Kodi MOSFET ndi chiyani? Kodi zigawo zikuluzikulu ndi ziti?

Mukamapanga magetsi osinthira kapena ma drive drive drive pogwiritsa ntchitoZithunzi za MOSFET, zinthu monga on-resistance, maximum voltage, ndi maximum current ya MOS nthawi zambiri zimaganiziridwa.

Machubu a MOSFET ndi mtundu wa FET womwe ukhoza kupangidwa ngati mtundu wowonjezera kapena wocheperako, P-channel kapena N-channel pamitundu inayi. kulimbikitsa ma NMOSFET ndi ma PMOSFET owonjezera amagwiritsidwa ntchito, ndipo ziwirizi zimatchulidwa nthawi zambiri.

Awiriwa amagwiritsidwa ntchito kwambiri ndi NMOS. chifukwa chake ndi chakuti kukana kwa conductive kumakhala kochepa komanso kosavuta kupanga. Chifukwa chake, NMOS nthawi zambiri imagwiritsidwa ntchito posinthira magetsi ndi ma drive drive.

Mkati mwa MOSFET, thyristor imayikidwa pakati pa kukhetsa ndi gwero, yomwe ili yofunika kwambiri pakuyendetsa katundu wa inductive monga ma motors, ndipo imapezeka mu MOSFET imodzi, osati kawirikawiri mu chipangizo chophatikizira.

Mphamvu ya parasitic ilipo pakati pa zikhomo zitatu za MOSFET, osati kuti timazifuna, koma chifukwa cholephera kupanga. Kukhalapo kwa parasitic capacitance kumapangitsa kuti zikhale zovuta kwambiri popanga kapena kusankha dera loyendetsa, koma silingapeweke.

 

Zigawo zazikulu zaMOSFET

1, voteji yotseguka VT

Vuto lotseguka (lomwe limadziwikanso kuti voltage): kotero kuti magetsi a pachipata amafunika kuti ayambe kupanga njira yoyendetsera pakati pa gwero la S ndi kukhetsa D; muyezo N-channel MOSFET, VT ndi za 3 ~ 6V; kudzera pakuwongolera njira, mtengo wa MOSFET VT ukhoza kuchepetsedwa kukhala 2 ~ 3V.

 

2, DC athandizira kukana RGS

Chiŵerengero cha magetsi owonjezera pakati pa gwero lachipata ndi chipata chamakono Chikhalidwe ichi nthawi zina chimawonetsedwa ndi chipata chomwe chikuyenda pakhomo, RGS ya MOSFET imatha kupitirira 1010Ω mosavuta.

 

3. Kukhetsa gwero kuwonongeka BVDS voteji.

Pansi pa VGS = 0 (yowonjezera), pakuwonjezera mphamvu yamagetsi, ID imakula kwambiri pomwe VDS imatchedwa DVDS-source breakdown voltage BVDS, ID imakula kwambiri chifukwa chazifukwa ziwiri: (1) avalanche. Kuwonongeka kwa tsinde pafupi ndi kukhetsa, (2) kuwonongeka kolowera pakati pa kukhetsa ndi magwero, ma MOSFET ena, omwe ali ndi utali waufupi wa ngalande, amawonjezera VDS kotero kuti kusanjikizako kudera la kukhetsa kukukulirakulira mpaka komwe kumayambira, kupanga Channel kutalika ndi zero, ndiko kuti, kutulutsa kulowera-gwero lolowera, kulowa, ambiri onyamula m'dera gwero adzakopeka mwachindunji ndi munda wa magetsi wa wosanjikiza depletion ku dera kukhetsa, kuchititsa ID lalikulu. .

 

4, chipata gwero kuwonongeka voteji BVGS

Pamene magetsi a pachipata akuwonjezeka, VGS pamene IG ikuwonjezeka kuchokera ku ziro imatchedwa gate source breakdown voltage BVGS.

 

5,Low frequency transconductance

Pamene VDS ndi mtengo wokhazikika, chiŵerengero cha microvariation ya kukhetsa panopa ndi microvariation ya magetsi a chipata chomwe chimayambitsa kusintha chimatchedwa transconductance, chomwe chimasonyeza mphamvu ya chipata cha magetsi kuti chiwongolere kukhetsa. gawo lofunikira lomwe likuwonetsa kuthekera kwa ma amplification aMOSFET.

 

6, kukana RON

Pa-resistance RON ikuwonetsa zotsatira za VDS pa ID, ndikosiyana kwa malo otsetsereka a mzere wa tangent wa mikhalidwe ya kukhetsa pamalo enaake, m'dera la saturation, ID pafupifupi sichisintha ndi VDS, RON ndi yayikulu kwambiri. mtengo, nthawi zambiri mu makumi a kilo-Ohms mpaka mazana a kilo-Ohms, chifukwa m'mabwalo a digito, ma MOSFET nthawi zambiri amagwira ntchito m'chigawo cha VDS = 0, kotero pakadali pano, kukana RON kumatha kuyerekezedwa ndi chiyambi cha RON kuyerekeza, kwa MOSFET wamba, mtengo wa RON mkati mwa mazana ochepa ohms.

 

7, inter-polar capacitance

Interpolar capacitance ilipo pakati pa ma elekitirodi atatu: chipata gwero capacitance CGS, chipata kuda capacitance CGD ndi kukhetsa gwero capacitance CDS-CGS ndi CGD pafupifupi 1 ~ 3pF, CDS pafupifupi 0.1 ~ 1pF.

 

8,Low pafupipafupi phokoso factor

Phokoso limayamba chifukwa cha kusayenda bwino kwa zonyamulira mu payipi. Chifukwa cha kupezeka kwake, ma voltage osakhazikika kapena kusiyanasiyana kwapano kumachitika pakutulutsa ngakhale palibe chizindikiro choperekedwa ndi amplifier. Kuchita kwaphokoso nthawi zambiri kumawonetsedwa motengera phokoso la NF. Chipangizocho ndi decibel (dB). Mtengo wocheperako, phokoso lochepa lomwe chubu limapanga. Phokoso lotsika kwambiri ndilo phokoso lomwe limayesedwa mumtundu wochepa. Phokoso la chubu logwira ntchito m'munda ndi pafupifupi dB pang'ono, kuchepera kwa triode ya bipolar.