MOSFET bayyana

MOSFET wutar lantarki kuma an raba shi zuwa nau'in junction da nau'in ƙofar da aka keɓe, amma yawanci yana nufin nau'in kofa mai rufi MOSFET (Metal Oxide Semiconductor FET), wanda ake kira MOSFET mai ƙarfi (Power MOSFET). Junction nau'in tasirin filin tasirin transistor gabaɗaya ana kiransa transistor induction transistor (Static Induction Transistor - SIT). Yana da halin ƙarfin wutar lantarki don sarrafa magudanar ruwa na yanzu, kewayawar tuƙi mai sauƙi ne, yana buƙatar ƙaramin ƙarfin tuƙi, saurin sauyawa mai sauri, mitar aiki mai girma, kwanciyar hankali ta thermal ya fi kyauGTR, amma ƙarfinsa na yanzu ƙarami ne, ƙarancin wutar lantarki, gabaɗaya yana amfani da wutar da bai wuce 10kW na na'urorin lantarki ba.

1. Tsarin MOSFET Power da ka'idar aiki

Nau'in MOSFET mai ƙarfi: bisa ga tashar tashar za a iya raba zuwa tashar P-tashar da N-tashar. Bisa ga gate ƙarfin lantarki amplitude za a iya raba zuwa kashi; nau'in raguwa; lokacin da ƙarfin wutar lantarki ya kasance sifili lokacin da magudanar ruwa-tushen igiyar ruwa tsakanin wanzuwar tashar gudanarwa, haɓakawa; don na'urar tashar N (P), wutar lantarki ta ƙofar ta fi (kasa da) sifili kafin wanzuwar tashar gudanarwa, MOSFET wutar lantarki an inganta ta musamman N-channel.

1.1 ƘarfiMOSFETtsari　　

Ƙarfin MOSFET na ciki da alamomin lantarki; Gudanarwarsa ɗaya ne kawai masu ɗaukar polarity (polys) da ke da hannu a cikin injin, shi ne transistor unipolar. Tsarin gudanarwa iri ɗaya ne da MOSFET mai ƙarancin ƙarfi, amma tsarin yana da babban bambanci, MOSFET mai ƙarancin ƙarfi shine na'ura mai ɗaukar nauyi a kwance, ikon MOSFET mafi yawan tsarin gudanarwa na tsaye, wanda kuma aka sani da VMOSFET (Vertical MOSFET). , wanda ke inganta ƙarfin wutar lantarki na na'urar MOSFET da ƙarfin juriya na yanzu.

Dangane da bambance-bambance a cikin tsarin gudanarwa na tsaye, amma kuma an raba shi zuwa amfani da tsagi mai siffar V don cimma daidaituwar daidaituwa na VVMOSFET kuma yana da tsarin MOSFET mai watsawa biyu na VDMOSFET (A tsaye Biyu-diffused).MOSFET), an tattauna wannan takarda musamman a matsayin misali na na'urorin VDMOS.

MOSFETs masu iko don tsarin haɗin kai da yawa, irin su Rectifier International (International Rectifier) ​​HEXFET ta amfani da naúrar hexagonal; Siemens (Siemens) SIPMOSFET ta amfani da sashin murabba'i; Motorola (Motorola) TMOS ta amfani da naúrar rectangular ta tsarin siffar "Pin".

1.2 Power MOSFET ka'idar aiki

Yanke-kashe: tsakanin magudanan magudanar ruwa tare da ingantaccen samar da wutar lantarki, sandunan tushen kofa tsakanin wutar lantarki ba shi da sifili. p tushe yankin da N drift yankin kafa tsakanin PN junction J1 baya son rai, babu gudana a halin yanzu tsakanin magudanar ruwa-tushen.

Gudanarwa: Tare da ingantacciyar wutar lantarki UGS da aka yi amfani da ita tsakanin tashoshi na tushen ƙofar, ƙofar tana cikin rufi, don haka babu kofa da ke gudana. Duk da haka, ingantaccen ƙarfin lantarki na ƙofar zai ture ramukan da ke cikin P-yankin da ke ƙasa da shi, kuma ya jawo hankalin oligons-electrons a cikin P-region zuwa saman P-yankin da ke ƙasa da ƙofar lokacin da UGS ya fi girma fiye da UT (nau'in wutar lantarki ko ƙarfin kofa), ƙaddamarwar electrons a saman P-yankin da ke ƙarƙashin ƙofar zai fi ƙarfin ramukan, ta yadda nau'in P-type. semiconductor ya juya zuwa nau'in N kuma ya zama juzu'i mai jujjuyawa, kuma jujjuyawar Layer ta samar da tashar N-ta kuma sanya mahadar PN J1 ta bace, magudanar ruwa da madogararsa.

1.3 Asalin Halayen Ƙarfin MOSFETs

1.3.1 Halayen A tsaye.

Dangantakar da ke tsakanin magudanar ruwa na yanzu da kuma ƙarfin wutar lantarki UGS tsakanin tushen ƙofar ana kiranta yanayin canja wuri na MOSFET, ID ya fi girma, alaƙar da ke tsakanin ID da UGS kusan layi ne, kuma an ayyana gangara na lanƙwasa azaman transconductance Gfs. .

Halayen magudanar wutar lantarki na volt-ampere (halayen fitarwa) na MOSFET: yanki mai yankewa (daidai da yankin yankewa na GTR); yankin jikewa (daidai da yankin haɓakawa na GTR); yankin da ba saturation (daidai da yankin jikewa na GTR). MOSFET mai iko yana aiki a cikin yanayin sauyawa, watau yana juyawa da gaba tsakanin yankin yankewa da yankin da ba ya cika. MOSFET mai iko yana da diode parasitic diode tsakanin tashoshin magudanar ruwa, kuma na'urar tana gudanar da ita lokacin da aka yi amfani da wutar lantarki ta baya tsakanin tashoshin magudanar ruwa. Juriya kan-jihar ikon MOSFET yana da ingantaccen madaidaicin zafin jiki, wanda ya dace don daidaita halin yanzu lokacin da aka haɗa na'urori a layi daya.

1.3.2 Halaye Mai Tsayi;

da da'irar gwajin da kuma sauya tsarin waveforms.

Tsarin kunnawa; lokacin jinkirin kunna kunna td (a kunne) - lokacin tsakanin lokacin gaba da lokacin da uGS = UT da iD suka fara bayyana; lokacin tashi tr- lokacin lokacin da uGS ke tashi daga uT zuwa ƙarfin wutar lantarki UGSP wanda MOSFET ta shiga cikin yankin da ba a cika ba; Tsayayyen ƙimar iD an ƙaddara ta wurin ƙarfin samar da magudanar ruwa, UE, da magudanar ruwa Girman UGSP yana da alaƙa da tsayayyen ƙimar iD. Bayan UGS ya isa UGSP, yana ci gaba da tashi a ƙarƙashin aikin sama har sai ya kai matsayi mai tsayi, amma iD bai canza ba. Kunna lokacin ton- jimlar lokacin jinkiri da lokacin tashi.

Kashe lokacin jinkiri td(kashe) -Lokacin lokacin da iD ya fara raguwa zuwa sifili daga lokacin sama ya faɗi zuwa sifili, ana fitar da Cin ta Rs da RG, kuma uGS ya faɗi zuwa UGSP bisa ga madaidaicin juzu'i.

Lokacin faɗuwa tf- Lokacin lokacin daga lokacin da uGS ke ci gaba da faɗuwa daga UGSP kuma iD yana raguwa har sai tashar ta ɓace a uGS <UT da ID sun faɗi zuwa sifili. Kashe lokacin toff- Jimlar lokacin jinkirin kashewa da lokacin faɗuwa.

1.3.3 MOSFET saurin sauyawa.

MOSFET saurin sauyawa da Cin caji da fitarwa yana da alaƙa mai girma, mai amfani ba zai iya rage Cin ba, amma yana iya rage juriya na cikin gida na tuki don rage yawan lokaci, don hanzarta saurin sauyawa, MOSFET kawai dogara ga haɓakar polytronic, babu tasirin oligotronic ajiya, kuma ta haka ne tsarin kashewa yana da sauri sosai, lokacin sauyawa na 10-100ns, mitar aiki na iya zama har zuwa 100kHz ko fiye, shine mafi girma daga cikin manyan na'urorin lantarki.

Na'urori masu sarrafa filin suna buƙatar kusan babu shigarwar halin yanzu a sauran. Koyaya, yayin aiwatar da sauyawa, ana buƙatar cajin capacitor na shigarwa da fitarwa, wanda har yanzu yana buƙatar takamaiman adadin ƙarfin tuƙi. Mafi girman mitar sauyawa, mafi girman ƙarfin tuƙi da ake buƙata.

1.4 Ingantaccen aiki mai ƙarfi

Baya ga na'urar aikace-aikace don la'akari da irin ƙarfin lantarki na'urar, halin yanzu, mita, amma kuma dole ne Master a cikin aikace-aikace na yadda za a kare na'urar, ba don yin na'urar a cikin wucin gadi canje-canje a cikin lalacewa. Tabbas thyristor hade ne na transistor guda biyu, haɗe tare da babban capacitance saboda babban yanki, don haka ƙarfin dv/dt ya fi rauni. Don di/dt shima yana da tsawaita matsalar yanki, don haka yana haifar da iyakoki sosai.

Lamarin ikon MOSFET ya bambanta sosai. Dv/dt da di/dt yawanci ana ƙididdige ƙarfinsa dangane da iyawar nanosecond (maimakon kowane microsecond). Amma duk da wannan, yana da iyakacin aiki mai ƙarfi. Ana iya fahimtar waɗannan dangane da ainihin tsarin MOSFET mai ƙarfi.

Tsarin MOSFET mai ƙarfi da madaidaicin da'irarsa. Bugu da kari ga capacitance a kusan kowane bangare na na'urar, dole ne a yi la'akari da cewa MOSFET yana da diode hade a layi daya. Daga wani ra'ayi, akwai kuma transistor parasitic. (Kamar yadda IGBT shima yana da thyristor parasitic). Waɗannan abubuwa ne masu mahimmanci a cikin nazarin halayen motsa jiki na MOSFETs.

Da farko dai diode na ciki da ke haɗe zuwa tsarin MOSFET yana da wasu iyawar dusar ƙanƙara. Yawancin lokaci ana bayyana wannan ta fuskar iyawar dusar ƙanƙara guda ɗaya da kuma maimaita ƙarfin dusar ƙanƙara. Lokacin da reverse di/dt ya yi girma, diode yana fuskantar saurin bugun bugun jini, wanda ke da yuwuwar shiga yankin dusar ƙanƙara kuma yana iya lalata na'urar da zarar ƙarfin dusar ƙanƙara ya wuce. Kamar yadda yake tare da kowane diode junction na PN, bincika halayensa masu ƙarfi yana da wahala sosai. Sun bambanta da sauƙin ra'ayi na haɗin gwiwar PN da ke gudana a gaba da kuma toshewa a baya. Lokacin da na yanzu ya faɗi da sauri, diode yana rasa ikonsa na baya na toshewa na ɗan lokaci wanda aka sani da lokacin dawo da baya. Hakanan akwai lokacin lokacin da ake buƙatar haɗin PN don gudanar da sauri kuma baya nuna juriya kaɗan. Da zarar an sami allura na gaba a cikin diode a cikin MOSFET mai ƙarfi, ƴan tsirarun dillalai da aka yi musu allura suma suna ƙara daɗaɗar MOSFET azaman na'urar multitronic.

Yanayi na wucin gadi suna da alaƙa da yanayin layi, kuma yakamata a ba da cikakkiyar kulawa a cikin aikace-aikacen. Yana da mahimmanci don samun zurfin ilimin na'urar don sauƙaƙe fahimta da nazarin matsalolin da suka dace.