Amanqaku oKhetho eMOSFET

Ukhetho lweI-MOSFETkubaluleke kakhulu, ukhetho olubi lunokuchaphazela ukusetyenziswa kwamandla esekethe yonke, i-master nuances yamacandelo ahlukeneyo e-MOSFET kunye neeparamitha kwiisekethe ezahlukeneyo zokutshintsha zinokunceda iinjineli ukuba ziphephe iingxaki ezininzi, ezi zilandelayo zezinye zeengcebiso zikaGuanhua Weiye. yokukhethwa kwee-MOSFETs.

 

Okokuqala, i-P-channel kunye ne-N-channel

Inyathelo lokuqala kukuqinisekisa ukusetyenziswa kwe-N-channel okanye i-P-channel MOSFETs. kwizicelo zamandla, xa umhlaba we-MOSFET, kunye nomthwalo uqhagamshelwe kumbane we-trunk, iI-MOSFETyenza iswitsha esecaleni enevoltage ephantsi. Kwi-voltage ephantsi yokutshintsha icala, i-N-channel MOSFETs zisetyenziswa ngokubanzi, nto leyo eqwalasela umbane ofunekayo ukuze ucime okanye uvule isixhobo. Xa i-MOSFET iqhagamshelwe kwindawo yebhasi kunye nendawo yokulayisha, iswitshi yecala lombane ophezulu iyasetyenziswa. Ii-MOSFET ze-P-channel zidla ngokusetyenziswa, ngenxa yokuqwalaselwa kwe-voltage drive. Ukukhetha amacandelo afanelekileyo kwisicelo, kubalulekile ukumisela umbane ofunekayo ukuqhuba isixhobo kunye nokuba kulula kangakanani ukuphumeza kuyilo. Isinyathelo esilandelayo kukumisela umlinganiselo ofunekayo wombane, okanye ubuninzi bombane onokuthi wenziwe licandelo. Ukuphakama komlinganiselo wombane, ixabiso eliphezulu lesixhobo. Enyanisweni, umlinganiselo wombane kufuneka ube mkhulu kunomthamo we-trunk okanye webhasi. Oku kuya kubonelela ngokhuseleko olwaneleyo ukwenzela ukuba i-MOSFET ingaphumeleli. Ukukhetha i-MOSFET, kubalulekile ukumisela amandla ombane aphezulu anokumelana ukusuka kwi-drain ukuya kwimvelaphi, oko kukuthi, i-VDS ephezulu, ngoko kubalulekile ukwazi ukuba amandla ombane aphezulu anokumelana ne-MOSFET ayahluka ngobushushu. Abaqulunqi kufuneka bavavanye uluhlu lwe-voltage kulo lonke ubushushu bokusebenza. I-voltage elinganisiweyo kufuneka ibe nomda owaneleyo ukugubungela olu luhlu ukuqinisekisa ukuba isekethe ayiphumeleli. Ukongeza, ezinye izinto zokhuseleko kufuneka zithathelwe ingqalelo kwi-voltage transients.

 

Okwesibini, misela ukulinganisa kwangoku

Ireyithingi yangoku ye-MOSFET ixhomekeke kulwakhiwo lwesekethe. Ukulinganiswa kwangoku ngowona mzuzu uphezulu onokuwuthwala umthwalo phantsi kwazo zonke iimeko. Ngokufana nemeko yombane, umyili kufuneka aqinisekise ukuba i-MOSFET ekhethiweyo iyakwazi ukuthwala lo mgangatho wangoku, nokuba inkqubo ivelisa i-spike yangoku. Iimeko ezimbini zangoku ekufuneka ziqwalaselwe ziimowudi eziqhubekayo kunye ne-pulse spikes. I-MOSFET ikwimo ezinzileyo kwimowudi yokuqhubela phambili, xa umsinga udlula ngokuqhubekayo kwisixhobo. I-Pulse spikes ibhekiselele kwinani elikhulu lokunyuka (okanye i-spikes of current) ehamba ngesixhobo, apho, xa ubuninzi bangoku buchongiwe, yinto nje yokukhetha ngokuthe ngqo isixhobo esinokumelana nalo mbane uphezulu.

 

Emva kokukhetha i-current rated, ilahleko yokuqhuba nayo ibalwa. Kwiimeko ezithile,I-MOSFETazikho amacandelo afanelekileyo ngenxa yokulahleka kombane okwenzeka ngexesha lenkqubo yokuqhuba, okubizwa ngokuba yilahleko yokuqhuba. Xa "ivuliwe", i-MOSFET isebenza njengesichasi esiguquguqukayo, esimiselwa yi-RDS(ON) yesixhobo kwaye sitshintsha kakhulu ngobushushu. Ilahleko yamandla yesixhobo ingabalwa kwi-Iload2 x RDS (ON), kwaye ekubeni i-on-resistance ihluka kunye nobushushu, ukulahlekelwa kwamandla kuyahluka ngokulinganayo. Xa iphezulu i-voltage ye-VGS esetyenziswa kwi-MOSFET, kokukhona isezantsi i-RDS(ON); ngokuchaseneyo, kokukhona iphezulu i-RDS(ON). Kumyili wenkqubo, kulapho urhwebo lungena khona ngokuxhomekeke kumbane wenkqubo. Kuyilo oluphathwayo, ii-voltages ezisezantsi zilula (kwaye ziqhelekile), ngelixa kuyilo lwamashishini, ii-voltages eziphezulu zinokusetyenziswa. Qaphela ukuba i-RDS (ON) ukuxhathisa inyuka kancinane ngoku.

 

 

Itekhnoloji inefuthe elikhulu kwiimpawu zecandelo, kwaye ezinye iitekhnoloji zikholisa ukukhokelela ekonyukeni kwe-RDS (ON) xa kunyuswa eyona VDS iphezulu. Kwezo teknoloji, ukunyuka kwesayizi ye-wafer kuyafuneka ukuba i-VDS kunye ne-RDS (ON) ziza kuthotywa, ngaloo ndlela ukwandisa ubungakanani bephakheji ehamba nayo kunye neendleko zophuhliso ezihambelanayo. Kukho inani letekhnoloji kwishishini elizama ukulawula ukwanda kobukhulu be-wafer, eyona nto ibalulekileyo kubo ngumsele kunye netekhnoloji yokulinganisa intlawulo. Kwitekhnoloji yetekhnoloji yomsele, umsele onzulu ufakwe kwi-wafer, uhlala ugcinwe kwii-voltages eziphantsi, ukunciphisa i-RDS (ON).

 

III. Qinisekisa iimfuno zokutshatyalaliswa kobushushu

Isinyathelo esilandelayo kukubala iimfuno ze-thermal zenkqubo. Iimeko ezimbini ezahlukeneyo kufuneka ziqwalaselwe, eyona meko imbi kunye neyokwenyani. I-TPV incoma ukubala iziphumo zeyona nto imbi kakhulu, njengoko olu lubalo lunikeza umda omkhulu wokhuseleko kwaye luqinisekisa ukuba inkqubo ayiyi kuphumelela.

 

IV. Ukutshintsha ukusebenza

Ekugqibeleni, ukusebenza kokutshintsha kweMOSFET. Kukho iiparitha ezininzi ezichaphazela ukusebenza kokutshintsha, ezona zibalulekileyo zisango / i-drain, isango / umthombo kunye ne-drain / source capacitance. Ezi zakhono zenza ilahleko zokutshintsha kwicandelo ngenxa yesidingo sokuzihlawulisa rhoqo xa zitshintshwa. Ngenxa yoko, isantya sokutshintsha kwe-MOSFET siyancipha kwaye ukusebenza kakuhle kwesixhobo kuyancipha. Ukuze ubale ilahleko epheleleyo kwisixhobo ngexesha lokutshintsha, umyili kufuneka abale ilahleko ngexesha lokuvula (i-Eon) kunye nelahleko ngexesha lokucima (Eoff). Oku kunokubonakaliswa ngolu nxaki lulandelayo: Psw = (Eon + Eoff) x ukutshintsha rhoqo. Kwaye intlawulo yesango (Qgd) inempembelelo enkulu ekutshintsheni ukusebenza.