當今科(ke)技所需求的(de)手機電池除了要能(neng)夠長時間供應(ying)穩定電源(yuan)外,體積小重量輕也是(shi)關(guan)鍵。縮小電路板面積、增(zeng)長供電時間與減少成(cheng)本該如(ru)何(he)畢(bi)其功于一(yi)役(yi)？將眾(zhong)多(duo)電源(yuan)管理組件整合在(zai)單一(yi)芯片上(shang)將是(shi)解決(jue)問題(ti)的(de)最好途(tu)徑。

    早期的(de)(de)(de)(de)行(xing)動(dong)電(dian)話不是(shi)體積笨重龐大,就(jiu)是(shi)必須受(shou)到(dao)汽車電(dian)池的(de)(de)(de)(de)束縛,但(dan)經過長時間(jian)的(de)(de)(de)(de)發(fa)展,今天的(de)(de)(de)(de)行(xing)動(dong)電(dian)話已變得非常輕巧,除了(le)電(dian)話功(gong)(gong)能(neng),它(ta)們還會做許多(duo)事。新型3.xG智(zhi)能(neng)型手機(ji)把傳(chuan)統(tong)的(de)(de)(de)(de)2G行(xing)動(dong)電(dian)話和多(duo)種其(qi)它(ta)功(gong)(gong)能(neng)結合在一(yi)(yi)起,包(bao)括PDA、數(shu)字相(xiang)(xiang)機(ji)、音樂播放(fang)機(ji)（MP3）以及全球定位(wei)系(xi)統(tong)（GPS）。如此多(duo)元的(de)(de)(de)(de)功(gong)(gong)能(neng)需要(yao)許多(duo)零件,其(qi)中絕大多(duo)數(shu)的(de)(de)(de)(de)電(dian)源電(dian)壓并不相(xiang)(xiang)同,電(dian)流(liu)需求則不斷增(zeng)加,使得它(ta)們需要(yao)更多(duo)電(dian)力(li)。(圖一(yi)(yi))是(shi)從2G語音電(dian)話升級到(dao)3G視(shi)訊電(dian)話后,功(gong)(gong)率需求增(zeng)加的(de)(de)(de)(de)估(gu)計值。

 

 

    圖(tu)一功(gong)耗值

    在(zai)此(ci)同時(shi)(shi),消費(fei)者卻想(xiang)要更(geng)精巧(qiao)的手(shou)機(ji)。本(ben)文(wen)介紹兩種(zhong)電源管理(li)系統,它們可以協助智(zhi)能型(xing)手(shou)機(ji)設計人員在(zai)彼此(ci)沖突的目標(biao)間取(qu)得平衡(heng),例如將封(feng)裝減至(zhi)最小(xiao),同時(shi)(shi)支持(chi)更(geng)大的功(gong)率需(xu)求(qiu);實現最佳效(xiao)率,讓電池提供(gong)最長的使用時(shi)(shi)間;以及將電源噪聲和(he)漣波降至(zhi)可接受(shou)水平,以支持(chi)新(xin)世代(dai)的行(xing)動電話。

    選擇(ze)電池

    選擇充電電池是電源管理系統設計的首要工作之一,鎳氫電池和鋰離子電池則(ze)是目前僅有的(de)兩種實(shi)際選(xuan)擇。鋰離子(zi)電(dian)(dian)(dian)池(chi)的(de)單位體積蓄(xu)電(dian)(dian)(dian)量為270～300Wh/l,單位重量蓄(xu)電(dian)(dian)(dian)量為110～130Wh/kg,都(dou)高于鎳氫(qing)電(dian)(dian)(dian)池(chi)的(de)220～300Wh/l以及75～100Wh/kg,因(yin)此(ci)在同樣蓄(xu)電(dian)(dian)(dian)量下,鋰離子(zi)電(dian)(dian)(dian)池(chi)的(de)體積和重量都(dou)小于鎳氫(qing)電(dian)(dian)(dian)池(chi);另外,鋰離子(zi)電(dian)(dian)(dian)池(chi)的(de)3.6V工作電(dian)(dian)(dian)壓也(ye)高于鎳氫(qing)電(dian)(dian)(dian)池(chi)的(de)1.2V。

    行動電(dian)(dian)(dian)話的(de)(de)多數功耗都(dou)來(lai)自于(yu)1.2V和3.3V電(dian)(dian)(dian)源,要讓交換(huan)式電(dian)(dian)(dian)源轉換(huan)器發揮最(zui)大工(gong)作效(xiao)率(lv),較(jiao)有效(xiao)的(de)(de)方法通(tong)常是從高電(dian)(dian)(dian)壓轉換(huan)至低電(dian)(dian)(dian)壓,而不是從低電(dian)(dian)(dian)壓轉換(huan)至高電(dian)(dian)(dian)壓,因此(ci)鋰離子電(dian)(dian)(dian)池是最(zui)佳選擇。

    要讓充電電池提供最長使用時間,適當的電池管理和控制就顯得格外重要。電池管理包含三個部份：充電控制、電池監視和電池保護。從使用外接導通組件的線性控制器開始,到內建開關組件且效率更高的交換式控制器,充電控制組件已有長足進步。電池充電器必(bi)須處理(li)500mA到1500mA范(fan)圍內的電流,以便提供快(kuai)速(su)的充(chong)電周期(qi)時間。

    電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)監(jian)(jian)視和保護組(zu)件(jian)通常都(dou)與電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)封裝在(zai)一起,電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)監(jian)(jian)視組(zu)件(jian)可(ke)以是簡(jian)單的(de)「電(dian)(dian)(dian)(dian)(dian)荷計量(liang)器(qi)」（coulombcounter）,由中央處理(li)器(qi)負責(ze)計算電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)剩余(yu)(yu)電(dian)(dian)(dian)(dian)(dian)力(li)(li)(li);也可(ke)以是內建微控制(zhi)器(qi)的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)量(liang)測組(zu)件(jian)（gasgauge）,由它透過(guo)DSP與處理(li)器(qi)之(zhi)間(jian)的(de)簡(jian)單界面,直(zhi)接(jie)提供剩余(yu)(yu)電(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)、剩余(yu)(yu)供電(dian)(dian)(dian)(dian)(dian)時間(jian)、電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓、溫(wen)度和平均電(dian)(dian)(dian)(dian)(dian)流量(liang)測值等資料。

    電源拓樸

    接著,設計工(gong)程師(shi)必須(xu)決定電(dian)源(yuan)(yuan)轉換(huan)(huan)(huan)組件的(de)種(zhong)類,它或許是(shi)(shi)(shi)以(yi)電(dian)感(gan)為基(ji)礎、并(bing)且內建FET開關(guan)的(de)交(jiao)換(huan)(huan)(huan)式電(dian)源(yuan)(yuan)轉換(huan)(huan)(huan)器、無(wu)電(dian)感(gan)的(de)交(jiao)換(huan)(huan)(huan)式電(dian)源(yuan)(yuan)轉換(huan)(huan)(huan)器（電(dian)荷(he)(he)泵浦）或是(shi)(shi)(shi)線性(xing)穩(wen)壓(ya)器。這些轉換(huan)(huan)(huan)器各有(you)其優點。就效(xiao)率(lv)而言,以(yi)電(dian)感(gan)為基(ji)礎的(de)轉換(huan)(huan)(huan)器擁(yong)有(you)最(zui)高的(de)整體效(xiao)率(lv),其次(ci)是(shi)(shi)(shi)電(dian)荷(he)(he)泵浦,最(zui)后(hou)才是(shi)(shi)(shi)線性(xing)穩(wen)壓(ya)器。成本(ben)通常反比于效(xiao)率(lv),因此(ci)線性(xing)穩(wen)壓(ya)器成本(ben)最(zui)低,然后(hou)是(shi)(shi)(shi)電(dian)荷(he)(he)泵浦,最(zui)后(hou)則是(shi)(shi)(shi)以(yi)電(dian)感(gan)為基(ji)礎的(de)轉換(huan)(huan)(huan)器。

  線性穩(wen)(wen)壓器(qi)沒有(you)(you)輸(shu)(shu)出(chu)(chu)漣(lian)波,電(dian)荷泵(beng)浦有(you)(you)一(yi)些(xie)輸(shu)(shu)出(chu)(chu)漣(lian)波,交換式(shi)穩(wen)(wen)壓器(qi)的(de)輸(shu)(shu)出(chu)(chu)漣(lian)波則在三者之間最(zui)(zui)高。就整個解(jie)決方(fang)案的(de)體(ti)積(ji)(ji)(ji)來(lai)看,線性穩(wen)(wen)壓器(qi)的(de)體(ti)積(ji)(ji)(ji)最(zui)(zui)小,通常(chang)只需(xu)輸(shu)(shu)入(ru)和輸(shu)(shu)出(chu)(chu)電(dian)容(rong),電(dian)荷泵(beng)浦除了輸(shu)(shu)入(ru)和輸(shu)(shu)出(chu)(chu)電(dian)容(rong)外,還需(xu)一(yi)顆或兩顆「飛馳」（flying）電(dian)容(rong),交換式(shi)穩(wen)(wen)壓器(qi)則需(xu)要電(dian)感器(qi),因此其封裝體(ti)積(ji)(ji)(ji)會有(you)(you)很大(da)差(cha)異。

    無論DSP或(huo)模擬(ni)數字轉換(huan)器(qi)(qi)等數字零件(jian),或(huo)是電(dian)(dian)(dian)源管(guan)理系統(tong)等模擬(ni)零件(jian),2G電(dian)(dian)(dian)話(hua)幾乎不提供(gong)任何(he)的(de)功(gong)能整合(he),系統(tong)設計人(ren)員在(zai)發展電(dian)(dian)(dian)源管(guan)理系統(tong)時,通(tong)常會以成本和體積為優先(xian)考慮,而不是轉換(huan)效(xiao)率。線(xian)(xian)性穩(wen)壓(ya)器(qi)(qi)只能將輸(shu)入(ru)電(dian)(dian)(dian)壓(ya)轉換(huan)成更(geng)低(di)的(de)輸(shu)出電(dian)(dian)(dian)壓(ya),因此(ci)電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)必須高(gao)于3.3V,此(ci)時可(ke)利用低(di)電(dian)(dian)(dian)流(liu)或(huo)中電(dian)(dian)(dian)流(liu)的(de)線(xian)(xian)性穩(wen)壓(ya)器(qi)(qi)進(jin)行電(dian)(dian)(dian)壓(ya)轉換(huan),以便提供(gong)電(dian)(dian)(dian)力給至2.8V范圍內的(de)其它電(dian)(dian)(dian)源需(xu)求。

    在3G芯片組中,基頻(pin)處(chu)(chu)(chu)理器現(xian)已包(bao)含DSP、微處(chu)(chu)(chu)理器／微控制器、模擬(ni)(ni)數(shu)字轉換器和數(shu)字模擬(ni)(ni)轉換器,用(yong)來控制射頻(pin)訊號(hao)和音頻(pin)訊號(hao)處(chu)(chu)(chu)理。這顆處(chu)(chu)(chu)理器的核心電(dian)(dian)壓(ya)(ya)已降至(zhi)(zhi)1.2V或是更(geng)低,I/O和外圍(wei)電(dian)(dian)壓(ya)(ya)也開始減(jian)少(shao)至(zhi)(zhi)2.5V至(zhi)(zhi)3.0V范圍(wei);由于3.xG電(dian)(dian)話的電(dian)(dian)流需(xu)(xu)求通常都(dou)超過2.G電(dian)(dian)話,3.xG設計(ji)人員需(xu)(xu)要(yao)效率高于線性(xing)穩壓(ya)(ya)器的直(zhi)流電(dian)(dian)源轉換器,以(yi)便提供更(geng)長的電(dian)(dian)池(chi)使用(yong)時間(jian)。為進(jin)一(yi)步延長電(dian)(dian)池(chi)壽命,許多設計(ji)人員必須(xu)盡量利(li)用(yong)鋰離子(zi)電(dian)(dian)池(chi)電(dian)(dian)力,直(zhi)到其(qi)電(dian)(dian)壓(ya)(ya)降至(zhi)(zhi)最小值為止(zhi);在此過程中,如何產(chan)生3.3V電(dian)(dian)壓(ya)(ya)就變成一(yi)項挑戰。

    從(cong)表(biao)面上來看,設計人員若能繼續(xu)使(shi)用電(dian)(dian)(dian)(dian)(dian)(dian)池直到2.7V,并(bing)利用正電(dian)(dian)(dian)(dian)(dian)(dian)源降壓(ya)(ya)―升壓(ya)(ya)轉換器(qi)或(huo)是SEPIC轉換器(qi)提(ti)供(gong)3.3V電(dian)(dian)(dian)(dian)(dian)(dian)源,可攜式(shi)裝置的電(dian)(dian)(dian)(dian)(dian)(dian)池壽(shou)命就會(hui)大幅(fu)延長,但是根據(表(biao)一(yi))針(zhen)對600mAh電(dian)(dian)(dian)(dian)(dian)(dian)池所做的簡(jian)單分析可發現(xian)情形并(bing)非如(ru)此,因(yin)為(wei)無論是采用效(xiao)率更高(gao)的降壓(ya)(ya)轉換器(qi),并(bing)將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)池使(shi)用到3.3V,或(huo)是采用SEPIC之類的轉換器(qi),并(bing)將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)力完全用盡,這兩種(zhong)方式(shi)的供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間幾乎(hu)沒有任(ren)何(he)區別。

    

 

    表(biao)一60mAh電池分析(xi)

    除(chu)此之外,無論是(shi)(shi)(shi)(shi)使(shi)用兩顆(ke)電(dian)感(gan)的(de)(de)SEPIC轉換(huan)器(qi)(qi),或是(shi)(shi)(shi)(shi)某些效(xiao)率(lv)更(geng)高(gao)的(de)(de)新(xin)型正電(dian)源(yuan)降(jiang)壓(ya)―升壓(ya)轉換(huan)器(qi)(qi),它們的(de)(de)成本都更(geng)高(gao),因(yin)此在做整(zheng)體評估時,只使(shi)用3.3V以(yi)上的(de)(de)電(dian)池電(dian)力,然后利(li)用高(gao)效(xiao)率(lv)交換(huan)式(shi)(shi)電(dian)源(yuan)轉換(huan)器(qi)(qi)提供3.3V電(dian)源(yuan)的(de)(de)方法(fa)不但更(geng)有效(xiao)率(lv),還可能是(shi)(shi)(shi)(shi)更(geng)具吸引力的(de)(de)選(xuan)擇。以(yi)下介紹的(de)(de)離散解決方案(an)就是(shi)(shi)(shi)(shi)使(shi)用降(jiang)壓(ya)轉換(huan)器(qi)(qi)提供3.3V電(dian)源(yuan),整(zheng)合式(shi)(shi)解決方案(an)則采(cai)用SEPIC轉換(huan)器(qi)(qi)。

   系統概述

    不同的(de)智能型(xing)手機零件有(you)著不同的(de)電(dian)(dian)(dian)源(yuan)(yuan)需求,(圖(tu)二)是(shi)行動電(dian)(dian)(dian)話中(zhong)需要(yao)電(dian)(dian)(dian)源(yuan)(yuan)的(de)主要(yao)零件簡單(dan)方(fang)塊圖(tu),例如射頻(pin)單(dan)元的(de)壓控振(zhen)蕩器(qi)(qi)（VCO）以(yi)及鎖相回(hui)路（PLL）就(jiu)需要(yao)極低噪聲(sheng)和(he)很(hen)高電(dian)(dian)(dian)源(yuan)(yuan)拒(ju)斥比的(de)電(dian)(dian)(dian)源(yuan)(yuan),確(que)保它們(men)提供最(zui)高的(de)傳送和(he)接收效能,因此雖然線(xian)性穩壓器(qi)(qi)的(de)效率(lv)不高,但由于(yu)它沒有(you)輸出(chu)漣波,所(suo)以(yi)是(shi)這類電(dian)(dian)(dian)源(yuan)(yuan)供應的(de)最(zui)佳選擇(ze);同樣重(zhong)要(yao)的(de)是(shi)將直(zhi)流轉換器(qi)(qi)的(de)開關頻(pin)率(lv),還有(you)它們(men)的(de)二階和(he)三(san)階諧波,都保持在中(zhong)頻(pin)頻(pin)帶之外。

    由(you)于DSP和(he)中央處(chu)理器(qi)的(de)核心電(dian)壓(ya)已降至(zhi)1V左右,以電(dian)感為基礎的(de)高效(xiao)率交換(huan)式降壓(ya)轉換(huan)器(qi)是理想選擇(ze)。至(zhi)于屏幕背光照(zhao)明所使用(yong)的(de)白光二極管,其電(dian)源(yuan)可(ke)來自(zi)電(dian)荷泵浦或電(dian)感式升壓(ya)／降壓(ya)轉換(huan)器(qi)。

    圖二智(zhi)能型手機電源方塊圖

    動態電壓調整（DynamicVoltageScaling）

    從圖一可看出,電(dian)源需求最高的兩顆零件是(shi)在射頻(pin)單元,分別是(shi)發射機的功(gong)率(lv)(lv)放(fang)大(da)器(qi)和基頻(pin)處理器(qi)。隨著電(dian)話與(yu)基地臺之(zhi)間的距離不同,功(gong)率(lv)(lv)放(fang)大(da)器(qi)在通話過程中最多消耗75％的總(zong)功(gong)耗,待命模式則只有(you)30％。采用非線(xian)性(xing)功(gong)率(lv)(lv)放(fang)大(da)器(qi)的舊型GSM電(dian)話發射機的典型工作效率(lv)(lv)約為50％,但是(shi)WCDMA等較新標準(zhun)卻同時(shi)需要振幅及相位(wei)調(diao)變,這只有(you)工作效率(lv)(lv)在25％至35％之(zhi)間的線(xian)性(xing)放(fang)大(da)器(qi)可以提供(gong)。

    除此之外,CDMA20001x手機的正(zheng)常基頻處理(li)(li)器(qi)負載需求是在60至(zhi)120mA范圍,因此提(ti)供最有(you)效率的電源給功率放大器(qi)和處理(li)(li)器(qi)就顯得極(ji)為重要。

    動態／可(ke)(ke)適性(xing)電壓調整(zheng)(zheng)(zheng)技(ji)術（DVS/AVS）與(yu)高整(zheng)(zheng)(zheng)合度組件所(suo)使(shi)用的(de)(de)(de)(de)方式很類似,它(ta)會(hui)把閉回(hui)路系(xi)統中的(de)(de)(de)(de)處理器(qi)和穩壓器(qi)連結(jie)在一起,并(bing)在確保系(xi)統正常工作(zuo)的(de)(de)(de)(de)情形下(xia)(xia),將(jiang)數字電源供應的(de)(de)(de)(de)輸出電壓動態調整(zheng)(zheng)(zheng)至最(zui)小值。功(gong)率(lv)(lv)放(fang)大(da)(da)器(qi)會(hui)被(bei)最(zui)佳(jia)化,使(shi)它(ta)在最(zui)大(da)(da)傳送(song)(song)功(gong)率(lv)(lv)下(xia)(xia)擁有最(zui)高效率(lv)(lv)。由于絕大(da)(da)多數手(shou)機都在基地(di)臺附近(jin)工作(zuo),手(shou)機的(de)(de)(de)(de)無(wu)線電功(gong)能(neng)會(hui)在維持通訊質量的(de)(de)(de)(de)前題下(xia)(xia),將(jiang)傳送(song)(song)功(gong)率(lv)(lv)降至最(zui)低(di)(di)水平。當(dang)功(gong)率(lv)(lv)放(fang)大(da)(da)器(qi)在較低(di)(di)的(de)(de)(de)(de)功(gong)率(lv)(lv)水平下(xia)(xia)工作(zuo)時,它(ta)的(de)(de)(de)(de)效率(lv)(lv)會(hui)受到影(ying)響,從(圖三)可(ke)(ke)以看出,利用動態電壓調整(zheng)(zheng)(zheng)技(ji)術來調整(zheng)(zheng)(zheng)功(gong)率(lv)(lv)放(fang)大(da)(da)器(qi)的(de)(de)(de)(de)電壓,它(ta)的(de)(de)(de)(de)工作(zuo)效率(lv)(lv)會(hui)增加10％至20％。

 

    圖(tu)三功率放大器效率

    數字處(chu)理(li)器的功(gong)耗正比(bi)于(yu)電(dian)(dian)(dian)壓平方,因(yin)此中央(yang)處(chu)理(li)器也(ye)能采(cai)用動態電(dian)(dian)(dian)壓調整技(ji)術;當中央(yang)處(chu)理(li)器進入待命模式或其它(ta)功(gong)能精簡模式,它(ta)就能在較低的頻率頻率下工作(zuo),此時(shi)可將處(chu)理(li)器電(dian)(dian)(dian)壓降低,以便減少功(gong)耗,提升(sheng)工作(zuo)效率,延長電(dian)(dian)(dian)池壽(shou)命。

    就以OMAP1510為例,假設(she)它(ta)的電源是由TPS62200供應,并(bing)使用(yong)1安培小時的3.6V鋰離子(zi)電池輸入,其它(ta)特性(xing)包括(kuo)：

    ●睡眠模式（TPS62200采用PFM調(diao)變）未用動態電(dian)壓調(diao)整：Vout=1.5V@300μA;效率=93％

    ●正常工(gong)作(zuo)模式（TPS62200采用PWM調變）：Vout=1.5V@100mA;效率=96％

    假(jia)設此(ci)組件95％時(shi)間處于(yu)睡眠模(mo)式,5％時(shi)間處于(yu)正常(chang)工作模(mo)式,則從(cong)輸出功率與時(shi)間的(de)關系圖可(ke)看出,將(jiang)動(dong)態電(dian)壓調整技術(shu)用(yong)于(yu)睡眠模(mo)式,電(dian)池壽命會最(zui)多(duo)延長9個小時(shi)。

離散解決方案

    (圖四)是利用離散組件實作(zuo)的電源(yuan)管理系統,電池電壓限制為3.3V。

    圖四利用(yong)離散(san)組件實作(zuo)的電源管理系統

    在這個(ge)解決方案(an)中,就(jiu)算鋰(li)離子電(dian)(dian)池下(xia)降至3.3V左右,在100％負載(zai)周(zhou)期模(mo)式(shi)下(xia)工作(zuo)的(de)高效率TPS62200降壓轉換器(qi)仍能提供3.3V的(de)I/O電(dian)(dian)壓。上(shang)述所有零件都采(cai)用(yong)SOT-23封裝,除了bq24020電(dian)(dian)池充(chong)電(dian)(dian)組(zu)件、TPS61020升壓轉換器(qi)以及(ji)TPS61042白光(guang)二極(ji)(ji)管驅動(dong)組(zu)件之外,它(ta)們是采(cai)用(yong)3×3平方厘(li)米的(de)QFN封裝。TPS61040和TPS61042還內建上(shang)端FET晶體管,每顆組(zu)件只需要一個(ge)外接二極(ji)(ji)管。bq24020、TPS622xx、TPS61020和線性穩壓器(qi)組(zu)件全都內建FET晶體管,功率放大器(qi)和中央處理器(qi)電(dian)(dian)源采(cai)用(yong)的(de)動(dong)態電(dian)(dian)壓調(diao)整技術可以提高每顆零件的(de)效率,進而協(xie)助(zhu)降低功耗。

    整合解決方案(an)

    最新制程技術使得工程師更容易(yi)結(jie)合(he)、迅速修改以及／或(huo)是利用(yong)(yong)現有的(de)(de)(de)(de)(de)離(li)散組(zu)件(jian)(jian)設(she)計,以便提供不同整合(he)程度(du)的(de)(de)(de)(de)(de)半導體芯片(pian),例如通用(yong)(yong)的(de)(de)(de)(de)(de)雙通道交換(huan)式(shi)轉換(huan)器(qi)和(he)電(dian)源(yuan)(yuan)拒(ju)斥比很(hen)高而噪聲很(hen)低的(de)(de)(de)(de)(de)雙信道線性穩壓(ya)器(qi)、特殊應用(yong)(yong)白(bai)光二極管的(de)(de)(de)(de)(de)電(dian)源(yuan)(yuan)供應以及行(xing)動(dong)電(dian)話、PDA和(he)數字(zi)相(xiang)機的(de)(de)(de)(de)(de)多電(dian)源(yuan)(yuan)管理解決方案,這(zhe)些產品(pin)都已開始供應。專門支持終(zhong)端設(she)備的(de)(de)(de)(de)(de)電(dian)源(yuan)(yuan)組(zu)件(jian)(jian)則會內(nei)建各種外圍(wei),其范圍(wei)從(cong)行(xing)動(dong)電(dian)話的(de)(de)(de)(de)(de)響鈴器(qi)和(he)蜂鳴器(qi)到PDA的(de)(de)(de)(de)(de)通用(yong)(yong)I/O接(jie)腳(jiao),例如圖四整合(he)解決方案所(suo)使用(yong)(yong)的(de)(de)(de)(de)(de)TPS65010就是這(zhe)類組(zu)件(jian)(jian)。

 

    圖五(wu)整合式(shi)解決方案

    在此解決方案中,3.3VI/O電源是由SEPIC轉換器提供,它讓應用系統能充份利用鋰離子電池電(dian)(dian)力,直到電(dian)(dian)池電(dian)(dian)壓(ya)降至最(zui)低(di)水平(ping)（大約(yue)2.7V）。和(he)離散解決方(fang)案一樣(yang),穩壓(ya)器(qi)(qi)輸(shu)(shu)出也來自3.3V輸(shu)(shu)入電(dian)(dian)源(yuan)(yuan),以(yi)便(bian)提高工作效率(lv)。TPS65010采用(yong)48只接腳QFN封(feng)裝,這些組件都(dou)內(nei)建(jian)(jian)FET晶體管(guan)。TPS61130SEPIC轉換器(qi)(qi)采用(yong)4×4平(ping)方(fang)厘米QFN封(feng)裝,并(bing)且內(nei)建(jian)(jian)FET晶體管(guan),最(zui)高達到90％以(yi)上效率(lv),TPS5100則(ze)是三(san)通(tong)道輸(shu)(shu)出控制器(qi)(qi),專門用(yong)來提供電(dian)(dian)源(yuan)(yuan)給顯示器(qi)(qi)。功(gong)率(lv)放大器(qi)(qi)和(he)中(zhong)央處理(li)器(qi)(qi)電(dian)(dian)源(yuan)(yuan)使用(yong)的動(dong)態電(dian)(dian)壓(ya)調整技術可以(yi)改善每顆零件的效率(lv),進而協助降低(di)功(gong)耗。

    離散(san)或(huo)整合？

    如(ru)何在離散或整合解決方案之間(jian)做出抉擇？一(yi)般說(shuo)來(lai),整合組件(jian)(jian)的(de)(de)(de)成本會低于同(tong)(tong)樣(yang)等級(ji)的(de)(de)(de)多(duo)顆離散零(ling)件(jian)(jian);除此(ci)之外,如(ru)同(tong)(tong)(圖(tu)六)的(de)(de)(de)電(dian)路(lu)板布(bu)局所示(shi),相(xiang)較(jiao)于執行(xing)同(tong)(tong)樣(yang)功(gong)能的(de)(de)(de)多(duo)顆離散零(ling)件(jian)(jian),TPS65010以(yi)及與其搭(da)配的(de)(de)(de)被動零(ling)件(jian)(jian)只需較(jiao)少(shao)的(de)(de)(de)電(dian)路(lu)板空間(jian),這主(zhu)要(yao)是(shi)因為離散零(ling)件(jian)(jian)之間(jian)需要(yao)額外空間(jian)來(lai)容納訊號線路(lu)。由于TPS65010還包含(han)原來(lai)由離散零(ling)件(jian)(jian)提供的(de)(de)(de)其它功(gong)能,例如(ru)電(dian)源供應順序(xu)、振動器(qi)和(he)二極管驅動組件(jian)(jian),因此(ci)整合解決方案可以(yi)節省更多(duo)電(dian)路(lu)板面積。

  

 

 

    圖六TPS65010與(yu)同等級離散解決方案的電路板(ban)布比較

    整(zheng)合組(zu)件(jian)過去主要支持特殊應(ying)用,彈性也不是很高,因此在設計(ji)流程(cheng)(cheng)后(hou)期,它(ta)們就無法再進行(xing)(xing)重(zhong)大(da)的(de)(de)設計(ji)變更。然(ran)而新(xin)的(de)(de)制程(cheng)(cheng)技術(shu),包括支持可程(cheng)(cheng)序輸出(chu)電(dian)壓(ya)以及封裝后(hou)調整(zheng)的(de)(de)整(zheng)合式EEPROM,卻使得工程(cheng)(cheng)師能以更低成(cheng)本,更簡單快(kuai)速的(de)(de)對(dui)現有組(zu)件(jian)（也就是不同固定輸出(chu)電(dian)壓(ya)的(de)(de)組(zu)件(jian)）重(zhong)復進行(xing)(xing)簡單修改。另一(yi)方面,整(zheng)合組(zu)件(jian)的(de)(de)供貨商通(tong)常只有一(yi)家,這可能迫使廠商必須采用離散(san)解決方案。

    未來挑戰

    消(xiao)費者想要操作時(shi)(shi)間(jian)更(geng)長(chang)(chang)的智能型手機(ji),新發展的半導(dao)體制程技(ji)術已能減少(shao)泄(xie)漏(lou)電流(liu)和(he)阻抗（有(you)時(shi)(shi)透過銅覆蓋(gai)層）,使(shi)得(de)FET晶(jing)體管的靜態電流(liu)更(geng)低,導(dao)通阻抗也變(bian)得(de)更(geng)小。然(ran)而不同于持續進步中的半導(dao)體技(ji)術,電池(chi)技(ji)術卻沒有(you)任(ren)何重大進展,無法(fa)在不增加(jia)電池(chi)體積的情(qing)形下延長(chang)(chang)供電時(shi)(shi)間(jian)。

    電(dian)(dian)(dian)(dian)(dian)容器(qi)技術的某(mou)些進(jin)展(zhan)使得充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)池(chi)和電(dian)(dian)(dian)(dian)(dian)容器(qi)之間的界限日益模糊,許(xu)多可攜(xie)式產品已(yi)開始(shi)使用高(gao)能量(liang)超級(ji)電(dian)(dian)(dian)(dian)(dian)容器(qi)（supercapacitor）,做為消費者(zhe)更換(huan)電(dian)(dian)(dian)(dian)(dian)池(chi)時(shi)(shi)的暫時(shi)(shi)電(dian)(dian)(dian)(dian)(dian)力(li)(li)來源;另外,高(gao)能量(liang)暨高(gao)功率的超高(gao)電(dian)(dian)(dian)(dian)(dian)容器(qi)（ultracapacitor）還能在短時(shi)(shi)間內(nei)提(ti)供很大電(dian)(dian)(dian)(dian)(dian)流,讓電(dian)(dian)(dian)(dian)(dian)池(chi)不必瞬間供應龐大電(dian)(dian)(dian)(dian)(dian)力(li)(li),可以延長電(dian)(dian)(dian)(dian)(dian)池(chi)的使用時(shi)(shi)間。這些超高(gao)電(dian)(dian)(dian)(dian)(dian)容器(qi)會整合至電(dian)(dian)(dian)(dian)(dian)池(chi)封裝內(nei),并在系統電(dian)(dian)(dian)(dian)(dian)力(li)(li)需求不太高(gao)時(shi)(shi),利用微小(xiao)電(dian)(dian)(dian)(dian)(dian)流充(chong)電(dian)(dian)(dian)(dian)(dian)。

    燃(ran)料電池近來(lai)是(shi)熱門話題,但由(you)于外形包裝尚未(wei)標準化(hua),使得燃(ran)料電池的(de)廣(guang)泛(fan)應用受到影(ying)響(xiang),商(shang)業化(hua)過(guo)程也(ye)不太順(shun)利。燃(ran)料電池的(de)輸出(chu)瞬時響(xiang)應也(ye)很(hen)糟糕,因(yin)此至少在最初(chu)階段(duan)燃(ran)料電池只會(hui)做為普(pu)通電池的(de)補強裝置(zhi),無法取代(dai)普(pu)通電池。

    消費者還希(xi)望(wang)產品(pin)的(de)體積更(geng)小(xiao),功能(neng)更(geng)加(jia)強大,創新的(de)電(dian)源管(guan)理組件設計(ji)以及封裝和制(zhi)程技術的(de)進步都能(neng)幫助實現此(ci)目標(biao)。日益(yi)精密的(de)制(zhi)程技術可(ke)以制(zhi)造(zao)出越來越小(xiao)的(de)FET晶體管(guan),讓晶粒(li)和封裝的(de)體積更(geng)小(xiao),工作(zuo)電(dian)壓更(geng)低(di),閘極電(dian)容更(geng)少,使得(de)晶體管(guan)的(de)開關速度更(geng)快

    ―對于以電(dian)(dian)感(gan)為基(ji)礎的(de)(de)交換(huan)式電(dian)(dian)源(yuan)供應,更(geng)(geng)快(kuai)的(de)(de)開關速(su)度(du)意味著更(geng)(geng)小的(de)(de)電(dian)(dian)感(gan)。新封裝(zhuang)技術則能在更(geng)(geng)小的(de)(de)封裝(zhuang)中容納更(geng)(geng)多功(gong)能,并且(qie)承(cheng)受(shou)更(geng)(geng)大的(de)(de)功(gong)耗,例如內建FET開關的(de)(de)鋰離子電(dian)(dian)池線性充電(dian)(dian)組件bq24010就采用3×3平方厘米的(de)(de)QFN封裝(zhuang),它(ta)在普通室溫環境下,最高能承(cheng)受(shou)1.5W功(gong)耗。

    要(yao)(yao)在(zai)較低的(de)(de)(de)(de)(de)(de)工(gong)作電(dian)(dian)(dian)(dian)壓(ya)下提供(gong)更強大(da)功(gong)能(neng),電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)管(guan)理單(dan)元(yuan)和低噪(zao)聲布局的(de)(de)(de)(de)(de)(de)容(rong)忍要(yao)(yao)求(qiu)通常也會變(bian)的(de)(de)(de)(de)(de)(de)更嚴格,例(li)如(ru)系統若要(yao)(yao)求(qiu)1.2V電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)(de)(de)(de)(de)(de)誤(wu)差(cha)(cha)小(xiao)于(yu)±3%,就(jiu)表示輸出電(dian)(dian)(dian)(dian)壓(ya)變(bian)動幅(fu)度不(bu)能(neng)超過±36mV;相形(xing)之下,使用3.3V電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)就(jiu)表示在(zai)同樣的(de)(de)(de)(de)(de)(de)±3%誤(wu)差(cha)(cha)限(xian)制下,它能(neng)容(rong)忍的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓(ya)變(bian)動高達±99mV。由于(yu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)電(dian)(dian)(dian)(dian)壓(ya)不(bu)斷(duan)降低,未來幾年內對于(yu)誤(wu)差(cha)(cha)更小(xiao)、電(dian)(dian)(dian)(dian)流(liu)更大(da)、效率更高和電(dian)(dian)(dian)(dian)磁干擾極(ji)低的(de)(de)(de)(de)(de)(de)直流(liu)電(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)轉(zhuan)換器的(de)(de)(de)(de)(de)(de)需求(qiu)將會增加。除(chu)此之外,隨著(zhu)封(feng)裝縮小(xiao),可供(gong)散熱的(de)(de)(de)(de)(de)(de)面積(ji)也會減少,讓(rang)這些高功(gong)耗組件(jian)的(de)(de)(de)(de)(de)(de)熱管(guan)理繼續成為困難挑戰。

    整合的力量

    本文(wen)介紹的(de)(de)(de)電(dian)(dian)(dian)(dian)源(yuan)解(jie)決方(fang)案使用不(bu)同整合程度的(de)(de)(de)電(dian)(dian)(dian)(dian)源(yuan)組(zu)件(jian)(jian)。把部(bu)份(fen)或全部(bu)的(de)(de)(de)模擬電(dian)(dian)(dian)(dian)源(yuan)組(zu)件(jian)(jian)和基頻(pin)處理(li)器等數字零件(jian)(jian)整合在一起會帶來許多(duo)優點(dian),包括節省更(geng)多(duo)的(de)(de)(de)電(dian)(dian)(dian)(dian)路板面(mian)積,并且降(jiang)低總(zong)成本。復雜電(dian)(dian)(dian)(dian)子系統的(de)(de)(de)每(mei)個部(bu)份(fen)都有著不(bu)同的(de)(de)(de)需求,這(zhe)是(shi)過去(qu)實現更(geng)高階(jie)數字和模擬零件(jian)(jian)整合的(de)(de)(de)障(zhang)礙(ai)之一,例(li)如(ru)數字基頻(pin)單元需要高密度制(zhi)程以支(zhi)持數字訊號處理(li),模擬基頻(pin)和電(dian)(dian)(dian)(dian)源(yuan)功能需要電(dian)(dian)(dian)(dian)壓(ya)更(geng)高的(de)(de)(de)組(zu)件(jian)(jian);射頻(pin)單元,特別是(shi)鎖相(xiang)回路,則需要最適(shi)合支(zhi)持高頻(pin)操(cao)作的(de)(de)(de)BiCMOS組(zu)件(jian)(jian)。

    傳統上,制(zhi)程發展是(shi)由數(shu)字(zi)設計人員負責管理(li),他們(men)通常只會推動高(gao)(gao)密(mi)度制(zhi)程發展,電(dian)路若需要高(gao)(gao)電(dian)壓組(zu)件(jian)(jian),就必須采(cai)用(yong)不同制(zhi)程,這(zhe)表示他們(men)需要獨立的(de)(de)數(shu)字(zi)組(zu)件(jian)(jian)。半導體(ti)廠(chang)商不但開(kai)始發展「最小閘極長(chang)度」更(geng)短的(de)(de)BiCMOS制(zhi)程,以便提供很(hen)高(gao)(gao)的(de)(de)組(zu)件(jian)(jian)密(mi)度和(he)工作速度,還有更(geng)高(gao)(gao)電(dian)壓的(de)(de)汲極延(yan)伸(shen)型組(zu)件(jian)(jian)（drainextendeddevices）,它們(men)已用(yong)于更(geng)多的(de)(de)模擬(ni)和(he)電(dian)源應(ying)用(yong)。包(bao)括(kuo)電(dian)源管理(li)在內的(de)(de)許多模擬(ni)和(he)數(shu)字(zi)功(gong)能(neng)最后都(dou)會整合成單顆芯(xin)片。

    不(bu)同(tong)(tong)程度的(de)組(zu)件(jian)整合(he)正在(zai)簡化可(ke)攜式電源設計,尤其是(shi)可(ke)攜式產品的(de)系統設計人員,他們(men)不(bu)必再擔心組(zu)件(jian)的(de)電源需(xu)求管(guan)理,整合(he)程度不(bu)同(tong)(tong)的(de)電源管(guan)理組(zu)件(jian)可(ke)以幫助他們(men)讓電池提供最(zui)長供電時(shi)間(jian),同(tong)(tong)時(shi)將電路板面積(ji)和成本減(jian)至最(zui)少。