AN051 Zaɓin Capacitor Input MP2130
Bayanin samfur
Jagorar Zaɓin Capacitor na shigarwa don MP2130
MP2130 mai jujjuya yanayin saukowa mataki ɗaya ne wanda ya zo tare da MOSFETs na ciki. Yana iya samar da 3.5A ci gaba da fitarwa na yanzu tare da kyakkyawan kaya da tsarin layi daga 2.7V-to-6Vtage. Na'urar tana da fasalin fasalin farawa mai laushi wanda ke taimakawa ramp sama fitarwa voltage a ƙimar kisa mai sarrafawa, yana hana overshoot a farawa. MP2130 kuma ya haɗa da lokacin tsayawa mai laushi na yawanci 1ms lokacin da aka kashe, wanda r.amps saukar da tunani na ciki, don haka a layi layi yana fitar da fitarwa.
Abtract
Wannan bayanin kula na aikace-aikacen yana ba da jagora don zaɓar madaidaicin ƙarfin shigarwa don MP2130. Yana bayyana tushen overshoots kuma yana ba da hanya don zaɓar madaidaicin ƙarfin shigar da bayanai don kare IC daga overvol.tage lalacewa.
Me yasa Overshoot Voltage Yana faruwa
Overshoot voltage yana faruwa saboda kwatsam fitar da inductor halin yanzu a lokacin taushi-tasha. Don hana wuce gona da iritage lalacewa, babban shigar da capacitor zai iya sha overshoot voltage.
Zaɓin Madaidaicin Ƙarfin Shigarwa
Don tabbatar da cewa halin yanzu na LS-FET bai wuce iyakar halin yanzu mara kyau ba, yi amfani da matsakaicin ƙimar don ƙididdige halin yanzu inductor. Idan mummunan inductor na halin yanzu ya kasa da iyakar halin yanzu, to fitarwa voltage za a iya daidaita shi daga ƙimar ƙima zuwa 0V a cikin ƙayyadadden lokacin tsayawa mai laushi. A lokacin tasha mai laushi, ƙididdige mafi ƙarancin inductor na yanzu ta amfani da ma'aunin da aka bayar a cikin jagorar.
Umarnin Amfani da samfur: Jagorar Zaɓin Capacitor na shigarwa don MP2130
Don zaɓar capacitor mai dacewa da shigarwa don MP2130:
- Karanta littafin a hankali don fahimtar tushen overshoot voltage da buqatar shigar capacitor.
- Yi ƙididdige matsakaicin ƙimar inductor na yanzu don tabbatar da cewa halin yanzu na LS-FET bai wuce iyakar halin yanzu mara kyau ba.
- Yi ƙididdige ƙarancin inductor mara kyau na halin yanzu yayin tsayawa mai laushi ta amfani da lissafin da aka bayar a cikin jagorar.
- Zaɓi capacitor na shigarwa wanda zai iya ɗaukar overshoot voltage da kuma saduwa da ƙaramin ƙarfin ƙarfin da aka ba da shawarar a cikin littafin.
- Shigar da capacitor na shigarwa bisa ga umarnin masana'anta.
Ta bin waɗannan matakan, zaku iya zaɓar madaidaicin shigarwar shigarwa don MP2130 wanda ke kare IC daga wuce gona da iri.tage lalacewa kuma yana tabbatar da aiki mai kyau na na'urar.
GASKIYA
Tushen dalilin voltage overshoot akan fil ɗin shigarwa yayin tasha mai laushi da yadda ake zaɓar capacitor na shigarwa an gabatar da su a cikin wannan bayanin kula. Ƙarƙashin nauyi-haske da babban-fitarwa – capacitor yanayin, buck IC yana aiki a cikin yanayin tsayawa mai laushi kuma yana iya zama azaman da'irar haɓakawa mara kyau. Wannan bayanin kula na aikace-aikacen yana bayyana yadda ake zaɓar capacitor mai shigar da ya dace don ɗaukar makamashi daga madaidaitan abubuwan fitarwa don hana shigarwar overvol.tage. Hakanan yana da amfani ga sauran sassan Buck tare da aikin tsayawa mai laushi.
Jagorar Zaɓin Capacitor na shigarwa don MP2130
MP2130 mai jujjuya yanayin saukowa mataki ɗaya ne tare da ginanniyar ƙarfin ciki MOSFETs. Yana samun ci gaba da fitarwa na 3.5A na yanzu daga 2.7V-zuwa-6Vtage tare da kyakkyawan kaya da tsarin layi. MP2130 yana da ginanniyar farawa mai laushi wanda ramps sama da fitarwa voltage a ƙimar kisa mai sarrafawa, guje wa overshoot a farawa. Lokacin da aka kashe, MP2130 ramps saukar da tunani na ciki don haka a layi layi yana fitar da fitarwa. Lokacin taushi-tsayawa yawanci kusan 1ms.
A lokacin tasha mai laushi, MOSFET ƙananan gefe na ciki yana canzawa don sarrafa adadin kashe wutar lantarki.tage wanda ke biye da tunani na ciki. Ƙarƙashin nauyi-haske da babban-fiti-fiti- capacitor yanayin, babban gefen MOSFET ya kusan kashewa yayin aikin tasha mai laushi. Ƙarfin da aka adana a cikin capacitor na fitarwa yana canjawa zuwa capacitor na shigarwa ta hanyar inductor. Topology yana canzawa zuwa mai canzawa mai haɓakawa tare da babban gefen MOSFET yana aiki azaman diode parasitic, kamar yadda aka nuna a hoto 1. Ƙarfafa vol.tage yana haifar da wuce gona da iri akan capacitor na shigarwa; wani lokacin wannan overshoot ya wuce cikakken iyakar voltage (VABS) na fil ɗin shigarwa kuma yana iya lalata IC. Don hana hakan, ƙara ƙimar ƙarfin shigarwa don ɗaukar wannan makamashi kamar yadda wannan jagorar zaɓin capacitor ɗin shigarwa yake.
GABATARWA
Wasu aikace-aikace na musamman ko matakan gwaji suna buƙatar fitarwa voltage don faɗuwa a ƙayyadaddun adadin na ƙayyadadden lokaci ana kashe: Wannan fasalin ana kiransa taushi-tasha. Yawancin lokaci, wannan aikin yana haifar da fitarwa voltage don faɗuwa da kyau, kwatankwacin farawa mai laushi. Dole ne a kula da nauyi mai sauƙi da babban yanayin capacitor na fitarwa saboda ana iya samun juzu'i mai yawatage akan fil ɗin shigarwa wanda wannan al'amari ya haifar. Don kare IC daga lalacewa ta wannan overshoot, na'urar shigar da bayanai yana buƙatar ƙarawa don ɗaukar wannan abin da ya wuce.
ME YA SA YA WUCE WUTATAGE YAKE FARUWA
Hoto na 1 yana nuna canjin topology yayin tsayawa mai laushi. A lokacin tasha mai laushi, MOSFET mai ƙananan gefe na ciki (LS-FET) tana canzawa don sarrafa adadin kashe wutar fitarwa.tage, wanda ke biye da tunani na ciki. Ƙarƙashin nauyi-haske da babban yanayin ƙarfin fitarwa, babban gefen MOSFET ya kasance a kunne na ɗan gajeren lokaci na lokacin tsayawa mai laushi. Lokacin da LS-FET ke juyawa, inductor na yanzu yana farawa daga capacitor na fitarwa zuwa fil ɗin SW. Abubuwan da ake fitarwa CO1 da CO2, inductor L, LS-FET, diode diode D1, da shigar da capacitor CIN sun zama da'ira mai haɓakawa. Wannan na iya haifar da voltage akan fil ɗin VIN don tashi da sauri kuma ya wuce gona da iri, kamar yadda aka nuna a cikin Hoto 2. Don kare IC daga overvol.tage lalacewa, yi amfani da babban ƙarfin shigar da bayanai don ɗaukar overshoot.
ZABEN MAGANAR DA YA DACE
a. LS-FET na yanzu ba zai iya ƙetare iyaka na yanzu mara kyau ba
Don sauƙaƙe bincike, yi amfani da matsakaicin ƙima don ƙididdige inductor na halin yanzu. Idan inductor mara kyau na halin yanzu bai wuce iyakar halin yanzu ba, to abin fitarwa voltage za a iya daidaita shi daga ƙimar ƙima zuwa 0V a cikin ƙayyadadden lokacin tsayawa mai laushi. Kuna iya komawa zuwa Hoto 2. A lokacin tausasawa, kimanta mafi ƙarancin inductor na yanzu ta amfani da lissafin da ke ƙasa:
Inda INeg shine mafi ƙarancin inductor na yanzu,
- OC shine capacitor na fitarwa,
- OV shine fitarwa voltage,
- SStopt shine lokacin tsayawa mai laushi.
A karkashin wannan yanayin, duk makamashin da aka adana a cikin capacitor na fitarwa yana canjawa zuwa capacitor na shigarwa. Yi la'akari da asarar tafiyarwa akan inductor, MOSFET ƙananan gefe (LS-FET) da diode parasitic, ƙididdige ƙimar 80% na haɓaka haɓakawa. Don haka ana iya ƙididdige makamashin da aka canjawa wuri ta wurin lissafin ƙasa:
Inda WBoost shine makamashin da aka canjawa wuri.
Don ɗaukar wannan makamashi da kare IC, shigarwar yanzu voltage plus da overshoot voltage ba zai iya wuce VABS akan fil ɗin shigarwa ba. Za a iya ƙididdige mafi ƙarancin ƙarfin shigar da ake buƙata a ƙasa:
Inda CIN(Min) shine mafi ƙarancin ƙarfin shigarwa, kuma VABS shine madaidaicin ƙimar shigarwar fil.
b. LS A halin yanzu Ya Wuce Ƙirar Ƙarya na Yanzu
Wani lokaci makamashin da aka adana a cikin capacitor na fitarwa yana da girma sosai (lokacin da fitarwa voltage yana da girma, ko ƙarfin fitarwa yana da girma, ko duka biyu). IC ba za ta iya tsara fitarwa voltage ta amfani da tunani na ciki a lokacin tasha mai laushi saboda ƙarancin ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun LS-FET yana hana babban aiki na yanzu. A cikin wannan halin da ake ciki, fitarwa voltage baya faɗuwa zuwa sifili yayin tsayawa mai laushi kuma inductor na halin yanzu yana iyakance da ƙarancin halin yanzu na LS-FET, kamar yadda aka nuna a Hoto 3.
Capacitor mai fitarwa yana fitarwa a iyakar halin yanzu. Idan capacitor na fitarwa ya wuce CO (Max), inductor na yanzu yana iyakance zuwa:
Inda CO (Max) shine ƙimar iyaka wanda inductor ke gudana a mummunan iyaka;
INeg_Lim shine madaidaicin iyakar LS-FET.
Hoto na 3 kuma yana nuna sauƙaƙan yanayin canja wuri idan halin yanzu ya kai mummunan iyakar halin yanzu. A cikin wannan yanayin, nutsewar halin yanzu mai ƙimar daidai da ƙarancin halin yanzu yana fitar da capacitor na fitarwa. Idan aka yi la'akari da asarar gudanarwa akan inductor, LS-FET, da diode parasitic, ƙididdige ƙimar haɓaka-mai canza canji na 80%. Sannan ana iya lissafin makamashin da aka canjawa wuri a ƙasa:
Ana iya ƙididdige mafi ƙarancin ƙarfin shigar da ake buƙata yanzu:
EXAMPLE ZANIN
Mai zuwa shine tsohonampLe Input-Capacitor lissafin ta amfani da cikakken zane tsarin da aka bayyana a baya ga MP2130. MP2130 monolithic ne, mai saukowa, mai sauya yanayin canzawa tare da ginanniyar ikon ciki MOSFETs. Yana samun 3.5A ci gaba da fitarwa na halin yanzu daga 2.7V-zuwa-6V shigarwar voltage. Yana da kyawawan kaya da tsarin layi. Lissafin sun dogara ne akan sigogi masu zuwa:
- VABS = 6.5V
- INeg_Lim=2.5A
- tSStop=1ms
- VIN=4.5V
- VO=3.3V
- L=1µH
- CO=10µF + 470µF E-Cap.
Na farko, CO_Max an ƙididdige shi bisa Equation (4):
A cikin wannan example, CO ya fi CO_Max ƙarami kuma inductor na yanzu ba zai wuce iyakar halin yanzu mara kyau ba. Yi ƙididdige ƙimar ƙarfin shigarwar shigarwa ta amfani da ma'auni (2) da (3), ko ma'auni (5) da (6). Mafi ƙarancin abin da ake buƙata na shigar da capacitor shine:
Don haka mafi ƙarancin ƙarfin shigarwar ya kamata ya fi girma fiye da 190µF, kuma zai fi dacewa amfani da capacitor 330µF don wannan tsohonample. A ƙasa akwai lanƙwan mafi ƙarancin ƙarfin shigarwa vs. ƙarfin fitarwa na wannan tsohonample.
KAMMALAWA
Tushen shigar da voltage overshoot a lokacin taushi tasha da yadda ake zabar capacitor na shigarwa an gabatar da su a cikin wannan bayanin kula. Ƙarƙashin yanayin nauyi mai haske tare da babban ƙarfin fitarwa, yanayin tsayawa mai laushi na iya aiki azaman da'irar haɓakawa. Wannan bayanin kula na aikace-aikacen yana bayyana yadda ake zaɓar ƙimar ƙarfin shigarwar da ta dace don ɗaukar makamashi daga madaidaitan abubuwan fitarwa. Zane example da hanya kuma suna taimaka wa injiniyoyi su haɓaka mafita masu sauƙi dangane da ƙimar ƙarfin fitarwa daban-daban.
SANARWA: Bayanin da ke cikin wannan takarda yana iya canzawa ba tare da sanarwa ba. Masu amfani yakamata su ba da garanti da ba da garantin cewa ba a keta haƙƙin mallaka na ɓangare na uku yayin haɗa samfuran MPS cikin kowace aikace-aikace. MPS ba za ta ɗauki kowane alhaki na doka ba na kowace aikace-aikacen da aka faɗi.
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