Dab tsi yog step-down switching power supply
Cia peb tham luv luv txog lub hauv paus ntsiab lus ntawm kev ua haujlwm ntawm cov kauj ruam-down switching fais fab mov: lub Circuit Court yog tsim los ntawm kev hloov (transistor lossis field effect tube nyob rau hauv qhov tseeb Circuit Court), lub freewheeling diode, lub zog cia inductor, thiab lim capacitor.
Thaum lub qhov hluav taws xob kaw, lub hwj huam mov muab lub zog rau lub load los ntawm kev hloov thiab lub inductor, thiab khaws ib feem ntawm lub zog hluav taws xob hauv inductor thiab capacitor. Vim yog tus kheej-inductance ntawm inductance, tom qab qhov hloov pauv tau qhib, tam sim no maj mam nce, uas yog, cov zis tsis tuaj yeem ncav cuag tus nqi hluav taws xob tam sim ntawd.
Tom qab qee lub sijhawm, qhov hloov pauv tau raug kaw, thiab vim yog tus kheej-inductance ntawm inductor (nws tuaj yeem muab piv rau qhov pom tau tias tam sim no hauv inductor muaj qhov cuam tshuam inertial), tam sim no hauv Circuit Court yuav tsis hloov pauv, uas yog, txuas ntxiv ntws los ntawm sab laug mus rau sab xis. Qhov tam sim no ntws los ntawm lub load, rov qab los ntawm av xaim, ntws mus rau lub anode ntawm lub freewheeling diode, hla lub diode, thiab rov qab mus rau sab laug kawg ntawm inductor, yog li tsim ib lub voj.
Los ntawm kev tswj xyuas thaum lub kaw lus kaw thiab qhib (piv txwv li PWM - Pulse Width Modulation), cov zis hluav taws xob tuaj yeem tswj tau. Yog hais tias lub sij hawm rau thiab tawm yog tswj los ntawm kev kuaj xyuas cov zis voltage kom cov zis voltage tas li, lub hom phiaj ntawm kev tswj voltage yog tiav.
Cov khoom siv hluav taws xob zoo sib xws thiab cov khoom siv hluav taws xob hloov pauv muaj tib lub ntsuas hluav taws xob hloov kho, uas siv cov lus qhia tawm tswv yim los tswj qhov voltage. Qhov txawv yog tias qhov hloov hluav taws xob hloov hluav taws xob siv lub raj xa hluav taws xob hloov kho, thiab cov khoom siv hluav taws xob zoo tib yam feem ntau siv cov kab hluav taws xob hauv cheeb tsam ntawm triode los kho. Nyob rau hauv kev sib piv, lub switching fais fab mov muaj tsawg zog noj, ntau yam ntawm daim ntawv thov rau AC voltage, thiab ib tug zoo ripple coefficient ntawm tso zis DC. Qhov tsis zoo yog switching pulse cuam tshuam.
Lub hauv paus ntsiab lus ntawm kev ua haujlwm tseem ceeb ntawm ib nrab choj hloov hluav taws xob yog qhov hloov pauv ntawm tus choj sab sauv thiab tus choj qis (thaum lub zaus siab, lub raj xa hluav taws xob yog VMOS) tig rau hauv lem. Ua ntej, qhov tam sim no ntws los ntawm kev hloov lub raj ntawm tus choj sab saud. Nyob rau hauv lub kauj, lub hloov raj ntawm tus choj sab sauv yog thaum kawg tua, thiab lub raj hloov ntawm tus choj qis yog qhib, thiab inductance coil thiab capacitor txuas ntxiv muab lub zog rau sab nraud. Tom qab ntawd tua lub qhov hluav taws xob hloov hluav taws xob ntawm tus choj qis dua, thiab tom qab ntawd qhib tus choj sab saud kom cov tam sim no nkag mus, thiab rov ua dua li qhov no, vim tias ob lub raj hloov pauv yuav tsum tau qhib thiab kaw, yog li nws raug hu ua lub zog hloov hluav taws xob. muab.
Cov khoom siv hluav taws xob linear txawv. Txij li thaum tsis muaj kev hloov pauv, cov kav dej sab saud yog ib txwm tso dej tawm. Yog tias muaj dej ntau dhau, nws yuav ntws tawm. Qhov no yog qhov peb feem ntau pom nyob rau hauv ib co linear fais fab mov hloov raj. Lub zog hluav taws xob tsis kawg yog txhua yam hloov mus rau hauv lub zog hluav taws xob. Los ntawm qhov kev pom no, kev hloov pauv kev ua tau zoo ntawm cov khoom siv hluav taws xob linear yog qhov tsawg heev, thiab thaum tshav kub kub, lub neej ntawm cov khoom yog khi kom txo qis, cuam tshuam rau kev siv kawg.
