Ungawakhetha kanjani kahle ama-MOSFET ama-voltage amancane

Ukukhethwa kwe-MOSFET yamandla amancane kuyingxenye ebaluleke kakhuluI-MOSFETUkukhetha akukuhle kungase kuthinte ukusebenza kahle kanye nezindleko zesifunda sonke, kodwa futhi kuzoletha izinkinga eziningi konjiniyela, ukuthi ungayikhetha kanjani i-MOSFET ngendlela efanele?

Ukukhetha i-N-channel noma i-P-channel Isinyathelo sokuqala ekukhetheni idivayisi elungile yokuklama ukunquma ukuthi uzosebenzisa i-N-channel noma i-P-channel MOSFET Ohlelweni lwamandla olujwayelekile, i-MOSFET yenza iswishi eseceleni ene-voltage ephansi i-MOSFET imisiwe futhi umthwalo uxhunywe ku-voltage ye-trunk. Kushintshwayo ohlangothini lwe-voltage ephansi, i-MOSFET yesiteshi se-N kufanele isetshenziswe ngenxa yokucatshangwa kwamandla kagesi adingekayo ukuze ucishwe noma uvule idivayisi.

Uma i-MOSFET ixhunywe ebhasini futhi umthwalo uphansi, inkinobho ye-voltage ephezulu kufanele isetshenziswe. Ama-MOSFET esiteshi se-P avame ukusetshenziswa kule topology, futhi ngokucatshangelwa kwe-voltage drive. Nquma isilinganiso samanje. Khetha isilinganiso samanje se-MOSFET. Ngokuya ngesakhiwo sesifunda, lesi silinganiso samanje kufanele sibe umkhawulo wamanje umthwalo ongamelana nawo ngaphansi kwazo zonke izimo.

Ngokufanayo nendaba ye-voltage, umklami kufanele aqinisekise ukuthi okukhethiweI-MOSFETingamelana nalesi silinganiso samanje, nanoma isistimu ikhiqiza ama-spike currents. Izimo ezimbili zamanje okufanele zicatshangelwe imodi eqhubekayo kanye nama-pulse spikes. Kumodi yokuqhuba eqhubekayo, i-MOSFET isesimweni esingaguquki, lapho okwamanje kudlula ngokuqhubekayo kudivayisi.

Ama-pulse spikes yilapho kukhona ama-surges amakhulu (noma ama-spikes of current) ageleza ocingweni. Uma inani eliphezulu lamanje ngaphansi kwalezi zimo selinqunyiwe, kumane nje kuyindaba yokukhetha ngokuqondile idivayisi engakwazi ukumelana nalesi silinganiso esiphezulu. Ukunquma Izidingo Zokushisa Ukukhetha i-MOSFET nakho kudinga ukubala izidingo ezishisayo zohlelo. Umklami kufanele acabangele izimo ezimbili ezihlukene, icala elibi kakhulu neliyiqiniso. Kutuswa ukuba kusetshenziswe isibalo esibi kakhulu ngoba sinikeza umkhawulo omkhulu wokuphepha futhi siqinisekisa ukuthi uhlelo ngeke lwehluleke. Kukhona nezilinganiso ezithile okufanele uziqaphele eshidini ledatha le-MOSFET; njengokumelana nokushisa phakathi kokuhlangana kwe-semiconductor yedivayisi yephakheji nendawo, kanye nezinga lokushisa eliphezulu lokuhlangana. Ukunquma ngokushintsha ukusebenza, isinyathelo sokugcina ekukhetheni i-MOSFET ukunquma ngokushintsha ukusebenza kweI-MOSFET.

Kunamapharamitha amaningi athinta ukusebenza kokushintsha, kodwa okubaluleke kakhulu yisango/ukukhipha amanzi, isango/umthombo, namandla okukhipha/umthombo. Lawa mandla adala ukulahlekelwa kokushintsha kudivayisi ngoba kufanele akhokhiswe ngesikhathi sokushintsha ngakunye. ijubane lokushintsha le-MOSFET ngakho-ke liyancishiswa futhi ukusebenza kahle kwedivayisi kuyehla. Ukuze ubale inani lokulahlekelwa kwedivayisi ngesikhathi sokushintsha, umklami kufanele abale ukulahlekelwa kokuvula (i-Eon) kanye nokulahlekelwa kokucisha.

Uma inani le-vGS lilincane, ikhono lokumunca ama-electron alinamandla, ukuvuza - umthombo phakathi kwezipho zesiteshi eziqhubekayo, i-vGS iyakhuphuka, imuncwe ongqimbeni lwangaphandle lwama-electron e-P substrate ekukhuleni, lapho i-vGS ifinyelela inani elithile, lawa ma-electron esangweni eduze nokubukeka kwe-P substrate enza ungqimba oluncane lwe-N-uhlobo, futhi ezinendawo emibili engu-N + exhunyiwe Lapho i-vGS ifinyelela inani elithile, lawa ma-electron isango eliseduze nokubukeka kwe-substrate engu-P lizokwenza ungqimba oluncane lwe-N, futhi lixhunywe endaweni emibili ye-N +, ku-drain - umthombo wakha isiteshi sokuhambisa sohlobo lwe-N, uhlobo lwaso lokuqhuba kanye nokuphambene ne-substrate engu-P, eyakha anti-uhlobo ungqimba. I-vGS inkulu, indima yokubukeka kwe-semiconductor yensimu kagesi enamandla kakhulu, ukumuncwa kwama-electron ngaphandle kwe-substrate ye-P, lapho isiteshi se-conductive sishubile, sinciphisa ukumelana nesiteshi. Okusho ukuthi, i-N-channel MOSFET ku-vGS <VT, ayikwazi ukwakha isiteshi esiqhutshwayo, ishubhu isesimweni sokunqamuka. Inqobo nje uma i-vGS ≥ VT, kuphela lapho ukwakheka kwesiteshi. Ngemva kokwakhiwa kwesiteshi, i-drain current ikhiqizwa ngokungeza i-voltage eya phambili i-vDS phakathi kwe-drain - source.

Kodwa i-Vgs iyaqhubeka nokukhula, ake sithi IRFPS40N60KVgs = 100V lapho i-Vds = 0 ne-Vds = 400V, izimo ezimbili, umsebenzi we-tube ukuletha yimuphi umphumela, uma ushiswa, imbangela kanye nendlela yangaphakathi yenqubo ukuthi i-Vgs ikhuphuka kanjani izonciphisa. I-Rds (on) inciphisa ukulahlekelwa kokushintsha, kodwa ngesikhathi esifanayo izokwandisa i-Qg, ukuze ukulahlekelwa kokuvula kube kukhulu, kuthinte ukusebenza kahle kwe- I-voltage ye-MOSFET GS nge-Vgg iya ku-Cgs iyashaja futhi ikhuphuke, ifike ku-voltage yokulungisa i-Vth, i-MOSFET iqala ukuqhutshwa; Ukwanda kwamanje kwe-MOSFET DS, i-Millier capacitance in the interval ngenxa yokukhishwa kwe-DS capacitance nokukhishwa, ukushaja kwe-GS capacitance akunawo umthelela omkhulu; Qg = Cgs * Vgs, kodwa inkokhiso izoqhubeka nokwakha.

I-voltage ye-DS ye-MOSFET yehla ifinyelela ku-voltage efanayo ne-Vgs, amandla e-Millier akhula kakhulu, i-voltage yangaphandle iyama ukushaja i-Millier capacitance, i-voltage ye-GS capacitance ayishintshile, i-voltage ku-Millier capacitance iyanda, kuyilapho i-voltage ikhuphuka. ku-DS amandla ayaqhubeka nokuncipha; i-voltage ye-DS ye-MOSFET yehla iye ku-voltage ekuqhubeni okugcwele, amandla e-Millier iba mancane I-voltage ye-DS ye-MOSFET yehla iye ku-voltage ekusetshenzisweni kwe-saturation, amandla e-Millier aba mancane futhi akhokhiswe kanye namandla e-GS ngedrayivu yangaphandle. i-voltage, kanye ne-voltage ku-GS capacitance ikhuphuka; iziteshi zokulinganisa amandla kagesi ziwuchungechunge lwasekhaya lwe-3D01, 4D01, kanye nochungechunge lwe-Nissan 3SK.

Ukuzimisela kwe-G-pole (isango): sebenzisa igiya le-diode le-multimeter. Uma unyawo nezinye izinyawo ezimbili phakathi kokwehla kwamandla kagesi ephozithivu nenegethivu kungaphezu kuka-2V, okungukuthi, isibonisi esithi "1", lolu nyawo kuyisango elingu-G. Bese ushintsha ipeni ukuze ulinganise zonke ezinye izinyawo ezimbili, i-voltage drop incane ngaleso sikhathi, ipeni elimnyama lixhunywe ku-D-pole (drain), ipeni elibomvu lixhunywe ku-S-pole (umthombo).