Ua ntej tshaj plaws, MOSFET hom thiab qauv,MOSFETyog FET (lwm tus yog JFET), tuaj yeem tsim kho rau hauv hom kev txhim kho lossis depletion, P-channel lossis N-channel tag nrho plaub hom, tab sis qhov tseeb daim ntawv thov ntawm tsuas yog txhim kho N-channel MOSFETs thiab txhim kho P-channel MOSFETs, yog li feem ntau hu ua NMOS lossis PMOS hais txog ob yam no. Rau ob hom kev txhim kho MOSFETs, feem ntau siv yog NMOS, yog vim li cas yog qhov kev tiv thaiv me me, thiab yooj yim los tsim. Yog li ntawd, NMOS feem ntau yog siv los hloov cov khoom siv hluav taws xob thiab kev siv lub cev muaj zog.
Hauv cov lus qhia hauv qab no, feem ntau ntawm cov xwm txheej yog tswj hwm los ntawm NMOS. parasitic capacitance muaj nyob nruab nrab ntawm peb tus pins ntawm MOSFET, qhov tshwj xeeb uas tsis xav tau tab sis tshwm sim vim muaj kev txwv kev tsim khoom. Lub xub ntiag ntawm parasitic capacitance ua rau nws yooj yim me ntsis los tsim lossis xaiv cov tsav tsheb. Muaj cov kab mob parasitic ntawm qhov ntws thiab qhov chaw. Qhov no yog hu ua lub cev diode thiab yog ib qho tseem ceeb hauv kev tsav tsheb inductive loads xws li motors. Los ntawm txoj kev, lub cev diode tsuas yog tam sim no nyob rau hauv ib tug neeg MOSFETs thiab feem ntau tsis nyob rau hauv ib tug IC nti.
MOSFETHloov lub raj poob, txawm tias nws yog NMOS lossis PMOS, tom qab qhov kev coj ua ntawm qhov kev tawm tsam tshwm sim, yog li qhov tam sim no yuav siv lub zog hauv qhov kev tawm tsam no, qhov no ntawm cov khoom siv hluav taws xob hu ua conduction poob. Kev xaiv ntawm MOSFETs uas tsis tshua muaj kev tiv thaiv yuav txo qhov poob ntawm kev tiv thaiv. Niaj hnub no, qhov kev tawm tsam ntawm MOSFETs tsis tshua muaj hluav taws xob feem ntau nyob ib puag ncig kaum ntawm milliohms, thiab ob peb milliohms kuj muaj.MOSFETs yuav tsum tsis txhob ua kom tiav hauv ib qho tam sim ntawd thaum lawv nyob thiab tawm.Muaj cov txheej txheem ntawm kev txo qhov voltage ntawm ob qhov kawg ntawm MOSFET, thiab muaj cov txheej txheem ntawm kev nce cov dej ntws los ntawm nws.Lub sijhawm no, qhov poob ntawm MOSFET yog qhov khoom ntawm qhov hluav taws xob thiab qhov tam sim no, uas yog hu ua kev hloov pauv. 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. Cov khoom ntawm voltage thiab tam sim no nyob rau hauv lub instant ntawm conduction yog heev loj, ua rau loj poob. 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 no txo cov kev poob qis.
Piv rau bipolar transistors, nws feem ntau ntseeg tias tsis muaj tam sim no yuav tsum tau uaMOSFETkev coj ua, tsuav yog qhov GS voltage siab dua ib qho nqi. Qhov no yooj yim ua, txawm li cas los xij, peb kuj xav tau ceev. Raws li koj tuaj yeem pom hauv cov qauv ntawm MOSFET, muaj cov kab mob parasitic capacitance ntawm GS, GD, thiab kev tsav tsheb ntawm MOSFET yog, nyob rau hauv qhov tseeb, qhov them thiab tawm ntawm lub capacitance. Them lub capacitor yuav tsum muaj tam sim no, vim hais tias them lub capacitor tam sim ntawd pom tau tias yog luv luv Circuit Court, yog li tam sim no tam sim no yuav siab dua. Thawj qhov uas yuav tsum nco ntsoov thaum xaiv / tsim tus tsav tsheb MOSFET yog qhov loj ntawm qhov tam sim no luv luv tam sim no uas tuaj yeem muab tau.
Qhov thib ob uas yuav tsum tau nco ntsoov yog tias, feem ntau siv nyob rau hauv high-end tsav NMOS, lub sij hawm lub rooj vag voltage yuav tsum tau ntau tshaj qhov voltage. High-end tsav MOSFET ntawm qhov hluav taws xob qhov hluav taws xob thiab qhov hluav taws xob ntws (VCC) tib yam, yog li ntawd lub rooj vag hluav taws xob ntau dua li VCC 4V lossis 10V. Yog tias nyob rau hauv tib lub cev, kom tau txais qhov hluav taws xob loj dua li VCC, peb yuav tsum tau tshwj xeeb hauv kev txhawb nqa Circuit Court. Ntau tus tsav tsheb muaj cov twj tso kua mis sib xyaw, nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias koj yuav tsum xaiv qhov tsim nyog sab nraud kom tau txais qhov luv luv tam sim no los tsav lub MOSFET. 4V lossis 10V yog qhov feem ntau siv MOSFET ntawm qhov hluav taws xob, qhov tsim ntawm chav kawm, koj yuav tsum 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. Tam sim no kuj tseem muaj me me nyob rau hauv lub xeev voltage MOSFETs siv nyob rau hauv txawv teb, tab sis nyob rau hauv lub 12V automotive electronics system, feem ntau 4V nyob rau hauv lub xeev yog txaus.MOSFETs feem ntau notable feature yog switching yam ntxwv ntawm qhov zoo, yog li nws yog dav siv nyob rau hauv lub xav tau cov hluav taws xob hloov hluav taws xob, xws li hloov hluav taws xob thiab lub cev muaj zog tsav, tab sis kuj tseem muaj teeb pom kev zoo dimming. Kev coj ua txhais tau tias yog kev hloov pauv, uas yog sib npaug rau qhov kev 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), ntev li ntawm lub rooj vag voltage ntawm 4V los yog 10V.PMOS yam ntxwv, Vgs tsawg dua ib tug tej yam nqi yuav coj, haum rau siv nyob rau hauv cov ntaub ntawv thaum lub qhov chaw txuas nrog VCC (high-end tsav). Txawm li cas los xij, txawm hais tias PMOS tuaj yeem siv tau yooj yim los ua tus tsav tsheb siab kawg, NMOS feem ntau yog siv rau cov tsav tsheb siab kawg vim muaj kev tiv thaiv loj, tus nqi siab, thiab ob peb hom hloov.
Tam sim no lub MOSFET tsav qis-voltage daim ntaub ntawv, thaum siv 5V fais fab mov, lub sij hawm no yog hais tias koj siv cov tsoos totem ncej qauv, vim hais tias ntawm lub transistor yog hais txog 0.7V voltage poob, ua rau qhov tseeb kawg ntxiv rau lub rooj vag ntawm lub voltage tsuas yog 4.3 V. Lub sijhawm no, peb xaiv lub rooj vag nominal voltage ntawm 4.5V ntawm MOSFET ntawm lub neej ntawm qee qhov kev pheej hmoo. Tib qhov teeb meem tshwm sim hauv kev siv 3V lossis lwm lub sijhawm siv hluav taws xob tsawg. Dual voltage yog siv nyob rau hauv ib co tswj circuits uas cov logic seem siv ib tug raug 5V los yog 3.3V digital voltage thiab lub hwj chim seem siv 12V los yog ntau dua. Ob qhov hluav taws xob txuas nrog siv ib qho av sib xyaw. Qhov no tso cai rau kev siv lub voj voog uas tso cai rau sab qis voltage kom zoo tswj MOSFET ntawm sab hluav taws xob siab, thaum MOSFET ntawm sab hluav taws xob siab yuav ntsib cov teeb meem tib yam uas tau hais hauv 1 thiab 2. Nyob rau hauv tag nrho peb kis, lub Totem ncej qauv tsis tuaj yeem ua tau raws li qhov yuav tsum tau ua, thiab ntau tus neeg tsav tsheb tawm ntawm MOSFET ICs tsis zoo li suav nrog lub rooj vag voltage txwv cov qauv. Lub input voltage tsis yog tus nqi ruaj khov, nws txawv nrog lub sijhawm lossis lwm yam. Qhov kev hloov pauv no ua rau cov tsav hluav taws xob muab rau MOSFET los ntawm PWM Circuit Court tsis ruaj khov. Txhawm rau ua kom MOSFET muaj kev nyab xeeb los ntawm lub rooj vag siab, ntau lub MOSFETs muaj cov tswj hluav taws xob tsim hluav taws xob kom txwv tsis pub muaj lub zog ntawm lub rooj vag voltage.
Nyob rau hauv cov ntaub ntawv no, thaum tsav voltage muab tshaj qhov voltage ntawm lub regulator, nws yuav ua rau ib tug loj zoo li qub zog noj nyob rau tib lub sij hawm, yog hais tias koj tsuas siv lub hauv paus ntsiab lus ntawm resistor voltage divider kom txo tau lub rooj vag voltage, yuav muaj ib tug kuj. siab input voltage, MOSFET ua hauj lwm zoo, thaum lub input voltage yog txo thaum lub rooj vag voltage tsis txaus yuav ua rau tsis txaus conduction, yog li nce zog noj.
Feem ntau cov Circuit Court ntawm no tsuas yog rau NMOS tsav Circuit Court ua ib qho yooj yim tsom xam: Vl thiab Vh yog qhov qis-kawg thiab high-end fais fab mov, raws li, ob qhov voltages yuav zoo ib yam, tab sis Vl yuav tsum tsis txhob tshaj Vh. Q1 thiab Q2 tsim ib qho inverted totem ncej, siv los ua kom tiav qhov kev sib cais, thiab tib lub sijhawm los xyuas kom meej tias ob lub raj tsav tsheb Q3 thiab Q4 yuav tsis nyob rau tib lub sijhawm. R2 thiab R3 muab PWM voltage siv, thiab los ntawm kev hloov cov ntaub ntawv no, koj tuaj yeem ua rau lub voj voog ua haujlwm zoo, thiab lub rooj vag hluav taws xob tsis txaus los ua kom muaj kev sib raug zoo, yog li ua kom lub zog siv tau. R2 thiab R3 muab lub PWM voltage siv, los ntawm kev hloov qhov kev siv no, koj tuaj yeem cia lub voj voog ua haujlwm hauv PWM teeb liab waveform yog qhov chaw siab thiab ncaj. Q3 thiab Q4 yog siv los muab cov tsav tam sim no, vim yog lub sijhawm, Q3 thiab Q4 txheeb ze rau Vh thiab GND tsuas yog qhov tsawg kawg nkaus ntawm Vce voltage poob, qhov kev poob qis no feem ntau tsuas yog 0.3V lossis li ntawd, qis dua. tshaj 0.7V Vce R5 thiab R6 yog cov lus tawm tswv yim rau lub rooj vag voltage sampling, tom qab kuaj qhov voltage, qhov voltage ntawm lub rooj vag yog siv raws li ib tug tawm tswv yim resistor rau lub rooj vag voltage, thiab qhov voltage ntawm tus qauv yog siv rau lub rooj vag voltage. R5 thiab R6 yog cov lus tawm tswv yim siv los ua piv txwv lub rooj vag hluav taws xob, uas yog tom qab ntawd dhau los ntawm Q5 los tsim cov lus tawm tswv yim tsis zoo ntawm lub hauv paus ntawm Q1 thiab Q2, yog li txwv lub rooj vag voltage mus rau qhov kawg. Tus nqi no tuaj yeem hloov kho los ntawm R5 thiab R6. Thaum kawg, R1 muab qhov kev txwv ntawm lub hauv paus tam sim no rau Q3 thiab Q4, thiab R4 muab qhov kev txwv ntawm lub rooj vag tam sim no rau MOSFETs, uas yog qhov txwv ntawm Ice ntawm Q3Q4. Ib qho acceleration capacitor tuaj yeem txuas nrog nyob rau hauv parallel saum R4 yog tias tsim nyog.
Thaum tsim cov khoom siv portable thiab cov khoom siv wireless, kev txhim kho cov khoom lag luam thiab kev siv sijhawm ntev ntawm cov roj teeb ua haujlwm yog ob qho teeb meem uas cov neeg tsim qauv yuav tsum tau fim.DC-DC converters muaj qhov zoo ntawm kev ua haujlwm siab, siab tso zis tam sim no thiab tsis tshua muaj quiescent tam sim no, uas yog qhov tsim nyog rau kev siv hluav taws xob portable. cov khoom siv.
DC-DC converters muaj qhov zoo ntawm kev ua haujlwm siab, siab tso zis tam sim no thiab tsis tshua muaj quiescent tam sim no, uas yog qhov tsim nyog rau lub zog siv hluav taws xob. Tam sim no, cov qauv tseem ceeb hauv kev txhim kho DC-DC converter tsim thev naus laus zis muaj xws li: cov cuab yeej siv hluav taws xob ntau: nrog rau kev hloov pauv ntau zaus, qhov loj ntawm qhov hloov pauv hloov kuj raug txo, lub zog ceev tau nce zuj zus, thiab cov dynamic. teb tau zoo lawm. Me me
Lub zog DC-DC converter hloov zaus yuav nce mus rau qib megahertz. Cov khoom siv hluav taws xob tsawg: Nrog kev txhim kho txuas ntxiv ntawm cov khoom siv hluav taws xob tsim hluav taws xob, microprocessors thiab cov khoom siv hluav taws xob portable hluav taws xob ua haujlwm tau qis dua thiab qis dua, uas yuav tsum muaj rau yav tom ntej DC-DC converter tuaj yeem muab cov zis hluav taws xob qis kom hloov mus rau microprocessor thiab cov khoom siv hluav taws xob portable, uas. xav tau yav tom ntej DC-DC converter tuaj yeem muab cov zis hluav taws xob qis kom hloov mus rau microprocessor.
Txaus los muab cov zis hluav taws xob tsawg kom hloov mus rau microprocessors thiab cov khoom siv hluav taws xob portable. Cov kev tsim kho thev naus laus zis no tau muab cov kev xav tau siab dua rau kev tsim cov khoom siv hluav taws xob chip circuits. Ua ntej ntawm tag nrho cov, nrog rau qhov nce switching zaus, qhov kev ua tau zoo ntawm lub switching Cheebtsam yog muab tso rau pem hauv ntej
Cov kev xav tau siab rau kev ua tau zoo ntawm cov khoom hloov pauv, thiab yuav tsum muaj cov khoom sib txuas sib txuas ntawm cov khoom siv hluav taws xob los xyuas kom meej tias cov khoom hloov pauv hauv qhov hloov zaus mus txog qib megahertz ntawm kev ua haujlwm ib txwm muaj. Qhov thib ob, rau cov khoom siv hluav taws xob siv hluav taws xob siv hluav taws xob, lub zog hluav taws xob ua haujlwm tsawg (xws li cov roj teeb lithium, piv txwv).
Lithium roj teeb, piv txwv li, kev khiav hauj lwm voltage ntawm 2.5 ~ 3.6V), yog li lub hwj chim mov nti rau qhov qis voltage.
MOSFET muaj kev tiv thaiv qis heev, kev siv hluav taws xob tsawg, nyob rau hauv cov khoom siv hluav taws xob tam sim no nrov DC-DC nti ntau MOSFET ua lub zog hloov. Txawm li cas los xij, vim qhov loj parasitic capacitance ntawm MOSFETs. Qhov no tso cov kev xav tau siab dua ntawm kev tsim cov kev hloov hluav taws xob hluav taws xob rau kev tsim hluav taws xob ua haujlwm siab DC-DC converters. Muaj ntau yam CMOS, BiCMOS logic circuits siv bootstrap boost qauv thiab tsav circuits raws li loj capacitive loads nyob rau hauv tsawg voltage ULSI tsim. Cov kab hluav taws xob no tuaj yeem ua haujlwm tau zoo nyob rau hauv cov xwm txheej tsawg dua 1V voltage mov, thiab tuaj yeem ua haujlwm raws li cov xwm txheej ntawm kev thauj khoom muaj peev xwm 1 ~ 2pF zaus tuaj yeem ncav cuag kaum tawm megabits lossis ntau pua megahertz. Nyob rau hauv daim ntawv no, lub bootstrap boost Circuit Court yog siv los tsim ib tug loj load capacitance tsav muaj peev xwm, haum rau tsawg-voltage, siab switching zaus boost DC-DC converter tsav Circuit Court. Tsawg-kawg voltage thiab PWM tsav high-end MOSFETs. me me amplitude PWM teeb liab los tsav lub rooj vag siab voltage ntawm MOSFETs.
Post lub sij hawm: Apr-12-2024
