Yini i-MOSFET? Yiziphi izinhlaka eziyinhloko?

Lapho uklama i-switching power supply noma i-motor drive circuit usebenzisaAma-MOSFET, izici ezifana nokumelana nokumelana, amandla kagesi aphezulu, namandla aphezulu we-MOS ngokuvamile ayacatshangelwa.

Amashubhu e-MOSFET awuhlobo lwe-FET olungakhiwa lube uhlobo lokuthuthukisa noma lokuncipha, isiteshi se-P noma se-N-channel yezinhlobo ezi-4 sezizonke. ama-NMOSFET okuthuthukisa kanye nama-PMOSFET okuthuthukisa ngokuvamile asetshenziswa, futhi lezi ezimbili zivame ukushiwo.

Lezi ezimbili zisetshenziswa kakhulu yi-NMOS. isizathu siwukuthi ukumelana conductive kuncane futhi kulula ukwenza. Ngakho-ke, i-NMOS ivamise ukusetshenziswa ekushintsheni ukunikezwa kwamandla kanye nezinhlelo zokusebenza zokushayela imoto.

Ngaphakathi kwe-MOSFET, i-thyristor ifakwa phakathi kwe-drain kanye nomthombo, ebaluleke kakhulu ekushayeleni imithwalo ye-inductive efana nama-motor, futhi ikhona kuphela ku-MOSFET eyodwa, hhayi ngokuvamile ku-chip yesekethe ehlanganisiwe.

Amandla e-Parasitic akhona phakathi kwamaphini amathathu e-MOSFET, hhayi ukuthi siyawadinga, kodwa ngenxa yemikhawulo yenqubo yokukhiqiza. Ukuba khona kwe-parasitic capacitance kwenza kube nzima kakhulu lapho uklama noma ukhetha umjikelezo womshayeli, kodwa awukwazi ukugwenywa.

 

Imingcele eyinhloko yeI-MOSFET

1, i-voltage evulekile ye-VT

I-voltage evulekile (eyaziwa nangokuthi i-threshold voltage): ukuze i-voltage yesango idingeke ukuze kuqalwe ukwenza umzila ohambayo phakathi komthombo S kanye nokukhipha u-D; standard N-channel MOSFET, VT imayelana 3 ~ 6V; ngokuthuthukiswa kwenqubo, inani le-MOSFET VT lingancishiswa libe ngu-2 ~ 3V.

 

I-2, i-RCS yokumelana nokokufaka kwe-DC

Isilinganiso se-voltage engezwe phakathi kwesigxobo somthombo wesango kanye nesango lamanje Lesi sici ngezinye izikhathi sivezwa isango lamanje eligeleza esangweni, i-RGS ye-MOSFET ingadlula kalula i-1010Ω.

 

3. Khipha umthombo we-voltage ye-BVDS.

Ngaphansi kwesimo se-VGS = 0 (ethuthukisiwe), ngesikhathi sokwandisa amandla kagesi womthombo, i-ID ikhula kakhulu lapho i-VDS ibizwa ngokuthi i-drain-source breakdown voltage BVDS, i-ID ikhuphuka kakhulu ngenxa yezizathu ezimbili: (1) i-avalanche. ukuwohloka kongqimba lokuwohloka eduze komsele, (2) ukuwohloka kokungena phakathi komsele nezigxobo zomthombo, amanye ama-MOSFET, anobude obufushane bomsele, akhuphula i-VDS ukuze ungqimba lokudonsa amanzi endaweni lunwetshwe endaweni yomthombo, ukwenza ubude besiteshi bube yi-zero, okungukuthi, ukukhiqiza ukungena komthombo wokukhipha amanzi, ukungena, iningi labathwali endaweni yomthombo lizokhangwa ngokuqondile inkambu kagesi yesendlalelo sokunciphisa endaweni yokudonsa, okuholela ku-ID enkulu. .

 

I-4, i-voltage yomthombo wokuqhekeka kwesango i-BVGS

Lapho i-voltage yesango inyuswa, i-VGS lapho i-IG inyuswa isuka ku-zero ibizwa ngokuthi i-voltage yokwehla komthombo wesango i-BVGS.

 

5,Ukudluliswa kwefrikhwensi ephansi

Uma i-VDS iyinani elinqunyiwe, isilinganiso se-microvariation ye-drain current kuya ku-microvariation ye-voltage yomthombo wesango ebangela ushintsho ibizwa ngokuthi i-transconductance, ebonisa ikhono le-voltage yomthombo wesango ukulawula ukugeleza kwamanje, futhi iyinhlangano. ipharamitha ebalulekile ekhombisa amandla okukhulisa i-I-MOSFET.

 

6, ukumelana ne-RON

I-on-resistance RON ibonisa umthelela we-VDS ku-ID, ukuphambana komthambeka womugqa we-tangent wezimpawu zokudonsa endaweni ethile, endaweni yokugcwala, i-ID cishe ayishintshi ne-VDS, i-RON inkulu kakhulu. inani, ngokuvamile emashumini ama-kilo-Ohms kuya kumakhulu ama-kilo-Ohms, ngoba kumasekethe edijithali, ama-MOSFET avame ukusebenza esimweni se-VDS eqhubayo = 0, ngakho-ke kuleli phuzu, i-on-resistance RON ingalinganiswa yi- umsuka we-RON ukuze ulinganisele, ku-MOSFET evamile, inani le-RON phakathi kwama-ohm angamakhulu ambalwa.

 

7, i-inter-polar capacitance

I-Interpolar capacitance ikhona phakathi kwama-electrode amathathu: amandla omthombo wesango i-CGS, i-CGD ye-drain capacitance kanye ne-drain source capacitance CDS-CGS kanye ne-CGD cishe i-1~3pF, i-CDS icishe ibe ngu-0.1~1pF.

 

8,Isici somsindo esiphansi

Umsindo udalwa ukungahambi kahle kokuhamba kwabathwali epayipini. Ngenxa yobukhona bayo, i-voltage engavamile noma ukushintshashintsha kwamanje kwenzeka ekuphumeni ngisho noma kungekho sibonakaliso esilethwa yi-amplifier. Ukusebenza komsindo kuvame ukuvezwa ngokwesici somsindo NF. Iyunithi iyi-decibel (dB). Inani elincane, umsindo omncane okhiqizwa yithubhu. Isici somsindo we-low-frequency isici somsindo esilinganiswa kububanzi befrikhwensi ephansi. Isici somsindo weshubhu yomthelela wasensimini cishe i-dB embalwa, ngaphansi kwaleyo ye-bipolar triode.