The ngbanwe ike ripple bụ ihe a na-apụghị izere ezere. Nzube kachasị anyị bụ ibelata mpụta mpụta n'ọkwa dị ike. Ihe ngwọta kachasị mkpa iji nweta nzube a bụ iji zere ọgbọ nke ripples. Mbụ Na ihe kpatara ya.
Site na ngbanwe nke SWITCH, nke dị ugbu a na inductance L na-agbanwekwa elu na ala na uru bara uru nke mmepụta ugbu a. Ya mere, a ga-enwekwa ripple nke bụ otu ugboro dị ka Switch na njedebe mmepụta. N'ozuzu, ripples nke riber na-ezo aka na nke a, nke metụtara ikike nke mmepụta capacitor na ESR. Ugboro nke ripple a bụ otu ihe na-enye ọkụ na-agbanwe, yana ọnụọgụ iri na iri na narị kHz.
Na mgbakwunye, Switch na-ejikarị transistor bipolar ma ọ bụ MOSFET. N'agbanyeghị nke ọ bụ, a ga-enwe ịrị elu na mbelata oge mgbe agbanyere ya ma nwụọ. N'oge a, a gaghị enwe mkpọtụ na sekit nke bụ otu oge na-abawanye dị ka Switch na-ebilite mbelata oge, ma ọ bụ ugboro ole na ole, na n'ozuzu iri nke MHz. N'otu aka ahụ, diode D na-agbake azụ. Sekit kwekọrọ na ya bụ usoro nke ndị na-eguzogide capacitors na inductor, nke ga-eme ka resonance, na ụda ụda bụ iri iri nke MHz. A na-akpọkarị ụda olu abụọ a elu-frequency mkpọtụ, na njupụta na-adịkarị ukwuu karịa mgbịrịgba.
Ọ bụrụ na ọ bụ ihe ntụgharị AC / DC, na mgbakwunye na mgbari abụọ (mkpọtụ), enwerekwa mkpọtụ AC. Ugboro bụ ugboro ntinye ọkụ ọkụ AC, ihe dịka 50-60Hz. Enwekwara mkpọtụ co-mode, n'ihi na ngwaọrụ ike nke ọtụtụ ọkụ ọkụ na-agbanwe na-eji shei dị ka radiator, nke na-emepụta ikike nhata.
Ntụnye nke ngbanwe ike ripples
Ihe ndị bụ isi chọrọ:
Njikọ na oscilloscope AC
Oke bandwidth 20MHz
Kwupu eriri ala nke nyocha
1.AC njikọ bụ iwepu superposition DC voltaji na-enweta ihe ziri ezi waveform.
2. Imeghe njedebe bandwidth 20MHz bụ iji gbochie nnyonye anya nke ụda ụda dị elu ma gbochie njehie ahụ. N'ihi na njupụta nke ihe mejupụtara elu-frequency dị ukwuu, a ga-ewepụ ya mgbe a tụrụ ya.
3. Kpupu obere mkpirisi ala nke nyocha oscilloscope, ma jiri nha nha ala iji belata nnyonye anya. Ọtụtụ ngalaba enweghị mgbanaka ala. Ma tụlee ihe a mgbe ị na-ekpe ikpe ma ò ruru eru.
Isi ihe ọzọ bụ iji ọdụ 50Ω. Dị ka ozi nke oscilloscope si kwuo, modul 50Ω bụ iwepụ akụkụ DC ma tụọ akụkụ AC nke ọma. Agbanyeghị, enwere oscilloscopes ole na ole nwere nyocha pụrụ iche dị otú ahụ. N'ọtụtụ ọnọdụ, a na-eji ihe nyocha sitere na 100kΩ ruo 10MΩ eme ihe, nke na-edoghị anya nwa oge.
Nke a dị n'elu bụ mkpachapụ anya mgbe ị na-atụ ngbanwe ripple. Ọ bụrụ na nyocha oscilloscope ekpughere ya ozugbo na ebe nrụpụta, a ga-eji ahịrị gbagọrọ agbagọ tụọ ya ma ọ bụ eriri coaxial 50Ω.
Mgbe ị na-atụ ụda ụda ugboro ugboro dị elu, igwe oscilloscope zuru oke bụ ọtụtụ narị mega ruo ọkwa GHz. Ndị ọzọ bụ otu ihe ahụ dị n'elu. Ikekwe ụlọ ọrụ dị iche iche nwere ụzọ nyocha dị iche iche. Na nyocha ikpeazụ, ị ga-amarịrị nsonaazụ ule gị.
Banyere oscilloscope:
Ụfọdụ oscilloscope dijitalụ enweghị ike ịlele ripples nke ọma n'ihi nnyonye anya na omimi nchekwa. N'oge a, ekwesịrị dochie oscilloscope. Mgbe ụfọdụ, ọ bụ ezie na bandwit oscilloscope ochie simulation bụ naanị iri puku kwuru iri mega, arụmọrụ dị mma karịa oscilloscope dijitalụ.
Mgbochi nke ngbanwe ike ripples
N'ihi na ịgbanwee ripples, theoretically na n'ezie dị. Enwere ụzọ atọ iji kwụsị ma ọ bụ belata ya:
1. Mụbaa inductance na mmepụta capacitor nzacha
Dị ka usoro nke mgbanwe ọkụ ọkọnọ, ugbu a fluctuation size na inductance uru nke inductive inductance na-aghọ ihe na-agbanwe agbanwe, na mmepụta ripples na mmepụta capacitors na-agbanwe agbanwe. Ya mere, ịba ụba ọkụ eletrik na mmepụta capacitors nwere ike ibelata ripples.
Foto dị n'elu bụ ụdị waveform dị ugbu a na inductor ọkụ na-agbanwe ọkụ L. Ya ripple ugbu a △ m nwere ike gbakọọ site na usoro a:
Enwere ike ịhụ na ịba ụba uru L ma ọ bụ ịba ụba ugboro ugboro nwere ike ibelata mgbanwe mgbanwe dị ugbu a na inductance.
N'otu aka ahụ, mmekọrịta dị n'etiti mpụta ripples na mmepụta capacitors: VRIPPLE = IMAX/(CO × F). Enwere ike ịhụ na ịbawanye uru capacitor mmepụta nwere ike ibelata ripple.
Usoro a na-emekarị bụ iji aluminum electrolytic capacitors maka mmepụta mmepụta iji nweta nzube nke nnukwu ikike. Otú ọ dị, electrolytic capacitors adịghị arụ ọrụ nke ọma n'igbochi ụda mkpọtụ dị elu, na ESR dị oke ibu, ya mere ọ ga-ejikọta capacitor seramiiki n'akụkụ ya iji mejupụta enweghị aluminom electrolytic capacitors.
N'otu oge ahụ, mgbe ọkụ eletrik na-arụ ọrụ, VIN voltaji nke ntinye ntinye adịghị agbanwe agbanwe, mana mgbanwe dị ugbu a na mgba ọkụ. N'oge a, ntinye ike ntinye adịghị enye olulu mmiri dị ugbu a, na-adịkarị nso na ntinye ntinye ugbu a (na-ewere ụdị buck dị ka ihe atụ, dị nso na Switch), ma jikọta ikike iji nye ugbu a.
Mgbe etinyere ihe mgbochi a, a na-egosi ihe ọkụ ọkụ Buck na foto dị n'okpuru:
Ụzọ a dị n'elu bụ naanị ibelata ripples. N'ihi oke olu, inductance agaghị adị nnukwu; mmepụta capacitor na-abawanye ruo n'ókè ụfọdụ, ọ dịghịkwa mmetụta doro anya na ibelata ripples; mmụba nke ugboro ngbanwe ga-eme ka mfu ngbanwe. Ya mere, mgbe ihe ndị a chọrọ siri ike, usoro a adịghị mma.
Maka ụkpụrụ nke ịgbanye ọkụ ọkụ, ị nwere ike na-ezo aka na ụdị dị iche iche nke ịgbanwee ike imepụta akwụkwọ ntuziaka.
2. Nzacha ọkwa abụọ bụ ịgbakwunye ihe nzacha LC nke mbụ
Mmetụta mgbochi nke nzacha LC na mkpọtụ mkpọtụ bụ ihe doro anya. Dị ka ugboro ripple ga-ewepụ, họrọ kwesịrị ekwesị inductor capacitor na-etolite nzacha sekit. N'ozuzu, ọ nwere ike ibelata ripples nke ọma. N'okwu a, ịkwesịrị ịtụle isi ihe nlele nke voltaji nzaghachi. (Dị ka egosiri n'okpuru)
A na-ahọrọ ebe nlele tupu nzacha LC (PA), na voltaji mmepụta ga-ebelata. N'ihi na inductance ọ bụla nwere nkwụsị nke DC, mgbe enwere mmepụta ugbu a, a ga-enwe ụda voltaji na inductance, na-eme ka mbelata mmepụta voltaji nke ike ọkụ. Na nke a voltaji dobe na-agbanwe na mmepụta ugbu a.
A na-ahọrọ ebe nlele mgbe LC filter (PB), nke mere na voltaji mmepụta bụ voltaji anyị chọrọ. Otú ọ dị, a na-ewebata inductance na capacitor n'ime usoro ike, nke nwere ike ime ka usoro ahụ gharazie ike.
3. Mgbe mmepụta nke ọkụ ọkụ na-agbanwe, jikọọ LDO nzacha
Nke a bụ ụzọ kachasị dị irè isi belata ripples na mkpọtụ. Mpụta voltaji na-adịgide adịgide na ọ dịghị mkpa ịgbanwe usoro nzaghachi mbụ, ma ọ bụkwa ọnụ ahịa kachasị ọnụ - dị irè na ike kachasị elu.
LDO ọ bụla nwere ihe nrịbama: oke mkpochapụ mkpọtụ. Ọ bụ usoro ugboro-DB, dị ka egosiri na ọnụ ọgụgụ dị n'okpuru bụ akụkụ nke LT3024 LT3024.
Mgbe LDO gasịrị, mgbanaka ngbanwe na-adịkarị n'okpuru 10mV. Ọnụ ọgụgụ na-esonụ bụ ntụnyere nke ripples tupu na mgbe LDO gasịrị:
E jiri ya tụnyere mgbanaka nke ọnụ ọgụgụ dị n'elu na ebili mmiri dị n'aka ekpe, a pụrụ ịhụ na mmetụta mgbochi nke LDO dị ezigbo mma maka ntụgharị nke ọtụtụ narị KHz. Ma n'ime oke ọnụọgụ dị elu, mmetụta nke LDO adịghị mma.
Belata ọgbaghara. Igwe PCB nke ọkụ ọkụ na-agbanwe dịkwa oke egwu. Maka ụda ụda dị elu, n'ihi nnukwu ugboro ugboro nke ugboro ugboro, ọ bụ ezie na nzacha post-stage nwere mmetụta ụfọdụ, mmetụta ahụ adịghị anya. Enwere ọmụmụ ihe pụrụ iche na nke a. Ụzọ dị mfe bụ ịnọ na diode na capacitance C ma ọ bụ RC, ma ọ bụ jikọọ inductance na usoro.
Ọnụ ọgụgụ dị n'elu bụ sekit yiri nke diode n'ezie. Mgbe diode dị elu-ọsọ, a ga-atụle parasitic parasitic. N'oge mgbake nke diode ahụ, inductance nhata na ikike nhata ghọrọ oscillator RC, na-emepụta oscillation ugboro ugboro. Iji gbochie oscillation a dị elu, ọ dị mkpa ijikọ capacitance C ma ọ bụ RC buffer network na nsọtụ abụọ nke diode. Nguzogide bụ n'ozuzu 10Ω-100 ω, na capacitance bụ 4.7PF-2.2NF.
Enwere ike ikpebi ikike C ma ọ bụ RC dị na diode C ma ọ bụ RC site na nnwale ugboro ugboro. Ọ bụrụ na ahọpụtaghị ya nke ọma, ọ ga-eme ka ọzịza dị njọ karịa.
Oge nzipu: Jul-08-2023
