Iphakheji elincane le-MOSFETs

Lapho i-MOSFET ixhunywe endaweni yebhasi kanye nendawo yokulayisha, kusetshenziswa iswishi ye-voltage ephezulu. Ngokuvamile i-P-channelAma-MOSFETzisetshenziswa kule topology, futhi ukucatshangelwa voltage drive. Ukunquma isilinganiso samanje Isinyathelo sesibili ukukhetha 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 ezicatshangelwayo ziyimodi eqhubekayo kanye nama-pulse spikes. Le pharamitha ikhonjiswa yi-FDN304P DATASHEET, lapho i-MOSFET isesimweni esizinzile kumodi yokuqhuba eqhubekayo, lapho i-current igeleza ngokuqhubekayo kudivayisi.

I-Pulse spikes yilapho kukhona ukukhuphuka okukhulu (noma i-spike) yamanje egeleza ocingweni. Uma inani eliphezulu lamanje ngaphansi kwalezi zimo selinqunyiwe, kumane nje kuyindaba yokukhetha ngokuqondile idivayisi engakwazi ukumelana nalesi silinganiso esiphezulu.

Ngemva kokukhetha i-current rated, ukulahlekelwa kokuqhuba kufanele kubalwe. Empeleni, ama-MOSFET awawona amadivaysi afanelekile ngoba kukhona ukulahleka kwamandla ngesikhathi senqubo yokuqhuba, ebizwa ngokuthi ukulahleka kokwenziwa.

I-MOSFET isebenza njengesivimbeli esiguquguqukayo uma "ivuliwe", njengoba kunqunywa i-RDS(ON) yedivayisi, futhi iyahluka kakhulu ngezinga lokushisa. Ukuchithwa kwamandla kwedivayisi kungabalwa ku-Iload2 x RDS(ON), futhi njengoba ukumelana nokumelana kushintshana nezinga lokushisa, ukuchithwa kwamandla kuyehluka ngokulinganayo. Uma iphezulu i-voltage VGS esetshenziswa ku-MOSFET, i-RDS(ON) izoba mancane; ngokuphambene lapho i-RDS(ON) izoba phezulu. Kumklami wesistimu, kulapho uhwebo luqala khona ukusebenza ngokuya ngevolthi yesistimu. Ngemiklamo ephathekayo, kulula (futhi kuvame kakhulu) ukusebenzisa ama-voltage aphansi, kuyilapho imiklamo yezimboni, ama-voltages aphezulu angasetshenziswa.

Qaphela ukuthi ukumelana ne-RDS(ON) kukhuphuka kancane ngokwamanje. Ukwehluka kumapharamitha ahlukahlukene kagesi we-RDS(ON) resistor ingatholakala eshidini ledatha yobuchwepheshe elinikezwe umenzi.

Ukunquma Izidingo Zokushisa Isinyathelo esilandelayo ekukhetheni i-MOSFET ukubala izidingo ezishisayo zesistimu. Umklami kufanele acabangele izimo ezimbili ezihlukene, icala elibi kakhulu neliyiqiniso. Kunconywa ukuthi kubalwe isimo esibi kakhulu kusetshenziswe, njengoba lo mphumela uhlinzeka ngesilinganiso esikhulu sokuphepha futhi uqinisekisa ukuthi uhlelo ngeke lwehluleke.

Kukhona nezilinganiso ezithile okufanele uziqaphele ku-I-MOSFETishidi le-data; njengokumelana nokushisa okuphakathi kwe-semiconductor junction yedivayisi epakishiwe nendawo ezungezile, kanye nezinga lokushisa eliphezulu lokuhlangana. Izinga lokushisa elihlanganayo ledivayisi lilingana nezinga lokushisa eliphakeme kakhulu le-ambient kanye nomkhiqizo wokumelana nokushisa kanye nokushabalaliswa kwamandla (izinga lokushisa lokuhlangana = izinga lokushisa eliphakeme le-ambient + [ukumelana nokushisa x ukuchithwa kwamandla]). Kusukela kulesi sibalo ubukhulu bokuchithwa kwamandla esistimu kungaxazululeka, okusho ngencazelo elingana ne-I2 x RDS(ON).

Njengoba umklami enqume inani eliphezulu lamanje elizodlula kudivayisi, i-RDS(ON) ingabalwa kumazinga okushisa ahlukene. Kubalulekile ukuqaphela ukuthi lapho usebenzisana namamodeli alula okushisa, umklami kufanele futhi acabangele amandla okushisa e-semiconductor junction/enclosure yedivayisi kanye nendawo ebiyelwe/imvelo; okungukuthi, kuyadingeka ukuthi ibhodi lesifunda eliphrintiwe kanye nephakheji lingafudumala ngokushesha.

Imvamisa, i-PMOSFET, kuzoba khona i-parasitic diode ekhona, umsebenzi we-diode ukuvimbela ukuxhumana okubuyela emuva komthombo, ku-PMOS, inzuzo ngaphezu kwe-NMOS ukuthi i-voltage yayo yokuvula ingaba ngu-0, kanye nomehluko we-voltage phakathi I-voltage ye-DS ayiningi, kuyilapho i-NMOS esesimweni idinga ukuthi i-VGS ibe nkulu kunombundu, okuzoholela ekutheni amandla okulawula abe mkhulu ngokungenakugwemeka kune-voltage edingekayo, futhi kuzoba khona inkathazo engadingekile. I-PMOS ikhethwa njenge-switch control, kunezinhlelo zokusebenza ezimbili ezilandelayo: isicelo sokuqala, i-PMOS yokwenza ukukhethwa kwamandla kagesi, uma i-V8V ikhona, khona-ke i-voltage inikezwa yi-V8V, i-PMOS izocishwa, i-VBAT ayinikezi i-voltage ku-VSIN, futhi uma i-V8V iphansi, i-VSIN inikwa amandla yi-8V. Qaphela ukumiswa kwe-R120, isivimbeli esidonsa kancane kancane i-voltage yesango ukuze siqinisekise ukuvuleka okufanele kwe-PMOS, ingozi yezwe ehlotshaniswa nokuphazamiseka kwesango eliphezulu okuchazwe ngaphambili.

Imisebenzi ye-D9 ne-D10 iwukuvimbela ukuhlehliswa kwe-voltage, futhi i-D9 ingashiywa. Kumele kuqashelwe ukuthi i-DS yesifunda empeleni iguqulwa, ukuze umsebenzi we-tube yokushintsha ayikwazi ukufezwa ngokuqhutshwa kwe-diode enamathiselwe, okufanele kuqashelwe ekusebenziseni okusebenzayo. Kule sekethe, isiginali yokulawula i-PGC ilawula ukuthi i-V4.2 inikeza amandla ku-P_GPRS. Le sekethe, amatheminali omthombo kanye nama-drain axhunyiwe kokuphambene, u-R110 no-R113 akhona ngomqondo wokuthi isango lokulawula isango elingu-R110 alilikhulu kakhulu, isango lokulawula elingu-R113 elijwayelekile, ukudonsa u-R113 ukuya phezulu, njenge-PMOS, kodwa futhi. kungabonakala njengokudonsela phezulu kusiginali yokulawula, lapho izikhonkwane zangaphakathi ze-MCU kanye nokudonsa, okungukuthi, ukuphuma kwe-drain evulekile lapho okukhiphayo kungacishi i-PMOS, kulokhu, i-Izodinga i-voltage yangaphandle ukuze inikeze ukudonsa, ngakho-ke i-resistor R113 idlala izindima ezimbili. u-r110 ungaba mncane, uye ku-100 ohms angaba.