Imihlahlandlela Yokukhetha Iphakheji ye-MOSFET

Okwesibili, ubukhulu bemikhawulo yesistimu

Amanye amasistimu kagesi anqunyelwe usayizi we-PCB nowangaphakathi ukuphakama, snjengezinhlelo zokuxhumana, ukunikezwa kwamandla nge-modular ngenxa yemikhawulo yokuphakama kuvame ukusebenzisa iphakheji ye-DFN5 * 6, DFN3 * 3; kokunye ukunikezwa kwamandla kwe-ACDC, ukusetshenziswa komklamo omncane kakhulu noma ngenxa yemikhawulo yegobolondo, ukuhlanganiswa kwephakheji ye-TO220 yezinyawo ze-MOSFET zamandla afakwe ngokuqondile empandeni yemikhawulo yokuphakama ayikwazi ukusebenzisa iphakheji ye-TO247. Enye idizayini ezacile kakhulu egoba ngokuqondile izikhonkwane zedivayisi, le nqubo yokukhiqiza yomklamo izoba yinkimbinkimbi.

Okwesithathu, inqubo yokukhiqiza yenkampani

I-TO220 inezinhlobo ezimbili zephakeji: iphakethe lensimbi elingenalutho kanye nephakethe lepulasitiki eligcwele, iphakethe lensimbi elingenalutho ukumelana nokushisa kuncane, amandla okushisa okushisa aqinile, kodwa inqubo yokukhiqiza, udinga ukwengeza ukwehla kokufakwa, inqubo yokukhiqiza iyinkimbinkimbi futhi iyabiza, kuyilapho iphakethe lepulasitiki eligcwele ukumelana nokushisa kukhulu, ikhono lokukhipha ukushisa libuthakathaka, kodwa inqubo yokukhiqiza ilula.

Ukuze kuncishiswe inqubo yokwenziwa yokukhiya izikulufu, eminyakeni yamuva nje, ezinye izinhlelo zikagesi zisebenzisa iziqeshana ukuze zibe namandla.Ama-MOSFET ziboshwe kusinki ukushisa, ukuze ukuvela bendabuko TO220 ingxenye engxenyeni engenhla ukususwa izimbobo ngendlela entsha encapsulation, kodwa futhi ukunciphisa ukuphakama idivayisi.

Okwesine, ukulawula izindleko

Kwezinye izinhlelo zokusebenza ezizwela kakhulu izindleko ezifana namabhodi omama wedeskithophu namabhodi, ama-MOSFET wamandla kumaphakheji e-DPAK avame ukusetshenziswa ngenxa yezindleko eziphansi zamaphakheji anjalo. Ngakho-ke, lapho ukhetha iphakheji ye-MOSFET yamandla, ehlanganiswe nesitayela senkampani yabo nezici zomkhiqizo, futhi ucabangele izici ezingenhla.

Okwesihlanu, khetha ukumelana ne-voltage BVDSS ezimweni eziningi, ngoba ukwakheka kwe-vo inputingxenye ye-elekthronikhi Uhlelo lulinganiselwe, inkampani ikhethe umphakeli othile wenombolo ethile yezinto ezibonakalayo, i-voltage elinganiselwe yomkhiqizo nayo ilungisiwe.

I-voltage yokuhlukanisa i-BVDSS yamandla e-MOSFET kudatha yedatha ichaze izimo zokuhlola, ezinamavelu ahlukene ngaphansi kwezimo ezihlukene, futhi i-BVDSS ine-coefficient yokushisa evumayo, ekusetshenzisweni kwangempela kwenhlanganisela yalezi zici kufanele kucatshangelwe ngendlela ebanzi.

Ulwazi oluningi kanye nezincwadi ezivame ukushiwo: uma uhlelo lwamandla i-MOSFET VDS ye-spike voltage ephakeme kakhulu uma inkulu kune-BVDSS, noma ngabe ubude be-spike pulse voltage bungaba ambalwa noma amashumi ama-ns, amandla e-MOSFET azongena ku-avalanche. futhi ngaleyo ndlela kwenzeka umonakalo.

Ngokungafani nama-transistors kanye ne-IGBT, amandla e-MOSFET anamandla okumelana ne-avalanche, futhi izinkampani eziningi ezinkulu ze-semiconductor amandla e-MOSFET avalanche energy emgqeni wokukhiqiza ukuhlola okugcwele, ukutholwa okungu-100%, okungukuthi, kudatha lokhu isilinganiso esiqinisekisiwe, i-avalanche voltage. ngokuvamile kwenzeka ngo-1.2 ~ 1.3 izikhathi ze-BVDSS, futhi ubude besikhathi ngokuvamile buba ngu-μs, ngisho nezinga le-ms, bese ubude besikhathi ambalwa kuphela noma amashumi ama-ns, aphansi kakhulu kune-avalanche voltage spike pulse voltage akuwona umonakalo kumandla we-MOSFET.

Isithupha, ngokukhethwa kwe-voltage yedrayivu VTH

Amasistimu kagesi ahlukene ama-MOSFET akhethiwe kagesi awafani, amandla kagesi e-AC/DC ngokuvamile asebenzisa i-12V drive voltage, i-motherboard ye-motherboard DC / DC converter esebenzisa i-5V drive voltage, ngakho-ke ngokuya nge-voltage yesistimu yokukhetha i-threshold voltage ehlukile. VTH amandla MOSFETs.

I-threshold voltage VTH yamandla ama-MOSFET kudathabhethi nayo inezimo zokuhlola ezichaziwe futhi inamanani ahlukene ngaphansi kwezimo ezihlukene, futhi i-VTH ine-coefficient yezinga lokushisa elibi. Ama-voltage ahlukene e-VGS ahambisana nokuphikisana okuhlukile, futhi ekusebenzeni okusebenzayo kubalulekile ukucabangela izinga lokushisa.

Ekusetshenzisweni okungokoqobo, ukuhluka kwezinga lokushisa kufanele kucatshangelwe ukuze kuqinisekiswe ukuthi amandla e-MOSFET avuliwe ngokugcwele, kuyilapho ngesikhathi esifanayo kuqinisekisa ukuthi ama-spike pulses ahlanganiswe ne-G-pole ngesikhathi senqubo yokuvala shaqa ngeke aqalwe ukucupha okungamanga khiqiza i-straight-through noma i-short-circuit.