Yintoni indima yamandla ombane amancinci eMOSFET?

Kukho iintlobo ezininzi zeIi-MOSFETs, ubukhulu becala zahlulwe zibe zii-MOSFET ezidityanisiweyo kunye nee-MOSFET zesango eligqunyiweyo ngamacandelo amabini, kwaye onke aneendawo ze-N-channel kunye ne-P-channel.

I-Metal-Oxide-Semiconductor Field-Effect Transistor, ekubhekiselwa kuyo njenge-MOSFET, yahlulwe yaba luhlobo lokuncipha lwe-MOSFET kunye nodidi lophuculo lwe-MOSFET.

Ii-MOSFETs zikwahlulwe ngokwesango elinye kunye netyhubhu enamasango amabini. I-MOSFET enamasango amabini anamasango amabini azimeleyo e-G1 kunye ne-G2, ukusuka kulwakhiwo olulingana neeMOSFET ezimbini zesango elinye eziqhagamshelwe kuthotho, kunye notshintsho lwayo lwangoku kulawulo lombane wesango ezimbini. Olu phawu lwee-MOSFET ezinamasango amabini luzisa uncedo olukhulu xa lusetyenziswa njengezandisi zesantya esiphezulu, ukufumana ii-amplifiers zolawulo, izixube kunye nee-demodulators.

1, I-MOSFETuhlobo kunye nesakhiwo

I-MOSFET luhlobo lwe-FET (olunye uhlobo yi-JFET), inokuveliswa ibe luhlobo oluphuculweyo okanye lokuncipha, itshaneli ye-P okanye i-N-channel zizonke iindidi ezine, kodwa ukusetyenziswa kwethiyori ye-N-channel MOSFET ephuculweyo kunye ne-P- itshaneli MOSFET, edla ngokubizwa ngokuba yi-NMOS, okanye i-PMOS ibhekisa kwezi ntlobo zimbini. Ngokuphathelele kutheni ungasebenzisi uhlobo lokuncipha kwee-MOSFET, ungacebisi ukukhangela oyena nobangela. Ngokumalunga neeMOSFET ezimbini eziphuculweyo, eyona isetyenziswa kakhulu yi-NMOS, isizathu kukuba ukuxhathisa kuncinci, kwaye kulula ukwenza. Ke ngoko ukutshintsha unikezelo lwamandla kunye nezicelo zokuqhuba iimoto, sebenzisa i-NMOS ngokubanzi. le sicatshulwa silandelayo, kodwa ngakumbi NMOS-based. izikhonkwane ezintathu ze-MOSFET ze-parasitic capacitance zikhona phakathi kwezikhonkwane ezintathu, ezingezomfuno zethu, kodwa ngenxa yokunciphisa inkqubo yokuvelisa. Ubukho be-parasitic capacitance ekuyilweni okanye ekukhethweni kwesekethe yokuqhuba ukugcina ixesha elithile, kodwa akukho ndlela yokuphepha, kwaye emva koko isingeniso esicacileyo. Kumzobo weskimu we-MOSFET unokubonwa, umjelo kunye nomthombo phakathi kwe-parasitic diode. Oku kubizwa ngokuba yi-diode yomzimba, ekuqhubeni imithwalo enengqondo, le diode ibaluleke kakhulu. Ngendlela, i-diode yomzimba ikhona kuphela kwi-MOSFET enye, ihlala ingekho ngaphakathi kwe-chip yesekethe edibeneyo.

2, iimpawu zokuqhuba ze-MOSFET

Ukubaluleka kokuqhuba kunjengokutshintsha, ukulingana nokuvalwa kokutshintsha. Iimpawu ze-NMOS, iiVgs ezinkulu kunexabiso elithile ziya kuqhuba, zilungele ukusetyenziswa kwimeko xa umthombo usekelwe (i-low-end drive), kuphela isango lombane lifika. kwiimpawu ze-4V okanye i-10V.PMOS, i-Vgs engaphantsi kwexabiso elithile iya kuqhuba, ilungele ukusetyenziswa kwimeko xa umthombo uxhunyiwe kwi-VCC (i-high-end drive).

Nangona kunjalo, ngokuqinisekileyo, i-PMOS ingaba lula kakhulu ukuyisebenzisa njengomqhubi ophezulu, kodwa ngenxa yokumelana, ixabiso eliphantsi, iintlobo ezincinci zokutshintshiselana kunye nezinye izizathu, kumqhubi ophezulu, ngokuqhelekileyo usebenzisa i-NMOS.

3, I-MOSFETilahleko yokutshintsha

Ingaba i-NMOS okanye i-PMOS, emva kokuba i-on-resistance ikhona, ukwenzela ukuba i-current iya kudla amandla kule nkcaso, le nxalenye yamandla asetyenzisiweyo ibizwa ngokuba yi-resistance loss. Ukukhetha i-MOSFET enokumelana okuncinci kuya kunciphisa ilahleko yokungaxhathisi. Isiqhelo samandla aphantsi we-MOSFET on-resistance idla ngokuba kumashumi eemiliyoni, iimiliyoni ezimbalwa apho. I-MOS ngexesha kunye ne-cut-off, akufuneki ibe ekugqityweni kwangoko kwamandla ombane kwi-MOS kukho inkqubo yokuwa, ukuhamba kwangoku kwinkqubo yokunyuka, ngeli xesha, ilahleko ye-MOSFET imveliso yombane kunye nekhoyo ibizwa ngokuba yilahleko yokutshintsha. Ngokuqhelekileyo ukulahleka kokutshintsha kukhulu kakhulu kunokulahleka kwe-conduction, kwaye ngokukhawuleza ukuguqulwa kwamaxesha amaninzi, ilahleko enkulu. Imveliso enkulu yombane kunye neyangoku ngephanyazo lokuqhutywa yenza ilahleko enkulu. Ukunciphisa ixesha lokutshintsha kunciphisa ilahleko ekuqhubeni ngalunye; ukunciphisa i-frequency switching kunciphisa inani lokutshintsha ngexesha leyunithi nganye. Zombini iindlela zinokunciphisa ilahleko yokutshintsha.

 
4, MOSFET drive

Xa kuthelekiswa ne-bipolar transistors, ngokuqhelekileyo kucingwa ukuba akukho okwangoku efunekayo ukwenza i-MOSFET iqhutywe, kuphela ukuba umbane we-GS ungaphezulu kwexabiso elithile. Oku kulula ukwenza, nangona kunjalo, sifuna isantya. Kwisakhiwo se-MOSFET unokubona ukuba kukho i-parasitic capacitance phakathi kwe-GS, GD, kunye nokuqhuba kwe-MOSFET, ngokwethiyori, ukutshaja kunye nokukhutshwa kwe-capacitance. Ukuhlawula i-capacitor kufuna i-current, kwaye ekubeni ukuhlawula i-capacitor ngokukhawuleza kunokujongwa njengesiphaluka esifutshane, i-current current iya kuba phezulu. Ukhetho / uyilo lwe-MOSFET drive into yokuqala ekufuneka uyithathele ingqalelo kubungakanani bomjelo okhawulezayo wesekethe yangoku inokunikezelwa. Into yesibini ekufuneka uyithathele ingqalelo kukuba, ngokuqhelekileyo isetyenziswa kwi-NMOS ye-high-end drive, kwimfuno yombane wesango mkhulu kunombane womthombo. I-high-end drive MOS tube conduction source voltage kunye ne-drain voltage (VCC) efanayo, ngoko ke isango lombane kune-VCC 4V okanye i-10V. sicinga ukuba kwinkqubo efanayo, ukufumana i-voltage enkulu kune-VCC, sifuna isiphaluka esikhethekileyo sokunyusa. Abaqhubi abaninzi beemoto badityanisiwe impompo yentlawulo, ukunikel' ingqalelo kufuneka ukhethe i-capacitor yangaphandle efanelekileyo, ukuze ufumane i-short-circuit yangoku eyaneleyo ukuqhuba i-MOSFET. I-4V okanye i-10V ekhankanywe ngasentla isetyenziswa ngokuqhelekileyo iMOSFET kumbane, uyilo ngokuqinisekileyo, imfuneko yokuba nomda othile. Okukhona uphezulu amandla ombane, kokukhona isantya sombane sikhawulezayo kwaye kokukhona sisezantsi ukuxhathisa kwimeko. Ngokwesiqhelo kukwakho nee-MOSFETs zombane ezincinci kurhulumente ezisetyenziswa kwiindidi ezahlukeneyo, kodwa kwiinkqubo ze-12V zeemoto zombane, i-4V eqhelekileyo kwimeko yanele.

Iiparamitha eziphambili zeMOSFET zezi zilandelayo:

1. isango umthombo breakdown voltage BVGS - kwinkqubo yokwandisa isango umthombo wombane, ukuze isango langoku IG ukusuka zero ukuqalisa ukunyuka kabukhali VGS, eyaziwa ngokuba isango umthombo breakdown ombane BVGS.

2. i-voltage yokuvula i-VT - i-voltage yokuvula (eyaziwa nangokuthi i-voltage ye-threshold): yenza umthombo we-S kunye ne-drain D phakathi kokuqala kwe-channel conductive ibandakanya i-voltage yesango efunekayo; - esemgangathweni ye-N-channel MOSFET, i-VT imalunga ne-3 ~ 6V; - emva kwenkqubo yokuphucula, inokwenza ixabiso le-MOSFET VT lihle ukuya kwi-2 ~ 3V.

3. Ukukhupha i-voltage breakdown ye-BVDS - phantsi kwemeko ye-VGS = 0 (yomeleziwe) , kwinkqubo yokwandisa i-drain voltage ukuze i-ID iqale ukunyuka ngokukhawuleza xa i-VDS ibizwa ngokuba yi-drain breakdown voltage BVDS - ID yanda kakhulu ngenxa le miba mibini ilandelayo:

(1) Ukuqhekeka kwe-avalanche yomaleko wokuncipha kufutshane ne-electrode yombhobho

(2) idrain-source inter-pole penetration breakdown - enye i-voltage encinci ye-MOSFET, ubude bayo bomjelo bufutshane, amaxesha ngamaxesha ukunyusa i-VDS kuya kwenza ummandla we-drain of the depletion layers amaxesha ngamaxesha ukwandisa ukuya kwindawo yomthombo. , ukwenzela ukuba ubude bomzila we-zero, oko kukuthi, phakathi kokungena kwe-drain-source, ukungena, indawo yomthombo uninzi lwabathwali, indawo yomthombo, iya kuba ngokuthe tye ukumelana nomgangatho wokunciphisa ukufunxa. kwintsimi yombane, ukufika kwindawo yokuvuza, kubangele i-ID enkulu.

4. I-DC input resistance resistance RGS-okt, umlinganiselo wombane wongeziweyo phakathi komthombo wesango kunye nesango langoku, olu phawu ngamanye amaxesha lubonakaliswa ngokwesango langoku elihamba ngesango le-MOSFET ye-RGS inokugqithisa ngokulula i-1010Ω. 5.

5. i-low-frequency transconductance gm kwi-VDS ngexabiso elimiselweyo leemeko, i-microvariance ye-drain current kunye ne-gate source voltage voltage microvariance ebangelwa olu tshintsho ibizwa ngokuba yi-transconductance gm, ebonisa ulawulo lombane womthombo wesango kwi-voltage. I-drain current ibonisa ukuba i-MOSFET yokwandisa iparamitha ebalulekileyo, ngokubanzi kuluhlu lwabambalwa ukuya kwi-mA / V ezimbalwa. I-MOSFET inokugqithisa ngokulula. 1010Ω.