Yuav Ua Li Cas Txhim Kho Pob MOSFETs Ua Haujlwm

Thaum tsim cov khoom siv hluav taws xob hloov hluav taws xob lossis lub cev muaj zog tsav hluav taws xob siv encapsulated MOSFETs, cov neeg feem coob xav txog qhov kev tiv thaiv ntawm MOS, qhov siab tshaj plaws voltage, thiab lwm yam, qhov siab tshaj plaws tam sim no, thiab lwm yam, thiab muaj ntau tus neeg uas xav txog cov yam ntxwv no xwb. Xws li circuits yuav ua hauj lwm, tab sis lawv tsis zoo heev thiab tsis raug tso cai raws li cov khoom tsim.

Cov hauv qab no yog cov ntsiab lus me ntsis ntawm cov hauv paus ntawm MOSFET thiabMOSFETtsav tsheb circuits, uas kuv xa mus rau ib tug xov tooj ntawm qhov chaw, tsis yog tag nrho cov qub. Nrog rau kev qhia txog MOSFETs, yam ntxwv, tsav thiab daim ntawv thov circuits. Ntim MOSFET hom thiab kev sib txuas MOSFET yog FET (lwm JFET), tuaj yeem tsim kho kom zoo lossis depletion hom, P-channel lossis N-channel tag nrho ntawm plaub hom, tab sis qhov tseeb daim ntawv thov 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 yam no.

Raws li yog vim li cas ho tsis siv depletion hom MOSFETs, nws tsis pom zoo kom mus rau hauv qab ntawm nws. Rau ob hom kev txhim kho MOSFETs, NMOS feem ntau yog siv vim nws tsis tshua muaj kev tiv thaiv thiab yooj yim ntawm fabrication. Yog li kev hloov fais fab mov thiab daim ntawv tsav tsheb tsav, feem ntau siv NMOS. cov lus qhia hauv qab no, tab sis kuj ntxivNMOs-raws li.

MOSFETs muaj cov kab mob parasitic ntawm peb tus pins, uas tsis 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 yuav ib co teeb meem, tab sis tsis muaj txoj kev yuav zam, thiab ces piav nyob rau hauv kom meej. Raws li koj tuaj yeem pom ntawm MOSFET schematic, 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 tus kheejMOSFETsthiab feem ntau tsis muaj nyob rau hauv kev sib xyaw ua ke chip.MOSFET ON yam ntxwvOn txhais tau hais tias ua raws li kev hloov, uas yog 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 hauv av (tsawg kawg tsav), tsuav yog lub rooj vag voltage 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, 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.

Ntim MOSFET hloov lub raj poob, txawm tias nws yog NMOS lossis PMOS, tom qab kev ua haujlwm muaj nyob rau ntawm qhov tsis kam, yog li tam sim no yuav siv lub zog hauv qhov kev tawm tsam, qhov no ntawm lub zog noj yog hu ua conduction poob. Xaiv ib tug MOSFET nrog ib tug me me ntawm-kuj yuav txo qhov conduction poob. Niaj hnub no, qhov kev tawm tsam ntawm lub zog me me MOSFET feem ntau nyob ib ncig ntawm kaum milliohms, thiab ob peb milliohms kuj muaj.MOS yuav tsum tsis txhob ua kom tiav hauv ib qho instant thaum nws ua thiab txiav tawm.Qhov voltage ntawm ob sab ntawm MOS muaj ib qho txheej txheem ntawm kev txo qis, thiab tam sim no ntws los ntawm nws muaj cov txheej txheem nce.Lub sijhawm no, qhov poob ntawm MOSFET yog cov khoom ntawm qhov hluav taws xob thiab qhov tam sim no, uas yog hu ua qhov hloov 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. Cov khoom ntawm voltage thiab tam sim no nyob rau hauv lub instant ntawm conduction yog heev loj, uas ua rau loj losses.

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 tuaj yeem txo qhov kev poob qis. Cov khoom ntawm qhov hluav taws xob thiab tam sim no ntawm qhov tam sim no yog qhov loj, thiab qhov tshwm sim poob kuj loj. Txo lub sijhawm hloov pauv tuaj yeem txo qhov poob ntawm txhua qhov kev coj ua; txo qhov hloov zaus tuaj yeem txo tus naj npawb ntawm cov keyboards ib lub sijhawm. Ob txoj hauv kev no tuaj yeem txo qhov kev hloov pauv. Tsav Tsheb Piv rau bipolar transistors, feem ntau ntseeg tau tias tsis muaj tam sim no yuav tsum tau tig rau lub pob MOSFET, 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. Tus qauv ntawm lub encapsulated MOSFET tuaj yeem pom nyob rau hauv lub xub ntiag ntawm parasitic capacitance ntawm GS, GD, thiab kev tsav tsheb ntawm lub MOSFET yog, qhov tseeb, lub 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 loj dua. Thawj qhov uas yuav tsum nco ntsoov thaum xaiv / tsim tus tsav tsheb MOSFET yog qhov loj ntawm qhov tam sim no luv-circuit tam sim no uas tuaj yeem muab tau.

Qhov thib ob uas yuav tsum 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 conduction qhov voltage thiab ntws voltage (VCC) tib yam, yog li lub rooj vag voltage tshaj VCC 4 V los yog 10 V. Yog hais tias nyob rau hauv tib lub cev, kom tau ib tug loj voltage tshaj lub VCC, peb yuav tsum tau tshwj xeeb hauv boosting circuits. Ntau tus neeg 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 capacitance, thiaj li yuav tau txais luv luv tam sim no los tsav lub MOSFET. 4V los yog 10V feem ntau yog siv nyob rau hauv lub xeev voltage ntawm MOSFET, tau kawg, tus tsim yuav tsum muaj ib tug tej yam margin. Qhov siab dua qhov hluav taws xob, qhov ceev ntawm lub xeev ceev thiab qis dua ntawm lub xeev tsis kam. Niaj hnub no, muaj MOSFETs nrog me me nyob rau hauv lub xeev voltage siv nyob rau hauv txawv teb, tab sis nyob rau hauv 12V automotive electronic systems, feem ntau 4V on-xeev yog txaus.MOSFET tsav Circuit Court thiab nws poob.