(zhong),接通市電(dian)(dian)后為內部蓄電(dian)(dian)池充(chong)電(dian)(dian)的同時(shi),此器件(jian)的輸出電(dian)(dian)壓(ya)為4.2 V,從(cong)而通過SMT插座為外部數碼產(chan)品(pin)充(chong)電(dian)(dian)。在充(chong)電(dian)(dian)過程中(zhong),電(dian)(dian)流(liu)(liu)開始恒流(liu)(liu)并(bing)且(qie)逐漸(jian)下(xia)降,而電(dian)(dian)壓(ya)逐漸(jian)上升(sheng)最后恒壓(ya)。電(dian)(dian)流(liu)(liu)接近零時(shi),充(chong)電(dian)(dian)完成。
2.3 邏輯控制照(zhao)明燈模塊
當(dang)接入干電池(chi)時(shi),按一(yi)下開關燈(deng)亮,再按一(yi)下燈(deng)滅。這個(ge)模(mo)塊里(li)的燈(deng)為手電筒用于照(zhao)明,其電流(liu)不超過200 mA。
3 PCB設計
通常的充電器都為單面板,并且體積比較小,而研制的充電器為雙面板,考(kao)慮到充電器外殼的形狀(zhuang)和大(da)小,所(suo)以(yi)元器件(jian)貼(tie)片(pian)的較多;因為有手壓裝置,所(suo)以(yi)要注意元器件(jian)的擺放位置。
4 數據測量
根據國家標準的要求,在實驗中:1)當輸入電壓范圍在90~264 V之間時,空載時輸出直流電壓在4.77~4.96 V,輸出電流在O.31~0.32 A;2)在測試電流波紋時,噪聲很少,輸入電壓90~260 V時模擬負載上電壓為1.49~4.75 V,輸出電流波紋限值150 mA/5.6 Ω~160 mA/11 Ω;3)在測試電壓波紋時,輸入電壓90~260 V時模擬負載上電壓為1.49~4.75 V,輸出電壓波紋限值150~160 mV;4)當輸入電壓9~260 V負載短路時,短路電流限值540~800 mA:5)當輸入電壓100~260 V空載時功率消耗限值為2.9 mA×100 V~1 mAx240 V;6)當輸入電壓220 V,輸入電流12 mA時輸入功率為640 mW。輸出電壓5.1 V,輸出電流0.3 A時輸出功率為1 530 mW:7)平均效率為57%;8)測量過程中電流無倒灌現象。此測試結果表明本充電器完全符合國家標準。
利用高壓模塊(kuai)(kuai)和充電(dian)(dian)管理模塊(kuai)(kuai)為外部數(shu)碼產(chan)品充電(dian)(dian),并且給出充電(dian)(dian)過程(cheng)中(zhong)電(dian)(dian)壓和電(dian)(dian)流的(de)測試數(shu)據及其(qi)變化趨勢。
1)通(tong)過(guo)市電(dian)(dian)利用(yong)標準USB給外部數碼(ma)產品充(chong)電(dian)(dian),電(dian)(dian)池為(wei)910mAh,每隔l min記一次電(dian)(dian)壓和電(dian)(dian)流(liu)的(de)變化,此實驗的(de)數據如(ru)表(biao)1。充(chong)電(dian)(dian)過(guo)程(cheng)電(dian)(dian)壓電(dian)(dian)流(liu)變化趨勢如(ru)圖3所示,從圖3中可(ke)明(ming)顯(xian)看(kan)出,充(chong)電(dian)(dian)過(guo)程(cheng)的(de)電(dian)(dian)壓由開始(shi)5.28 V逐漸
