Ho na le mefuta e mengata eaMOSFETs, haholo-holo e arotsoe ka li-MOSFET tsa matekoane le liheke tse sirelelitsoeng MOSFET mekhahlelo e 'meli, 'me kaofela li na le lintlha tsa N-channel le P-channel.
Metal-Oxide-Semiconductor Field-Effect Transistor, e bitsoang MOSFET, e arotsoe ka mofuta oa depletion MOSFET le mofuta oa ntlafatso oa MOSFET.
Li-MOSFET li boetse li arotsoe ka li-tubes tse nang le heke e le 'ngoe le tse nang le liheke tse peli. MOSFET ea liheke tse peli e na le liheke tse peli tse ikemetseng tsa G1 le G2, ho tloha kahong ea tse lekanang le li-MOSFET tse peli tsa heke e le 'ngoe tse hokahaneng ka letoto, le liphetoho tsa eona tsa hajoale ke taolo ea motlakase ea liheke tse peli. Tšobotsi ena ea li-MOSFET tse nang le liheke tse peli e tlisa boiketlo bo boholo ha e sebelisoa e le li-amplifiers tsa maqhubu a phahameng, ho fumana li-amplifiers tsa taolo, li-mixer le li-demodulator.
1, MOSFETmofuta le sebopeho
MOSFET ke mofuta oa FET (mofuta o mong ke JFET), e ka etsoa ho ba mofuta o ntlafalitsoeng kapa oa ho fokotseha, P-channel kapa N-channel ea mefuta e mene, empa ts'ebeliso ea khopolo-taba ea MOSFET e ntlafalitsoeng ea N-channel le P- e ntlafalitsoeng. kanale MOSFET, eo hangata e bitsoang NMOS, kapa PMOS e bua ka mefuta ena e 'meli. Mabapi le hore na hobaneng u sa sebelise li-MOSFET tsa mofuta oa depletion, u se khothaletse ho batla sesosa sa sesosa. Mabapi le li-MOSFET tse peli tse ntlafalitsoeng, tse sebelisoang haholo ke NMOS, lebaka ke hore khanyetso e nyane, 'me ho bonolo ho e etsa. Kahoo ho chencha phepelo ea motlakase le lits'ebetso tsa koloi, hangata sebelisa NMOS. qotsa e latelang, empa hape e thehiloe ho feta NMOS. lithapo tse tharo tsa MOSFET parasitic capacitance e teng pakeng tsa lithapo tse tharo, e seng litlhoko tsa rona, empa ka lebaka la mefokolo ea ts'ebetso ea tlhahiso. Ho ba teng ha parasitic capacitance ka moralo kapa kgetho ya ka koloi potoloho ho boloka nako e itseng, empa ha ho na mokhoa oa ho qoba, 'me joale e qaqileng selelekela. Setšoantšong sa schematic sa MOSFET se ka bonoa, drain le mohloli pakeng tsa diode ea parasitic. Sena se bitsoa diode ea 'mele, ha ho khanna meroalo e utloahalang, diode ena e bohlokoa haholo. Ka tsela, diode ea 'mele e fumaneha feela ho MOSFET e le' ngoe, hangata eseng ka har'a chip ea potoloho e kopaneng.
2, litšobotsi tsa MOSFET conduction
Bohlokoa ba conduction ke ho fetoha, ho lekana le ho koala ha switjha. Litšobotsi tsa NMOS, Vgs tse kholo ho feta boleng bo itseng li tla tsamaisa, tse loketseng ho sebelisoa ha mohloli o thehiloe (mokhanni o tlase-tlase), ke motlakase oa heke feela o fihlang. ho 4V kapa 10V.PMOS litšobotsi, Vgs tlase ho boleng bo itseng e tla tsamaisa, e loketseng ho sebelisoa tabeng ha mohloli o kopantsoe le VCC (high-end drive).
Leha ho le joalo, ha e le hantle, PMOS e ka ba bonolo haholo ho e sebelisa e le mokhanni ea phahameng, empa ka lebaka la ho hanyetsa, ho theko e boima, mefuta e fokolang ea phapanyetsano le mabaka a mang, ho mokhanni ea phahameng, hangata a ntse a sebelisa NMOS.
3, MOSFETtahlehelo ea ho fetoha
Ebang ke NMOS kapa PMOS, ka mor'a hore ho hanyetsane ho be teng, e le hore hona joale ho tla ja matla ho hanyetsa hona, karolo ena ea matla a sebelisoang e bitsoa tahlehelo ea ho hanyetsa. Ho khetha MOSFET e nang le khanyetso e nyane ho tla fokotsa tahlehelo ea ho hanyetsa. Ka tloaelo matla a tlase a MOSFET a ho hanyetsa hangata ke mashome a li-milliohm, li-millione tse 'maloa moo. MOS ka nako le ho khaola, ha ea tlameha ho ba ho phethoa hang-hang ha motlakase ho pholletsa le MOS ho na le ts'ebetso ea ho oa, hona joale ho phalla ka mokhoa oa ho phahama, nakong ena, tahlehelo ea MOSFET ke. sehlahisoa sa motlakase le sa hona joale se bitsoa switching loss. Hangata tahlehelo ea ho fetoha e kholo haholo ho feta tahlehelo ea conduction, 'me ha lebelo la ho fetola ka potlako, tahlehelo e kholoanyane. Sehlahisoa se seholo sa motlakase le hona joale ka nako ea conduction se baka tahlehelo e kholo. Ho khutsufatsa nako ea ho fetola nako ho fokotsa tahlehelo ho conduction e 'ngoe le e' ngoe; ho fokotsa lebelo la ho fetoha ho fokotsa palo ea li-switches ka nako ea yuniti. Mekhoa ena ka bobeli e ka fokotsa tahlehelo ea switching.
4, koloi ea MOSFET
Ha ho bapisoa le li-transistors tsa bipolar, hangata ho nahanoa hore ha ho hlokahale hona joale ho etsa boitšoaro ba MOSFET, feela hore motlakase oa GS o ka holimo ho boleng bo itseng. Sena se bonolo ho se etsa, leha ho le joalo, re boetse re hloka lebelo. Ka sebopeho sa MOSFET u ka bona hore ho na le capacitance parasitic pakeng tsa GS, GD, le ho khanna ha MOSFET ke, ka khopolo, ho tjhaja le ho ntša matla. Ho lefisa capacitor ho hloka hona joale, 'me kaha ho tjhaja capacitor hang-hang ho ka nkoa e le potoloho e khutšoanyane, hona joale hona joale ho tla ba holimo. Khetho / moralo oa koloi ea MOSFET ntho ea pele eo u lokelang ho e ela hloko ke boholo ba nako e khutšoanyane ea nako e khutšoanyane e ka fanoang. Ntho ea bobeli eo u lokelang ho e ela hloko ke hore, e sebelisoang ka kakaretso ho NMOS ea likoloi tse phahameng, ka tlhokahalo ke hore motlakase oa heke o moholo ho feta motlakase oa mohloli. High-end drive MOS tube conduction source voltage le drain voltage (VCC) e ts'oanang, kahoo motlakase oa heke ho feta VCC 4V kapa 10V. ho nka hore tsamaisong e tšoanang, ho fumana motlakase o moholo ho feta VCC, re hloka potoloho e khethehileng ea ho matlafatsa. Bakhanni ba bangata ba likoloi ke pompo e kopantsoeng ea tefiso, ho ela hloko ke ho lokela ho khetha capacitor e loketseng ea ka ntle, e le hore u fumane chelete e lekaneng ea nako e khutšoanyane ea ho khanna MOSFET. 4V kapa 10V e boletsoeng ka holimo e atisa ho sebelisoa MOSFET ho voltage, moralo ehlile, tlhoko ea ho ba le moeli o itseng. Ha matla a motlakase a phahame, a potlakisa lebelo la mmuso mme a theola khanyetso ea mmuso. Hangata ho boetse ho na le li-MOSFET tse nyane tsa motlakase tse sebelisoang ka mekhahlelo e fapaneng, empa lits'ebetsong tsa elektroniki tsa likoloi tsa 12V, 4V e tloaelehileng ea mmuso e lekane.
Lintlha tse ka sehloohong tsa MOSFET ke tse latelang:
1. heke mohloli karohano gagamalo BVGS - ka tshebetso ya ho eketsa heke mohloli gagamalo, e le hore heke hona joale IG ho tloha lefela ho qala keketseho e bohale ka VGS, e tsejoang e le heke mohloli ho senyeha gagamalo BVGS.
2. motlakase oa ho bulela VT - motlakase oa ho bulela (hape o tsejoa e le motlakase oa threshold): etsa mohloli oa S le drain D pakeng tsa qaleho ea mocha oa conductive o etsa hore motlakase oa heke o hlokehe; - MOSFET e tloaelehileng ea N-channel, VT e ka bang 3 ~ 6V; - kamora ts'ebetso ea ntlafatso, e ka etsa hore boleng ba MOSFET VT bo theohele ho 2 ~ 3V.
3. Drain breakdown voltage BVDS - tlas'a boemo ba VGS = 0 (matlafalitsoe) , nakong ea ho eketsa motlakase oa drain e le hore ID e qala ho eketseha haholo ha VDS e bitsoa "drain breakdown voltage" BVDS - ID e ile ea eketseha ka mokhoa o tsotehang ka lebaka la likarolo tse peli tse latelang:
(1) ho senyeha ha avalanche ea lera la ho fokotseha haufi le electrode ea drain
(2) karohano ea ho kenella ka har'a li-drain-source inter-pole - motlakase o mong o monyane oa MOSFET, bolelele ba mocha oa eona o khuts'oane, nako le nako ho eketsa VDS ho tla etsa hore sebaka sa drainage sa lera la depletion nako le nako se atolose sebakeng sa mohloli. , e le hore bolelele ba mocha oa zero, ke hore, pakeng tsa ho kenella ha mohloli oa drainage, ho kenella, sebaka sa mohloli oa bajari ba bangata, sebaka sa mohloli, se tla ba se otlolohileng ho mamella lera la ho fokotseha ha ho kenngoa ha tšimo ea motlakase, ho fihla sebakeng sa ho lutla, ho fella ka ID e kholo.
4. DC input resistance RGS-ke hore, karo-karolelano ea gagamalo eketsoa pakeng tsa mohloli oa heke le heke hona joale, tšobotsi ena ka linako tse ling e hlalosoa ka ho ya ka heke hona joale e phallang ka heke MOSFET oa RGS ka habonolo feta 1010Ω. 5.
5. low-frequency transconductance gm in VDS for the fixed value of the conditions, the microvariance of drain current le heke source voltage microvariance e bakoang ke phetoho ena e bitsoa transconductance gm, e bonahatsang taolo ea motlakase oa mohloli oa heke holim'a drain current ke ho bontša hore MOSFET amplification ea parameter ea bohlokoa, ka kakaretso ho tloha ho tse seng kae ho ea ho tse seng kae ho ea ho tse seng kae mA / V. MOSFET e ka feta 1010Ω habonolo.
Nako ea poso: May-14-2024
