Lub luag haujlwm ntawm me me voltage MOSFETs yog dab tsi?

Muaj ntau ntau yam ntawmMOSFETs, feem ntau muab faib ua junction MOSFETs thiab insulated rooj vag MOSFETs ob pawg, thiab tag nrho cov muaj N-channel thiab P-channel ntsiab lus.

Hlau-Oxide-Semiconductor Field-Effect Transistor, hu ua MOSFET, tau muab faib ua hom depletion MOSFET thiab kev txhim kho hom MOSFET.

MOSFETs kuj tau muab faib ua ib lub rooj vag thiab ob lub rooj vag. Dual-gate MOSFET muaj ob lub rooj vag ywj pheej G1 thiab G2, los ntawm kev tsim kho ntawm qhov sib npaug ntawm ob lub rooj vag MOSFET txuas nrog hauv series, thiab nws cov zis tam sim no hloov pauv los ntawm ob lub rooj vag voltage tswj. Qhov tus yam ntxwv ntawm ob lub rooj vag MOSFETs coj tau yooj yim thaum siv los ua lub suab nrov nrov, nce kev tswj cov amplifiers, mixers thiab demodulators.

1, MOSFEThom thiab qauv

MOSFET yog ib hom FET (lwm yam yog JFET), tuaj yeem tsim kho rau hauv hom kev txhim kho lossis depletion, P-channel lossis N-channel tag nrho ntawm plaub hom, tab sis kev siv theoretical ntawm tsuas yog txhim kho N-channel MOSFET thiab txhim kho P- channel MOSFET, yog li feem ntau hu ua NMOS, lossis PMOS hais txog ob hom no. Raws li yog vim li cas ho tsis siv depletion hom MOSFETs, tsis pom zoo kom nrhiav lub hauv paus. Hais txog ob qho kev txhim kho MOSFETs, feem ntau siv yog NMOS, yog vim li cas yog qhov kev tiv thaiv me me, thiab yooj yim rau kev tsim khoom. Yog li kev hloov fais fab mov thiab daim ntawv tsav tsheb tsav, feem ntau siv NMOS. cov lus hauv qab no, tab sis kuj muaj ntau NMOS-raws li. peb tus pins ntawm MOSFET parasitic capacitance muaj nyob nruab nrab ntawm peb tus pins, uas tsis yog peb cov kev xav tau, tab sis vim muaj kev txwv kev tsim khoom. Lub hav zoov ntawm parasitic capacitance nyob rau hauv kev tsim los yog xaiv ntawm lub tsav Circuit Court kom txuag tau qee lub sij hawm, tab sis tsis muaj txoj hauv kev kom zam, thiab tom qab ntawd cov lus qhia ntxaws. Hauv MOSFET schematic daim duab tuaj yeem pom, qhov ntws thiab qhov chaw ntawm cov kab mob parasitic. Qhov no yog hu ua lub cev diode, nyob rau hauv kev tsav tsheb rational loads, no diode tseem ceeb heev. Los ntawm txoj kev, lub cev diode tsuas muaj nyob rau hauv ib lub MOSFET nkaus xwb, feem ntau tsis nyob rau hauv lub integrated circuit nti.

2, MOSFET conduction yam ntxwv

Qhov tseem ceeb ntawm conduction yog raws li kev hloov pauv, sib npaug rau qhov hloov kaw.NMOS cov yam ntxwv, Vgs ntau dua li ib qho txiaj ntsig yuav coj, tsim nyog siv rau hauv rooj plaub thaum lub hauv paus yog grounded (tsawg kawg tsav), tsuas yog lub rooj vag voltage tuaj txog. ntawm 4V lossis 10V.PMOS cov yam ntxwv, Vgs tsawg dua ib qho nqi yuav coj, tsim nyog siv rau hauv rooj plaub thaum lub hauv paus txuas nrog VCC (high-end drive).

Txawm li cas los xij, tau kawg, PMOS tuaj yeem siv tau yooj yim heev los ua tus tsav tsheb siab, tab sis vim yog qhov kev tawm tsam, kim, tsawg hom kev sib pauv thiab lwm yam laj thawj, nyob rau hauv high-end tsav tsheb, feem ntau tseem siv NMOS.

3, MOSFEThloov poob

Txawm hais tias nws yog NMOS lossis PMOS, tom qab qhov kev tawm tsam tshwm sim, yog li tam sim no yuav siv lub zog hauv qhov kev tawm tsam no, qhov no ntawm lub zog noj yog hu ua qhov poob ntawm qhov tsis kam. Xaiv ib tug MOSFET nrog ib tug me me nyob rau hauv-kuj yuav txo tau qhov kev tiv thaiv poob. Lub zog qis ib txwm muaj MOSFET ntawm kev ua haujlwm feem ntau yog nyob rau hauv kaum tawm milliohms, ob peb milliohms nyob ntawd. MOS nyob rau hauv lub sij hawm thiab txiav-tawm, yuav tsum tsis txhob nyob rau hauv lub instantaneous tiav ntawm lub voltage nyob rau hauv lub MOS muaj ib tug txheej txheem ntawm ntog, tam sim no ntws los ntawm ib tug txheej txheem ntawm nce, lub sij hawm no, qhov poob ntawm MOSFET yog. cov khoom ntawm qhov voltage thiab tam sim no yog hu ua qhov hloov pauv poob. Feem ntau qhov kev hloov pauv yog qhov loj dua qhov kev poob qis, thiab qhov nrawm dua qhov hloov pauv, qhov loj dua qhov poob. Ib qho khoom loj ntawm qhov hluav taws xob thiab tam sim no ntawm qhov tam sim no ntawm kev ua haujlwm ua rau poob loj. Shortening lub sij hawm hloov yuav txo qhov poob ntawm txhua qhov conduction; txo qhov hloov zaus txo tus lej ntawm cov keyboards ib lub sijhawm. Ob txoj hauv kev tuaj yeem txo qhov kev hloov pauv.

 
4, MOSFET tsav

Piv rau bipolar transistors, feem ntau xav tias tsis muaj tam sim no yuav tsum tau ua rau MOSFET kev coj ua, tsuas yog tias GS voltage yog siab dua ib qho nqi. Qhov no yooj yim ua, txawm li cas los xij, peb kuj xav tau ceev. Hauv cov qauv ntawm MOSFET koj tuaj yeem pom tias muaj cov kab mob parasitic capacitance ntawm GS, GD, thiab kev tsav tsheb ntawm MOSFET yog, nyob rau hauv kev xav, kev them nyiaj thiab tawm ntawm lub peev xwm. Them lub capacitor yuav tsum muaj tam sim no, thiab txij li thaum them lub capacitor tam sim ntawd tuaj yeem pom raws li luv luv Circuit Court, tam sim no tam sim no yuav siab. Kev xaiv / tsim ntawm MOSFET tsav yog thawj qhov uas yuav tsum tau them sai sai rau yog qhov loj ntawm qhov tam sim no luv-circuit tam sim no tuaj yeem muab tau. Qhov thib ob uas yuav tsum tau them sai sai rau yog tias, feem ntau siv nyob rau hauv high-end tsav NMOS, ntawm kev thov yog lub rooj vag voltage yog ntau dua qhov voltage. High-end tsav MOS tube conduction qhov hluav taws xob thiab qhov hluav taws xob ntws (VCC) tib yam, yog li lub rooj vag hluav taws xob ntau dua li VCC 4V lossis 10V. Piv txwv tias nyob rau hauv tib lub cev, kom tau txais qhov hluav taws xob loj dua li VCC, peb xav tau ib qho kev txhawb zog tshwj xeeb. Ntau tus neeg tsav tsheb lub cev muaj zog yog cov twj tso kua mis sib xyaw, kom ua tib zoo saib yog yuav tsum xaiv qhov tsim nyog sab nraud capacitor, txhawm rau kom tau txais luv luv tam sim no los tsav MOSFET. 4V lossis 10V tau hais los saum toj no feem ntau siv MOSFET ntawm qhov hluav taws xob, qhov tsim ntawm chav kawm, qhov xav tau kom muaj qee qhov npoo. Qhov siab dua qhov hluav taws xob, qhov ceev ntawm lub xeev ceev thiab qis dua ntawm lub xeev tsis kam. Feem ntau kuj tseem muaj cov hluav taws xob me me hauv lub xeev MOSFETs siv nyob rau hauv ntau pawg, tab sis hauv 12V automotive electronics systems, zoo tib yam 4V ntawm lub xeev yog txaus.

Lub ntsiab parameter ntawm MOSFET yog raws li nram no:

1. rooj vag qhov chaw tawg voltage BVGS - nyob rau hauv tus txheej txheem ntawm nce lub rooj vag qhov voltage, thiaj li hais tias lub rooj vag tam sim no IG los ntawm xoom mus pib ib tug ntse nce nyob rau hauv VGS, lub npe hu ua lub rooj vag qhov chaw tawg voltage BVGS.

2. tig-on voltage VT - tig-on voltage (tseem hu ua qhov pib voltage): ua qhov chaw S thiab ntws D ntawm qhov pib ntawm cov channel conductive constitutes lub rooj vag voltage yuav tsum tau; - txheem N-channel MOSFET, VT yog hais txog 3 ~ 6V; - tom qab cov txheej txheem ntawm kev txhim kho, tuaj yeem ua rau MOSFET VT tus nqi qis rau 2 ~ 3V.

3. Dej tawg voltage BVDS - nyob rau hauv cov xwm txheej ntawm VGS = 0 (reinforced), nyob rau hauv tus txheej txheem ntawm nce lub ntws voltage thiaj li hais tias tus ID pib nce ntau heev thaum lub VDS hu ua lub ntws tawg voltage BVDS - ID nce ntau heev vim yog ob yam nram qab no:

(1) avalanche tawg ntawm lub depletion txheej nyob ze ntawm lub ntws electrode

(2) ntws-qhov kev sib tshuam ntawm tus ncej nkag mus tawg - qee qhov me me voltage MOSFET, nws cov channel ntev yog luv, los ntawm lub sij hawm mus rau lub sij hawm mus nce lub VDS yuav ua rau lub ntws cheeb tsam ntawm lub depletion txheej los ntawm lub sij hawm mus rau lub sij hawm mus rau nthuav mus rau lub hauv paus cheeb tsam. , yog li ntawd lub channel ntev ntawm xoom, uas yog, nruab nrab ntawm qhov ntws-qhov nkag mus, nkag mus, thaj tsam ntawm feem ntau ntawm cov neeg nqa khoom, thaj tsam ntawm qhov chaw, yuav ncaj nraim kom tiv taus cov txheej txheem depletion ntawm cov khoom siv. nqus ntawm cov hluav taws xob teb, kom tuaj txog ntawm thaj av xau, ua rau muaj tus ID loj.

4. DC input tsis kam RGS-ie, qhov piv ntawm qhov voltage ntxiv ntawm lub rooj vag qhov chaw thiab lub rooj vag tam sim no, cov yam ntxwv no yog qee zaum qhia nyob rau hauv cov nqe lus ntawm lub rooj vag tam sim no ntws los ntawm lub rooj vag MOSFET's RGS tau yooj yim tshaj 1010Ω. 5.

5. low-frequency transconductance gm nyob rau hauv VDS rau tus nqi ruaj khov ntawm cov xwm txheej, qhov microvariance ntawm cov dej ntws tam sim no thiab lub qhov rooj qhov hluav taws xob qhov hluav taws xob microvariance tshwm sim los ntawm qhov kev hloov pauv no hu ua transconductance gm, qhia txog kev tswj ntawm lub rooj vag qhov hluav taws xob ntawm lub ntws tam sim no yog qhia tau hais tias MOSFET amplification ntawm ib qho tseem ceeb parameter, feem ntau nyob rau hauv qhov ntau ntawm ob peb mus rau ob peb mA / V. Lub MOSFET tau yooj yim tshaj. 1010Ω