在市場上，能(neng)量(liang)收(shou)(shou)集(ji)(ji) IC 剛(gang)剛(gang)進入最初采用階段。能(neng)量(liang)收(shou)(shou)集(ji)(ji) IC 可將適合的換能(neng)器輸(shu)出轉換成電流，用于(yu)電池充電器設備。盡(jin)管能(neng)量(liang)收(shou)(shou)集(ji)(ji)自 2000 年(nian)初就已經出現了，但(dan)是最近的技術(shu)發展才將能(neng)量(liang)收(shou)(shou)集(ji)(ji)推進到可商用的程度。在能(neng)量(liang)收(shou)(shou)集(ji)(ji)應用領域有很多機會(hui)，包括(kuo)：

　　? 在(zai)更(geng)換電(dian)池不方便、不現實(shi)或危險的情(qing)況下，取代電(dian)池供(gong)電(dian)系統或給電(dian)池供(gong)電(dian)系統再充電(dian)

　　? 無需導線(xian)來供(gong)電(dian)或(huo)傳送(song)數據

　　? 用智能無線傳(chuan)感器網絡監視和優(you)化復雜的工業過程(cheng)、安裝(zhuang)在偏(pian)遠現場的設備、以及(ji)大樓的加熱(re)和冷卻系(xi)統(tong)

　　? 從工業(ye)過程(cheng)、太陽能(neng)電池(chi)板、內燃機(ji)等(deng)收集(ji)否則會浪費掉的熱量

　　? 各種不同的消費電子產品的附屬充電器

　　在這些應(ying)用中，有很(hen)多(duo)含(han)有固(gu)有的斷(duan)續(xu)或低(di)功(gong)率電(dian)源。而且，有很(hen)多(duo)應(ying)用將需要給電(dian)池充(chong)電(dian)，以提供一(yi)個備份(fen)電(dian)源。

　　并聯(lian)電(dian)(dian)(dian)壓基準簡單易用，已經出(chu)現很多年了，有(you)大量產品(pin)。不過，這類基準不能有(you)效地給電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)。要配置一(yi)個并聯(lian)電(dian)(dian)(dian)壓基準以給電(dian)(dian)(dian)池(chi)有(you)效充電(dian)(dian)(dian)是極端復雜(za)的(de)。此(ci)外，用一(yi)個小電(dian)(dian)(dian)流(liu)電(dian)(dian)(dian)源或一(yi)個斷續性能量收集(ji)電(dian)(dian)(dian)源準確和安(an)全地給鋰離子 / 聚合(he)物(wu)、幣(bi)形電(dian)(dian)(dian)池(chi)或薄(bo)膜電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)，一(yi)直是難以實(shi)現的(de)。

　　從電(dian)(dian)(dian)(dian)池(chi)(chi)方面來看，盡管技術(shu)(shu)已(yi)(yi)經改(gai)進了，但是(shi)(shi)便(bian)攜式(shi)電(dian)(dian)(dian)(dian)子設備(bei)的(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)或電(dian)(dian)(dian)(dian)池(chi)(chi)組仍(reng)然需要保護(hu)和(he)查驗，以(yi)保持電(dian)(dian)(dian)(dian)池(chi)(chi)在最(zui)佳狀態運行。鋰離子 / 聚合(he)物電(dian)(dian)(dian)(dian)池(chi)(chi)技術(shu)(shu)已(yi)(yi)經成熟，是(shi)(shi)很(hen)(hen)多電(dian)(dian)(dian)(dian)子設備(bei)流行的(de)(de)(de)電(dian)(dian)(dian)(dian)源選擇，因為這(zhe)類電(dian)(dian)(dian)(dian)池(chi)(chi)能(neng)量(liang)密(mi)度(du)(du)高、自放電(dian)(dian)(dian)(dian)很(hen)(hen)少、需要很(hen)(hen)少的(de)(de)(de)維護(hu)、電(dian)(dian)(dian)(dian)壓(ya)范(fan)圍很(hen)(hen)寬并具有(you)(you)其他一(yi)些(xie)特色。幣(bi)形電(dian)(dian)(dian)(dian)池(chi)(chi)能(neng)量(liang)密(mi)度(du)(du)高、放電(dian)(dian)(dian)(dian)特性穩定(ding)、重量(liang)輕(qing)且外(wai)形尺寸小。薄膜(mo)電(dian)(dian)(dian)(dian)池(chi)(chi)是(shi)(shi)一(yi)種(zhong)新(xin)出現的(de)(de)(de)技術(shu)(shu)，優勢(shi)是(shi)(shi)允許非常多的(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)周(zhou)期(qi)次數(shu)，并具有(you)(you)物理靈活性，即視最(zui)終應用的(de)(de)(de)不同(tong)而不同(tong)，薄膜(mo)電(dian)(dian)(dian)(dian)池(chi)(chi)可(ke)以(yi)做成幾乎任何形狀。不過，如果(guo)不能(neng)正確充(chong)電(dian)(dian)(dian)(dian)和(he)查驗，那么所有(you)(you)這(zhe)些(xie)類型(xing)的(de)(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)都(dou)可(ke)能(neng)受到一(yi)些(xie)有(you)(you)害影響(xiang)。

　　低(di)功耗充電器的設計挑戰

　　可調并聯基(ji)準可被設定以(yi)提供(gong)恰(qia)當的(de)電(dian)(dian)池(chi)(chi)浮(fu)置電(dian)(dian)壓，但(dan)是這類基(ji)準缺乏電(dian)(dian)池(chi)(chi)充電(dian)(dian)器的(de) NTC 功(gong)能。更重(zhong)要的(de)是，所需的(de)工作(zuo)電(dian)(dian)流太高了，以(yi)至于用(yong)低功(gong)率電(dian)(dian)源或斷(duan)續(xu)性電(dian)(dian)源給電(dian)(dian)池(chi)(chi)充電(dian)(dian)是不(bu)現(xian)(xian)實的(de)。或者，可以(yi)用(yong)一(yi)個(ge)(ge)齊納二極管、一(yi)些電(dian)(dian)阻器、一(yi)個(ge)(ge) NPN 晶體管和一(yi)些比較器構成一(yi)個(ge)(ge)分(fen)立式并聯基(ji)準，以(yi)提供(gong) NTC 功(gong)能。不(bu)過，這樣的(de)并聯基(ji)準仍然受到(dao)前述限制。此外(wai)，分(fen)立式并聯基(ji)準實現(xian)(xian)起來(lai)比較復雜，相比之下，會占用(yong)更多(duo)寶貴的(de) PCB 面積。

　　典(dian)型(xing)的(de)(de)電(dian)(dian)池(chi)充(chong)電(dian)(dian)器(qi) IC 需(xu)要恒(heng)定 DC 輸入電(dian)(dian)壓，而且不能處理能量突發(fa)。不過(guo)，諸如室內光伏(fu)陣(zhen)列或壓電(dian)(dian)換能器(qi)等(deng)斷續性(xing)能量收集電(dian)(dian)源提(ti)供的(de)(de)是功率(lv)突發(fa)。要用這類能源給電(dian)(dian)池(chi)充(chong)電(dian)(dian)，一(yi)個靜(jing)態工作電(dian)(dian)流低于 1uA 的(de)(de)獨特 IC 是必需(xu)的(de)(de)。

　　鋰離(li)(li)子(zi) / 聚合物化學組成的(de)電(dian)(dian)池(chi)提供便(bian)攜(xie)式(shi)電(dian)(dian)子(zi)設(she)備必需的(de)高性能(neng)，但是這類電(dian)(dian)池(chi)必須小心使用(yong)。例如，如果用(yong)比建(jian)議(yi)浮置電(dian)(dian)壓(ya)高 100mV 的(de)電(dian)(dian)壓(ya)充(chong)電(dian)(dian)，鋰離(li)(li)子(zi) / 聚合物電(dian)(dian)池(chi)可能(neng)變得不穩定。此外，高壓(ya)和(he)高溫同(tong)時(shi)(shi)存在會(hui)對(dui)電(dian)(dian)池(chi)壽命產(chan)生(sheng)有害影響(xiang)，而且在極端情況(kuang)下，可能(neng)導致電(dian)(dian)池(chi)自毀。就幣(bi)形電(dian)(dian)池(chi)和(he)薄膜電(dian)(dian)池(chi)而言，除(chu)了高溫和(he)高壓(ya)同(tong)時(shi)(shi)存在可能(neng)產(chan)生(sheng)有害影響(xiang)，還有容量問題，因為它們的(de)外形尺寸很小。

　　并聯架構的基本(ben)要(yao)素和(he)好處(chu)

　　并(bing)(bing)聯(lian)基(ji)(ji)準(zhun)(zhun)(zhun)是(shi)電(dian)(dian)流饋送型、兩端子電(dian)(dian)路，在(zai)達到目標(biao)電(dian)(dian)壓之前不吸取電(dian)(dian)流。并(bing)(bing)聯(lian)基(ji)(ji)準(zhun)(zhun)(zhun)用起來像一(yi)個(ge)齊納二(er)極(ji)管(guan)，而且在(zai)電(dian)(dian)路原(yuan)理圖上(shang)常常顯示為一(yi)個(ge)齊納二(er)極(ji)管(guan)。不過，大多數并(bing)(bing)聯(lian)基(ji)(ji)準(zhun)(zhun)(zhun)實際上(shang)都是(shi)基(ji)(ji)于帶隙基(ji)(ji)準(zhun)(zhun)(zhun)電(dian)(dian)壓的。

　　一(yi)個(ge)并聯基準僅需要單個(ge)外部電阻器來調節輸出電壓(ya)，從而極其容易使用。沒有最高輸入(ru)電壓(ya)限制(zhi)，最低輸入(ru)電壓(ya)由基準電壓(ya)值設定，因為需要一(yi)些空間以正常運行。

　　此外，并聯(lian)基(ji)準在(zai)(zai)寬電流范(fan)圍內有(you)良(liang)好的穩定性。很多并聯(lian)基(ji)準在(zai)(zai)有(you)大型(xing)或小(xiao)型(xing)容性負載時都是穩定的。

　　滿足前述電池充電器 IC 設計限(xian)制的(de)任何解決方案都必須兼有如下特(te)性：并(bing)聯(lian)穩壓器(qi)的(de)特(te)性;能用低功率(lv)連續或(huo)斷續性電(dian)源(yuan)充電(dian)的(de)電(dian)池(chi)(chi)(chi)(chi)充電(dian) IC 的(de)特(te)性。這樣的(de)器(qi)件(jian)還需要保(bao)護鋰離(li)子/聚合物電(dian)池(chi)(chi)(chi)(chi)、幣(bi)形(xing)電(dian)池(chi)(chi)(chi)(chi)、薄膜電(dian)池(chi)(chi)(chi)(chi)或(huo)電(dian)池(chi)(chi)(chi)(chi)組的(de)安全(quan)，并(bing)使電(dian)池(chi)(chi)(chi)(chi)或(huo)電(dian)池(chi)(chi)(chi)(chi)組達到最高性能。

　　凌力爾特開發(fa)了業界第(di)一款并(bing)聯(lian)架構電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi) LTC4070 和 LTC4071，以(yi)(yi)(yi)滿足這(zhe)類(lei)應(ying)用(yong)的(de)(de)需求(qiu)。LTC4070 是一款易(yi)用(yong)、纖巧(qiao)的(de)(de)并(bing)聯(lian)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)系統 IC，適用(yong)于鋰(li)離(li)子(zi) / 聚(ju)合物(wu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)、幣(bi)形(xing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)或薄膜電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。該 IC 的(de)(de)工(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)流為 450nA，可(ke)保護(hu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)，并(bing)可(ke)用(yong)以(yi)(yi)(yi)前(qian)不能使(shi)用(yong)的(de)(de)非(fei)(fei)常(chang)小電(dian)(dian)(dian)(dian)(dian)(dian)流的(de)(de)斷(duan)續性或連續性充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)給(gei)這(zhe)些電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。增加一個(ge)外部 PMOS 并(bing)聯(lian)器(qi)件，LTC4070 的(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流就可(ke)以(yi)(yi)(yi)從 50mA 提高到 500mA。當電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)溫度升高時，內部電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)熱量(liang)查(cha)驗器(qi)降低(di)浮(fu)置電(dian)(dian)(dian)(dian)(dian)(dian)壓，以(yi)(yi)(yi)保護(hu)鋰(li)離(li)子(zi) / 聚(ju)合物(wu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)安全。通過串(chuan)聯(lian)配置幾個(ge) LTC4070，可(ke)以(yi)(yi)(yi)給(gei)由多(duo)節(jie)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組成的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)組充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，并(bing)實現(xian)各節(jie)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)容量(liang)平衡(heng)。LTC4070 采用(yong)扁(bian)平 (0.75mm) 8 引(yin)線 2mm x 3mm DFN 封(feng)裝，僅用(yong)單個(ge)外部電(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi) (要求(qiu)與輸入電(dian)(dian)(dian)(dian)(dian)(dian)壓串(chuan)聯(lian)) 就能組成一個(ge)完整(zheng)和超(chao)緊湊的(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)解決方案。該器(qi)件的(de)(de)功能集(ji)(ji)使(shi)其非(fei)(fei)常(chang)適用(yong)于連續性和斷(duan)續性低(di)功率充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)應(ying)用(yong)，包(bao)括鋰(li)離(li)子(zi) / 聚(ju)合物(wu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)備份、薄膜電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)、幣(bi)形(xing)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)、存儲器(qi)備份、太陽能供電(dian)(dian)(dian)(dian)(dian)(dian)系統、嵌入式(shi)汽車和能量(liang)收集(ji)(ji)。

　　LTC4070提供引腳可選的(de)(de) 4.0V、4.1V 和(he) 4.2V 設(she)置，其準確(que)度為 1% 的(de)(de)電(dian)(dian)(dian)(dian)(dian)池浮置電(dian)(dian)(dian)(dian)(dian)壓允(yun)許(xu)用戶(hu)在電(dian)(dian)(dian)(dian)(dian)池能(neng)(neng)量(liang)密度和(he)壽命之間進行取舍。獨立的(de)(de)低電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)量(liang)和(he)高電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)量(liang)監察狀(zhuang)(zhuang)態輸出(chu)(chu)指示放電(dian)(dian)(dian)(dian)(dian)或完全充電(dian)(dian)(dian)(dian)(dian)的(de)(de)電(dian)(dian)(dian)(dian)(dian)池。再加上一個與負載(zai)(zai)串聯的(de)(de)外部 P-FET，該低電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)量(liang)狀(zhuang)(zhuang)態輸出(chu)(chu)可實現鎖斷(duan)功(gong)能(neng)(neng)，該功(gong)能(neng)(neng)自動斷(duan)接系統負載(zai)(zai)和(he)電(dian)(dian)(dian)(dian)(dian)池，以防止(zhi)電(dian)(dian)(dian)(dian)(dian)池深度放電(dian)(dian)(dian)(dian)(dian)。

　　除(chu)了緊湊的(de) 2mm x 3mm 8 引線(xian)(xian) DFN 封裝，LTC4070 還(huan)采用 8 引線(xian)(xian) MSOP。這些器件規定在 -40?C 至 125?C 的(de)溫度范圍內工作。

　　通過(guo)防止電(dian)池(chi)電(dian)壓(ya)超過(guo)設(she)定水平(ping)，LTC4070 提供了一(yi)個簡單、可(ke)靠(kao)、高(gao)性(xing)能的電(dian)池(chi)保護和(he)充電(dian)解決方案。其并聯(lian)架構在(zai)輸入(ru)(ru)電(dian)源(yuan)和(he)電(dian)池(chi)之間僅需要一(yi)個電(dian)阻器，就可(ke)應(ying)對(dui)多種電(dian)池(chi)應(ying)用。當輸入(ru)(ru)電(dian)源(yuan)去掉，且電(dian)池(chi)電(dian)壓(ya)低于高(gao)的電(dian)池(chi)輸出(chu)門限時，LTC4070 僅從(cong)電(dian)池(chi)吸取 450nA 電(dian)流。

　　當(dang)電(dian)(dian)(dian)池電(dian)(dian)(dian)壓低于設定(ding)的浮(fu)置電(dian)(dian)(dian)壓時(shi)，充電(dian)(dian)(dian)速率由輸(shu)入(ru)電(dian)(dian)(dian)壓、電(dian)(dian)(dian)池電(dian)(dian)(dian)壓和(he)輸(shu)入(ru)電(dian)(dian)(dian)阻器決定(ding)：

　　ICHG = (VIN ? VBAT) / RIN

　　當電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓接(jie)近(jin)浮置電(dian)(dian)(dian)(dian)(dian)(dian)壓時(shi)，LTC4070 從電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)分(fen)走一部分(fen)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，從而降(jiang)低了充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。在整個溫度范圍內變化浮置電(dian)(dian)(dian)(dian)(dian)(dian)壓的準確(que)度為 ±1% 時(shi)，LTC4070 可(ke)以分(fen)走高達 50mA 的電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。分(fen)流(liu)限制(zhi)了最(zui)大充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，不過通(tong)過增加(jia)一個外(wai)部 P 溝道 MOSFET，50mA 的內部分(fen)流(liu)能(neng)力(li)還可(ke)以提高，參見圖 1。

　　在內部，LTC4070 采用了一個由放大器 EA (參見圖(tu) 2) 驅(qu)動的(de) P 溝道 MOSFET。VCC 和 GND 之(zhi)間(jian)(jian)的(de)電(dian)壓(ya)達(da)到 VF (即并(bing)聯(lian)電(dian)壓(ya)) 之(zhi)前，流(liu)(liu)(liu)經該(gai)器件的(de)電(dian)流(liu)(liu)(liu)為零。VF 可(ke)以由 ADJ 和 NTC 改變，但始終在 3.8V 到 4.2V 之(zhi)間(jian)(jian)。如(ru)果 VCC 電(dian)壓(ya)低于這個值(zhi)，那么 PFET 中的(de)電(dian)流(liu)(liu)(liu)為零。如(ru)果 VCC電(dian)壓(ya)試圖(tu)上(shang)升到超(chao)過 VF，那么電(dian)流(liu)(liu)(liu)將流(liu)(liu)(liu)過該(gai)器件，以防止電(dian)壓(ya)上(shang)升，這就是分流(liu)(liu)(liu)。

　　工作電流是給該芯片中(zhong)其(qi)余所(suo)(suo)有電路供電所(suo)(suo)需的電流。如(ru)果不存在外部電源(yuan)，那么這(zhe)就是從電池吸取的電流。

　　當(dang)電(dian)(dian)池(chi)(chi)電(dian)(dian)壓低時(shi)(shi)，更多的(de)電(dian)(dian)壓加在輸入電(dian)(dian)阻(zu)器兩端，因此進(jin)入電(dian)(dian)池(chi)(chi)的(de)電(dian)(dian)流(liu) (即充電(dian)(dian)電(dian)(dian)流(liu)) 略大于(yu)電(dian)(dian)池(chi)(chi)完全充電(dian)(dian)時(shi)(shi)的(de)電(dian)(dian)流(liu)。當(dang)電(dian)(dian)池(chi)(chi)充滿電(dian)(dian)時(shi)(shi)，將沒(mei)有電(dian)(dian)流(liu)進(jin)入電(dian)(dian)池(chi)(chi)，所有的(de)輸入電(dian)(dian)流(liu)都將進(jin)入分(fen)流(liu)器。

　　工作電(dian)(dian)流很(hen)重要(yao)，因為它(ta)給(gei)“實際”輸(shu)入電(dian)(dian)源(yuan)的(de)電(dian)(dian)流能(neng)力(li)設定了一個低(di)限制。顯然，一個僅有(you) 100nA驅動(dong)能(neng)力(li)的(de)輸(shu)入電(dian)(dian)源(yuan)不可能(neng)給(gei)采用 LTC4070 的(de)電(dian)(dian)池充電(dian)(dian)。不過，如果有(you) 1uA 的(de)驅動(dong)能(neng)力(li)，就(jiu)能(neng)剩(sheng)下少量電(dian)(dian)流去充電(dian)(dian)。如果能(neng)得到 10uA 的(de)驅動(dong)能(neng)力(li)，那(nei)么該電(dian)(dian)流 90% 以上都可用于充電(dian)(dian)。

　　NTC 電池查驗電路保護電池

　　LTC4070 用一(yi)個(ge)通(tong)過熱(re)量耦合到(dao)電(dian)(dian)池的負溫(wen)度(du)(du)系(xi)數熱(re)敏電(dian)(dian)阻(zu)測量電(dian)(dian)池溫(wen)度(du)(du)。NTC 熱(re)敏電(dian)(dian)阻(zu)的溫(wen)度(du)(du)特(te)性在(zai)電(dian)(dian)阻(zu)-溫(wen)度(du)(du)轉換表(biao)中規(gui)定。在(zai)溫(wen)度(du)(du)高(gao)于(yu) 40°C 以后，每(mei)上升 10°C，內部 NTC 電(dian)(dian)路就降(jiang)低(di)一(yi)次浮置電(dian)(dian)壓，以防止電(dian)(dian)池過熱(re) (參見圖 3 以了(le)解詳細信息)。

　　LTC4070 采用一個電(dian)阻值之比來測(ce)量(liang)(liang)電(dian)池溫(wen)度(du)。LTC4070 在 NTCBIAS 與(yu) GND 引腳(jiao)(jiao)之間(jian)布設了(le)一個具 4 個抽頭(tou)的內部(bu)固定(ding)電(dian)阻分壓(ya)(ya)器。定(ding)期地(di)將這(zhe)些(xie)抽頭(tou)上(shang)的電(dian)壓(ya)(ya)與(yu) NTC 引腳(jiao)(jiao)上(shang)的電(dian)壓(ya)(ya)進行比較，以測(ce)量(liang)(liang)電(dian)池溫(wen)度(du)。為(wei)了(le)節(jie)省(sheng)功率，通過以大約每(mei) 1.5s 一次的頻度(du)把 NTCBIAS 引腳(jiao)(jiao)偏置至 VCC 來定(ding)期測(ce)量(liang)(liang)電(dian)池溫(wen)度(du)。

    LTC4070 具有一個與 ADJ 引腳(jiao)(jiao)相連(lian)(lian)的(de)內置(zhi)(zhi)三態(tai)解碼器，用以提(ti)供 3 種可編程浮置(zhi)(zhi)電(dian)(dian)(dian)壓：4.0V、4.1V、或(huo) 4.2V。當 ADJ 引腳(jiao)(jiao)連(lian)(lian)接(jie)至 GND、浮置(zhi)(zhi)或(huo)連(lian)(lian)接(jie)至 VCC 時，浮置(zhi)(zhi)電(dian)(dian)(dian)壓將被分別設置(zhi)(zhi)為 4.0V、4.1V 或(huo) 4.2V。大(da)約每 1.5s 對 ADJ 引腳(jiao)(jiao)的(de)狀(zhuang)態(tai)進行一次采樣。當 ADJ 引腳(jiao)(jiao)被采樣時，LTC4070 在(zai)其上(shang)施加一個相對較低的(de)阻抗電(dian)(dian)(dian)壓。這種做法可以防(fang)止(zhi)低水平(ping)的(de)電(dian)(dian)(dian)路板漏(lou)電(dian)(dian)(dian)流(liu)破(po)壞設定的(de)浮置(zhi)(zhi)電(dian)(dian)(dian)壓。免(mian)除電(dian)(dian)(dian)阻器不僅縮(suo)減了(le)解決方案的(de)外形(xing)尺寸，而(er)且還由于無需使用大(da)阻值的(de)電(dian)(dian)(dian)阻器而(er)降低了(le)靜態(tai)電(dian)(dian)(dian)流(liu)。

　　另外，該(gai)器(qi)(qi)件(jian)還具有(you)狀態(tai)(tai)輸(shu)出及發送(song)指(zhi)示(shi)信(xin)號(hao)的(de)能力(li)。高電(dian)(dian)池電(dian)(dian)量監視(shi)器(qi)(qi)輸(shu)出 (HBO) 是(shi)(shi)一個高態(tai)(tai)有(you)效 CMOS 輸(shu)出，當(dang)電(dian)(dian)池充滿(man)電(dian)(dian)且電(dian)(dian)流(liu)通過分路(lu)離開 BAT 時，該(gai)輸(shu)出將發出指(zhi)示(shi)信(xin)號(hao)。低(di)電(dian)(dian)池電(dian)(dian)量監視(shi)器(qi)(qi)輸(shu)出 (LBO) 也是(shi)(shi)一個高態(tai)(tai)有(you)效 CMOS 輸(shu)出，當(dang)電(dian)(dian)池放電(dian)(dian)至(zhi) 3.2V 以下(xia)時，此(ci)輸(shu)出將發出對應(ying)的(de)指(zhi)示(shi)信(xin)號(hao)。最(zui)后(hou)，外部驅動器(qi)(qi)輸(shu)出引腳 DRV 可連接至(zhi)外部 P-FET 的(de)柵極以增加分路(lu)電(dian)(dian)流(liu)，從而滿(man)足那些需要(yao) 50mA 以上充電(dian)(dian)電(dian)(dian)流(liu) (最(zui)大 500mA) 的(de)應(ying)用。

　　LTC4071 集成電池組(zu)保護功能

　　LTC4071 也是(shi)一(yi)(yi)(yi)個并聯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)系統，而(er)且(qie)還是(shi)首(shou)款具有集成型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組保(bao)護(hu)功能(neng)(neng)(neng)(neng)(neng) (包括(kuo)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)斷(duan)接(jie)) 的(de)(de)器(qi)(qi)件。相(xiang)比于(yu) LTC4070，LTC4071 的(de)(de)不(bu)同之處包括(kuo)：其(qi)擁有集成型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組保(bao)護(hu)功能(neng)(neng)(neng)(neng)(neng) (低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)斷(duan)接(jie)) 、但充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流能(neng)(neng)(neng)(neng)(neng)力較低(di) (50mA)、靜(jing)態(tai)(tai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流較高 (550nA) 、且(qie)不(bu)具備 LBO。對于(yu)避免低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)由(you)于(yu)自(zi)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)而(er)受損(sun)而(er)言，低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)斷(duan)接(jie)是(shi)一(yi)(yi)(yi)種必(bi)需的(de)(de)關(guan)鍵性功能(neng)(neng)(neng)(neng)(neng)。雖(sui)然(ran) LTC4070 能(neng)(neng)(neng)(neng)(neng)夠利(li)用 LBO 和一(yi)(yi)(yi)個外部 P-FET 來實(shi)現(xian)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)斷(duan)接(jie)功能(neng)(neng)(neng)(neng)(neng)，但該 IC 仍將繼續從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)消耗全部 IQ (約 0.5μA)。即使是(shi)如此之小的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)漏電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流也會在一(yi)(yi)(yi)夜之間導致低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)損(sun)壞。相(xiang)反，LTC4071 集成了(le)(le)(le)一(yi)(yi)(yi)個徹(che)底(di)的(de)(de)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)(liang)(liang)斷(duan)接(jie)功能(neng)(neng)(neng)(neng)(neng)，當(dang)斷(duan)接(jie)時(shi)，從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)吸取(qu)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流接(jie)近零 (在室溫時(shi) <1nA，在 125°C 時(shi) < 25nA)。為了(le)(le)(le)在 LTC4071 中提(ti)供這一(yi)(yi)(yi)功能(neng)(neng)(neng)(neng)(neng)，相(xiang)應于(yu) LTC4070 的(de)(de) LBO 和 DRV 引腳(jiao)被去掉了(le)(le)(le)。參(can)見(jian)圖 4 以了(le)(le)(le)解詳細信(xin)息(xi)。這使 LTC4071 的(de)(de)最大(da)分流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流固定為 50mA (LTC4070 是(shi) 50mA，但采用一(yi)(yi)(yi)個外部 FET，就(jiu)能(neng)(neng)(neng)(neng)(neng)達到 500mA)，而(er)且(qie)將該 IC 的(de)(de)靜(jing)態(tai)(tai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流提(ti)高到了(le)(le)(le) 550nA (LTC4070 的(de)(de)靜(jing)態(tai)(tai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流為 450nA)。下(xia)表 1 總結了(le)(le)(le)這兩個相(xiang)互關(guan)聯的(de)(de) IC 之間的(de)(de)差別(bie)。

　　結論

　　并(bing)聯基(ji)準(zhun)有(you)很(hen)多(duo)(duo)應(ying)用(yong)，而(er)(er)且視其功(gong)(gong)(gong)能的(de)不同(tong)而(er)(er)不同(tong)，并(bing)聯基(ji)準(zhun)甚(shen)至可以(yi)用(yong)來給(gei)電(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)。不過(guo)，這(zhe)種(zhong)類型的(de)應(ying)用(yong)有(you)很(hen)多(duo)(duo)缺(que)點，包括大靜(jing)態電(dian)(dian)(dian)(dian)流(liu)和(he)缺(que)乏電(dian)(dian)(dian)(dian)池保(bao)(bao)護(hu)(hu)功(gong)(gong)(gong)能。現在，有(you)了合適(shi)的(de) DC-DC 轉換器或電(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)器，因此可以(yi)對(dui)低功(gong)(gong)(gong)率能量(liang)收集應(ying)用(yong)進行查(cha)驗了。凌力爾特公(gong)司開發了 LTC4070 和(he) LTC4071 并(bing)聯充(chong)(chong)電(dian)(dian)(dian)(dian)器系統，這(zhe)兩款器件適(shi)用(yong)于鋰離子 / 聚合物(wu)電(dian)(dian)(dian)(dian)池、幣形電(dian)(dian)(dian)(dian)池、薄(bo)膜電(dian)(dian)(dian)(dian)池和(he)電(dian)(dian)(dian)(dian)池組(zu)，可為(wei)具(ju)有(you)低功(gong)(gong)(gong)率電(dian)(dian)(dian)(dian)源的(de)領先(xian)應(ying)用(yong)提供一(yi)種(zhong)簡單、有(you)效(xiao)的(de)電(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)和(he)電(dian)(dian)(dian)(dian)池組(zu)保(bao)(bao)護(hu)(hu)解決方案(an)。