Phukusi Laling'ono MOSFETs

MOSFET ikalumikizidwa ndi mabasi ndi malo onyamula katundu, chosinthira chamagetsi chachikulu chimagwiritsidwa ntchito. Nthawi zambiri P-channelZithunzi za MOSFETamagwiritsidwa ntchito mu topology iyi, komanso pakuganizira za ma voltage drive. Kuzindikira mlingo wamakono Gawo lachiwiri ndikusankha mlingo wamakono wa MOSFET. Kutengera kapangidwe ka dera, mlingo wapanowu uyenera kukhala wokwera kwambiri womwe katunduyo ungathe kupirira nthawi zonse.

Mofanana ndi vuto la magetsi, wopanga ayenera kuonetsetsa kuti osankhidwaMOSFETimatha kupirira izi, ngakhale makinawo akupanga mafunde a spike. Milandu iwiri yomwe ikuganiziridwayi ndi yopitilira komanso ma pulse spikes. Parameter iyi imatchulidwa ndi FDN304P DATASHEET, pomwe MOSFET imakhala yokhazikika mumayendedwe opitilira, pomwe pakali pano ikuyenda mosalekeza kudzera pa chipangizocho.

Ma pulse spikes ndi pamene pali mafunde aakulu (kapena spike) akuyenda mu chipangizocho. Pamene mphamvu yapamwamba pansi pazimenezi yatsimikiziridwa, ndi nkhani yosankha mwachindunji chipangizo chomwe chingathe kupirira pakali pano.

Pambuyo posankha pakali pano, kutayika kwa conduction kuyeneranso kuwerengedwa. M'zochita, MOSFETs si zipangizo zabwino chifukwa pali kutaya mphamvu pa conductive ndondomeko, amatchedwa conduction imfa.

MOSFET imagwira ntchito ngati chopinga chosinthika chikakhala "choyaka", monga momwe RDS(ON) ya chipangizocho, imasiyanasiyana kwambiri ndi kutentha. Kutaya mphamvu kwa chipangizochi 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, RDS (ON) idzakhala yaying'ono; m'malo mwake, RDS (ON) idzakhala yokwera. Kwa wopanga makina, apa ndipamene tradeoffs imagwira ntchito kutengera mphamvu yamagetsi. Pazojambula zonyamula, ndizosavuta (komanso zofala) kugwiritsa ntchito ma voltages otsika, pomwe pamapangidwe a mafakitale, ma voltages apamwamba angagwiritsidwe ntchito.

Dziwani kuti kukana kwa RDS(ON) kumakwera pang'ono ndi pano. Kusiyanasiyana kwamagawo osiyanasiyana amagetsi a RDS(ON) resistor atha kupezeka muzolemba zaukadaulo zoperekedwa ndi wopanga.

Kudziwa Zofunikira Zotentha Gawo lotsatira posankha MOSFET ndikuwerengera zofunikira za kutentha kwa dongosolo. Wopangayo ayenera kuganizira zochitika ziwiri zosiyana, zoyipitsitsa komanso zowona. Ndikofunikira kuti kuwerengera kwa zochitika zoipitsitsa kugwiritsidwe ntchito, chifukwa chotsatirachi chimapereka malire ochuluka a chitetezo ndikuonetsetsa kuti dongosololi silidzalephera.

Palinso miyeso ina yofunika kudziwa paMOSFETtsamba lazambiri; monga kukana kwamafuta pakati pa mphambano ya semiconductor ya chipangizo chopakidwa ndi malo ozungulira, komanso kutentha kwambiri kwa mphambano. Kutentha kwapamtunda kwa chipangizocho ndi kofanana ndi kutentha kwakukulu kozungulira kuphatikizapo chinthu cha kukana kutentha ndi kutaya mphamvu (kutentha kwapakati = kutentha kwakukulu kozungulira + [kukana kutentha x kutayika kwa mphamvu]). Kuchokera pa equation iyi mphamvu yochuluka yotaya mphamvu ya dongosolo ikhoza kuthetsedwa, yomwe ndi tanthauzo lofanana ndi I2 x RDS (ON).

Popeza wopanga adatsimikiza kuchuluka kwamakono komwe kudzadutsa pa chipangizocho, RDS(ON) imatha kuwerengedwa kutentha kosiyanasiyana. Ndikofunika kuzindikira kuti pochita ndi zitsanzo zosavuta zotentha, wopanga ayenera kuganiziranso mphamvu ya kutentha kwa semiconductor junction / enclosure chipangizo ndi enclosure / chilengedwe; mwachitsanzo, pamafunika kuti bolodi losindikizidwa ndi phukusi zisatenthe nthawi yomweyo.

Nthawi zambiri, PMOSFET, padzakhala parasitic diode yomwe ilipo, ntchito ya diode ndikuletsa kulumikizana kwa gwero-drain reverse, kwa PMOS, mwayi pa NMOS ndikuti mphamvu yake yoyatsa imatha kukhala 0, komanso kusiyana kwamagetsi pakati pa DS voteji si zambiri, pamene NMOS pa chikhalidwe amafuna kuti VGS kukhala wamkulu kuposa pakhomo, zomwe zidzachititsa kuti mphamvu voteji ndi mosalephera kuposa voteji chofunika, ndipo padzakhala zovuta zosafunikira. PMOS imasankhidwa ngati chosinthira chowongolera, pali mapulogalamu awiri otsatirawa: ntchito yoyamba, PMOS yosankha voteji, V8V ikakhalapo, ndiye kuti magetsi onse amaperekedwa ndi V8V, PMOS idzazimitsidwa, VBAT. sichipereka voteji ku VSIN, ndipo V8V ikatsika, VSIN imayendetsedwa ndi 8V. Zindikirani kukhazikitsidwa kwa R120, chopinga chomwe chimakokera pang'onopang'ono magetsi a pachipata kuti zitsimikizire kuyatsa koyenera kwa PMOS, chiwopsezo chaboma cholumikizidwa ndi chitseko chachikulu chomwe tafotokoza kale.

Ntchito za D9 ndi D10 ndikuletsa kubweza voteji, ndipo D9 ikhoza kusiyidwa. Tiyenera kuzindikira kuti DS ya dera imasinthidwa kwenikweni, kotero kuti ntchito ya chubu yosinthira sichikhoza kutheka mwa kuyendetsa diode yophatikizidwa, yomwe iyenera kuzindikiridwa muzogwiritsira ntchito. Muderali, chizindikiro chowongolera PGC chimawongolera ngati V4.2 ikupereka mphamvu ku P_GPRS. Dera ili, magwero ndi ma terminals akukhetsa samalumikizidwa ku mbali ina, R110 ndi R113 alipo m'lingaliro lakuti R110 control gate panopa si yaikulu kwambiri, R113 control gate normality, R113 kukoka mmwamba, monga PMOS, komanso. chitha kuwonedwa ngati kukokera pa siginecha yowongolera, pomwe zikhomo zamkati za MCU ndi kukokera, ndiko kuti, kutulutsa kwamadzi otseguka pomwe zotuluka sizimathamangitsa PMOS, pa nthawi iyi, Idzafunika mphamvu yakunja kuti ipereke chikoka, kotero resistor R113 imakhala ndi maudindo awiri. R110 ikhoza kukhala yaying'ono, mpaka 100 ohms ikhoza kukhala.