Indlela Iphakheji Ethuthukisiwe Ye-MOSFETs Asebenza Ngayo

Lapho uklama ugesi oshintshwayo noma isekethe yedrayivu yezimoto usebenzisa ama-MOSFET ahlanganisiwe, abantu abaningi bacabangela ukumelana ne-MOS, i-voltage ephezulu, njll., umthamo wamanje, njll., futhi baningi abacabangela lezi zici kuphela. Izifunda ezinjalo zingase zisebenze, kodwa azinhle kakhulu futhi azivunyelwe njengemiklamo esemthethweni yomkhiqizo.

Okulandelayo isifinyezo esincane sezisekelo ze-MOSFET kanyeI-MOSFETizifunda zomshayeli, engibhekisela emithonjeni eminingi, hhayi yonke eyangempela. Kubandakanya ukwethulwa kwama-MOSFET, izici, idrayivu kanye namasekethe okusebenza. Ukupakishwa kwezinhlobo ze-MOSFET kanye nokuhlangana kwe-MOSFET kuyi-FET (enye i-JFET), ingakhiqizwa ibe uhlobo oluthuthukisiwe noma oluncishayo, i-P-channel noma i-N-channel ingqikithi yezinhlobo ezine, kodwa ukusetshenziswa kwangempela kwe-N-channel MOSFET ethuthukisiwe kuphela kanye ne-P ethuthukisiwe. -Channel MOSFET, evame ukubizwa ngokuthi i-NMOS, noma i-PMOS ibhekisela kulezi zinhlobo ezimbili.

Mayelana nokuthi kungani ungasebenzisi uhlobo lokunciphisa ama-MOSFET, akunconywa ukuthi ufinyelele ekugcineni kwawo. Kulezi zinhlobo ezimbili zama-MOSFET athuthukisiwe, i-NMOS isetshenziswa kakhulu ngenxa yokumelana kwayo okuphansi kanye nokwenza lula kwayo. Ngakho-ke ukushintsha ukunikezwa kwamandla kanye nezinhlelo zokusebenza zokushayela imoto, ngokuvamile zisebenzisa i-NMOS. isingeniso esilandelayo, kodwa futhi ngaphezuluI-NMOS-sekelwe.

Ama-MOSFET ane-parasitic capacitance phakathi kwezikhonkwane ezintathu, okungadingeki, kodwa ngenxa yemikhawulo yenqubo yokukhiqiza. Ukuba khona kwe-parasitic capacitance ekuklanyeni noma ekukhethweni kwesekethe yedrayivu ukuba kube yinkinga ethile, kodwa ayikho indlela yokugwema, bese ichazwa ngokuningiliziwe. Njengoba ubona kuhlelo lwe-MOSFET, kune-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 kumuntu ngamunyeAma-MOSFETfuthi ngokuvamile ayikho ngaphakathi kwe-chip yesekethe ehlanganisiwe.I-MOSFET ON CharacteristicsOn isho ukusebenza njengeswishi, okulingana nokuvalwa kweswishi.

Izici ze-NMOS, ama-Vgs amakhulu kunevelu ethile azoqhutshwa, alungele ukusetshenziswa esimweni lapho umthombo usekelwe (idrayivu esezingeni eliphansi), inqobo nje uma i-voltage yesango engu-4V noma engu-10V. Izici ze-PMOS, ama-Vgs angaphansi kwenani elithile azoqhuba, alungele ukusetshenziswa esimweni lapho umthombo uxhunywe ku-VCC (idrayivu ephezulu). 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.

Ukupakishwa kwe-MOSFET ukushintsha ukulahleka kweshubhu, kungakhathaliseki ukuthi i-NMOS noma i-PMOS, ngemva kokwenziwa kukhona ukuphikisa okukhona, ukuze okwamanje kuzodla amandla kulokhu kumelana, le ngxenye yamandla esetshenzisiwe ibizwa ngokuthi ukulahlekelwa kwe-conduction. Ukukhetha i-MOSFET enokumelana okuncane kuzonciphisa ukulahleka kokuqhuba. Namuhla, ukumelana nokumelana kwamandla amancane e-MOSFET ngokuvamile kucishe kube amashumi ama-milliohm, futhi ama-miliohm ambalwa ayatholakala. I-MOS akumele iqedwe ngokuphazima kweso lapho iqhuba futhi inqamuka. Amandla kagesi ezinhlangothini zombili ze-MOS ane- inqubo yokuncipha, futhi yamanje egeleza kuyo inenqubo yokwanda.Ngalesi sikhathi, ukulahlekelwa kwe-MOSFET kuwumkhiqizo we-voltage kanye nesimanje, 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 zinganciphisa ukulahlekelwa kokushintsha. Umkhiqizo we-voltage ne-current ngesikhathi sokuqhuba mkhulu, futhi ukulahlekelwa okuwumphumela nakho kukhulu. Ukunciphisa isikhathi sokushintsha kunganciphisa ukulahlekelwa ekuqhubeni ngakunye; ukunciphisa imvamisa yokushintsha kunganciphisa inani lokushintshwa ngesikhathi seyunithi. Zombili lezi zindlela zinganciphisa ukulahlekelwa kokushintsha. Ukushayela Uma kuqhathaniswa nama-bipolar transistors, ngokuvamile kukholakala ukuthi akukho okwamanje okudingekayo ukuze uvule i-MOSFET epakishiwe, inqobo nje uma i-voltage ye-GS ingaphezu kwevelu ethile. Lokhu kulula ukukwenza, nokho, sidinga nesivinini. Isakhiwo se-MOSFET ehlanganisiwe singabonakala phambi kwe-parasitic capacitance 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 i-current instantaneous izoba nkulu. 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. I-high-end drive MOSFET conduction source voltage kanye ne-drain voltage (VCC) ngokufanayo, ngakho-ke i-voltage yesango kune-VCC 4 V noma i-10 V. Uma ohlelweni olufanayo, ukuze sithole i-voltage enkulu kune-VCC, kufanele sigxile izifunda zokuthuthukisa. Abashayeli abaningi bezimoto banamaphampu wokushaja ahlanganisiwe, kubalulekile ukuqaphela ukuthi kufanele ukhethe amandla angaphandle afanelekile, ukuze uthole okwamanje okwanele we-short-circuit ukushayela i-MOSFET. I-4V noma i-10V ivamise ukusetshenziswa kugesi wesimo se-MOSFET, vele, umklamo udinga ukuba nemajini ethile. Lapho i-voltage iphakeme, isivinini se-on-state sishesha kakhulu futhi sinciphisa ukumelana nesimo. Namuhla, kunama-MOSFET anama-voltage amancane akusimo sezwe asetshenziswa emikhakheni ehlukene, kodwa ezinhlelweni zikagesi zezimoto eziyi-12V, ngokuvamile i-4V on-state yanele.I-MOSFET drive circuit kanye nokulahlekelwa kwayo.