Ndeipi basa remagetsi madiki MOSFETs?

Kune marudzi akawanda eMOSFETs, yakanyanya kukamurwa kuita junction MOSFETs uye insulated gedhi MOSFETs mapoka maviri, uye ese ane N-chiteshi uye P-chiteshi mapoinzi.

 

Metal-Oxide-Semiconductor Field-Effect Transistor, inonzi MOSFET, yakakamurwa kuita depletion mhando MOSFET uye yekusimudzira mhando MOSFET.

 

MOSFETs zvakare akakamurwa kuita rimwe-gedhi uye maviri-gedhi machubhu. Dual-gedhi MOSFET ine maviri akazvimirira gedhi G1 neG2, kubva pakuvaka akaenzana maviri egedhi rimwe chete MOSFETs akabatana munhevedzano, uye kubuda kwayo ikozvino shanduko neaviri gedhi voltage control. Hunhu uhu hwemaviri-gedhi MOSFETs hunounza kurerukirwa kukuru kana uchishandiswa seyepamusoro-frequency amplifiers, kuwana magadziriso ekudzora, musanganiswa uye demodulators.

 

1, MOSFETmhando uye chimiro

MOSFET imhando yeFET (imwe rudzi iJFET), inogona kugadzirwa kuva yakakwidziridzwa kana kuperevedza mhando, P-channel kana N-channel akazara emhando ina, asi theoretical application yeinovandudza N-channel MOSFET uye yakagadziridzwa P- chiteshi MOSFET, inowanzonzi NMOS, kana PMOS inoreva marudzi maviri aya. Kana zviri zvekuti sei usingashandise depletion type MOSFETs, usakurudzire kutsvaga kwechikonzero. Nezve maviri akakwidziridzwa MOSFETs, anonyanya kushandiswa iNMOS, chikonzero ndechekuti iyo-kupikisa idiki, uye iri nyore kugadzira. Saka kushandura magetsi uye mota drive application, kazhinji shandisa NMOS. iyo inotevera quote, asiwo yakawanda NMOS-yakavakirwa. mapini matatu eMOSFET parasitic capacitance iripo pakati pemapini matatu, izvo zvisiri izvo zvatinoda, asi nekuda kwekupikiswa kwemaitiro ekugadzira. Kuvapo kweparasitic capacitance mukugadzira kana kusarudzwa kwedhiraivha yedhiraivha kuchengetedza imwe nguva, asi hapana nzira yekudzivisa, uyezve yakadzama sumo. Mune iyo MOSFET schematic dhizaini inogona kuoneka, iyo yekudonha uye sosi pakati peparasitic diode. Izvi zvinonzi diode yemuviri, mukufambisa mitoro inonzwisisika, iyi diode yakakosha zvikuru. Nenzira, iyo diode yemuviri inongowanikwa mune imwechete MOSFET, kazhinji kwete mukati meiyo yakabatanidzwa yedunhu chip.

 

2, MOSFET conduction maitiro

Kukosha kwe conduction kwakafanana nekuchinja, kwakaenzana nekuvhara kwekuchinja.NMOS maitiro, Vgs yakakura kudarika imwe kukosha ichaitisa, yakakodzera kushandiswa munyaya iyo iyo inobva yadzika (yakaderera-kuguma drive), chete gedhi remagetsi rinosvika. pa 4V kana 10V.PMOS maitiro, Vgs isingasviki imwe kukosha ichaitisa, yakakodzera kushandiswa munyaya iyo iyo sosi yakabatana neVCC (high-end drive).

Zvisinei, hongu, PMOS inogona kuva nyore kwazvo kushandisa semutyairi wepamusoro, asi nekuda kwekudzivisa, kudhura, kuderera kwemhando dzekuchinjana uye zvimwe zvikonzero, mumutyairi wepamusoro, kazhinji achiri kushandisa NMOS.

 

3, MOSFETkuchinja kurasikirwa

Ingave iyo NMOS kana PMOS, mushure me-kupokana kuripo, kuitira kuti ikozvino inodya simba mukupikisa uku, chikamu ichi chesimba rinoshandiswa chinonzi ku-resistance kurasikirwa. Kusarudza MOSFET ine diki pa-resistance inoderedza kurasikirwa kwekupokana. Iyo yakajairika-yakaderera-simba MOSFET pa-kupokana kazhinji mumakumi emamiliohms, mashoma miliohm ipapo. MOS mune-nguva uye kucheka-kubviswa, haifanirwe kunge iri mukungopedzwa kwemagetsi paMOS pane maitiro ekudonha, ikozvino inoyerera kuburikidza nemaitiro ekusimuka, panguva ino, kurasikirwa kweMOSFET ndiko. chigadzirwa chemagetsi uye ikozvino chinonzi switching loss. Kazhinji kurasikirwa kwekuchinja kwakakura zvakanyanya kudarika kurasikirwa kwekuita, uye nekukurumidza kuchinja kwekuchinja, kunowedzera kurasikirwa. Chigadzirwa chikuru chevoltage uye chazvino panguva yekuitisa inoumba kurasikirwa kukuru. Kupfupisa nguva yekuchinja kunoderedza kurasikirwa pane imwe neimwe conduction; kudzikisa kushandura frequency kunoderedza huwandu hwekuchinja pane imwe unit nguva. Nzira mbiri idzi dzinogona kuderedza kurasikirwa kwekuchinja.

 
4, MOSFET drive

Kuenzaniswa nebipolar transistors, zvinowanzofungidzirwa kuti hapana ikozvino inodikanwa kuita MOSFET mufambiro, chete kuti GS voltage iri pamusoro pehumwe kukosha. Izvi zviri nyore kuita, zvisinei, tinodawo kukurumidza. Muchimiro cheMOSFET unogona kuona kuti pane parasitic capacitance pakati peGS, GD, uye kutyaira kweMOSFET ndiko, mukufungidzira, kuchaja uye kuburitswa kweiyo capacitance. Kuchaja iyo capacitor inoda ikozvino, uye kubva kubhadharisa iyo capacitor pakarepo inogona kutariswa sepfupi pfupi, iyo pakarepo ikozvino ichave yakakwirira. Sarudzo / dhizaini yeMOSFET dhiraivha chinhu chekutanga kutarisisa iko kukura kweiyo pakarepo pfupi-yedunhu yazvino inogona kupihwa. Chechipiri chekutarisa ndechekuti, chinowanzo shandiswa mu-high-end drive NMOS, painodiwa igedhi regedhi rakakura kupfuura iro sosi voltage. High-end drive MOS chubhu conduction source voltage uye drain voltage (VCC) zvakafanana, saka gedhi voltage pane VCC 4V kana 10V. tichifunga kuti mune imwecheteyo system, kuti tiwane yakakura voltage kupfuura iyo VCC, isu tinoda yakakosha yekusimudzira dunhu. Vazhinji vatyairi vemota vakasanganiswa yekuchaja pombi, kuterera kune inofanirwa kusarudza yakakodzera yekunze capacitor, kuitira kuti uwane yakakwana yepfupi-yedunhu ikozvino kutyaira iyo MOSFET. 4V kana 10V yakataurwa pamusoro inowanzoshandiswa MOSFET pamagetsi, dhizaini hongu, kudiwa kwekuve neimwe margin. Kukwira kwevoltage, ndiko kukurumidza kwe-on-state kumhanya uye kuderera kwe-on-state kuramba. Kazhinji kunewo madiki pa-state voltage MOSFETs anoshandiswa muzvikamu zvakasiyana, asi mu12V mota dzemagetsi masisitimu, akajairwa 4V pa-nyika anokwana.

 

 

Iwo makuru ma paramita eMOSFET ndeaya anotevera:

 

1. gedhi tsime kukoromoka voltage BVGS - ari muitiro kuwedzera gedhi tsime voltage, kuitira kuti gedhi ikozvino IG kubva razero kutanga unopinza kuwedzera VGS, rinozivikanwa suwo tsime kuparara voltage BVGS.

 

2. turn-on voltage VT - turn-on voltage (inozivikanwawo sechikumbaridzo voltage): ita chitubu S uye dhiraivha D pakati pekutanga kwegwara rinoita rinoumba gedhi voltage inodiwa; - yakarongeka N-chiteshi MOSFET, VT inenge 3 ~ 6V; - mushure mekuita kwekuvandudza, inogona kuita iyo MOSFET VT kukosha pasi kusvika 2 ~ 3V.

 

3. Drain breakdown voltage BVDS - pasi pemamiriro eVGS = 0 (yakasimbiswa) , mukuwedzera kwekuwedzera kwemagetsi kuitira kuti ID itange kuwedzera zvakanyanya apo VDS inonzi iyo drain breakdown voltage BVDS - ID yakawedzera zvakanyanya nekuda kwe zvinhu zviviri zvinotevera:

 

(1) avalanche kuputsika kweiyo depletion layer pedyo nedrain electrode

 

(2) Drain-source inter-pole penetration breakdown - imwe diki voltage MOSFET, kureba kwayo chiteshi ipfupi, nguva nenguva kuwedzera VDS kuchaita kuti nzvimbo yekudonhedza yedepletion layer nguva nenguva kuti iwedzere kudunhu rekubva. , kuitira kuti kureba kwechiteshi che zero, ndiko kuti, pakati pe-drain-source penetration, kupinza, kwakabva nharaunda yevatakuri vazhinji, iyo source region, ichave yakatwasuka kumirisana nedepletion layer yekutorwa kwemunda wemagetsi, kuti usvike kunzvimbo inodonha, zvichikonzera ID hombe.

 

4. DC inopinza kuramba RGS-kureva, chiyero chemagetsi chakawedzerwa pakati pegedhi chitubu uye gedhi ikozvino, hunhu uhu dzimwe nguva hunoratidzwa maererano negedhi ikozvino inoyerera nepagedhi MOSFET's RGS inogona kudarika 1010Ω nyore. 5.

 

5. low-frequency transconductance gm muVDS yemutengo wakatarwa wemamiriro, iyo microvariance yekudonhedza ikozvino uye gedhi source voltage microvariance inokonzerwa neshanduko iyi inonzi transconductance gm, inoratidza kutonga kwegedhi source voltage pa Drain ikozvino kuratidza kuti MOSFET amplification yeakakosha parameter, kazhinji muhuwandu hwevashoma kusvika mashoma maA / V. Iyo MOSFET inogona kudarika 1010Ω nyore.