3-A Synchronous Step-Down Down Voltage Converter Isekethe edityanisiweyo IC LMR33630BQRNXRQ1

1.

Umsebenzi we-buck converter kukunciphisa i-voltage yegalelo kwaye uyifanise nomthwalo.I-topology esisiseko ye-buck converter iquka umtshintshi oyintloko kunye ne-diode switch esetyenziswe ngexesha lekhefu.Xa i-MOSFET iqhagamshelwe ngokunxuseneyo ne-continuity diode, ibizwa ngokuba yi-synchronous buck converter.Ukusebenza kobu buck converter uyilo kuphezulu kunolo lwabaguquli bebhaka bangaphambili ngenxa yoqhagamshelo olungqameneyo lweMOSFET ekwicala elisezantsi kunye ne-Schottky diode.Umzobo woku-1 ubonisa iskimu somguquleli webhanti we-synchronous, olona yilo luqhelekileyo olusetyenziswa kwi-desktop kunye ne-notebook computer namhlanje.

2.

Indlela yokubala esisiseko

I-transistor itshintsha i-Q1 kunye ne-Q2 zombini i-N-channel yamandla e-MOSFETs.ezi MOSFET zimbini zidla ngokubizwa ngokuba zizitshixo ezikwicala eliphezulu okanye ezisezantsi kwaye iMOSFET ekwicala elisezantsi iqhagamshelwe ngokunxuseneyo neSchottky diode.Ezi MOSFET zimbini kunye ne-diode zenza ijelo lamandla eliphambili lomguquli.Ilahleko kula macandelo ikwayinxalenye ebalulekileyo yelahleko iyonke.Ubungakanani bemveliso ye-LC yokucoca inokumiselwa yi-ripple current kunye ne-ripple voltage.Ngokuxhomekeke kwi-PWM ethile esetyenzisiweyo kwimeko nganye, uthungelwano lwe-resistor ye-R1 kunye ne-R2 inokukhethwa kwaye ezinye izixhobo zinomsebenzi wokucwangcisa ingqiqo yokuseta i-voltage ephumayo.I-PWM kufuneka ikhethwe ngokwenqanaba lamandla kunye nokusebenza okusebenzayo kwifrikhwensi efunwayo, okuthetha ukuba xa ubuninzi bezandiso zonyuswa, kufuneka kubekho isakhono esaneleyo sokuqhuba ukuqhuba amasango e-MOSFET, enza elona nani lincinane lamacandelo afunekayo. kumguquli osemgangathweni webhaka ohambelanayo.

Umyili kufuneka aqale ajonge iimfuno, oko kukuthi igalelo le-V, imveliso ye-V kunye nemveliso ye-I kunye neemfuno zobushushu bokusebenza.Ezi mfuno zisisiseko ziye zidityaniswe nokuhamba kwamandla, ukuphindaphinda, kunye neemfuno zobungakanani bomzimba ezifunyenweyo.

3.

Indima ye-buck-boost topology

I-Buck-boost topologies iyasebenza kuba igalelo lombane linokuba lincinci, libe likhulu, okanye lifane nombane ophumayo ngelixa lifuna amandla aphumayo angaphezu kwama-50 W. Kumandla aphumayo angaphantsi kwe-50 W, i-converter yokuqala ye-inductor (SEPIC) ) lukhetho olungabizi kakhulu njengoko lusebenzisa amacandelo ambalwa.

Iziguquli ze-Buck-boost zisebenza kwimowudi ye-buck xa i-voltage yegalelo inkulu kune-voltage ephumayo kwaye ikwimo yokunyusa xa i-voltage yegalelo ingaphantsi kombane wokuphuma.Xa isiguquli sisebenza kwindawo yothumelo apho amandla ombane akhoyo akuluhlu lwamandla ombane, kukho iikhonsepthi ezimbini zokujongana nezi meko: nokuba ibuck kunye nenqanaba lokunyusa liyasebenza ngaxeshanye, okanye imijikelo yokutshintsha iyatshintshana phakathi kwebhanti. kunye nezigaba zokunyusa, ngalinye lihlala lisebenza kwisiqingatha sesiqhelo sokutshintsha okuqhelekileyo.Umbono wesibini unokubangela ingxolo engaphantsi kwe-harmonic kwisiphumo, ngelixa ukuchaneka kwe-voltage ephumayo kunokuchaneka kancinane xa kuthelekiswa ne-buck eqhelekileyo okanye i-boost operation, kodwa umguquli uya kusebenza ngakumbi xa kuthelekiswa nombono wokuqala.