Zosankha za MOSFET

Kusankha kwaMOSFETndikofunikira kwambiri, kusankha koyipa kungakhudze kugwiritsa ntchito mphamvu kwa dera lonselo, kudziwa kuchuluka kwa magawo osiyanasiyana a MOSFET ndi magawo m'magawo osiyanasiyana osinthira kungathandize akatswiri kupeŵa mavuto ambiri, zotsatirazi ndi zina mwazotsatira za Guanhua Weiye. posankha ma MOSFET.

Choyamba, P-channel ndi N-channel

Gawo loyamba ndikuzindikira kugwiritsa ntchito ma MOSFET a N-channel kapena P-channel. mu ntchito mphamvu, pamene MOSFET pansi, ndi katundu chikugwirizana ndi thunthu voteji, ndiMOSFETimapanga chosinthira chamagetsi chotsika. Pakusintha kwamagetsi otsika, ma MOSFET a N-channel nthawi zambiri amagwiritsidwa ntchito, zomwe zimaganiziridwa kuti magetsi azimitsidwa kapena kuyatsa chipangizocho. MOSFET ikalumikizidwa ndi mabasi ndi malo onyamula katundu, chosinthira chamagetsi chachikulu chimagwiritsidwa ntchito. P-channel MOSFETs nthawi zambiri amagwiritsidwa ntchito, chifukwa cha ma voltage drive. Kuti musankhe zida zoyenera zogwiritsira ntchito, ndikofunikira kudziwa mphamvu yamagetsi yomwe ikufunika kuyendetsa chipangizocho komanso momwe zimakhalira zosavuta kuziyika pakupanga. Chotsatira ndicho kudziwa kuchuluka kwa voteji yofunikira, kapena mphamvu yayikulu kwambiri yomwe gawolo linganyamule. Kukwera kwa voteji kumakwera mtengo wa chipangizocho. M'malo mwake, voteji iyenera kukhala yayikulu kuposa mphamvu ya thunthu kapena basi. Izi zidzapereka chitetezo chokwanira kuti MOSFET isalephere. Pakusankha kwa MOSFET, ndikofunikira kudziwa kuchuluka kwamagetsi komwe kungathe kupirira kuchokera kukhetsa kupita ku gwero, mwachitsanzo, VDS yayikulu, kotero ndikofunikira kudziwa kuti mphamvu yayikulu yomwe MOSFET imatha kupirira imasiyanasiyana ndi kutentha. Okonza amafunika kuyesa kuchuluka kwa magetsi pamtundu wonse wa kutentha kwa ntchito. Ma voliyumu ovotera amafunika kukhala ndi malire okwanira kuti atseke izi kuti zitsimikizire kuti dera silikulephera. Kuphatikiza apo, zinthu zina zachitetezo ziyenera kuganiziridwa ngati ma voltage transients.

Chachiwiri, dziwani mlingo wamakono

Mlingo wapano wa MOSFET umadalira mawonekedwe adera. Chiyembekezo chamakono ndi chiwerengero chapamwamba chomwe katunduyo angathe kupirira muzochitika zonse. Mofanana ndi ma voliyumu, wopanga amayenera kuwonetsetsa kuti MOSFET yosankhidwa imatha kunyamula pakali pano, ngakhale makinawo apanga spike pano. Zochitika ziwiri zomwe zikuyenera kuganiziridwa ndizomwe zimachitika mosalekeza komanso ma pulse spikes. MOSFET ili m'malo okhazikika pamachitidwe opitilira apo, pomwe magetsi akudutsa mosalekeza pa chipangizocho. Ma spikes a pulse amatanthawuza kuchuluka kwa ma surges (kapena ma spikes of current) omwe akuyenda kudzera mu chipangizocho, pamenepa, pamene mphamvu yapamwamba yatsimikiziridwa, ndi nkhani yosankha mwachindunji chipangizo chomwe chingathe kupirira pakali pano.

Pambuyo posankha pakali pano, kutayika kwa conduction kumawerengedwanso. Muzochitika zenizeni,MOSFETsali zigawo zabwino chifukwa cha zotayika zamagetsi zomwe zimachitika panthawi ya conductive, zomwe zimatchedwa zotayika za conduction. Pamene "pa", MOSFET imakhala ngati chotsutsa chosinthika, chomwe chimatsimikiziridwa ndi RDS (ON) ya chipangizocho ndikusintha kwambiri ndi kutentha. Kutayika kwa mphamvu kwa chipangizocho kumatha kuwerengedwa kuchokera ku Iload2 x RDS (ON), ndipo popeza kukana kumasiyana ndi kutentha, kutayika kwa mphamvu kumasiyana mosiyanasiyana. Kukwera kwa VGS komwe kumagwiritsidwa ntchito ku MOSFET, kumachepetsa RDS (ON); m'malo mwake, kukwezeka kwa RDS(ON). Kwa wopanga makina, apa ndipamene tradeoffs imagwira ntchito kutengera mphamvu yamagetsi. Kwa mapangidwe onyamula, ma voltages otsika ndi osavuta (komanso ochulukirapo), pomwe pamapangidwe a mafakitale, ma voltages apamwamba angagwiritsidwe ntchito. Dziwani kuti kukana kwa RDS(ON) kumakwera pang'ono ndi pano.

Ukadaulo umakhudza kwambiri mawonekedwe azinthu, ndipo matekinoloje ena amakonda kupangitsa kuti RDS(ON) ichuluke pakukulitsa VDS yayikulu. Pamatekinoloje oterowo, kuwonjezereka kwa kukula kwawafa kumafunika ngati VDS ndi RDS(ON) zitsitsidwe, motero kukulitsa kukula kwa phukusi komwe kumayendera ndi mtengo wofananira nawo wachitukuko. Pali matekinoloje angapo m'makampani omwe amayesa kuwongolera kuchuluka kwa kukula kwa zopindika, zofunika kwambiri zomwe ndiukadaulo wamakina ndi ma charger. Muukadaulo wa ngalande, ngalande yakuya imayikidwa mu chowotcha, nthawi zambiri imasungidwa ma voltages otsika, kuti muchepetse kukana kwa RDS (ON).

III. Dziwani zofunikira za kutaya kutentha

Chotsatira ndikuwerengera zofunikira za kutentha kwa dongosolo. Zochitika ziwiri zosiyana ziyenera kuganiziridwa, zovuta kwambiri komanso zenizeni. TPV imalimbikitsa kuwerengera zotsatira za zochitika zoipitsitsa, monga momwe kuwerengeraku kumapereka chitetezo chokwanira ndikuonetsetsa kuti dongosololi silidzalephera.

IV. Kusintha Magwiridwe

Pomaliza, kusintha kwa magwiridwe antchito a MOSFET. Pali magawo ambiri omwe amakhudza kusintha kwa ntchito, zofunika kwambiri ndi chipata / kukhetsa, chipata / gwero ndi kukhetsa / gwero la mphamvu. Ma capacitances awa amapanga zotayika zosinthika mu gawoli chifukwa chofuna kuwalipiritsa nthawi iliyonse akasinthidwa. Zotsatira zake, liwiro losinthira la MOSFET limachepa ndipo mphamvu ya chipangizocho imachepa. Kuti awerengere zotayika zonse mu chipangizochi posinthira, wopanga amayenera kuwerengera zotayika pakuyatsa (Eon) ndi zotayika pakuzimitsa (Eoff). Izi zitha kuwonetsedwa ndi equation yotsatirayi: Psw = (Eon + Eoff) x kusintha pafupipafupi. Ndipo chipata cha chipata (Qgd) chimakhudza kwambiri kusintha magwiridwe antchito.