Yuav ua li cas xaiv cov me me voltage MOSFETs

Me me voltage MOSFET xaiv yog ib qho tseem ceeb heev ntawm covMOSFETkev xaiv tsis zoo yuav cuam tshuam rau kev ua tau zoo thiab tus nqi ntawm tag nrho cov Circuit Court, tab sis kuj yuav ua rau muaj teeb meem ntau rau cov engineers, yuav ua li cas xaiv MOSFET kom raug?

Xaiv N-channel lossis P-channel Thawj kauj ruam hauv kev xaiv cov cuab yeej tsim nyog rau kev tsim qauv yog txiav txim siab seb puas yuav siv N-channel lossis P-channel MOSFET Hauv daim ntawv thov fais fab, MOSFET suav nrog qhov hloov hluav taws xob qis thaum MOSFET yog grounded thiab lub load txuas nrog lub cev voltage. Hauv qhov hluav taws xob qis sab hloov, N-channel MOSFET yuav tsum tau siv vim qhov kev txiav txim siab ntawm qhov hluav taws xob yuav tsum tau tua lossis qhib lub cuab yeej.

Thaum lub MOSFET txuas nrog lub tsheb npav thiab cov load yog grounded, lub siab voltage sab hloov yuav tsum tau siv. P-channel MOSFETs feem ntau yog siv nyob rau hauv no topology, dua rau voltage tsav xav txog. Txiav txim siab qhov ntsuas tam sim no. Xaiv qhov ntsuas tam sim no ntawm MOSFET. Nyob ntawm cov qauv hauv Circuit Court, qhov kev ntsuas tam sim no yuav tsum yog qhov siab tshaj plaws tam sim no uas lub load tuaj yeem tiv taus txhua qhov xwm txheej.

Zoo ib yam li cov teeb meem ntawm qhov hluav taws xob, tus tsim qauv yuav tsum xyuas kom meej tias qhov kev xaivMOSFETtuaj yeem tiv taus qhov kev ntsuas tam sim no, txawm tias thaum lub kaw lus tsim cov kab hluav taws xob loj. Ob qhov xwm txheej tam sim no los xav txog yog hom txuas ntxiv thiab mem tes spikes. Nyob rau hauv kev nruam conduction hom, MOSFET nyob rau hauv tsis tu ncua, thaum tam sim no dhau mus tas li los ntawm lub cuab yeej.

Pulse spikes yog thaum muaj surges loj (los yog spikes ntawm tam sim no) ntws los ntawm lub cuab yeej. Thaum qhov siab tshaj plaws tam sim no nyob rau hauv cov xwm txheej no tau txiav txim siab, nws tsuas yog ib qho teeb meem ntawm kev xaiv ncaj qha rau lub cuab yeej uas tuaj yeem tiv taus qhov siab tshaj plaws tam sim no. Kev txiav txim siab Thermal Requirements Xaiv ib tug MOSFET kuj yuav tsum tau xam cov thermal uas yuav tsum tau ntawm lub system. Tus tsim qauv yuav tsum xav txog ob qhov xwm txheej sib txawv, qhov xwm txheej phem tshaj plaws thiab qhov tseeb. Nws raug nquahu kom siv qhov kev suav phem tshaj plaws vim tias nws muab kev nyab xeeb ntau dua thiab ua kom ntseeg tau tias lub kaw lus yuav tsis poob. Kuj tseem muaj qee qhov kev ntsuas kom paub txog ntawm MOSFET cov ntaub ntawv; xws li cov thermal kuj ntawm cov semiconductor hlws ris ntawm lub pob khoom thiab ib puag ncig, thiab qhov siab tshaj plaws hlws ris kub. Kev txiav txim siab ntawm kev hloov pauv kev ua tau zoo, cov kauj ruam kawg ntawm kev xaiv MOSFET yog txiav txim siab ntawm kev hloov pauv ntawm qhov kev ua tau zoo.MOSFET.

Muaj ntau qhov tsis zoo uas cuam tshuam rau kev hloov pauv kev ua haujlwm, tab sis qhov tseem ceeb tshaj plaws yog rooj vag / qhov dej, qhov rooj / qhov chaw, thiab qhov dej / qhov peev xwm. Cov capacitances no tsim kev hloov pauv hauv cov cuab yeej vim tias lawv yuav tsum tau them nyiaj thaum txhua qhov hloov pauv. Yog li ntawd, qhov hloov pauv ceev ntawm MOSFET txo qis thiab kev ua haujlwm ntawm cov cuab yeej txo qis. Txhawm rau xam tag nrho cov cuab yeej poob thaum hloov pauv, tus tsim qauv yuav tsum suav qhov poob ntawm qhov poob (Eon) thiab qhov poob poob.

Thaum tus nqi ntawm vGS me me, muaj peev xwm nqus tau cov hluav taws xob tsis muaj zog, qhov xau - qhov chaw ntawm qhov tseem tsis muaj cov kab hluav taws xob nthuav tawm, vGS nce, absorbed rau hauv P substrate txheej txheej ntawm electrons ntawm qhov nce, thaum lub vGS nce mus txog ib tej yam nqi, cov electrons nyob rau hauv lub rooj vag ze P substrate zoo li yog ib tug nyias txheej ntawm N-hom, thiab nrog rau ob lub N + cheeb tsam kev cob cog rua Thaum vGS mus txog ib tug tej yam nqi, cov electrons nyob rau hauv lub rooj vag. Nyob ze ntawm P substrate zoo li yuav tsim N-hom nyias txheej, thiab txuas nrog ob thaj tsam N +, hauv qhov ntws tawm - qhov chaw tsim N-hom conductive channel, nws hom conductive thiab qhov sib txawv ntawm P substrate, tsim los tiv thaiv. hom txheej. vGS loj dua, lub luag hauj lwm ntawm lub semiconductor tsos ntawm lub zog ntawm hluav taws xob teb, nqus ntawm electrons mus rau sab nrauv ntawm lub P substrate, qhov ntau conductive channel yog thicker, qhov qis dua channel kuj. Ntawd yog, N-channel MOSFET hauv vGS < VT, tsis tuaj yeem tsim cov channel conductive, lub raj yog nyob rau hauv lub xeev txiav. Ntev npaum li thaum vGS ≥ VT, tsuas yog thaum cov channel muaj pes tsawg leeg. Tom qab cov channel tau tsim, cov dej ntws tawm yog tsim los ntawm kev ntxiv rau pem hauv ntej voltage vDS ntawm qhov ntws - qhov chaw.

Tab sis Vgs tseem nce ntxiv, cia peb hais tias IRFPS40N60KVgs = 100V thaum Vds = 0 thiab Vds = 400V, ob yam xwm txheej, lub raj ua haujlwm kom coj tau dab tsi tshwm sim, yog hlawv, qhov ua rau thiab cov txheej txheem sab hauv ntawm cov txheej txheem yog li cas Vgs nce yuav txo tau. Rds (on) txo qhov kev hloov pauv, tab sis tib lub sijhawm yuav ua rau Qg nce ntxiv, yog li ntawd qhov kev poob qis yuav loj dua, cuam tshuam rau kev ua haujlwm. ntawm MOSFET GS voltage los ntawm Vgg mus rau Cgs them thiab nce, tuaj txog ntawm cov txij nkawm voltage Vth, MOSFET pib conductive; MOSFET DS tam sim no nce, Millier capacitance nyob rau hauv lub ncua sij hawm vim qhov tso tawm ntawm DS capacitance thiab tawm, GS capacitance them tsis muaj kev cuam tshuam ntau; Qg = Cgs * Vgs, tab sis tus nqi yuav txuas ntxiv mus.

Lub DS voltage ntawm MOSFET poob mus rau tib qhov voltage li Vgs, Millier capacitance nce zoo heev, sab nraud tsav voltage nres them lub Millier capacitance, qhov voltage ntawm GS capacitance tseem tsis hloov, voltage ntawm Millier capacitance nce, thaum lub voltage. ntawm DS capacitance tseem txo qis; DS voltage ntawm MOSFET txo mus rau qhov voltage ntawm saturated conduction, lub Millier capacitance yuav me dua Lub DS voltage ntawm lub MOSFET poob mus rau lub voltage ntawm saturation conduction, lub Millier capacitance yuav me me thiab raug them ua ke nrog lub GS capacitance los ntawm sab nraud tsav. voltage, thiab qhov voltage ntawm GS capacitance nce; cov kev ntsuas hluav taws xob yog cov domestic 3D01, 4D01, thiab Nissan's 3SK series.

G-ncej (qhov rooj) kev txiav txim siab: siv lub diode iav ntawm multimeter. Yog hais tias ib tug ko taw thiab ob txhais taw ntawm qhov zoo thiab qhov tsis zoo voltage poob siab tshaj 2V, uas yog, cov zaub "1", qhov no taw yog lub rooj vag G. Thiab ces pauv tus cwj mem los ntsuas qhov seem ntawm ob txhais taw, qhov hluav taws xob poob qis me me thaum lub sijhawm ntawd, tus cwj mem dub txuas nrog D-ncej (drain), tus cwj mem liab txuas nrog S-ncej (qhov chaw).