Okokuqala, uhlobo lwe-MOSFET kunye nolwakhiwo,I-MOSFETyi-FET (enye yi-JFET), inokuveliswa ibe luhlobo oluphuculweyo okanye lokuncipha, i-P-channel okanye i-N-channel zizonke iindidi ezine, kodwa usetyenziso lwe-MOSFETs ephuculweyo ye-N-channel kunye nee-MOSFETs eziphuculweyo ze-P-channel, ngoko ke. edla ngokubizwa ngokuba yi-NMOS okanye i-PMOS ibhekisa kwezi ntlobo zimbini. Kwezi ntlobo zimbini zee-MOSFETs eziphuculweyo, eyona isetyenziswa kakhulu yi-NMOS, isizathu kukuba ukuxhathisa kuncinci, kwaye kulula ukwenza. Ke ngoko, i-NMOS isetyenziswa ngokubanzi ekutshintsheni unikezelo lwamandla kunye nezicelo zokuqhuba iimoto.
Kwintshayelelo elandelayo, uninzi lwamatyala alawulwa yi-NMOS. amandla e-parasitic akhona phakathi kwezikhonkwane ezintathu ze-MOSFET, uphawu olungafunekiyo kodwa oluvela ngenxa yonyino lwenkqubo yokwenziwa kwemveliso. Ubukho be-parasitic capacitance yenza kube nzima ukuyila okanye ukukhetha isekethe yomqhubi. Kukho i-parasitic diode phakathi kombhobho kunye nomthombo. Oku kubizwa ngokuba yi-diode yomzimba kwaye ibalulekile ekuqhubeni imithwalo ye-inductive efana neemoto. Ngendlela, i-diode yomzimba ikhona kuphela kwi-MOSFETs nganye kwaye ihlala ingekho ngaphakathi kwe-IC chip.
I-MOSFETukutshintsha i-tube yokulahleka, nokuba yi-NMOS okanye i-PMOS, emva kokuqhutyelwa kwe-on-resistance ikhona, ukwenzela ukuba i-current iya kudla amandla kule nkcaso, le nxalenye yamandla asetyenzisiweyo ibizwa ngokuba yilahleko yokuqhuba. Ukukhethwa kwee-MOSFETs ezinokumelana okuphantsi kuya kunciphisa ilahleko yokunganyangeki. Kule mihla, ukunganyangeki kwee-MOSFETs zamandla aphantsi ngokuqhelekileyo kumalunga namashumi eemiliyohm, kwaye iimiliyohm ezimbalwa zikwafumaneka.Ii-MOSFETs akufunekanga zigqitywe ngephanyazo xa zilayita okanye zicinyiwe.Kukho inkqubo yokunciphisa amandla ombane ekhompyutheni. iziphelo ezimbini ze-MOSFET, kwaye kukho inkqubo yokunyusa ikhoyo ngoku ehamba ngayo.Ngeli xesha lexesha, ukulahlekelwa kwe-MOSFET kuyimveliso ye-voltage kunye ne-current, ebizwa ngokuba yi-switching loss. Ngokuqhelekileyo ukulahleka kokutshintsha kukhulu kakhulu kunokulahleka kwe-conduction, kwaye ngokukhawuleza ukuguqulwa kwamaxesha amaninzi, ilahleko enkulu. Imveliso ye-voltage kunye yangoku kwi-instant conduction inkulu kakhulu, ibangele ilahleko enkulu. Ukunciphisa ixesha lokutshintsha kunciphisa ilahleko ekuqhubeni ngalunye; ukunciphisa i-frequency switching kunciphisa inani lokutshintsha ngexesha leyunithi nganye. Zombini ezi ndlela zinciphisa ilahleko yokutshintsha.
Xa kuthelekiswa ne-bipolar transistors, kukholelwa ngokubanzi ukuba akukho msinga ofunekayo ukwenza aI-MOSFETqhuba, okoko umbane we-GS ungaphezulu kwexabiso elithile. Oku kulula ukwenza, nangona kunjalo, sifuna isantya. Njengoko ubona kulwakhiwo lwe-MOSFET, kukho i-parasitic capacitance phakathi kwe-GS, GD, kunye nokuqhuba kwe-MOSFET, enyanisweni, kukutshaja kunye nokukhupha amandla. Ukuhlawula i-capacitor kufuna i-current, kuba ukutshaja i-capacitor ngokukhawuleza kunokubonwa njengesiphaluka esifutshane, ngoko ke umbane okhawulezayo uya kuba phezulu. Into yokuqala ekufuneka uyiqaphele xa ukhetha/uyila umqhubi we-MOSFET bubungakanani bombane okhawulezayo okhawulezileyo onokubonelelwa.
Into yesibini ekufuneka uyiqaphele kukuba, isetyenziswa ngokubanzi kwi-NMOS yesiphelo esiphezulu, i-voltage yexesha lesango kufuneka ibe nkulu kunombane womthombo. I-High-end drive MOSFET kumthombo wombane kunye ne-drain voltage (VCC) efanayo, ngoko ke isango lombane lesango kune-VCC 4V okanye i-10V. ukuba kwinkqubo efanayo, ukufumana i-voltage enkulu kune-VCC, kufuneka sigxininise kwisekethe yokunyusa. Abaqhubi beemoto abaninzi baneempompo zokuhlawulisa ezidibeneyo, kubalulekile ukuba uqaphele ukuba kufuneka ukhethe i-capacitance yangaphandle efanelekileyo ukuze ufumane i-short-circuit current eyaneleyo ukuqhuba i-MOSFET. I-4V okanye i-10V yi-MOSFET esetyenziswa ngokuqhelekileyo kumbane, uyilo ngokuqinisekileyo, kufuneka ube nomda othile. Okukhona uphezulu amandla ombane, kokukhona isantya sombane sikhawulezayo kwaye kokukhona sisezantsi ukuxhathisa kwimeko. Ngoku kukwakho nee-MOSFETs zamandla ombane amancinci asetyenziswa kwiindawo ezahlukeneyo, kodwa kwi-12V ye-automotive electronics system, ngokubanzi i-4V on-state yanele. Isidingo seesekethe zokutshintsha nge-elektroniki, ezinjengokutshintsha umbane kunye ne-motor drive, kodwa kunye nokukhanya kokukhanya. Ukuqhuba kuthetha ukusebenza njengotshintshi, olulingana nokuvalwa kokutshintsha. Iimpawu ze-NMOS, iiVgs ezinkulu kunexabiso elithile ziya kuqhuba, zilungele ukusetyenziswa kwimeko xa umthombo usekelwe (i-low-end drive), nje ngokuba isango I-voltage ye-4V okanye i-10V.PMOS iimpawu, i-Vgs engaphantsi kwexabiso elithile iya kuqhuba, ilungele ukusetyenziswa kwimeko xa umthombo uxhunyiwe kwi-VCC (i-high-end drive). Nangona kunjalo, nangona i-PMOS inokusetyenziswa ngokulula njengomqhubi wesiphelo esiphezulu, i-NMOS ihlala isetyenziswa kubaqhubi abaphezulu ngenxa yokumelana okukhulu, ixabiso eliphezulu, kunye neentlobo ezimbalwa zokutshintsha.
Ngoku i-MOSFET iqhube izicelo ze-voltage ephantsi, xa kusetyenziswa umbane we-5V, ngeli xesha ukuba usebenzisa isakhiwo se-totem pole yendabuko, ngenxa ye-transistor ibe malunga ne-0.7V ye-voltage drop, ekhokelela ekufakweni kokugqibela kongezwe kwisango I-voltage kuphela yi-4.3 V. Ngeli xesha, sikhetha i-voltage ye-nominal gate ye-4.5V ye-MOSFET kubukho beengozi ezithile. Ingxaki efanayo yenzeka ekusebenziseni i-3V okanye ezinye izihlandlo zonikezelo lwamandla aphantsi. Amandla ombane amabini asetyenziswa kwezinye iisekethe zolawulo apho icandelo lengqiqo lisebenzisa i-5V eqhelekileyo okanye i-3.3V yombane wedijithali kwaye icandelo lamandla lisebenzisa i-12V okanye nangaphezulu. Amandla ombane amabini axhunyiwe kusetyenziswa umhlaba oqhelekileyo. Oku kubeka imfuneko yokusebenzisa isekethe evumela icala lamandla ombane aphantsi ukuba lilawule ngokufanelekileyo iMOSFET kwicala lamandla ombane aphezulu, ngelixa iMOSFET kwicala lamandla ombane aphezulu iya kujongana neengxaki ezifanayo ezikhankanywe ku-1 no-2. Ulwakhiwo lwepali yetotem alukwazi ukuhlangabezana neemfuno zemveliso, kwaye uninzi lwee-IC zomqhubi we-MOSFET azibonakali ngathi zibandakanya ubume bomda wesango lombane. I-voltage yegalelo ayilona xabiso elimiselweyo, liyahluka kunye nexesha okanye ezinye izinto. Olu tshintsho lubangela ukuba amandla ombane okuqhuba abonelelwa kwi-MOSFET yisekethe ye-PWM angazinzi. Ukuze kwenziwe i-MOSFET ikhuseleke kumbane wombane wesango eliphezulu, ii-MOSFET ezininzi zinezilawuli zombane ezakhelwe ngaphakathi ukuze zinciphise ngamandla amandla ombane wesango.
Kule meko, xa i-voltage ye-drive ebonelelweyo idlula i-voltage yomlawuli, iya kubangela ukusetyenziswa kwamandla amakhulu angatshintshiyo Kwangaxeshanye, ukuba usebenzisa nje umgaqo we-resistor voltage divider ukunciphisa i-voltage yesango, kuya kubakho amandla ombane aphezulu, i-MOSFET isebenza kakuhle, ngelixa amandla ombane ancitshiswayo xa i-voltage yesango ingonelanga ukubangela ukuqhutywa okungonelanga, oko konyusa amandla ombane.
Ngokufanelekileyo isiphaluka esiqhelekileyo apha kuphela kwisekethe yomqhubi we-NMOS ukwenza uhlalutyo olulula: I-Vl kunye ne-Vh yi-low-end kunye ne-high-end power supply, ngokulandelanayo, i-voltages ezimbini zinokufana, kodwa i-Vl ayifanele idlule i-Vh. I-Q1 kunye ne-Q2 zenza i-totem pole inverted, esetyenziselwa ukufezekisa ukuhlukaniswa, kwaye ngexesha elifanayo ukuqinisekisa ukuba iibhubhu ezimbini zomqhubi i-Q3 kunye ne-Q4 aziyi kuba ngexesha elifanayo. I-R2 kunye ne-R3 zibonelela ngereferensi yombane we-PWM, kwaye ngokutshintsha le nkcazo, unokwenza umsebenzi wesiphaluka usebenze kakuhle, kwaye i-voltage yesango ayanele ukuba ibangele ukuqhuba ngokucokisekileyo, ngaloo ndlela ukwandisa ukusetyenziswa kwamandla. I-R2 kunye ne-R3 zibonelela ngereferensi yombane we-PWM, ngokutshintsha le referensi, unokuvumela ukuba umsebenzi wesekethe kwi-wave wave ye-PWM iphakame kwaye ithe tye. I-Q3 kunye ne-Q4 zisetyenziselwa ukubonelela nge-drive yangoku, ngenxa yexesha, i-Q3 kunye ne-Q4 ngokumalunga ne-Vh kunye ne-GND kuphela ubuncinci bokuhla kwe-Vce, oku kuhla kwamandla ombane ngokuqhelekileyo kuphela yi-0.3V okanye kunjalo, ephantsi kakhulu. kune-0.7V Vce R5 kunye ne-R6 zixhathisi zempendulo kwisampulu yombane wesango, emva kwesampulu yombane, i-voltage yesango isetyenziswa njengesixhobo sokumelana nombane wesango, kwaye umbane wesampulu usetyenziswa kumbane wesango. I-R5 kunye ne-R6 yi-resistors yempendulo esetyenziselwa ukusampula i-voltage yesango, ethi ke idluliselwe kwi-Q5 ukudala impendulo enamandla engalunganga kwiziseko ze-Q1 kunye ne-Q2, ngaloo ndlela inciphisa umbane wesango kwixabiso elilinganiselwe. Eli xabiso lingahlengahlengiswa nge-R5 kunye ne-R6. Ekugqibeleni, i-R1 ibonelela ngokukhawulelana kwesiseko sangoku kwi-Q3 kunye ne-Q4, kwaye i-R4 inika umda wesango langoku kwii-MOSFETs, okukukunciphisa i-Ice ye-Q3Q4. I-acceleration capacitor inokudityaniswa ngokuhambelana ngasentla kwe-R4 ukuba kuyimfuneko.
Xa uyila izixhobo eziphathwayo kunye neemveliso ezingenazingcingo, ukuphucula ukusebenza kwemveliso kunye nokwandisa ixesha lokusebenza kwebhetri yimiba emibini abaqulunqi kufuneka bajongane nayo. Abaguquleli beDC-DC banenzuzo yokusebenza okuphezulu, imveliso ephezulu yangoku kunye nephantsi epholileyo yangoku, efanelekileyo kakhulu ukunika amandla okuphathekayo. izixhobo.
Iziguquli ze-DC-DC zinezibonelelo zokusebenza okuphezulu, imveliso ephezulu yangoku kunye ne-quiescent yangoku ephantsi, efanelekileyo kakhulu ukunika amandla izixhobo eziphathwayo. Okwangoku, ezona ndlela ziphambili zophuhliso lwetekhnoloji yoyilo lwe-DC-DC yokuguqulela ibandakanya: itekhnoloji ye-high-frequency: kunye nokwanda kokutshintsha kokutshintsha, ubungakanani bokuguqula ukuguquguquka buye bancitshiswa, ukuxinana kwamandla kuye kwanda kakhulu, kunye nokuguquguquka. impendulo iphuculwe. Incinci
Amandla e-DC-DC converter frequency switching aya kunyuka aye kwinqanaba le-megahertz. Itekhnoloji yamandla ombane asezantsi: Ngophuhliso oluqhubekayo lwetekhnoloji yokuvelisa i-semiconductor, ii-microprocessors kunye nesixhobo sombane esiphathwayo sombane sisiya sisezantsi kwaye sisezantsi, nto leyo efuna ikamva le-DC-DC converter inokubonelela ngemveliso ephantsi yombane ukuze iqhelane ne-microprocessor kunye nezixhobo zombane eziphathwayo, ezithi ifuna ikamva le-DC-DC converter inokubonelela ngemveliso yombane ephantsi ukuziqhelanisa ne-microprocessor.
Kwanele ukunika i-voltage yemveliso ephantsi ukuziqhelanisa ne-microprocessors kunye nezixhobo eziphathwayo ze-elektroniki. Olu phuhliso lwetekhnoloji lubeka phambili iimfuno eziphezulu zoyilo lweesekethe zetshiphu zobonelelo lwamandla. Okokuqala, ngokunyuka kwamaxesha okutshintsha, ukusebenza kwamacandelo okutshintsha kubekwa phambili
Iimfuno eziphezulu zokusebenza kwento yokutshintsha, kwaye kufuneka ibe nesekethe ehambelanayo yokutshintsha i-element drive ukuqinisekisa ukuba into yokutshintsha kwi-frequency yokutshintsha ukuya kwinqanaba le-megahertz yokusebenza okuqhelekileyo. Okwesibini, kwi-battery-powered portable electronic devices, i-voltage yokusebenza yesekethe iphantsi (kwimeko yeebhetri ze-lithium, umzekelo).
Iibhetri zeLithium, umzekelo, amandla ombane osebenzayo we-2.5 ~ 3.6V), ngoko ke i-chip ye-power supply ye-voltage ephantsi.
I-MOSFET inokumelana okuphantsi kakhulu, ukusetyenziswa kwamandla aphantsi, kwitshiphu yangoku edumileyo ye-DC-DC engaphezulu kwe-MOSFET njengokutshintsha kwamandla. Nangona kunjalo, ngenxa yomthamo omkhulu we-parasitic we-MOSFETs. Oku kubeka iimfuno eziphezulu kuyilo lokutshintsha iisekethe zomqhubi wetyhubhu ukuyila iziguquli ze-DC-DC eziphezulu zokusebenza. Kukho ii-CMOS ezahlukeneyo, iisekethe ezinengqondo ze-BiCMOS zisebenzisa i-bootstrap boost structure kunye neesekethe zomqhubi njengemithwalo emikhulu ye-capacitive kuyilo lwe-ULSI yombane ophantsi. Ezi sekethe ziyakwazi ukusebenza ngokufanelekileyo phantsi kweemeko zobonelelo lombane ongaphantsi kwe-1V, kwaye zinokusebenza phantsi kweemeko zomthwalo we-1 ~ 2pF frequency inokufikelela kumashumi eemegabhithi okanye namakhulu emegahertz. Kweli phepha, i-bootstrap boost circuit isetyenziselwa ukuyila umthamo omkhulu we-capacitance drive, ilungele i-low-voltage, i-high switching frequency boost DC-DC converter drive circuit. Amandla ombane asezantsi kunye ne-PWM ukuqhuba ii-MOSFET eziphezulu. Isiginali ye-PWM encinci yeamplitude yokuqhuba iimfuno zombane wesango eliphezulu kwiiMOSFETs.
Ixesha lokuposa: Apr-12-2024
