Cov pob loj MOSFET Tsav Circuit Court

Ua ntej tshaj plaws, MOSFET hom thiab cov qauv, MOSFET yog FET (lwm tus yog JFET), tuaj yeem tsim kho kom zoo lossis depletion hom, P-channel lossis N-channel tag nrho plaub hom, tab sis qhov tseeb daim ntawv thov tsuas yog txhim kho N. -channel MOSFETs thiab txhim kho P-channel MOSFETs, yog li feem ntau hu ua NMOSFET, los yog PMOSFET yog hais txog qhov feem ntau hais NMOSFET, los yog PMOSFET hais txog ob hom no. Rau ob hom kev txhim kho MOSFETs, NMOSFETs tau siv ntau dua vim tias lawv tsis tshua muaj kev ua haujlwm thiab yooj yim ntawm kev tsim khoom. Yog li ntawd, NMOSFETs feem ntau yog siv los hloov cov khoom siv hluav taws xob thiab kev siv lub cev muaj zog, thiab cov lus qhia hauv qab no tseem tsom rau NMOSFETs. parasitic capacitance muaj nyob nruab nrab ntawm peb tus pinsMOSFET, uas tsis xav tau, tab sis theej vim muaj kev txwv ntawm cov txheej txheem 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.

 

  

 

Tam sim no lubMOSFETtsav cov ntawv siv hluav taws xob tsawg, thaum siv 5V fais fab mov, lub sijhawm no yog tias koj siv cov qauv totem ncej, vim tias lub transistor yog li ntawm 0.7V voltage poob, uas ua rau qhov tseeb kawg ntxiv rau lub rooj vag ntawm qhov 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 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 tau hais hauv 1 thiab 2.

 

Hauv peb qhov xwm txheej, tus qauv totem ncej tsis tuaj yeem ua tau raws li qhov yuav tsum tau ua, thiab ntau tus neeg tsav tsheb 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 ntau tshaj qhov voltage regulator, nws yuav ua rau ib tug loj static 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, lubMOSFETua hauj lwm zoo, thaum lub input voltage yog txo thaum lub rooj vag voltage tsis txaus los ua ib tug tsawg tshaj li ua tiav conduction, yog li ua kom lub zog noj.

 

Feem ntau cov Circuit Court ntawm no tsuas yog rau NMOSFET tsav Circuit Court los ua ib qho yooj yim tsom xam: Vl thiab Vh yog qhov qis-kawg thiab high-end fais fab mov, 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 paub txog kev sib cais, thiab tib lub sijhawm los xyuas kom meej tias ob lub raj tsav tsheb Q3 thiab Q4 yuav tsis yog tib lub sijhawm ua haujlwm. R2 thiab R3 muab PWM voltage R2 thiab R3 muab PWM voltage siv, los ntawm kev hloov cov ntaub ntawv 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 tawm tswv yim resistors, siv rau rooj vag R5 thiab R6 yog cov lus tawm tswv yim resistors siv los ua qauv lub rooj vag voltage, uas yog tom qab ntawd dhau los ntawm Q5 los ua kom muaj kev tawm tswv yim tsis zoo ntawm lub hauv paus ntawm Q1 thiab Q2, yog li txwv lub rooj vag voltage mus rau tus nqi finite. 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.