Okokuqala, uhlobo lwe-MOSFET nesakhiwo,I-MOSFETiyi-FET (enye i-JFET), ingakhiwa ibe uhlobo oluthuthukisiwe noma olunciphayo, i-P-channel noma i-N-channel ingqikithi yezinhlobo ezine, kodwa ukusetshenziswa kwangempela kwama-MOSFET e-N-channel athuthukisiwe kuphela nama-MOSFET esiteshi se-P athuthukisiwe, ngokuvamile ebizwa ngokuthi i-NMOS noma i-PMOS ibhekisela kulezi zinhlobo ezimbili. Kulezi zinhlobo ezimbili zama-MOSFET athuthukisiwe, okuvame ukusetshenziswa kakhulu yi-NMOS, isizathu siwukuthi ukumelana nokumelana kuncane, futhi kulula ukuwenza. Ngakho-ke, i-NMOS ngokuvamile isetshenziswa ekushintsheni ukunikezwa kwamandla kanye nezinhlelo zokusebenza zokushayela imoto.
Esingeniso esilandelayo, iningi lamacala aphethwe yi-NMOS. amandla e-parasitic akhona phakathi kwezikhonkwane ezintathu ze-MOSFET, isici esingadingeki kodwa esivela ngenxa yemikhawulo yenqubo yokukhiqiza. Ukuba khona kwe-parasitic capacitance kwenza kube nzima ukuklama noma ukukhetha isekethe yomshayeli. Kukhona i-diode ye-parasitic phakathi kwe-drain kanye nomthombo. Lokhu kubizwa ngokuthi i-diode yomzimba futhi kubalulekile ekushayeleni imithwalo ye-inductive efana namamotho. Ngendlela, i-diode yomzimba ikhona kuphela kuma-MOSFET ngamanye futhi ngokuvamile ayikho ngaphakathi kwe-IC chip.
I-MOSFETukushintsha ukulahlekelwa kwe-tube, kungakhathaliseki ukuthi i-NMOS noma i-PMOS, ngemva kokuqhutshwa kokumelana okukhona, ukuze i-current izodla amandla kulokhu kumelana, le ngxenye yamandla asetshenzisiwe ibizwa ngokuthi ukulahlekelwa kwe-conduction. Ukukhethwa kwama-MOSFET anokumelana okuphansi kuzonciphisa ukulahleka kokumelana. Namuhla, ukumelana nokumelana kwama-MOSFET anamandla aphansi ngokuvamile kucishe kube amashumi ama-milliohm, futhi ama-miliohm ambalwa nawo ayatholakala.Ama-MOSFET akumele aqedwe ngokuphazima kweso lapho ekhanya futhi ecisha.Kunenqubo yokunciphisa amandla kagesi iziphetho ezimbili ze-MOSFET, futhi kukhona inqubo yokwandisa okwamanje egeleza kuyo.Phakathi nalesi sikhathi, ukulahlekelwa kwe-MOSFET kungumkhiqizo we-voltage kanye namanje, okubizwa ngokuthi ukulahlekelwa kokushintsha. Ngokuvamile ukulahlekelwa kokushintsha kukhulu kakhulu kunokulahlekelwa kwe-conduction, futhi ngokushesha imvamisa yokushintsha, ukulahlekelwa kukhulu. Umkhiqizo we-voltage kanye ne-current ngesikhathi sokuqhuba mkhulu kakhulu, okuholela ekulahlekelweni okukhulu. Ukunciphisa isikhathi sokushintsha kunciphisa ukulahlekelwa ekuqhubeni ngakunye; ukunciphisa imvamisa yokushintsha kunciphisa inani lokushintshwa ngesikhathi seyunithi. Zombili lezi zindlela zinciphisa ukulahleka kokushintsha.
Uma kuqhathaniswa nama-bipolar transistors, kukholelwa ukuthi akukho okwamanje okudingekayo ukwenza i-aI-MOSFETukuziphatha, inqobo nje uma i-voltage ye-GS ingaphezu kwenani elithile. Lokhu kulula ukukwenza, nokho, sidinga nesivinini. Njengoba ubona esakhiweni se-MOSFET, kukhona amandla e-parasitic phakathi kwe-GS, GD, kanye nokushayela kwe-MOSFET, empeleni, ukushaja nokukhipha amandla. Ukushaja i-capacitor kudinga okwamanje, ngoba ukushaja i-capacitor ngokushesha kungabonakala njengesifunda esifushane, ngakho-ke okwamanje kuzoba phezulu. Into yokuqala okufanele uyiqaphele lapho ukhetha/uklama umshayeli we-MOSFET usayizi we-short-circuit yamanje enganikezwa.
Into yesibili okufanele uyiqaphele ukuthi, ngokuvamile esetshenziswa ku-NMOS yedrayivu ephezulu, i-voltage yesango elisebenza ngesikhathi idinga ukuba nkulu kune-voltage yomthombo. High-ekugcineni drive MOSFET ku-voltage umthombo kanye drain voltage (VCC) okufanayo, ngakho-ke voltage esangweni kuka VCC 4V noma 10V. uma ohlelweni olufanayo, ukuze sithole i-voltage enkulu kune-VCC, sidinga uchwepheshe kusekethe ye-boost. Abashayeli abaningi bezimoto banamaphampu wokushaja ahlanganisiwe, kubalulekile ukuqaphela ukuthi kufanele ukhethe amandla angaphandle afanelekile ukuze uthole okwamanje okwanele we-short-circuit ukuze uqhube i-MOSFET. I-4V noma i-10V iyi-MOSFET evame ukusetshenziswa ku-voltage, umklamo weqiniso, udinga ukuba nemajini ethile. Lapho i-voltage iphezulu, isivinini se-on-state sishesha kakhulu futhi sinciphisa ukumelana nesimo. Manje kukhona nama-MOSFET amancane asebenza ku-state voltage asetshenziswa emikhakheni ehlukene, kodwa ohlelweni lwe-automotive electronics engu-12V, ngokuvamile i-4V on-state yanele.Isici esiphawuleka kakhulu sama-MOSFET izici zokushintshwa kokuhle, ngakho-ke isetshenziswa kabanzi isidingo samasekethe okushintsha i-elekthronikhi, njengokushintshwa kwamandla kagesi kanye ne-motor drive, kodwa nokufiphala kokukhanyisa. Ukuqhuba kusho ukusebenza njengeswishi, okulingana nokuvalwa kweswishi.Izici ze-NMOS, i-Vgs enkulu kunevelu ethile izoqhutshwa, elungele ukusetshenziswa esimweni lapho umthombo usekelwe (ukushayela okuphansi), inqobo nje uma isango I-voltage yezimpawu ze-4V noma i-10V.PMOS, i-Vgs engaphansi kwenani elithile izoqhuba, ifanele ukusetshenziswa esimweni lapho umthombo uxhumeke ku-VCC (i-high-end drive). Kodwa-ke, nakuba i-PMOS ingasetshenziswa kalula njengomshayeli oseqophelweni eliphezulu, i-NMOS ivamise ukusetshenziswa kubashayeli abasezingeni eliphezulu ngenxa yokumelana okukhulu, intengo ephezulu, kanye nezinhlobo ezimbalwa zokushintshwa.
Manje i-MOSFET ishayela izinhlelo ze-voltage low-voltage, lapho kusetshenziswa amandla kagesi angu-5V, kulokhu uma usebenzisa isakhiwo se-totem pole yendabuko, ngenxa yokuthi i-transistor ibe cishe ukwehla kwamandla kagesi angu-0.7V, okuholela ekutheni okokugcina kwangempela kwengezwe esangweni ku- I-voltage ingu-4.3 V kuphela. Ngalesi sikhathi, sikhetha amandla kagesi wesango elingu-4.5V we-MOSFET ngokuba khona kwezingozi ezithile. Inkinga efanayo iyenzeka ekusetshenzisweni kwe-3V noma ezinye izikhathi zokuphakelwa kwamandla kagesi aphansi. Amandla kagesi amabili asetshenziswa kumasekhethi okulawula athile lapho isigaba sokucabanga sisebenzisa i-voltage yedijithali engu-5V noma engu-3.3V ejwayelekile futhi ingxenye yamandla isebenzisa i-12V noma ngaphezulu. Ama-voltages amabili axhunywe kusetshenziswa indawo evamile. Lokhu kubeka imfuneko yokusebenzisa isekethe evumela uhlangothi lukagesi oluphansi ukuthi lulawule ngempumelelo i-MOSFET ohlangothini lwamandla kagesi aphezulu, kuyilapho i-MOSFET ohlangothini lwamandla kagesi aphezulu izobhekana nezinkinga ezifanayo ezishiwo ku-1 no-2. Kuzo zontathu izimo, i Isakhiwo sesigxobo se-totem asikwazi ukuhlangabezana nezidingo zokukhiphayo, futhi ama-IC amaningi omshayeli we-MOSFET angekho eshalofini abonakala engabandakanyi isakhiwo sokukhawulela ugesi wesango. I-voltage yokufaka ayilona inani elingaguquki, iyahlukahluka ngokuya kwesikhathi noma ezinye izici. Lokhu kuhluka kubangela ukuthi i-voltage yokushayela enikezwe i-MOSFET yisekethe ye-PWM ingazinzi. Ukuze kwenziwe i-MOSFET iphephe kuma-voltage amasango aphezulu, ama-MOSFET amaningi anezilawuli zikagesi ezakhelwe ngaphakathi ukuze zibeke umkhawulo ngamandla we-voltage yesango.
Kulokhu, lapho i-voltage yokushayela enikeziwe idlula i-voltage yesilawuli, izodala ukusetshenziswa kwamandla amakhulu amile Ngesikhathi esifanayo, uma nje usebenzisa isimiso se-resistor voltage divider ukunciphisa i-voltage yesango, kuyoba khona i-voltage ephezulu yokufaka, i-MOSFET isebenza kahle, kuyilapho i-voltage yokufaka iyancipha lapho i-voltage yesango inganele ukubangela ukuqhutshwa okuphelele okunganele, ngaleyo ndlela andise ukusetshenziswa kwamandla.
Isekethe evamile lapha kuphela kumjikelezo womshayeli we-NMOS ukwenza ukuhlaziya okulula: I-Vl ne-Vh amandla aphansi futhi aphezulu, ngokulandelana, ama-voltages amabili angafana, kodwa i-Vl akufanele idlule i-Vh. I-Q1 ne-Q2 zakha i-totem pole ehlanekezelwe, esetshenziselwa ukufeza ukuhlukaniswa, futhi ngesikhathi esifanayo ukuqinisekisa ukuthi amashubhu amabili omshayeli i-Q3 ne-Q4 ngeke avule ngesikhathi esisodwa. I-R2 ne-R3 ihlinzeka ngereferensi ye-PWM ye-voltage, futhi ngokushintsha lesi sithenjwa, ungenza isifunda sisebenze kahle, futhi i-voltage yesango ayanele ukubangela ukuqhutshwa okuphelele, ngaleyo ndlela ukwandisa ukusetshenziswa kwamandla. I-R2 ne-R3 ihlinzeka ngereferensi kagesi ye-PWM, ngokushintsha lesi sithenjwa, ungavumela umsebenzi wesifunda ku-waveform yesignali ye-PWM ibe umqansa futhi uqondile. I-Q3 ne-Q4 zisetshenziselwa ukuhlinzeka ngedrayivu yamanje, ngenxa yesikhathi esibekiwe, i-Q3 ne-Q4 ehlobene ne-Vh ne-GND iyinani elincane kuphela lokwehla kwamandla kagesi e-Vce, lokhu kwehla kwamandla kagesi kuvame ukuba ngu-0.3V kuphela noma ngaphezulu, okuphansi kakhulu. kune-0.7V Vce R5 kanye ne-R6 yizinqamuleli zempendulo zesampula ye-voltage yesango, ngemva kokuthatha isampula kagesi, i-voltage yesango isetshenziswa njengendlela yokumelana nempendulo ku-voltage yesango, futhi i-voltage yesampula isetshenziswa ku-voltage yesango. I-R5 kanye ne-R6 yizinqamuli zempendulo ezisetshenziselwa ukusampula amandla kagesi wesango, abese edluliswa ku-Q5 ukuze kwakheke impendulo eqinile engemihle ezisekelweni ze-Q1 ne-Q2, ngaleyo ndlela kukhawulelwe ugesi wesango enanini elilinganiselwe. Leli nani lingalungiswa ngo-R5 no-R6. Ekugcineni, i-R1 inikeza umkhawulo wesisekelo samanje ku-Q3 ne-Q4, futhi i-R4 inikeza umkhawulo wesango lamanje kuma-MOSFET, okuwumkhawulo we-Ice ye-Q3Q4. I-acceleration capacitor ingaxhunywa ngokuhambisana ngenhla kuka-R4 uma kunesidingo.
Lapho udizayina izinto eziphathwayo nemikhiqizo engenantambo, ukuthuthukisa ukusebenza komkhiqizo nokwelula isikhathi sokusebenza kwebhethri yizingqinamba ezimbili abaklami okufanele babhekane nazo. Iziguquli zeDC-DC zinezinzuzo zokusebenza kahle kakhulu, okukhiphayo okuphezulu kwamanje kanye nokuthule okuphansi kwamanje, ezifanele kakhulu ukunika amandla okuphathekayo. amadivaysi.
Iziguquli ze-DC-DC zinezinzuzo zokusebenza kahle okuphezulu, ukuphuma okuphezulu kwamanje kanye nokwamanje okuthule okuphansi, ezifanele kakhulu ukunika amandla amadivayisi aphathwayo. Njengamanje, izitayela eziyinhloko ekuthuthukisweni kobuchwepheshe bokuklama i-DC-DC converter zifaka: ubuchwepheshe be-high-frequency: ngokunyuka kwemvamisa yokushintsha, usayizi wesiguquli sokushintsha nawo uyancishiswa, ukuminyana kwamandla kuye kwanda kakhulu, kanye namandla ashukumisayo. impendulo ithuthukisiwe. Encane
Imvamisa yokushintsha isiguquli samandla e-DC-DC izokhuphukela kuleveli ye-megahertz. Ubuchwepheshe bamandla kagesi okukhipha okuphansi: Ngokuthuthuka okuqhubekayo kobuchwepheshe bokukhiqiza i-semiconductor, ama-microprocessors kanye ne-voltage ye-electronic ephathekayo yokusebenza iya ngokuya yehla iphinde ibe phansi, okudinga i-converter ye-DC-DC yesikhathi esizayo ingahlinzeka nge-voltage ephansi ephumayo ukuze ivumelane ne-microprocessor kanye nemishini ye-elekthronikhi ephathekayo, okuyinto idinga i-converter ye-DC-DC yesikhathi esizayo ingahlinzeka nge-voltage ephansi yokukhipha ukuze ivumelane ne-microprocessor.
Kwanele ukunikeza i-voltage ephansi yokukhipha ukuze ivumelane nama-microprocessors kanye nemishini ephathekayo ye-elekthronikhi. Lokhu kuthuthukiswa kwezobuchwepheshe kubeka phambili izidingo eziphakeme zokuklanywa kwamasekhethi ama-chip anikezela amandla. Okokuqala, ngokunyuka kwemvamisa yokushintsha, ukusebenza kwezingxenye zokushintsha kubekwa phambili
Izidingo eziphakeme zokusebenza kwe-elementi yokushintsha, futhi kufanele ibe nesekhethi ye-switching element ehambisanayo yokushayela ukuze kuqinisekiswe ukuthi isici sokushintsha imvamisa yokushintsha sikhuphukele ezingeni le-megahertz lokusebenza okuvamile. Okwesibili, kumadivayisi we-elekthronikhi anamandla ebhethri, i-voltage yokusebenza yesekethe iphansi (uma kwenzeka amabhethri e-lithium, isibonelo).
Amabhethri e-lithium, isibonelo, i-voltage yokusebenza engu-2.5 ~ 3.6V), ngakho-ke i-chip yamandla kagesi ye-voltage ephansi.
I-MOSFET inokumelana okuphansi kakhulu, ukusetshenziswa kwamandla okuphansi, ku-chip ye-DC-DC ethandwa kakhulu esebenza kahle kakhulu i-MOSFET njengesishintshi samandla. Nokho, ngenxa yekhono elikhulu le-parasitic lama-MOSFET. Lokhu kubeka izidingo eziphakeme ekwakhiweni kokushintsha amasekhethi omshayeli weshubhu ukuze adizayine iziguquli ze-DC-DC ezisebenza kakhulu. Kunamasekhethi ahlukahlukene e-CMOS, e-BiCMOS anengqondo asebenzisa ukwakheka kwe-bootstrap kanye namasekethe omshayeli njengemithwalo emikhulu ye-capacitive ekwakhiweni kwe-ULSI kagesi ophansi. Lawa masekethi ayakwazi ukusebenza kahle ngaphansi kwezimo zokuhlinzekwa kwamandla kagesi angaphansi kuka-1V, futhi angasebenza ngaphansi kwezimo zomthamo womthwalo ongu-1 ~ 2pF imvamisa ingafinyelela amashumi ama-megabits noma ngisho namakhulu ama-megahertz. Kuleli phepha, i-bootstrap boost circuit isetshenziselwa ukuklama umthamo omkhulu we-capacitance drive, ofanele i-low-voltage, i-high switching frequency boost DC-DC converter drive circuit. I-voltage esezingeni eliphansi kanye ne-PWM yokushayela ama-MOSFET aphezulu. Isignali encane ye-PWM ye-amplitude yokushayela izidingo zamandla kagesi wesango eliphezulu lama-MOSFET.
Isikhathi sokuthumela: Apr-12-2024
