Okokuqala, uhlobo nesakhiwo se-MOSFET, i-MOSFET iyi-FET (enye i-JFET), ingakhiqizwa ibe uhlobo oluthuthukisiwe noma oluncishayo, i-P-channel noma i-N-channel ingqikithi yezinhlobo ezine, kodwa ukusetshenziswa kwangempela kwe-N ethuthukisiwe kuphela. -ama-MOSFET amashaneli kanye nama-MOSFET esiteshi se-P athuthukisiwe, ngokuvamile abizwa ngokuthi i-NMOSFET, noma i-PMOSFET ibhekisela ku-So ngokuvamile eshiwo i-NMOSFET, noma i-PMOSFET ibhekisela kulezi zinhlobo ezimbili. Kulezi zinhlobo ezimbili zama-MOSFET athuthukisiwe, ama-NMOSFET asetshenziswa kakhulu ngenxa yokungazweli kwawo okuphansi kanye nokwenza lula kwawo. Ngakho-ke, ama-NMOSFET ngokuvamile asetshenziswa ekushintsheni ukunikezwa kwamandla kanye nezicelo zokushayela izithuthuthu, futhi isingeniso esilandelayo siphinde sigxile kuma-NMOSFET. i-parasitic capacitance ikhona phakathi kwezikhonkwane ezintathu ze-I-MOSFET, okungadingeki, kodwa kunalokho ngenxa yokulinganiselwa kwenqubo yokukhiqiza. Ukuba khona kwe-parasitic capacitance kwenza kube nzima ukuklama noma ukukhetha isekethe yomshayeli. Kukhona i-diode ye-parasitic phakathi kwe-drain kanye nomthombo. Lokhu kubizwa ngokuthi i-diode yomzimba futhi kubalulekile ekushayeleni imithwalo ye-inductive efana namamotho. Ngendlela, i-diode yomzimba ikhona kuphela kuma-MOSFET ngamanye futhi ngokuvamile ayikho ngaphakathi kwe-IC chip.
Manje iI-MOSFETukushayela low-voltage izicelo, lapho ukusetshenziswa 5V amandla kagesi, kulokhu uma usebenzisa bendabuko totem pole isakhiwo, ngenxa transistor kube mayelana 0.7V ukwehla kwamandla kagesi, okuholela ekugcineni langempela wanezela esangweni ku-voltage kuphela. 4.3 V. Ngalesi sikhathi, sikhetha amandla kagesi wesango elingu-4.5V we-MOSFET ngobukhona bezingozi ezithile. Inkinga efanayo iyenzeka ekusetshenzisweni kwe-3V noma ezinye izikhathi zokuphakelwa kwamandla kagesi aphansi. Amandla kagesi amabili asetshenziswa kumasekhethi okulawula athile lapho isigaba sokucabanga sisebenzisa i-voltage yedijithali engu-5V noma engu-3.3V ejwayelekile futhi ingxenye yamandla isebenzisa i-12V noma ngaphezulu. Ama-voltages amabili axhunywe kusetshenziswa indawo evamile. Lokhu kubeka imfuneko yokusebenzisa isekethe evumela uhlangothi lwe-voltage ephansi ukuthi lulawule ngempumelelo i-MOSFET ohlangothini lwamandla kagesi aphezulu, kuyilapho i-MOSFET ohlangothini lwamandla kagesi aphezulu izobhekana nezinkinga ezifanayo ezishiwo ku-1 no-2.
Kuzo zontathu izimo, ukwakheka kwesigxobo se-totem akukwazi ukuhlangabezana nezidingo zokukhiphayo, futhi ama-IC amaningi omshayeli we-MOSFET angekho eshalofini abonakala engabandakanyi isakhiwo somkhawulo kagesi wesango. I-voltage yokufaka ayilona inani elingaguquki, iyahlukahluka ngokuya kwesikhathi noma ezinye izici. Lokhu kuhluka kubangela ukuthi i-voltage yokushayela enikezwe i-MOSFET yisekethe ye-PWM ingazinzi. Ukuze kwenziwe i-MOSFET iphephe kuma-voltage amasango aphezulu, ama-MOSFET amaningi anezilawuli zikagesi ezakhelwe ngaphakathi ukuze zibeke umkhawulo ngamandla we-voltage yesango. Kulokhu, lapho i-voltage yokushayela ihlinzeka ngaphezu kwesilawuli se-voltage, izodala ukusetshenziswa kwamandla amakhulu angaguquki ngasikhathi sinye, uma umane usebenzise isimiso se-resistor voltage divider ukuze unciphise i-voltage yesango, kuzoba khona ukuphakama okuthe xaxa. i-voltage yokufaka, iI-MOSFETisebenza kahle, kuyilapho i-voltage yokufaka iyancipha lapho i-voltage yesango inganele ukubangela ukuqhutshwa okungaphansi kokuphelele, ngaleyo ndlela kukhulise ukusetshenziswa kwamandla.
Isekhethi evamile lapha kuphela ukuze isekethe yomshayeli we-NMOSFET yenze ukuhlaziya okulula: I-Vl ne-Vh amandla aphansi futhi asezingeni eliphezulu, ama-voltages amabili angafana, kodwa i-Vl akufanele idlule i-Vh. I-Q1 ne-Q2 zakha i-totem pole ehlanekezelwe, esetshenziselwa ukubona ukuhlukaniswa, futhi ngesikhathi esifanayo ukuqinisekisa ukuthi amashubhu amabili omshayeli i-Q3 ne-Q4 ngeke abe ukuqhutshwa kwesikhathi esifanayo. I-R2 ne-R3 ihlinzeka nge-voltage ye-PWM engu-R2 kanye ne-R3 ihlinzeka ngereferensi yamandla kagesi ye-PWM, ngokushintsha lesi sithenjwa, ungavumela umsebenzi wesifunda ku-waveform yesignali ye-PWM ibe umqansa futhi uqondile. I-Q3 ne-Q4 zisetshenziselwa ukuhlinzeka ngedrayivu yamanje, ngenxa yesikhathi esibekiwe, i-Q3 ne-Q4 ehlobene ne-Vh ne-GND iyinani elincane kuphela lokwehla kwamandla kagesi e-Vce, lokhu kwehla kwamandla kagesi kuvame ukuba ngu-0.3V kuphela noma ngaphezulu, okuphansi kakhulu. kune-0.7V Vce R5 kanye ne-R6 yizinqamuleli zempendulo, ezisetshenziselwa isango u-R5 kanye ne-R6 ziyizinqamuleli zempendulo ezisetshenziselwa isampula kagesi wesango, bese idluliswa ku-Q5 ukuze kukhiqizwe impendulo enamandla engalungile ezisekelweni ze-Q1 ne-Q2, ngaleyo ndlela kukhawulelwe. i-voltage yesango ibe yinani elilinganiselwe. Leli nani lingalungiswa ngo-R5 no-R6. Ekugcineni, i-R1 inikeza umkhawulo wesisekelo samanje ku-Q3 ne-Q4, futhi i-R4 inikeza umkhawulo wesango lamanje kuma-MOSFET, okuwumkhawulo we-Ice ye-Q3Q4. I-acceleration capacitor ingaxhunywa ngokuhambisana ngenhla kuka-R4 uma kunesidingo.
Isikhathi sokuthumela: Apr-21-2024
