Thaum MOSFET txuas nrog lub tsheb npav thiab thauj khoom hauv av, siv lub zog hluav taws xob sab nraud. Feem ntau P-channelMOSFETsyog siv nyob rau hauv no topology, dua rau voltage tsav xav txog. Kev txiav txim siab qhov ntsuas tam sim no Qhov thib ob yog xaiv qhov ntsuas tam sim no ntawm MOSFET. Nyob ntawm cov qauv hauv Circuit Court, qhov kev ntsuas tam sim no yuav tsum yog qhov siab tshaj plaws tam sim no uas lub load tuaj yeem tiv taus txhua qhov xwm txheej.
Zoo ib yam li cov teeb meem ntawm qhov hluav taws xob, tus tsim qauv yuav tsum xyuas kom meej tias qhov kev xaivMOSFETtuaj yeem tiv taus qhov ntsuas tam sim no, txawm tias thaum lub kaw lus tau tsim cov kab hluav taws xob loj. Ob qhov xwm txheej tam sim no suav tias yog hom txuas ntxiv thiab mem tes spikes. Qhov kev ntsuas no yog hais los ntawm FDN304P DATASHEET, qhov twg MOSFET nyob rau hauv lub xeev khov kho nyob rau hauv kev nruam conduction hom, thaum tam sim no tsis tu ncua ntws los ntawm lub cuab yeej.
Pulse spikes yog thaum muaj kev nce siab loj (lossis spike) ntawm tam sim no ntws los ntawm lub cuab yeej. Thaum qhov siab tshaj plaws tam sim no nyob rau hauv cov xwm txheej no tau txiav txim siab, nws tsuas yog ib qho teeb meem ntawm kev xaiv ncaj qha rau lub cuab yeej uas tuaj yeem tiv taus qhov siab tshaj plaws tam sim no.
Tom qab xaiv qhov ntsuas tam sim no, qhov kev poob qis yuav tsum raug xam. Hauv kev xyaum, MOSFETs tsis yog cov khoom siv zoo tagnrho vim tias muaj lub zog poob thaum lub sijhawm ua haujlwm, uas yog hu ua conduction poob.
MOSFET ua raws li qhov sib txawv ntawm qhov sib txawv thaum nws "rau", raws li kev txiav txim los ntawm RDS (ON) ntawm lub cuab yeej, thiab nws txawv nrog qhov kub thiab txias. Lub zog dissipation ntawm lub cuab yeej tuaj yeem xam los ntawm Iload2 x RDS (ON), thiab txij li qhov kev tiv thaiv ntawm qhov sib txawv nrog qhov kub thiab txias, lub zog dissipation txawv proportionally. Qhov siab dua qhov voltage VGS thov rau MOSFET, qhov me me RDS (ON) yuav yog; conversely qhov siab dua RDS(ON) yuav. Rau cov neeg tsim qauv, qhov no yog qhov kev lag luam tawm tuaj rau hauv kev ua si nyob ntawm qhov system voltage. Rau cov qauv tsim qauv, nws yooj yim dua (thiab ntau dua) siv cov hluav taws xob qis dua, thaum rau cov qauv tsim, cov hluav taws xob ntau dua tuaj yeem siv tau.
Nco ntsoov tias RDS (ON) tsis kam nce me ntsis nrog tam sim no. Kev hloov pauv ntawm ntau yam hluav taws xob tsis sib xws ntawm RDS (ON) resistor tuaj yeem pom nyob rau hauv daim ntawv qhia kev qhia los ntawm cov chaw tsim khoom.
Kev txiav txim siab Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Thermal Requirements Tus tsim qauv yuav tsum xav txog ob qhov xwm txheej sib txawv, qhov xwm txheej phem tshaj plaws thiab qhov tseeb. Nws raug nquahu kom siv qhov kev suav rau qhov xwm txheej phem tshaj plaws, vim tias qhov tshwm sim no muab kev nyab xeeb ntau dua thiab ua kom ntseeg tau tias lub kaw lus yuav tsis poob.
Kuj tseem muaj qee qhov kev ntsuas kom paub txog ntawmMOSFETcov ntaub ntawv; xws li cov thermal tsis kam ntawm cov semiconductor hlws ris ntawm lub ntim khoom thiab lub ambient ib puag ncig, thiab qhov siab tshaj plaws hlws ris kub. Qhov ntsuas kub ntawm cov cuab yeej sib npaug sib npaug rau qhov siab tshaj plaws ambient kub ntxiv rau cov khoom ntawm thermal kuj thiab lub zog dissipation (hluav taws kub = qhov siab tshaj plaws ambient kub + [thermal resistance x power dissipation]). Los ntawm qhov sib npaug no qhov siab tshaj plaws lub zog dissipation ntawm lub kaw lus tuaj yeem daws tau, uas yog los ntawm cov ntsiab lus sib npaug rau I2 x RDS (ON).
Txij li thaum tus tsim qauv tau txiav txim siab qhov siab tshaj plaws tam sim no uas yuav dhau los ntawm lub cuab yeej, RDS (ON) tuaj yeem suav rau qhov kub sib txawv. Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias thaum ua raws li cov qauv thermal yooj yim, tus tsim qauv kuj tseem yuav tsum xav txog qhov muaj peev xwm ntawm cov khoom siv hluav taws xob semiconductor hlws ris / cov khoom siv thiab cov ntaub thaiv npog / ib puag ncig; piv txwv li, nws yog qhov yuav tsum tau ua kom lub rooj tsav xwm luam tawm thiab lub pob tsis sov tam sim ntawd.
Feem ntau, PMOSFET, yuav muaj cov kab mob parasitic tam sim no, lub diode txoj haujlwm yog los tiv thaiv qhov chaw-drain rov qab kev sib txuas, rau PMOS, qhov zoo dua NMOS yog tias nws qhov hluav taws xob tig tuaj yeem yog 0, thiab qhov sib txawv ntawm qhov voltage. DS voltage tsis ntau, thaum NMOS ntawm qhov xwm txheej xav kom VGS ntau dua li qhov pib, uas yuav ua rau kev tswj hluav taws xob yog qhov tsis muaj zog tshaj qhov xav tau, thiab yuav muaj teeb meem tsis tsim nyog. PMOS raug xaiv los ntawm kev hloov pauv, muaj ob daim ntawv thov hauv qab no: thawj daim ntawv thov, PMOS los ua qhov kev xaiv qhov hluav taws xob, thaum V8V tshwm sim, tom qab ntawd qhov hluav taws xob yog muab los ntawm V8V, PMOS yuav raug tua, VBAT tsis muab hluav taws xob rau VSIN, thiab thaum V8V qis, VSIN yog siv los ntawm 8V. Nco ntsoov lub grounding ntawm R120, ib tug resistor uas tsis tu ncua rub lub rooj vag voltage mus kom zoo PMOS tig-on, lub xeev muaj kev phom sij cuam tshuam nrog lub rooj vag siab impedance tau piav qhia ua ntej.
Cov haujlwm ntawm D9 thiab D10 yog los tiv thaiv qhov hluav taws xob rov qab, thiab D9 tuaj yeem raug tshem tawm. Nws yuav tsum tau muab sau tseg tias DS ntawm lub Circuit Court yog tiag tiag reversed, yog li ntawd lub functionality ntawm lub switching raj tsis tuaj yeem ua tiav los ntawm conduction ntawm lub diode txuas, uas yuav tsum tau muab sau tseg nyob rau hauv kev siv tswv yim. Hauv Circuit Court no, lub teeb liab PGC tswj xyuas seb V4.2 muab lub zog rau P_GPRS. Qhov no Circuit Court, lub hauv paus thiab ntws terminals tsis txuas rau qhov opposite, R110 thiab R113 muaj nyob rau hauv lub siab hais tias R110 tswj rooj vag tam sim no tsis loj, R113 tswj rooj vag normality, R113 rub-up rau siab, raws li PMOS, tab sis kuj tuaj yeem pom raws li kev rub tawm ntawm lub teeb liab tswj, thaum MCU sab hauv pins thiab rub-up, uas yog, qhov tso tawm ntawm qhov qhib-drain thaum cov zis tsis tsav PMOS tawm, lub sijhawm no, Nws yuav xav tau ib qho hluav taws xob sab nraud los muab qhov rub tawm, yog li resistor R113 plays ob lub luag haujlwm. r110 tuaj yeem ua me me, mus txog 100 ohms tuaj yeem ua tau.
Cov pob me me MOSFETs muaj lub luag haujlwm tshwj xeeb los ua si.
Post lub sij hawm: Apr-27-2024
