在市場上，能(neng)量(liang)收(shou)(shou)集 IC 剛剛進入最初(chu)采用階段。能(neng)量(liang)收(shou)(shou)集 IC 可將適合(he)的(de)換能(neng)器輸出(chu)轉換成電(dian)流，用于電(dian)池充電(dian)器設備(bei)。盡(jin)管(guan)能(neng)量(liang)收(shou)(shou)集自 2000 年初(chu)就(jiu)已經出(chu)現了，但是最近的(de)技術發展才將能(neng)量(liang)收(shou)(shou)集推(tui)進到可商(shang)用的(de)程度。在能(neng)量(liang)收(shou)(shou)集應用領(ling)域有很多機會，包括：

　　? 在更換電(dian)(dian)池不方便、不現(xian)實或危險的情況下(xia)，取代電(dian)(dian)池供電(dian)(dian)系統或給(gei)電(dian)(dian)池供電(dian)(dian)系統再充(chong)電(dian)(dian)

　　? 無需(xu)導(dao)線(xian)來供電或傳送數(shu)據(ju)

　　? 用(yong)智能無線傳感(gan)器網絡監視(shi)和優(you)化復雜的工業過程(cheng)、安(an)裝在偏遠現場的設(she)備、以及大樓(lou)的加熱和冷卻系(xi)統(tong)

　　? 從工業過程、太陽(yang)能(neng)電池(chi)板、內(nei)燃機等(deng)收集否則會浪(lang)費掉的熱量

　　? 各種不同的消費電子產品的附屬充電器

　　在(zai)這些應用中，有(you)很(hen)多含有(you)固有(you)的(de)斷續或(huo)低功率電源。而且，有(you)很(hen)多應用將需要給(gei)電池充電，以(yi)提供一(yi)個備份電源。

　　并(bing)聯電壓基準簡單(dan)易用(yong)(yong)，已經(jing)出現很(hen)多年了，有(you)大量產品。不(bu)(bu)過，這(zhe)類基準不(bu)(bu)能(neng)有(you)效(xiao)地給(gei)電池(chi)充(chong)電。要配置(zhi)一個并(bing)聯電壓基準以給(gei)電池(chi)有(you)效(xiao)充(chong)電是極端復(fu)雜的(de)。此外，用(yong)(yong)一個小電流電源(yuan)或一個斷續性(xing)能(neng)量收集電源(yuan)準確(que)和安全(quan)地給(gei)鋰離子 / 聚合物、幣形電池(chi)或薄膜電池(chi)充(chong)電，一直是難以實現的(de)。

　　從電(dian)(dian)(dian)(dian)池方面來看，盡管技術(shu)已經(jing)改進了，但是(shi)便攜式(shi)電(dian)(dian)(dian)(dian)子(zi)設備的(de)電(dian)(dian)(dian)(dian)池或(huo)電(dian)(dian)(dian)(dian)池組仍然需(xu)要保護和(he)查(cha)驗，以保持電(dian)(dian)(dian)(dian)池在最佳狀(zhuang)態(tai)運行。鋰離子(zi) / 聚合(he)物電(dian)(dian)(dian)(dian)池技術(shu)已經(jing)成(cheng)熟，是(shi)很(hen)多(duo)電(dian)(dian)(dian)(dian)子(zi)設備流行的(de)電(dian)(dian)(dian)(dian)源(yuan)選擇，因為這(zhe)類電(dian)(dian)(dian)(dian)池能量(liang)密度高(gao)、自放電(dian)(dian)(dian)(dian)很(hen)少、需(xu)要很(hen)少的(de)維(wei)護、電(dian)(dian)(dian)(dian)壓(ya)范圍很(hen)寬并具有(you)其他一些特色。幣(bi)形電(dian)(dian)(dian)(dian)池能量(liang)密度高(gao)、放電(dian)(dian)(dian)(dian)特性穩(wen)定、重量(liang)輕且外形尺(chi)寸小。薄膜電(dian)(dian)(dian)(dian)池是(shi)一種(zhong)新出現(xian)的(de)技術(shu)，優(you)勢是(shi)允許非常多(duo)的(de)充(chong)電(dian)(dian)(dian)(dian)周期(qi)次數，并具有(you)物理靈活(huo)性，即視(shi)最終應用的(de)不同(tong)而不同(tong)，薄膜電(dian)(dian)(dian)(dian)池可以做成(cheng)幾乎任(ren)何(he)形狀(zhuang)。不過，如果不能正(zheng)確(que)充(chong)電(dian)(dian)(dian)(dian)和(he)查(cha)驗，那(nei)么所有(you)這(zhe)些類型的(de)電(dian)(dian)(dian)(dian)池都可能受到(dao)一些有(you)害影(ying)響。

　　低功耗充(chong)電器的設(she)計挑戰

　　可(ke)調并聯基(ji)準可(ke)被設定以(yi)(yi)提供恰當的(de)電池浮置電壓，但是這類基(ji)準缺乏電池充電器的(de) NTC 功能。更(geng)重(zhong)要的(de)是，所需的(de)工作電流太高了(le)，以(yi)(yi)至于用(yong)低功率電源或(huo)斷續性(xing)電源給電池充電是不現實(shi)的(de)。或(huo)者，可(ke)以(yi)(yi)用(yong)一(yi)個齊納二極(ji)管(guan)、一(yi)些(xie)電阻器、一(yi)個 NPN 晶體管(guan)和(he)一(yi)些(xie)比較(jiao)器構成一(yi)個分立(li)(li)式并聯基(ji)準，以(yi)(yi)提供 NTC 功能。不過(guo)，這樣的(de)并聯基(ji)準仍然受到前述限制。此外，分立(li)(li)式并聯基(ji)準實(shi)現起來比較(jiao)復雜，相比之下，會占用(yong)更(geng)多寶貴(gui)的(de) PCB 面(mian)積。

　　典型的(de)(de)(de)(de)電(dian)(dian)池充(chong)電(dian)(dian)器 IC 需要恒定 DC 輸入電(dian)(dian)壓，而(er)且不能(neng)(neng)處理(li)能(neng)(neng)量突發。不過，諸(zhu)如室內(nei)光(guang)伏陣列或壓電(dian)(dian)換能(neng)(neng)器等斷續性(xing)能(neng)(neng)量收集電(dian)(dian)源提供(gong)的(de)(de)(de)(de)是(shi)功率突發。要用(yong)這類能(neng)(neng)源給電(dian)(dian)池充(chong)電(dian)(dian)，一個靜態工作電(dian)(dian)流(liu)低于 1uA 的(de)(de)(de)(de)獨特 IC 是(shi)必需的(de)(de)(de)(de)。

　　鋰(li)離子 / 聚(ju)合(he)物化學組成的(de)電(dian)(dian)池(chi)(chi)(chi)提供便攜式電(dian)(dian)子設備必需的(de)高(gao)性能，但是這類電(dian)(dian)池(chi)(chi)(chi)必須小心使用(yong)。例如(ru)(ru)，如(ru)(ru)果用(yong)比建議浮置(zhi)電(dian)(dian)壓(ya)(ya)高(gao) 100mV 的(de)電(dian)(dian)壓(ya)(ya)充電(dian)(dian)，鋰(li)離子 / 聚(ju)合(he)物電(dian)(dian)池(chi)(chi)(chi)可(ke)能變得不穩定(ding)。此(ci)外(wai)，高(gao)壓(ya)(ya)和(he)高(gao)溫同(tong)時存(cun)(cun)在會(hui)對電(dian)(dian)池(chi)(chi)(chi)壽命產生有(you)害影響，而且在極(ji)端情況下(xia)，可(ke)能導(dao)致電(dian)(dian)池(chi)(chi)(chi)自毀。就幣形電(dian)(dian)池(chi)(chi)(chi)和(he)薄膜(mo)電(dian)(dian)池(chi)(chi)(chi)而言(yan)，除了高(gao)溫和(he)高(gao)壓(ya)(ya)同(tong)時存(cun)(cun)在可(ke)能產生有(you)害影響，還有(you)容量(liang)問題，因(yin)為它們的(de)外(wai)形尺寸很小。

　　并聯架構的(de)基本要素和好處

　　并聯基準(zhun)是電流饋送型、兩端子(zi)電路，在達到目標(biao)電壓(ya)之前不吸取電流。并聯基準(zhun)用起(qi)來像一個齊(qi)納二(er)極管，而且(qie)在電路原理圖上(shang)常常顯示為(wei)一個齊(qi)納二(er)極管。不過(guo)，大多(duo)數并聯基準(zhun)實際(ji)上(shang)都是基于(yu)帶隙基準(zhun)電壓(ya)的。

　　一個并(bing)聯基準僅需(xu)要單(dan)個外部電(dian)(dian)(dian)阻器來調節輸出電(dian)(dian)(dian)壓，從而(er)極其容易使用。沒(mei)有最高輸入(ru)電(dian)(dian)(dian)壓限制(zhi)，最低輸入(ru)電(dian)(dian)(dian)壓由(you)基準電(dian)(dian)(dian)壓值設定，因(yin)為需(xu)要一些(xie)空間(jian)以正常運行。

　　此(ci)外(wai)，并聯(lian)基(ji)準在寬電流范圍內(nei)有良好(hao)的穩定性(xing)。很(hen)多并聯(lian)基(ji)準在有大型(xing)或(huo)小型(xing)容性(xing)負載時都(dou)是穩定的。

　　滿足前述電池充電器 IC 設(she)計限制的(de)(de)任何解決方案都必須兼有如下特性(xing)(xing)：并(bing)聯穩壓(ya)器的(de)(de)特性(xing)(xing);能(neng)用低(di)功率連續或斷續性(xing)(xing)電(dian)源充電(dian)的(de)(de)電(dian)池(chi)充電(dian) IC 的(de)(de)特性(xing)(xing)。這樣的(de)(de)器件還需要(yao)保護鋰離子/聚合物(wu)電(dian)池(chi)、幣(bi)形電(dian)池(chi)、薄膜電(dian)池(chi)或電(dian)池(chi)組(zu)的(de)(de)安全，并(bing)使電(dian)池(chi)或電(dian)池(chi)組(zu)達到(dao)最高性(xing)(xing)能(neng)。

　　凌力爾特開發了業界第(di)一款(kuan)并(bing)(bing)(bing)聯架構電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi) LTC4070 和 LTC4071，以(yi)滿足這(zhe)類應用(yong)(yong)的(de)(de)(de)(de)(de)需(xu)求。LTC4070 是(shi)一款(kuan)易用(yong)(yong)、纖巧的(de)(de)(de)(de)(de)并(bing)(bing)(bing)聯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)系統(tong)(tong) IC，適用(yong)(yong)于鋰離子(zi) / 聚(ju)合(he)物電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)、幣(bi)形(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)或(huo)(huo)薄(bo)膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)。該 IC 的(de)(de)(de)(de)(de)工作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)為(wei) 450nA，可(ke)保護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)，并(bing)(bing)(bing)可(ke)用(yong)(yong)以(yi)前不能使用(yong)(yong)的(de)(de)(de)(de)(de)非常小電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)(de)斷(duan)續性或(huo)(huo)連續性充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源給這(zhe)些電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。增加一個(ge)(ge)外(wai)部(bu)(bu)(bu) PMOS 并(bing)(bing)(bing)聯器(qi)(qi)件，LTC4070 的(de)(de)(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)就可(ke)以(yi)從(cong) 50mA 提高(gao)(gao)到(dao) 500mA。當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)溫度升高(gao)(gao)時，內部(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)熱量(liang)查驗(yan)器(qi)(qi)降低(di)浮置電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，以(yi)保護(hu)鋰離子(zi) / 聚(ju)合(he)物電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)(de)(de)(de)安(an)全。通(tong)過(guo)串(chuan)聯配(pei)置幾個(ge)(ge) LTC4070，可(ke)以(yi)給由(you)多節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)組成的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)組充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，并(bing)(bing)(bing)實(shi)現各節電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)(de)(de)(de)容量(liang)平衡。LTC4070 采用(yong)(yong)扁平 (0.75mm) 8 引線(xian) 2mm x 3mm DFN 封裝(zhuang)，僅(jin)用(yong)(yong)單個(ge)(ge)外(wai)部(bu)(bu)(bu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi) (要求與(yu)輸(shu)入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)串(chuan)聯) 就能組成一個(ge)(ge)完整和超緊湊的(de)(de)(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)解決方案。該器(qi)(qi)件的(de)(de)(de)(de)(de)功(gong)能集使其非常適用(yong)(yong)于連續性和斷(duan)續性低(di)功(gong)率充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源應用(yong)(yong)，包括鋰離子(zi) / 聚(ju)合(he)物電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)備份(fen)、薄(bo)膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)、幣(bi)形(xing)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)、存儲器(qi)(qi)備份(fen)、太陽能供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)系統(tong)(tong)、嵌入式(shi)汽車和能量(liang)收集。

　　LTC4070提供引腳可選(xuan)的(de) 4.0V、4.1V 和(he) 4.2V 設(she)置(zhi)，其準確度(du)為 1% 的(de)電(dian)池(chi)(chi)浮(fu)置(zhi)電(dian)壓允許(xu)用戶在電(dian)池(chi)(chi)能量(liang)密度(du)和(he)壽命之間(jian)進(jin)行取舍。獨(du)立的(de)低電(dian)池(chi)(chi)電(dian)量(liang)和(he)高電(dian)池(chi)(chi)電(dian)量(liang)監察狀態輸(shu)出(chu)指(zhi)示放(fang)電(dian)或完(wan)全充電(dian)的(de)電(dian)池(chi)(chi)。再加上一個與負載串聯的(de)外部 P-FET，該低電(dian)池(chi)(chi)電(dian)量(liang)狀態輸(shu)出(chu)可實(shi)現鎖斷(duan)功能，該功能自動斷(duan)接(jie)系統(tong)負載和(he)電(dian)池(chi)(chi)，以防(fang)止電(dian)池(chi)(chi)深度(du)放(fang)電(dian)。

　　除了緊湊的 2mm x 3mm 8 引線 DFN 封裝，LTC4070 還(huan)采(cai)用(yong) 8 引線 MSOP。這些(xie)器件規定在(zai) -40?C 至 125?C 的溫(wen)度(du)范圍(wei)內工(gong)作。

　　通過防止電(dian)池電(dian)壓(ya)超過設定水平，LTC4070 提供了一個簡單(dan)、可靠(kao)、高性能的電(dian)池保護和充(chong)電(dian)解決方案。其(qi)并聯(lian)架(jia)構(gou)在輸(shu)(shu)入電(dian)源(yuan)(yuan)和電(dian)池之間僅需要一個電(dian)阻器(qi)，就(jiu)可應(ying)(ying)對(dui)多種電(dian)池應(ying)(ying)用。當輸(shu)(shu)入電(dian)源(yuan)(yuan)去掉(diao)，且電(dian)池電(dian)壓(ya)低于高的電(dian)池輸(shu)(shu)出門限時，LTC4070 僅從(cong)電(dian)池吸取 450nA 電(dian)流。

　　當電(dian)(dian)池電(dian)(dian)壓(ya)(ya)低于設定的浮(fu)置電(dian)(dian)壓(ya)(ya)時，充電(dian)(dian)速率由輸(shu)入(ru)電(dian)(dian)壓(ya)(ya)、電(dian)(dian)池電(dian)(dian)壓(ya)(ya)和輸(shu)入(ru)電(dian)(dian)阻器決定：

　　ICHG = (VIN ? VBAT) / RIN

　　當電(dian)池電(dian)壓接近浮(fu)置電(dian)壓時，LTC4070 從(cong)電(dian)池分走一(yi)部分電(dian)流(liu)，從(cong)而降低了(le)充(chong)電(dian)電(dian)流(liu)。在(zai)整(zheng)個(ge)溫度范圍內(nei)變化浮(fu)置電(dian)壓的準確度為 ±1% 時，LTC4070 可以分走高達 50mA 的電(dian)流(liu)。分流(liu)限制了(le)最大充(chong)電(dian)電(dian)流(liu)，不過(guo)通過(guo)增加一(yi)個(ge)外部 P 溝道 MOSFET，50mA 的內(nei)部分流(liu)能(neng)力(li)還(huan)可以提高，參見圖 1。

　　在內部，LTC4070 采用(yong)了一(yi)個(ge)由(you)放大(da)器(qi) EA (參見(jian)圖(tu) 2) 驅(qu)動的(de) P 溝道(dao) MOSFET。VCC 和(he) GND 之(zhi)間的(de)電(dian)(dian)壓達到 VF (即(ji)并聯電(dian)(dian)壓) 之(zhi)前，流(liu)經該(gai)器(qi)件(jian)的(de)電(dian)(dian)流(liu)為零。VF 可以(yi)由(you) ADJ 和(he) NTC 改(gai)變，但始(shi)終(zhong)在 3.8V 到 4.2V 之(zhi)間。如(ru)果 VCC 電(dian)(dian)壓低(di)于這(zhe)個(ge)值(zhi)，那么(me) PFET 中的(de)電(dian)(dian)流(liu)為零。如(ru)果 VCC電(dian)(dian)壓試圖(tu)上升到超過 VF，那么(me)電(dian)(dian)流(liu)將(jiang)流(liu)過該(gai)器(qi)件(jian)，以(yi)防止(zhi)電(dian)(dian)壓上升，這(zhe)就是(shi)分(fen)流(liu)。

　　工作電(dian)(dian)流是給該芯片中(zhong)其余所(suo)有電(dian)(dian)路供電(dian)(dian)所(suo)需的電(dian)(dian)流。如果不存在外部(bu)電(dian)(dian)源，那么這就是從電(dian)(dian)池吸(xi)取的電(dian)(dian)流。

　　當電(dian)(dian)池(chi)(chi)電(dian)(dian)壓低時(shi)(shi)(shi)，更多的電(dian)(dian)壓加在(zai)輸(shu)入(ru)電(dian)(dian)阻(zu)器兩端，因此進入(ru)電(dian)(dian)池(chi)(chi)的電(dian)(dian)流(liu)(liu) (即(ji)充電(dian)(dian)電(dian)(dian)流(liu)(liu)) 略大于電(dian)(dian)池(chi)(chi)完全充電(dian)(dian)時(shi)(shi)(shi)的電(dian)(dian)流(liu)(liu)。當電(dian)(dian)池(chi)(chi)充滿電(dian)(dian)時(shi)(shi)(shi)，將沒有電(dian)(dian)流(liu)(liu)進入(ru)電(dian)(dian)池(chi)(chi)，所有的輸(shu)入(ru)電(dian)(dian)流(liu)(liu)都將進入(ru)分(fen)流(liu)(liu)器。

　　工作(zuo)電(dian)流(liu)很重要，因為它(ta)給“實際(ji)”輸(shu)入電(dian)源的(de)電(dian)流(liu)能(neng)(neng)力(li)設定(ding)了一(yi)個低限制。顯然，一(yi)個僅有 100nA驅動(dong)(dong)能(neng)(neng)力(li)的(de)輸(shu)入電(dian)源不(bu)可(ke)能(neng)(neng)給采用(yong) LTC4070 的(de)電(dian)池充(chong)電(dian)。不(bu)過，如果(guo)有 1uA 的(de)驅動(dong)(dong)能(neng)(neng)力(li)，就(jiu)能(neng)(neng)剩下少量電(dian)流(liu)去充(chong)電(dian)。如果(guo)能(neng)(neng)得(de)到 10uA 的(de)驅動(dong)(dong)能(neng)(neng)力(li)，那(nei)么該電(dian)流(liu) 90% 以(yi)上都可(ke)用(yong)于充(chong)電(dian)。

　　NTC 電池查驗(yan)電路保護電池

　　LTC4070 用(yong)一(yi)個通過(guo)熱(re)(re)量耦合(he)到電(dian)(dian)(dian)池的(de)負(fu)溫(wen)(wen)度系數熱(re)(re)敏電(dian)(dian)(dian)阻(zu)測(ce)量電(dian)(dian)(dian)池溫(wen)(wen)度。NTC 熱(re)(re)敏電(dian)(dian)(dian)阻(zu)的(de)溫(wen)(wen)度特(te)性在電(dian)(dian)(dian)阻(zu)-溫(wen)(wen)度轉換(huan)表中規定。在溫(wen)(wen)度高(gao)于(yu) 40°C 以后(hou)，每上升 10°C，內(nei)部 NTC 電(dian)(dian)(dian)路就降低一(yi)次(ci)浮置電(dian)(dian)(dian)壓(ya)，以防止電(dian)(dian)(dian)池過(guo)熱(re)(re) (參見圖 3 以了(le)解詳細(xi)信息)。

　　LTC4070 采用一個電(dian)阻(zu)值(zhi)之比來測量電(dian)池溫度。LTC4070 在 NTCBIAS 與 GND 引(yin)腳(jiao)之間布(bu)設了一個具(ju) 4 個抽(chou)頭的內部固定電(dian)阻(zu)分壓(ya)器。定期地將這(zhe)些抽(chou)頭上的電(dian)壓(ya)與 NTC 引(yin)腳(jiao)上的電(dian)壓(ya)進行比較，以(yi)測量電(dian)池溫度。為了節(jie)省功率，通過以(yi)大約每 1.5s 一次的頻(pin)度把(ba) NTCBIAS 引(yin)腳(jiao)偏置至(zhi) VCC 來定期測量電(dian)池溫度。

    LTC4070 具有一(yi)個與 ADJ 引(yin)(yin)(yin)腳相連(lian)的(de)內置三態(tai)(tai)解(jie)碼器，用以(yi)提(ti)供(gong) 3 種可編(bian)程(cheng)浮(fu)(fu)置電(dian)(dian)壓(ya)：4.0V、4.1V、或 4.2V。當 ADJ 引(yin)(yin)(yin)腳連(lian)接至(zhi) GND、浮(fu)(fu)置或連(lian)接至(zhi) VCC 時(shi)，浮(fu)(fu)置電(dian)(dian)壓(ya)將被(bei)(bei)分別(bie)設(she)置為 4.0V、4.1V 或 4.2V。大約每 1.5s 對 ADJ 引(yin)(yin)(yin)腳的(de)狀態(tai)(tai)進行一(yi)次采(cai)樣(yang)(yang)。當 ADJ 引(yin)(yin)(yin)腳被(bei)(bei)采(cai)樣(yang)(yang)時(shi)，LTC4070 在其上施加一(yi)個相對較(jiao)低的(de)阻(zu)抗電(dian)(dian)壓(ya)。這種做法可以(yi)防止低水平(ping)的(de)電(dian)(dian)路(lu)板漏(lou)電(dian)(dian)流(liu)(liu)破(po)壞設(she)定的(de)浮(fu)(fu)置電(dian)(dian)壓(ya)。免除電(dian)(dian)阻(zu)器不僅縮(suo)減了解(jie)決方案的(de)外形尺寸，而且還由于無需使(shi)用大阻(zu)值的(de)電(dian)(dian)阻(zu)器而降低了靜態(tai)(tai)電(dian)(dian)流(liu)(liu)。

　　另外，該器件還具有(you)狀態(tai)輸(shu)(shu)出(chu)(chu)及發送指(zhi)示信號的(de)(de)能力。高(gao)電(dian)(dian)(dian)池電(dian)(dian)(dian)量監(jian)視(shi)器輸(shu)(shu)出(chu)(chu) (HBO) 是一(yi)個(ge)高(gao)態(tai)有(you)效 CMOS 輸(shu)(shu)出(chu)(chu)，當電(dian)(dian)(dian)池充滿電(dian)(dian)(dian)且電(dian)(dian)(dian)流(liu)通過分(fen)路(lu)離開 BAT 時，該輸(shu)(shu)出(chu)(chu)將發出(chu)(chu)指(zhi)示信號。低電(dian)(dian)(dian)池電(dian)(dian)(dian)量監(jian)視(shi)器輸(shu)(shu)出(chu)(chu) (LBO) 也是一(yi)個(ge)高(gao)態(tai)有(you)效 CMOS 輸(shu)(shu)出(chu)(chu)，當電(dian)(dian)(dian)池放電(dian)(dian)(dian)至 3.2V 以下時，此輸(shu)(shu)出(chu)(chu)將發出(chu)(chu)對應的(de)(de)指(zhi)示信號。最后(hou)，外部驅動器輸(shu)(shu)出(chu)(chu)引腳 DRV 可(ke)連(lian)接至外部 P-FET 的(de)(de)柵極以增加(jia)分(fen)路(lu)電(dian)(dian)(dian)流(liu)，從而滿足那些需要 50mA 以上充電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu) (最大(da) 500mA) 的(de)(de)應用。

　　LTC4071 集成電(dian)池(chi)組保護功(gong)能

　　LTC4071 也(ye)是(shi)(shi)一(yi)(yi)個并聯電(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)器(qi)系(xi)統(tong)，而(er)且(qie)還是(shi)(shi)首款具有集(ji)成(cheng)型電(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)保護功(gong)能 (包括低(di)(di)電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)) 的(de)(de)器(qi)件。相(xiang)比(bi)于 LTC4070，LTC4071 的(de)(de)不(bu)同(tong)之處包括：其擁有集(ji)成(cheng)型電(dian)(dian)(dian)池(chi)(chi)(chi)組(zu)保護功(gong)能 (低(di)(di)電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)) 、但(dan)(dan)充電(dian)(dian)(dian)電(dian)(dian)(dian)流能力較(jiao)低(di)(di) (50mA)、靜(jing)態(tai)(tai)電(dian)(dian)(dian)流較(jiao)高 (550nA) 、且(qie)不(bu)具備 LBO。對于避免低(di)(di)電(dian)(dian)(dian)量(liang)電(dian)(dian)(dian)池(chi)(chi)(chi)由于自放電(dian)(dian)(dian)而(er)受損(sun)而(er)言，低(di)(di)電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)是(shi)(shi)一(yi)(yi)種必需的(de)(de)關(guan)(guan)鍵性(xing)功(gong)能。雖(sui)然 LTC4070 能夠利用 LBO 和一(yi)(yi)個外部(bu) P-FET 來實現低(di)(di)電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)功(gong)能，但(dan)(dan)該 IC 仍將繼續從電(dian)(dian)(dian)池(chi)(chi)(chi)消耗全部(bu) IQ (約 0.5μA)。即使是(shi)(shi)如此之小的(de)(de)電(dian)(dian)(dian)池(chi)(chi)(chi)漏電(dian)(dian)(dian)流也(ye)會在一(yi)(yi)夜之間導(dao)致(zhi)低(di)(di)電(dian)(dian)(dian)量(liang)電(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)損(sun)壞。相(xiang)反，LTC4071 集(ji)成(cheng)了(le)(le)一(yi)(yi)個徹底的(de)(de)低(di)(di)電(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)量(liang)斷(duan)(duan)接(jie)功(gong)能，當斷(duan)(duan)接(jie)時，從電(dian)(dian)(dian)池(chi)(chi)(chi)吸取的(de)(de)電(dian)(dian)(dian)流接(jie)近零(ling) (在室(shi)溫時 <1nA，在 125°C 時 < 25nA)。為(wei)了(le)(le)在 LTC4071 中提供這(zhe)一(yi)(yi)功(gong)能，相(xiang)應于 LTC4070 的(de)(de) LBO 和 DRV 引腳被去(qu)掉了(le)(le)。參見圖 4 以了(le)(le)解詳細信息(xi)。這(zhe)使 LTC4071 的(de)(de)最大(da)分流電(dian)(dian)(dian)流固定(ding)為(wei) 50mA (LTC4070 是(shi)(shi) 50mA，但(dan)(dan)采用一(yi)(yi)個外部(bu) FET，就能達(da)到 500mA)，而(er)且(qie)將該 IC 的(de)(de)靜(jing)態(tai)(tai)電(dian)(dian)(dian)流提高到了(le)(le) 550nA (LTC4070 的(de)(de)靜(jing)態(tai)(tai)電(dian)(dian)(dian)流為(wei) 450nA)。下表 1 總結了(le)(le)這(zhe)兩個相(xiang)互關(guan)(guan)聯的(de)(de) IC 之間的(de)(de)差(cha)別。

　　結論

　　并聯基準有(you)(you)很(hen)多應(ying)用(yong)，而且視其功(gong)(gong)能(neng)(neng)的不同而不同，并聯基準甚至可以用(yong)來給(gei)電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)。不過(guo)，這種(zhong)類(lei)型的應(ying)用(yong)有(you)(you)很(hen)多缺點，包括(kuo)大靜態電(dian)(dian)(dian)(dian)流和(he)缺乏電(dian)(dian)(dian)(dian)池(chi)(chi)保護功(gong)(gong)能(neng)(neng)。現在(zai)，有(you)(you)了合適的 DC-DC 轉換器(qi)或電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)器(qi)，因此可以對低(di)功(gong)(gong)率能(neng)(neng)量收集應(ying)用(yong)進(jin)行查驗了。凌力爾特公(gong)司開(kai)發了 LTC4070 和(he) LTC4071 并聯充電(dian)(dian)(dian)(dian)器(qi)系(xi)統，這兩款器(qi)件(jian)適用(yong)于鋰離子 / 聚合物電(dian)(dian)(dian)(dian)池(chi)(chi)、幣形電(dian)(dian)(dian)(dian)池(chi)(chi)、薄膜電(dian)(dian)(dian)(dian)池(chi)(chi)和(he)電(dian)(dian)(dian)(dian)池(chi)(chi)組，可為具有(you)(you)低(di)功(gong)(gong)率電(dian)(dian)(dian)(dian)源的領先應(ying)用(yong)提供(gong)一種(zhong)簡單(dan)、有(you)(you)效(xiao)的電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)和(he)電(dian)(dian)(dian)(dian)池(chi)(chi)組保護解決方案。