Mosfet - abin da yake da shi? Tsarin da fasaha fasali

A wannan labarin, za ka koyi game da wannan kashi a matsayin mosfet. Wannan shi ne, abin da kaddarorin, wanda aka yi amfani da zamani a Electronics, za a tattauna a kasa. Za ka iya samun iri biyu ikon transistors - MOSFET da IGBT. Suna amfani da pulsed high ikon converters - inverters, ikon kayayyaki. Ya kamata la'akari da duk na fasali na wadannan abubuwa.

asali bayanai

Ya kamata a lura da cewa IGBT da mosfet transistors iya ba da wani sosai high ikon zuwa load. A duk wannan na'urar bayyana su zama sosai a cikin kananan size. Yadda ya dace ya wuce transistors da dabi'u na 95%. A mosfet da IGBT da abu daya a cikin kowa - da suka yi shutters ware, sakamako - alaka iko sigogi. Korau da zazzabi coefficient na wadannan na'urorin da cewa ba irin transistors zama resistant zuwa short haihuwarka. Don nema mosfety da bisa al'ada obalodi lokaci darajar samar da kusan duk kamfanoni.

Drivers for management

Tun da babu wani halin yanzu a cikin iko kewaye, a wani a tsaye yanayin, ba za ka iya amfani da daidaitattun makirci. Shi ya sa mafi ji don amfani na musamman direban - wani hadedde kewaye. Mutane da yawa kamfanonin tsirar na'urorin da cewa ba ka damar gudanar da guda ikon transistors, kazalika da gadoji da kuma rabin mil (uku-lokaci da kuma biyu-lokaci). Za su iya yin wani iri-iri na goyon bayan ayyuka - don kare da overcurrent ko gajarta da'ira, kazalika da manyan ƙarfin lantarki digo a cikin mosfet direban kewaye. Abin da irin kewaye da za a tattauna a more daki-daki a kasa. Ya kamata a lura da cewa irin ƙarfin lantarki drop fadin ikon transistor iko kewaye - wannan shi ne mai matukar hatsari sabon abu. Iko mosfety iya canza zuwa wani aiki yanayin (mikakke), don haka da cewa zai kāsa. Crystal transistor overheats da konewa daga.

laifi yanayin

Home mataimaki aiki direbobi - yana da overcurrent kariya. Wajibi ne a duba a hankali da ikon transistor aiki a daya daga cikin halaye - short-kewaye. Overcurrent iya faruwa ga kowane dalili, amma ya fi kowa - kewaye da kaya ko a jiki. Saboda haka, ya kamata ka yadda ya kamata yi management mosfetami.

Overloading auku saboda wasu siffofin na kewaye. Zai yiwu faru na mai shudewa ko kuma baya da dawo da halin yanzu da wani semiconductor diode transistor kafadu. Kau da irin obalodi faruwa kewaye zane Hanyar. Used sarkar kafa hanya (snubbers), da za'ayi a cikin resistor selection ƙofar iko kewaye da aka ware daga high ƙarfin lantarki da kuma na yanzu hula.

Kamar yadda transistor jũya a kan lokacin da wani laifi na faruwa a load

Lokacin da wani laifi na faruwa a cikin kaya, yanzu a tara kewaye da aka iyakance zuwa wani irin ƙarfin lantarki a ƙofar, da kuma transconductance halaye na transistor. Da wadata da kewaye haka yana da wani damar, don haka da ciki juriya na tushen kanta ba zai iya exert da tasiri a kan gajarta da'ira halin yanzu. Da zarar da canji ya auku, a cikin transistor halin yanzu damar hankali ya fara faruwa, saboda akwai parasitic inductance a tara kewaye. Wannan hujja ne dalilin da cewa akwai wani irin ƙarfin lantarki tsoma.

ƙarya galaba

Bayan mika mulki da aka gama, to da ikon transistor ne cikakken amfani da ƙarfin lantarki. Wannan zai kai ga cewa mafi yawan na da ikon za a dissipated a semiconductor crystal. Yana iya ƙarasa da cewa short-kewaye yanayin ne tabbatar da za a katse bayan wani lokaci. Ya kamata a isa ya kawar da ƙarya da ƙararrawa. Yawanci, a lokacin da yake a cikin kewayon 1 ... 10 microseconds. transistor halaye dole kamar yin tsayayya da obalodi sauƙi.

Load gajarta da'ira a lokacin da transistor

Hakazalika da hali tattauna a sama, a halin yanzu da aka iyakance da halaye na transistor. Ya ke tsiro a wani kudi wanda aka ƙaddara da inductance (parasitic). Kafin wannan halin yanzu ya kai wani m kwari-jihar darajar, da harajin ƙarfin lantarki zai kara. Ƙofar ƙarfin lantarki ta ƙara saboda da Miller sakamako.

A halin yanzu a tara ƙaruwa, kuma shi zai iya ƙwarai ƙetare kwari-jihar darajar. Shi ne wannan yanayin da aka bayar ba kawai cewa tashar mosfet ke a kashe, amma kuma shi ne yiwuwar cikin irin ƙarfin lantarki da iyaka.

A irin ƙarfin lantarki amfani da Ƙofar transistor dogara kai tsaye takaice kewaye halin yanzu. Amma tare da wani karu a ƙofar ƙarfin lantarki na semiconductor kashi ne fairly ban sha'awa hoton. Jikewa ƙarfin lantarki ta ƙara da kuma matsayin sakamako, madugu asarar da aka ƙara. Stability na gajarta da'ira transistor ne a hankali alaka da steepness na da halaye.

RS da kuma na yanzu karawa factor

A mafi girma KU a mosfetov halin yanzu, ƙananan jikewa ƙarfin lantarki. Su ma iya yin tsayayya short lokaci obalodi. A daya hannun, semiconductors, wanda sun fi resistant zuwa short haihuwarka da sosai high jikewa ƙarfin lantarki. Asarar da da ma tana da muhimmanci.

A ya fi girma matsakaicin darajar da gajeren kewaye halin yanzu yana da majagaba mosfet fiye da sauki bipolar transistor. Yawanci, shi ne sau goma maras muhimmanci halin yanzu darajar (bayar da ƙofar ƙarfin lantarki halal ne). Mafi yawa daga cikin masana'antun (Turai da Asiya) tsirarwa transistors cewa za su iya jure irin kãyan nauyinsu, kuma ba su lalace.

kare direban daga high-gefen obalodi

Akwai hanyoyi daban-daban domin obalodi tafiya abubuwa. Da taimakon direbobi daga daban-daban masana'antun iya yi wani m ayyuka, mafi m hanya. Idan wani obalodi wajibi ne don rage ƙofar ƙarfin lantarki. A wannan yanayin, da amincewa da gaggawa aiki lokaci ƙaruwa.

Wannan results don kawar da ƙarya triggering kariya haihuwarka. Ga yadda za a duba mosfet: kokarin canza capacitance na capacitor. Idan ka canza martani lokaci zuwa takaice kewaye, dukan kewaye da aka aiki daidai. A kewaye amfani da dama abubuwa da cewa suna da wani nauyi. Alal misali, guda biyu zuwa wani direban, "ɓatar da" ka damar sanin lokaci-capacitor obalodi analysis.

gaggawa aiki

Wannan lokaci tazara da aka sanya m halin yanzu sharuddan sauyawa kewaye a tara kewaye. Wannan ba wani irin ƙarfin lantarki drop a ƙofar semiconductor kashi. A wannan yanayin, idan akwai wata gushẽwa na obalodi, da transistor an akshe bayan 10 ms. Kariya ne kashe bayan za a iya cire daga shigar sigina. Tare da wannan yi jawo kariya kewaye.

Lokacin shi ne amfani, shi wajibi ne don kula da su tsawon lokaci, ta hanyar abin da reclosing mosfet transistor. Wane irin ya sauya sheka a kuma abin da su ne siffofin? Ka lura da cewa wannan lokacin ya zama mafi girma daga thermal lokaci m (lokaci) na semiconductor guntu a kan wanda wani transistor ne kerarre.

Disadvantages na kewaye

A kewaye resistors an yi amfani da cewa suna da wani babban iya aiki, amma suna da wani sosai high inductance (parasitic, saboda da yin amfani da wasu kayan da kimiyoyi). Kuma ga cikakken aiki na makircinsu wajibi ne cewa ganga ya kasance kusa da sifili. Resistors amfani ga aunawa bugun jini halin yanzu dole ne hadu sama yanayin. A saman resistors an rasa babban iko. Kuma shi rinjayar da yadda ya dace da dukkan high-gefen direba kewaye.

Amma akwai sauya sheka haihuwarka, wanda rage ikon hasãra. jikewa ƙarfin lantarki a kowane hali ya dogara da yanzu haraji. Mosfet (cewa an tattauna a cikin labarin) ya nuna wannan dangantaka, shi za a iya ce mikakke saboda gaskiyar cewa daga transistor magudana halin yanzu ba ya dogara ne a kan tashar juriya (aiki). Amma iko IGBT transistors wannan dangantaka shi ne ba mikakke, amma zaka iya zaɓar da irin ƙarfin lantarki cewa yayi dace da ake bukata yanzu kariya.

Uku-lokaci gada direba

A cikin irin wannan makirci a matsayin amfani da wani resistor aunawa da halin yanzu darajar. kariya yanzu aka ƙaddara ta hanyar wani irin ƙarfin lantarki divider. Tartsatsi shahararsa samu direban IR2130, da samar da wani barga kewaye aiki a voltages up zuwa 600 volts. A kewaye hada da wani filin sakamako irin transistor wanda magudana, aka buɗe (shi hidima don nuna gaban laifinsu). Mosfet saka a kan jirgin, ta hanyar m jumpers a cikin ingantaccen kadaici ga wadannan dalilai. Yana hada da wani amfilifa wanda ya haifar da wani tunani da kuma feedback sakonni. Tare da direba ne kafa ta wani bata lokaci lokaci tsakanin sharuddan sauyawa transistors na ƙananan kuma babba kafadu su hana abin da ya faru na wani ta hanyar halin yanzu.

Kullum, dangane da gyara lokaci na 0.2 ms ... 2. A IR2130 direban ake amfani da su aiwatar da kariya makirci, babu wani aiki na rage matsakaicin darajar ƙofar ƙarfin lantarki a lokacin gajeren kewaye. A ci gaban zamani hannu haihuwarka dole ne a tuna da cewa kashewa na gada auku bayan 1 ms bayan da farkon a takaice kewaye. Sakamakon haka, yanzu (musamman a gaban wani aiki load) ne mafi girma daga darajar da aka lasafta. Don sake saita kariya yanayin da komawa zuwa aiki, shi ya kamata nuna ikon kashe direba ko jerawa na ta bayanai tarewa ƙarfin lantarki.

Low-gefen direbobi

Don samar da iko mosfet transistors na ƙananan hannu, akwai high quality-guntu kamfanonin da Motorola, misali, MS33153. Wannan direban ne na musamman, kamar yadda za a iya samu nasarar amfani ga iri biyu kariya (ƙarfin lantarki da kuma na yanzu). Akwai kuma wani yanayin da ya raba biyu halaye - obalodi da kuma gajeren kewaye. Yana yiwuwa a samar da wani irin ƙarfin lantarki (korau iko). Wannan na da amfani domin lokuta inda shi wajibi ne don yin iko kayayyaki da high iya aiki da kuma isasshe high ƙofar cajin. IGBT kariya yanayin ne naƙasasshe (wannan shi ne mafi kusa analogues mosfetov) bayan da ikon samar da irin ƙarfin lantarki da dama a kasa 11 volts.