Menene MOSFET? Menene manyan sigogi?

Lokacin zana wutar lantarki mai sauyawa ko da'irar tuƙi ta amfani da itaMOSFETs, abubuwa irin su juriya, matsakaicin ƙarfin lantarki, da matsakaicin halin yanzu na MOS ana la'akari da su gabaɗaya.

MOSFET bututun nau'in FET ne waɗanda za'a iya ƙirƙira su azaman haɓakawa ko nau'in ragewa, tashar P-channel ko tashar N-tashar duka nau'ikan 4. Haɓaka NMOSFETs da haɓaka PMOSFETs ana amfani da su gabaɗaya, kuma galibi ana ambaton waɗannan biyun.

Wadannan biyun da aka fi amfani dasu shine NMOS. Dalilin shi ne cewa juriya na gudanarwa yana da ƙananan kuma mai sauƙin ƙira. Sabili da haka, ana amfani da NMOS yawanci wajen sauya wutar lantarki da aikace-aikacen tuƙi.

A cikin MOSFET, an sanya thyristor tsakanin magudanar ruwa da tushen, wanda ke da matukar mahimmanci wajen tuki lodin inductive kamar injina, kuma yana cikin MOSFET guda ɗaya kawai, ba yawanci a cikin guntun da'ira ba.

Matsakaicin ƙarfin parasitic yana wanzu tsakanin fil uku na MOSFET, ba wai muna buƙatarsa ​​ba, amma saboda iyakancewar tsarin masana'anta. Kasancewar iya karfin parasitic yana sa ya zama mai wahala yayin zayyana ko zabar da'irar direba, amma ba za a iya kauce masa ba.

Babban sigogi naMOSFET

1, Wutar lantarki VT

Buɗe wutar lantarki (wanda kuma aka sani da ƙarfin ƙarfin kofa): ta yadda ƙarfin ƙarfin ƙofar da ake buƙata don fara ƙirƙirar tashar gudanarwa tsakanin tushen S da magudanar D; daidaitaccen N-tashar MOSFET, VT yana kusan 3 ~ 6V; ta hanyar inganta tsarin, ana iya rage ƙimar MOSFET VT zuwa 2 ~ 3V.

2, DC shigar da juriya RGS

Matsakaicin ƙarfin wutar lantarki da aka ƙara tsakanin sandar tushen ƙofar kofa da halin yanzu na kofa Wannan sifa tana bayyana wani lokaci ta hanyar ƙofofin da ke gudana ta ƙofar, MOSFET's RGS na iya wuce 1010Ω cikin sauƙi.

3. Magudanar ruwa ta rushewar wutar lantarki BVDS.

Ƙarƙashin yanayin VGS = 0 (inganta), yayin da ake haɓaka ƙarfin wutar lantarki na magudanar ruwa, ID yana ƙaruwa sosai lokacin da ake kira VDS mai rushewar wutar lantarki BVDS, ID yana ƙaruwa sosai saboda dalilai biyu: (1) ƙazamar ruwa. Rushewar Layer na ragewa kusa da magudanar ruwa, (2) shiga tsakani tsakanin magudanar ruwa da sandunan tushe, wasu MOSFETs, waɗanda ke da ɗan gajeren tsayin rami, suna ƙara VDS ta yadda magudanar ruwa a cikin An fadada yankin magudanar ruwa zuwa yankin maɓuɓɓugar ruwa, wanda ya sa tsawon tashar ya zama sifili, wato, don samar da shigar da magudanar ruwa, shigar, mafi yawan dillalan da ke yankin tushen za su kasance masu jan hankali kai tsaye ta hanyar wutar lantarki na Layer depletion. yankin magudanar ruwa, wanda ya haifar da babban ID.

4, Ƙofar rushewar wutar lantarki BVGS

Lokacin da ƙãra ƙarfin ƙofar, VGS lokacin da IG ya karu daga sifili ana kiran shi BVGS rushewar wutar lantarki.

5,Ƙananan mitar transconductance

Lokacin da VDS ta kasance ƙayyadaddun ƙima, rabon microvariation na magudanar ruwa zuwa microvariation na ƙarfin wutar lantarki na ƙofar da ke haifar da canjin ana kiransa transconductance, wanda ke nuna ikon ƙarfin tushen ƙofar don sarrafa magudanar ruwa, kuma shine mahimmancin siga wanda ke nuna ƙarfin haɓakawa naMOSFET.

6, kan juriya RON

On-resistance RON yana nuna tasirin VDS akan ID, shine juzu'in gangaren layin tangent na halayen magudanar ruwa a wani wuri, a cikin yankin jikewa, ID kusan baya canzawa tare da VDS, RON babban girma ne. darajar, gabaɗaya a cikin dubun kilo-Ohms zuwa ɗaruruwan kilo-Ohms, saboda a cikin da'irori na dijital, MOSFETs galibi suna aiki a cikin yanayin VDS mai gudanarwa = 0, don haka a wannan lokacin, RON-kan-juriya ana iya ƙididdige shi ta asalin RON zuwa ƙima, don MOSFET gabaɗaya, ƙimar RON a cikin 'yan ohms ɗari.

7, iyawar inter-polar capacitance

Interpolar capacitance wanzu tsakanin uku electrodes: ƙofar tushen capacitance CGS, ƙofar magudanar capacitance CGD da magudanar ruwa capacitance CDS-CGS da CGD ne game da 1 ~ 3pF, CDS ne game da 0.1 ~ 1pF.

8,Matsakaicin amo mara ƙarancin mitar

Ana haifar da hayaniya ta rashin daidaituwa a cikin motsin masu ɗaukar kaya a cikin bututun. Saboda kasancewarsa, rashin daidaiton ƙarfin lantarki ko bambance-bambancen halin yanzu suna faruwa a wurin fitarwa ko da babu siginar da amplifier ke bayarwa. Ayyukan amo yawanci ana bayyana su ta cikin ma'aunin amo na NF. Naúrar ita ce decibel (dB). Karancin ƙimar, ƙarancin ƙarar bututun yana samarwa. Matsakaicin ƙararrakin ƙararrakin ƙarar ƙararrawa shine yanayin amo wanda aka auna a cikin ƙananan mitoci. Matsakaicin amo na bututun tasirin filin kusan ƴan dB ne, ƙasa da na na'urar triode bipolar.