大三下英語(yǔ)課件課程unit12

SpecialEnglishforElectronicsandInformation電子信息專業(yè)英語(yǔ)

1-2Howdoesalogicgateinamicrochipwork?Agateseemslikeadevicethatmustswingopenandclosed,yetmicrochipsareetchedontosiliconwafersthathavenomovingparts.Sohowcanthegateopenandclose?門似乎是一種必須打開和關(guān)閉的裝置，然而，微芯片刻蝕到硅晶片上，并沒有移動(dòng)部件。那么門是如何打開和關(guān)閉的呢？1-2Howdoesalogicgateinamicrochipwork?LarryWissel,ASICApplicationsEngineeratIBMMicroelectronics,replies:“Thoseofuswhodesignlogicgatesforcomputersseldomreminisceonhowthetermsweusetodescribetechnologycameintouse.Thevisionofagateswingingbackandforthclearlydoesnotliterallyrepresentthestructuresonasiliconchip.Butthereasonfortheusageoftheterm‘gate’forcomputerlogiccanbeappreciatedbyexaminingthebasicfunctionofagate:tocontrolaflow.”拉里維塞爾，一名IBM微電子的ASIC應(yīng)用工程師，回答道：我們這些為計(jì)算機(jī)設(shè)計(jì)邏輯門電路的人很少能夠回憶起我們使用的術(shù)語(yǔ)如何描述投入使用的技術(shù)。一個(gè)來(lái)回?cái)[動(dòng)清晰的門的視覺形象并不能表示硅芯片的結(jié)構(gòu)。但是使用術(shù)語(yǔ)“門”作為計(jì)算機(jī)邏輯的原因可以理解為門基本功能的檢查：控制電路。1-2Howdoesalogicgateinamicrochipwork?LarryWissel,ASICApplicationsEngineeratIBMMicroelectronics,replies:“Thoseofuswhodesignlogicgatesforcomputersseldomreminisceonhowthetermsweusetodescribetechnologycameintouse.Thevisionofagateswingingbackandforthclearlydoesnotliterallyrepresentthestructuresonasiliconchip.Butthereasonfortheusageoftheterm‘gate’forcomputerlogiccanbeappreciatedbyexaminingthebasicfunctionofagate:tocontrolaflow.”拉里維塞爾，一名IBM微電子的ASIC應(yīng)用工程師，回答道：我們這些為計(jì)算機(jī)設(shè)計(jì)邏輯門電路的人很少能夠回憶起我們使用的術(shù)語(yǔ)如何描述投入使用的技術(shù)。一個(gè)來(lái)回?cái)[動(dòng)清晰的門的視覺形象并不能表示硅芯片的結(jié)構(gòu)。但是使用術(shù)語(yǔ)“門”作為計(jì)算機(jī)邏輯的原因可以理解為門基本功能的檢查：控制電路。1-2Howdoesalogicgateinamicrochipwork?Onafarm,gatesmaybeusedtocontrolthe‘flow’ofsheeporgoatsbetweenpens.Inthiscase,thegateconsistsofaphysicalbarrierwhosepositioniscontrolledbyafarmer.Thefarmermakesadecisionabouttheflowofanimalsandthenmovesthephysicalbarriertopermitthedesiredflow.在農(nóng)場(chǎng)中，門可以用來(lái)控制圍欄之間山羊或綿羊的流通。這種情況下，門是由農(nóng)民控制的一個(gè)物理屏障組成。農(nóng)民對(duì)動(dòng)物的流通作出決策。通過移動(dòng)物理屏障以允許期望的流通量。1-2Howdoesalogicgateinamicrochipwork?Inacomputer,agatecontrolstheflowofelectriccurrentthroughacircuit.Thegateconsistsoftransistors;thetransistorsareselectedbythechipdesignerfromtwotypes(PMOSandNMOStransistors)thatarefoundintheubiquitousCOMS(complementarymetal-oxidesemiconductor)technology在電腦中，門控制著通過電路的電流。門電路由晶體管組成,而這些晶體管是由芯片設(shè)計(jì)者從廣泛應(yīng)用的COMS（互補(bǔ)金屬氧化物半導(dǎo)體）技術(shù)中出現(xiàn)的兩種基本類型的晶體管（PMOS晶體管和NMOS晶體管）中選擇的。1-2Howdoesalogicgateinamicrochipwork?Thecurrentthatflowsthroughagateestablishesavoltageataparticularpointinthecircuit.Thisvoltagerepresentsasingle'bit'ofinformation.Thevoltagemayeitherbehigh(representingthevalue'1’)orlow(representingthevalue'0')."通過一個(gè)門的電流在電路的特定的點(diǎn)確立一個(gè)電壓。這個(gè)電壓代表一比特的信息，該電壓可以為高電平（1），也可以為低電平（0）。1-2Howdoesalogicgateinamicrochipwork?Toestablisha1onacircuit,thecurrentflowissteeredtothecircuit(controlled)by‘turningon’aPMOStransistorconnectedbetweenthecircuitandthepositivesupplyvoltage.Thesupplyvoltageisusuallyanindustry-standardvaluesuchas3.3or5.0volts.電流被驅(qū)動(dòng)送到一個(gè)電路上，是通過“接通”一個(gè)連接該電路點(diǎn)和正向電源電壓的PMOS管來(lái)控制的。供電電壓通常是一個(gè)行業(yè)標(biāo)準(zhǔn)值，比如3.3v或5.0v。1-2Howdoesalogicgateinamicrochipwork?For

theverybriefintervalthatisrequiredforalogicgatetoswitch(ontheorderofananosecond,orabillionthofasecond),currentwillflowthroughaPMOStransistorfromthepositivepowersupplytothecircuit.對(duì)于一個(gè)邏輯門的切換需要在很短的時(shí)間間隔內(nèi)（納秒、或十億分之一秒），電流將從電源正極流經(jīng)PMOS管到達(dá)該電路點(diǎn)。1-2Howdoesalogicgateinamicrochipwork?Thecurrentflowthatchargesthecircuitnodetoa0issteeredawayfromthecircuitthroughadifferentkindoftransistor(NMOS)connectedbetweenthecircuitandthenegativesupplyvoltage,orelectricalground.Again,currentwillflowtroughtheNMOStransistorforaverybriefinterval,butfortheNOMSthecurrentisbetweenthecircuitandthenegativesupply.電路上的“0”值的確立是通過另一種連接該電路點(diǎn)和負(fù)極電壓或接地的晶體管（NMOS）來(lái)實(shí)現(xiàn)的。并且，電流將在很短的時(shí)間內(nèi)流過NMOS晶體管，但是對(duì)于NMOS晶體管，電流處于電路和負(fù)電源之間。1-2Howdoesalogicgateinamicrochipwork?Ineithercase,thecurrentflowresultsinach