xov xwm

Cov ntsiab lus

Inductors yog cov khoom tseem ceeb hauv kev hloov pauv hloov pauv, xws li lub zog cia thiab lub zog lim. Muaj ntau hom inductors, xws li rau kev siv sib txawv (los ntawm tsawg zaus mus rau siab zaus), los yog cov khoom siv sib txawv uas cuam tshuam rau cov yam ntxwv ntawm inductor, thiab lwm yam. Inductors siv nyob rau hauv kev hloov pauv hloov pauv yog cov khoom sib nqus sib nqus siab. Txawm li cas los xij, vim muaj ntau yam xws li cov khoom siv, kev ua haujlwm (xws li voltage thiab tam sim no), thiab qhov kub thiab txias, cov yam ntxwv thiab kev xav tau nthuav tawm txawv heev. Yog li ntawd, nyob rau hauv lub Circuit Court tsim, nyob rau hauv tas li ntawd mus rau lub hauv paus parameter ntawm tus nqi inductance, kev sib raug zoo ntawm impedance ntawm inductor thiab AC tsis kam thiab zaus, cov tub ntxhais poob thiab saturation tam sim no cov yam ntxwv, thiab lwm yam. Kab lus no yuav qhia txog ntau yam tseem ceeb inductor cov ntaub ntawv tseem ceeb thiab lawv cov yam ntxwv, thiab tseem qhia cov kws tsim hluav taws xob xaiv cov khoom lag luam muaj cov qauv inductors.

Ua ntej

Inductor yog ib qho electromagnetic induction tivthaiv, uas yog tsim los ntawm winding ib co coils (coil) ntawm ib tug bobbin los yog core nrog ib tug insulated hlau. Cov kauj no hu ua inductance coil lossis Inductor. Raws li lub hauv paus ntsiab lus ntawm electromagnetic induction, thaum lub kauj thiab lub magnetic teb txav mus rau ib leeg, los yog lub kauj generates ib tug alternating magnetic teb los ntawm ib tug alternating tam sim no, ib tug induced voltage yuav raug generated los tiv thaiv qhov kev hloov ntawm thawj magnetic teb, thiab tus yam ntxwv ntawm kev txwv qhov kev hloov tam sim no yog hu ua inductance.

Cov qauv ntawm inductance tus nqi yog raws li cov qauv (1), uas yog proportional rau magnetic permeability, lub square ntawm winding lem N, thiab sib npaug sib nqus Circuit Court cross-sectional cheeb tsam Ae, thiab yog inversely proportional rau qhov sib npaug magnetic Circuit Court ntev le. . Muaj ntau hom inductance, txhua qhov tsim nyog rau kev siv sib txawv; qhov inductance muaj feem xyuam rau cov duab, qhov loj me, txoj kev winding, tus naj npawb ntawm cov lem, thiab hom khoom sib nqus sib nqus.

(1)

Nyob ntawm cov duab ntawm cov tub ntxhais hlau, cov inductance suav nrog toroidal, E core thiab nruas; Nyob rau hauv cov nqe lus ntawm cov khoom siv hlau, feem ntau yog ceramic core thiab ob hom magnetic mos. Lawv yog ferrite thiab hlau hmoov. Nyob ntawm cov qauv lossis cov txheej txheem ntim khoom, muaj cov hlau qhov txhab, ntau txheej, thiab molded, thiab cov hlau qhov txhab tsis muaj shielded thiab ib nrab ntawm cov hlau nplaum nplaum Shielded (semi-shielded) thiab shielded (shielded), thiab lwm yam.

Lub inductor ua zoo li luv luv Circuit Court tam sim no, thiab nthuav tawm siab impedance rau alternating tam sim no. Cov kev siv yooj yim hauv circuits muaj xws li choking, filtering, tuning, thiab lub zog cia. Nyob rau hauv daim ntawv thov ntawm lub converter hloov, lub inductor yog qhov tseem ceeb tshaj plaws lub zog cia tivthaiv, thiab tsim ib tug tsawg-pass lim nrog cov zis capacitor kom txo tau cov zis voltage ripple, yog li nws kuj plays lub luag hauj lwm tseem ceeb nyob rau hauv lub filtering muaj nuj nqi.

Tsab ntawv xov xwm no yuav qhia txog ntau yam ntaub ntawv tseem ceeb ntawm inductors thiab lawv cov yam ntxwv, nrog rau qee yam ntawm cov yam ntxwv hluav taws xob ntawm inductors, raws li qhov kev ntsuam xyuas tseem ceeb rau kev xaiv inductors thaum tsim hluav taws xob. Nyob rau hauv daim ntawv thov piv txwv, yuav ua li cas xam tus nqi inductance thiab yuav ua li cas xaiv tus qauv muaj nyob rau hauv inductor yuav qhia los ntawm cov qauv siv.

Hom ntawm cov khoom tseem ceeb

Inductors siv nyob rau hauv kev hloov pauv hloov pauv yog cov khoom sib nqus sib nqus siab. Cov khoom tseem ceeb nyob rau hauv qhov chaw feem ntau cuam tshuam rau cov yam ntxwv ntawm inductor, xws li impedance thiab zaus, inductance tus nqi thiab zaus, los yog cov yam ntxwv saturation tseem ceeb. Cov hauv qab no yuav qhia txog kev sib piv ntawm ntau yam khoom siv hlau thiab lawv cov yam ntxwv saturation raws li ib qho tseem ceeb siv rau xaiv lub hwj chim inductors:

1. Ceramic core

Ceramic core yog ib qho ntawm cov khoom siv inductance. Nws yog tsuas yog siv los muab cov qauv txhawb nqa siv thaum winding lub kauj. Nws tseem hu ua "air core inductor". Vim tias cov tub ntxhais hlau siv yog cov khoom siv tsis sib nqus nrog qhov kub tsis tshua muaj coefficient, tus nqi inductance yog qhov ruaj khov heev hauv qhov kub thiab txias. Txawm li cas los xij, vim yog cov khoom tsis sib nqus raws li qhov nruab nrab, qhov inductance tsawg heev, uas tsis haum rau daim ntawv thov ntawm lub zog hloov pauv.

2. Ferrite

ferrite core siv nyob rau hauv dav dav zaus inductors yog ib tug ferrite compound uas muaj nickel zinc (NiZn) los yog manganese zinc (MnZn), uas yog ib tug mos magnetic ferromagnetic khoom uas tsis muaj coercivity. Daim duab 1 qhia txog hysteresis nkhaus (BH voj) ntawm cov tub ntxhais sib nqus dav dav. Lub zog coercive HC ntawm cov khoom siv hlau nplaum kuj hu ua coercive force, uas txhais tau hais tias thaum cov khoom sib nqus tau raug magnetized rau magnetic saturation, nws magnetization (magnetization) txo mus rau xoom Lub zog magnetic teb nyob rau lub sijhawm. Lower coercivity txhais tau hais tias qis tsis kam rau demagnetization thiab kuj txhais tau tias qis hysteresis poob.

Manganese-zinc thiab nickel-zinc ferrites muaj cov txheeb ze permeability (μr), txog 1500-15000 thiab 100-1000, raws li. Lawv lub siab sib nqus permeability ua rau cov tub ntxhais hlau siab dua hauv ib lub ntim. Qhov inductance. Txawm li cas los xij, qhov tsis zoo yog tias nws qhov kev txaus siab tam sim no tsis tshua muaj, thiab thaum cov tub ntxhais hlau saturated, qhov sib nqus permeability yuav poob qis. Saib daim duab 4 rau qhov txo qis ntawm kev sib nqus permeability ntawm ferrite thiab hmoov hlau cores thaum cov tub ntxhais hlau saturated. Kev sib piv. Thaum siv nyob rau hauv lub hwj chim inductors, qhov sib txawv ntawm huab cua yuav nyob rau hauv lub ntsiab sib nqus Circuit Court, uas yuav txo tau permeability, tsis txhob saturation thiab khaws cia ntau zog; Thaum cov huab cua sib txawv yog suav nrog, qhov sib npaug ntawm cov txheeb ze permeability tuaj yeem yog li 20- Ntawm 200. Txij li thaum lub siab resistivity ntawm cov khoom nws tus kheej tuaj yeem txo qhov poob los ntawm eddy tam sim no, qhov poob qis dua ntawm qhov siab zaus, thiab nws yog qhov tsim nyog rau high-frequency transformers, EMI lim inductors thiab lub zog cia inductors ntawm lub zog hloov pauv. Nyob rau hauv cov nqe lus ntawm kev khiav hauj lwm zaus, nickel-zinc ferrite yog haum rau siv (> 1 MHz), thaum manganese-zinc ferrite yog haum rau qis zaus bands (<2 MHz).

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Daim duab 1. Lub hysteresis nkhaus ntawm lub magnetic core (BR: remanence; BSAT: saturation magnetic flux density)

3. hmoov hlau tub ntxhais

Hmoov hlau cores kuj yog cov khoom muag-magnetic ferromagnetic. Lawv yog ua los ntawm hlau hmoov alloys ntawm cov khoom sib txawv los yog tsuas yog hlau hmoov. Cov mis muaj cov khoom tsis sib nqus nrog ntau qhov sib txawv, yog li qhov saturation nkhaus kuj maj mam. Cov hmoov hlau core feem ntau yog toroidal. Daim duab 2 qhia tau hais tias cov hmoov hlau tseem ceeb thiab nws txoj kev saib hla ntu.

Feem ntau cov hmoov hlau hlau muaj xws li hlau-nickel-molybdenum alloy (MPP), sendust (Sendust), hlau-nickel alloy (siab flux) thiab hlau hmoov core (hlau hmoov). Vim yog cov khoom sib txawv, nws cov yam ntxwv thiab tus nqi kuj txawv, uas cuam tshuam rau kev xaiv ntawm inductors. Cov hauv qab no yuav qhia txog cov ntsiab lus uas tau hais los saum no thiab sib piv lawv cov yam ntxwv:

A. Hlau-nickel-molybdenum alloy (MPP)

Fe-Ni-Mo alloy yog abbreviated li MPP, uas yog lub ntsiab lus ntawm molypermalloy hmoov. Tus txheeb ze permeability yog li 14-500, thiab saturation magnetic flux ntom yog li 7500 Gauss (Gauss), uas yog siab tshaj qhov saturation magnetic flux ntom ntawm ferrite (li 4000-5000 Gauss). Ntau tawm. MPP muaj qhov tsawg tshaj plaws hlau poob thiab muaj qhov zoo tshaj plaws kub stability ntawm hmoov hlau cores. Thaum DC sab nraud tam sim no mus txog qhov saturation tam sim no ISAT, tus nqi inductance txo qis qis yam tsis muaj kev cuam tshuam sai. MPP muaj kev ua tau zoo dua tab sis tus nqi siab dua, thiab feem ntau yog siv los ua lub zog inductor thiab EMI lim rau cov khoom siv hluav taws xob.

B. Sendust

Cov hlau-silicon-aluminium alloy hlau core yog cov hlau alloy hlau uas muaj hlau, silicon, thiab txhuas, nrog cov txheeb ze sib nqus permeability ntawm 26 mus rau 125. Cov hlau poob yog nruab nrab ntawm cov hlau hmoov core thiab MPP thiab hlau-nickel alloy. . Lub saturation magnetic flux ceev yog siab tshaj MPP, txog 10500 Gauss. Kub stability thiab saturation tam sim no cov yam ntxwv yog me ntsis qis dua MPP thiab hlau-nickel alloy, tab sis zoo dua li hlau hmoov core thiab ferrite core, thiab tus txheeb ze tus nqi pheej yig dua MPP thiab hlau-nickel alloy. Nws feem ntau yog siv hauv EMI filtering, fais fab kev kho (PFC) circuits thiab fais fab inductors ntawm switching fais fab converters.

C. Hlau-nickel alloy (siab flux)

Cov hlau-nickel alloy core yog ua los ntawm hlau thiab npib tsib xee. Tus txheeb ze sib nqus permeability yog li 14-200. Cov hlau poob thiab kub stability yog nyob nruab nrab ntawm MPP thiab hlau-silicon-aluminium alloy. Cov hlau-nickel alloy core muaj qhov siab tshaj plaws saturation sib nqus flux ceev, txog 15,000 Gauss, thiab tuaj yeem tiv taus DC siab dua tam sim no, thiab nws cov yam ntxwv DC tsis zoo kuj zoo dua. Daim ntawv thov Scope: Active fais fab hloov kho, lub zog cia inductance, lim inductance, siab zaus transformer ntawm flyback converter, thiab lwm yam.

D. Hlau hmoov

Cov hlau hmoov core yog ua los ntawm high-purity hlau hmoov hmoov uas muaj me me heev uas yog insulated ntawm ib leeg. Cov txheej txheem tsim khoom ua rau nws muaj qhov sib txawv ntawm huab cua. Ntxiv nrog rau lub nplhaib puab, cov hlau hmoov hlau cov duab tseem muaj E-hom thiab stamping hom. Tus txheeb ze sib nqus permeability ntawm cov hlau hmoov hlau yog li 10 txog 75, thiab qhov siab saturation sib nqus flux ceev yog li 15000 Gauss. Ntawm cov hmoov hlau cores, hlau hmoov cores muaj cov hlau tsis zoo tshaj plaws tab sis tus nqi qis tshaj.

Daim duab 3 qhia txog BH nkhaus ntawm PC47 manganese-zinc ferrite tsim los ntawm TDK thiab hmoov hlau cores -52 thiab -2 tsim los ntawm MICROMETALS; Cov txheeb ze sib nqus permeability ntawm manganese-zinc ferrite yog ntau dua li cov hmoov hlau cores thiab yog saturated Lub sib nqus flux ntom kuj txawv heev, cov ferrite yog li 5000 Gauss thiab hlau hmoov cores ntau tshaj 10000 Gauss.

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Daim duab 3. BH nkhaus ntawm manganese-zinc ferrite thiab hlau hmoov cores ntawm cov khoom sib txawv

Hauv cov ntsiab lus, cov yam ntxwv saturation ntawm cov tub ntxhais hlau yog txawv; Thaum cov saturation tam sim no dhau lawm, qhov sib nqus permeability ntawm ferrite core yuav poob qis, thaum hlau hmoov core tuaj yeem maj mam txo. Daim duab 4 qhia tau hais tias qhov sib nqus permeability poob cov yam ntxwv ntawm cov hmoov hlau hlau nrog tib qhov sib nqus permeability thiab cov ferrite nrog cov cua sib txawv hauv qhov sib txawv ntawm qhov sib nqus. Qhov no kuj piav qhia txog qhov inductance ntawm ferrite core, vim tias qhov permeability poob qis thaum lub cores saturated, raws li pom tau los ntawm kev sib npaug (1), nws kuj ua rau inductance poob sharply; Thaum cov hmoov core nrog cov pa sib txawv, qhov sib nqus permeability Tus nqi txo qis thaum cov tub ntxhais hlau saturated, yog li cov inductance txo qis dua maj mam, uas yog, nws muaj cov yam ntxwv zoo DC bias. Nyob rau hauv daim ntawv thov ntawm lub hwj chim converters, tus yam ntxwv no tseem ceeb heev; Yog hais tias tus yam ntxwv qeeb saturation ntawm inductor tsis zoo, lub inductor tam sim no nce mus rau qhov saturation tam sim no, thiab tam sim ntawd poob rau hauv inductance yuav ua rau cov kev ntxhov siab tam sim no ntawm cov hloov siv lead ua kom nce siab, uas yooj yim ua rau kev puas tsuaj.

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Daim duab 4. Sib nqus permeability poob cov yam ntxwv ntawm hmoov hlau core thiab ferrite hlau core nrog huab cua sib txawv nyob rau hauv sib txawv magnetic teb zog.

Inductor hluav taws xob yam ntxwv thiab pob qauv

Thaum tsim ib qho kev hloov pauv hloov thiab xaiv tus inductor, tus nqi inductance L, impedance Z, AC kuj ACR thiab Q tus nqi (zoo yam), ntsuas tam sim no IDC thiab ISAT, thiab cov tub ntxhais poob (core poob) thiab lwm yam tseem ceeb hluav taws xob yam ntxwv yog txhua yam yuav tsum tau. raug txiav txim siab. Tsis tas li ntawd, cov qauv ntim ntawm cov inductor yuav cuam tshuam qhov loj ntawm cov hlau nplaum, uas ua rau muaj kev cuam tshuam EMI. Cov hauv qab no yuav tham txog cov yam ntxwv saum toj no cais raws li kev txiav txim siab rau kev xaiv inductors.

1. Inductance tus nqi (L)

Tus nqi inductance ntawm inductor yog qhov tseem ceeb tshaj plaws hauv kev tsim hluav taws xob, tab sis nws yuav tsum tau kuaj xyuas seb tus nqi inductance puas ruaj khov ntawm kev khiav hauj lwm zaus. Tus nqi nominal ntawm inductance feem ntau yog ntsuas ntawm 100 kHz lossis 1 MHz yam tsis muaj DC sab nraud. Thiab txhawm rau kom ntseeg tau tias muaj peev xwm ntawm cov khoom siv hluav taws xob ntau, qhov ua siab ntev ntawm inductor feem ntau yog ± 20% (M) thiab ± 30% (N). Daim duab 5 yog qhov inductance-frequency characteristic graph ntawm Taiyo Yuden inductor NR4018T220M ntsuas nrog Wayne Kerr's LCR meter. Raws li pom nyob rau hauv daim duab, tus nqi inductance nkhaus yog tiaj tus ua ntej 5 MHz, thiab tus nqi inductance yuav luag suav tias yog qhov tas li. Nyob rau hauv lub siab zaus band vim lub resonance generated los ntawm parasitic capacitance thiab inductance, tus nqi inductance yuav nce. Qhov no resonance zaus yog hu ua tus kheej-resonant zaus (SRF), uas feem ntau yuav tsum tau ntau dua qhov kev khiav hauj lwm zaus.

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Daim duab 5, Taiyo Yuden NR4018T220M inductance-frequency tus yam ntxwv ntsuas daim duab

2. impedance (Z)

Raws li pom hauv daim duab 6, daim duab impedance kuj tuaj yeem pom los ntawm kev ua haujlwm ntawm inductance ntawm ntau zaus. Lub impedance ntawm inductor yog kwv yees li proportional rau qhov zaus (Z = 2πfL), yog li qhov ntau zaus, qhov reactance yuav loj dua AC tsis kam, yog li cov impedance coj zoo li inductance ntshiab (theem yog 90˚). Nyob rau hauv high zaus, vim muaj cov nyhuv parasitic capacitance, tus kheej-resonant zaus point ntawm impedance tuaj yeem pom. Tom qab lub ntsiab lus no, lub impedance poob thiab ua capacitive, thiab cov theem maj mam hloov mus rau -90 ˚.

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3. Q tus nqi thiab AC kuj (ACR)

Q tus nqi nyob rau hauv lub ntsiab lus ntawm inductance yog qhov piv ntawm reactance rau kuj, uas yog, qhov piv ntawm qhov xav txog ib feem rau qhov tiag ib feem ntawm impedance, raws li nyob rau hauv formula (2).

(2)

Qhov twg XL yog qhov reactance ntawm inductor, thiab RL yog AC tsis kam ntawm inductor.

Nyob rau hauv qhov tsawg zaus ntau, AC kuj yog loj dua qhov reactance tshwm sim los ntawm inductance, yog li nws tus nqi Q tsawg heev; Raws li qhov zaus nce, qhov reactance (kwv yees li 2πfL) yuav loj dua thiab loj dua, txawm tias qhov kev tiv thaiv vim yog cov nyhuv ntawm daim tawv nqaij (tawv tawv nqaij) thiab qhov sib thooj (qhov sib thooj) cov nyhuv yuav loj dua thiab loj dua, thiab Q tus nqi tseem nce nrog zaus. ; Thaum mus txog SRF, qhov inductive reactance maj mam offset los ntawm lub capacitive reactance, thiab Q tus nqi maj mam ua me; Thaum SRF dhau los ua xoom, vim tias qhov inductive reactance thiab capacitive reactance yog tib yam ploj lawm. Daim duab 7 qhia txog kev sib raug zoo ntawm Q tus nqi thiab zaus ntawm NR4018T220M, thiab kev sib raug zoo yog nyob rau hauv cov duab ntawm lub tswb inverted.

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Daim duab 7. Kev sib raug zoo ntawm Q tus nqi thiab zaus ntawm Taiyo Yuden inductor NR4018T220M

Hauv daim ntawv thov zaus band ntawm inductance, qhov siab dua Q tus nqi, qhov zoo dua; Nws txhais tau tias nws cov reactance ntau dua li AC tsis kam. Feem ntau hais lus, qhov zoo tshaj plaws Q tus nqi yog siab dua 40, uas txhais tau hais tias qhov zoo ntawm inductor yog qhov zoo. Txawm li cas los xij, feem ntau raws li DC bias nce, tus nqi inductance yuav txo qis thiab Q tus nqi kuj yuav txo. Yog hais tias lub tiaj tus enameled hlau los yog ntau txoj hlua enameled hlau siv, cov nyhuv ntawm daim tawv nqaij, uas yog, AC kuj, tuaj yeem txo qis, thiab Q tus nqi ntawm inductor tuaj yeem nce ntxiv.

DC tsis kam DCR feem ntau suav tias yog DC tsis kam ntawm cov hlau tooj liab, thiab qhov kev tiv thaiv tuaj yeem suav tau raws li txoj kab uas hla thiab qhov ntev. Txawm li cas los xij, feem ntau ntawm cov qis tam sim no SMD inductors yuav siv ultrasonic vuam los ua cov ntawv tooj liab ntawm SMD ntawm lub davhlau ya nyob twg winding. Txawm li cas los xij, vim hais tias cov hlau tsis ntev ntev thiab qhov kev tiv thaiv tus nqi tsis siab, qhov vuam tsis kam feem ntau suav rau feem ntau ntawm tag nrho DC tsis kam. Noj TDK's hlau-hloov SMD inductor CLF6045NIT-1R5N ua piv txwv, ntsuas DC tsis kam yog 14.6mΩ, thiab DC tsis kam suav raws li cov xaim kab thiab ntev yog 12.1mΩ. Cov txiaj ntsig tau pom tias qhov vuam tsis kam no suav txog li 17% ntawm tag nrho DC tsis kam.

AC kuj ACR muaj cov nyhuv ntawm daim tawv nqaij thiab qhov sib thooj, uas yuav ua rau ACR nce nrog zaus; nyob rau hauv daim ntawv thov ntawm cov inductance dav dav, vim hais tias cov AC tivthaiv yog tsawg tshaj li DC tivthaiv, lub cawv los ntawm ACR yog tsis pom tseeb; tab sis ntawm lub teeb load, Vim hais tias DC tivthaiv raug txo, qhov poob los ntawm ACR tsis tuaj yeem tsis quav ntsej. Cov nyhuv ntawm daim tawv nqaij txhais tau hais tias nyob rau hauv AC tej yam kev mob, tam sim no tis nyob rau hauv tus neeg xyuas pib yog tsis ncaj ncees lawm thiab concentrated nyob rau saum npoo ntawm cov hlau, uas ua rau ib tug txo nyob rau hauv qhov sib npaug ntawm cov hlau hla ntu ntu, uas nyob rau hauv lem nce qhov sib npaug ntawm cov hlau nrog. zaus. Tsis tas li ntawd, nyob rau hauv ib tug hlau winding, nyob ib sab ntawm cov xov hlau uas nyob ib sab yuav ua rau qhov sib ntxiv thiab rho tawm ntawm cov hlau nplaum vim qhov tam sim no, yog li cov tam sim no yog concentrated nyob rau saum npoo uas nyob ib sab ntawm cov hlau (los yog qhov chaw deb tshaj plaws, nyob ntawm qhov kev taw qhia ntawm qhov tam sim no. ), uas kuj ua rau sib npaug hlau cuam tshuam. Qhov tshwm sim uas qhov chaw txo qis thiab qhov sib npaug ntawm qhov sib npaug nce yog qhov kev sib thooj ntawm qhov sib thooj; nyob rau hauv inductance daim ntawv thov ntawm ib tug multilayer winding, qhov sib thooj nyhuv yog txawm ntau pom tseeb.

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Daim duab 8 qhia txog kev sib raug zoo ntawm AC tsis kam thiab zaus ntawm cov hlau-qhov txhab SMD inductor NR4018T220M. Ntawm qhov zaus ntawm 1kHz, qhov tsis kam yog li 360mΩ; ntawm 100kHz, qhov tsis kam nce mus rau 775mΩ; ntawm 10MHz, tus nqi kuj yog ze rau 160Ω. Thaum kwv yees qhov poob ntawm tooj liab, qhov kev suav yuav tsum xav txog ACR tshwm sim los ntawm cov tawv nqaij thiab qhov sib thooj, thiab hloov nws mus rau formula (3).

4. Saturation tam sim no (ISAT)

Saturation tam sim no ISAT feem ntau yog qhov tsis ncaj ncees tam sim no cim thaum tus nqi inductance yog attenuated xws li 10%, 30%, lossis 40%. Rau huab cua-gap ferrite, vim hais tias nws cov saturation tam sim no tus yam ntxwv yog ceev heev, tsis muaj ntau qhov sib txawv ntawm 10% thiab 40%. Xa mus rau daim duab 4. Txawm li cas los xij, yog tias nws yog cov hmoov hlau hlau (xws li stamped inductor), qhov saturation nkhaus kuj yog ib qho yooj yim, raws li pom hauv daim duab 9, qhov kev tsis ncaj ncees tam sim no ntawm 10% lossis 40% ntawm inductance attenuation yog ntau. sib txawv, yog li tus nqi tam sim no saturation yuav sib tham sib cais rau ob hom hlau cores raws li hauv qab no.

Rau cov huab cua-gap ferrite, nws yog tsim nyog los siv ISAT raws li lub sab sauv txwv ntawm lub siab tshaj plaws inductor tam sim no rau daim ntawv thov Circuit Court. Txawm li cas los xij, yog tias nws yog cov hmoov hlau hlau, vim tias tus cwj pwm tsis txaus siab qeeb, yuav tsis muaj teeb meem txawm tias qhov siab tshaj plaws tam sim no ntawm daim ntawv thov Circuit Court tshaj ISAT. Yog li ntawd, cov yam ntxwv ntawm cov tub ntxhais hlau no yog qhov tsim nyog tshaj plaws rau kev hloov pauv cov ntawv thov. Nyob rau hauv hnyav load, txawm hais tias tus nqi inductance ntawm inductor yog tsawg, raws li qhia nyob rau hauv daim duab 9, qhov tam sim no ripple yam yog siab, tab sis tam sim no capacitor tam sim no kam rau siab yog siab, yog li nws yuav tsis muaj teeb meem. Nyob rau hauv lub teeb load, tus nqi inductance ntawm lub inductor yog loj, uas yuav pab txo tau lub ripple tam sim no ntawm inductor, yog li txo cov hlau poob. Daim duab 9 piv cov saturation tam sim no nkhaus ntawm TDK lub qhov txhab ferrite SLF7055T1R5N thiab stamped hlau hmoov core inductor SPM6530T1R5M nyob rau hauv tib lub nominal nqi ntawm inductance.

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Daim duab 9. Saturation tam sim no nkhaus ntawm qhov txhab ferrite thiab stamped hlau hmoov core nyob rau hauv tib lub nominal nqi ntawm inductance

5. Rated tam sim no (IDC)

Tus nqi IDC yog DC bias thaum lub inductor kub nce mus rau Tr˚C. Cov lus qhia tshwj xeeb kuj qhia txog nws tus nqi DC tsis kam RDC ntawm 20˚C. Raws li qhov kub thiab txias coefficient ntawm tooj liab hlau yog li ntawm 3,930 ppm, thaum qhov kub ntawm Tr nce, nws tus nqi kuj yog RDC_Tr = RDC (1 + 0.00393Tr), thiab nws lub zog noj yog PCU = I2DCxRDC. Qhov no tooj liab poob yog dissipated rau saum npoo ntawm inductor, thiab cov thermal kuj ΘTH ntawm inductor yuav xam tau:

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Table 2 hais txog cov ntaub ntawv ntawm TDK VLS6045EX series (6.0 × 6.0 × 4.5mm), thiab suav cov thermal kuj ntawm qhov kub siab ntawm 40˚C. Obviously, rau inductors ntawm tib series thiab loj, cov xam thermal kuj yuav luag zoo tib yam vim tib qhov chaw tshav kub dissipation; Hauv lwm lo lus, qhov ntsuas tam sim no IDC ntawm cov inductors sib txawv tuaj yeem kwv yees. Txawv series (pob khoom) ntawm inductors muaj sib txawv thermal resistances. Table 3 piv cov thermal kuj ntawm inductors ntawm TDK VLS6045EX series (semi-shielded) thiab SPM6530 series (molded). Qhov loj dua qhov thermal tsis kam, qhov siab dua qhov kub nce generated thaum lub inductance ntws los ntawm lub load tam sim no; txwv tsis pub, qis dua.

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Table 2. Thermal tsis kam ntawm VLS6045EX series inductors ntawm qhov kub thiab txias ntawm 40˚C

Nws tuaj yeem pom los ntawm Table 3 tias txawm tias qhov loj ntawm inductors zoo sib xws, cov thermal tsis kam ntawm cov stamped inductors yog tsawg, uas yog, cov cua kub dissipation zoo dua.

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Table 3. Kev sib piv ntawm thermal kuj ntawm txawv pob inductors.

6. Core poob

Core poob, hu ua hlau poob, feem ntau yog tshwm sim los ntawm eddy tam sim no poob thiab hysteresis poob. Qhov loj ntawm qhov poob tam sim no feem ntau yog nyob ntawm seb cov khoom siv tseem ceeb puas yooj yim rau "ua"; Yog hais tias tus conductivity yog siab, uas yog, lub resistivity yog tsawg, lub eddy tam sim no poob yog siab, thiab yog hais tias tus resistivity ntawm lub ferrite yog siab, lub eddy tam sim no poob yog tsawg. Eddy tam sim no poob kuj muaj feem xyuam nrog zaus. Qhov ntau zaus, qhov ntau dua qhov eddy tam sim no poob. Yog li ntawd, cov khoom siv tseem ceeb yuav txiav txim siab qhov kev ua haujlwm zoo ntawm cov tub ntxhais. Feem ntau hais lus, kev ua haujlwm zaus ntawm cov hmoov hlau hlau tuaj yeem ncav cuag 1MHz, thiab kev ua haujlwm zaus ntawm ferrite tuaj yeem ncav cuag 10MHz. Yog hais tias qhov kev khiav hauj lwm zaus tshaj qhov zaus no, qhov eddy tam sim no poob yuav nce sai heev thiab cov tub ntxhais hlau kub kuj yuav nce. Txawm li cas los xij, nrog txoj kev loj hlob sai ntawm cov khoom siv hlau, cov cores hlau nrog kev ua haujlwm ntau dua yuav tsum nyob ib ncig ntawm lub ces kaum.

Lwm qhov poob ntawm cov hlau yog qhov hysteresis poob, uas yog proportional rau thaj tsam ntawm lub hysteresis nkhaus, uas muaj feem xyuam rau lub viav vias amplitude ntawm AC tivthaiv tam sim no; qhov loj dua AC viav vias, qhov ntau dua qhov hysteresis poob.

Nyob rau hauv qhov sib npaug ntawm ib qho inductor, ib qho resistor txuas nyob rau hauv parallel nrog inductor feem ntau yog siv los qhia cov hlau poob. Thaum qhov zaus sib npaug rau SRF, qhov inductive reactance thiab capacitive reactance tshem tawm, thiab qhov sib npaug reactance yog xoom. Nyob rau lub sijhawm no, qhov impedance ntawm inductor yog sib npaug rau cov hlau tsis muaj zog nyob rau hauv series nrog lub winding tsis kam, thiab cov hlau tsis kam yog ntau dua li cov winding tsis kam, yog li cov impedance ntawm SRF yog kwv yees li sib npaug ntawm cov hlau tsis kam. Ua ib qho piv txwv ntawm qhov qis-voltage inductor, nws cov hlau tsis kam yog li 20kΩ. Yog hais tias tus nqi hluav taws xob zoo ntawm ob qho kawg ntawm qhov inductor yog kwv yees li 5V, nws cov hlau poob yog li 1.25mW, uas tseem qhia tau tias qhov loj dua cov hlau tsis kam, qhov zoo dua.

7. Cov qauv ntaub thaiv npog

Cov qauv ntim ntawm ferrite inductors muaj xws li tsis-shielded, semi-shielded nrog magnetic kua nplaum, thiab shielded, thiab muaj qhov sib txawv ntawm huab cua nyob rau hauv ib qho ntawm lawv. Pom tseeb, qhov sib txawv ntawm huab cua yuav muaj cov hlau nplaum sib nqus, thiab qhov phem tshaj plaws, nws yuav cuam tshuam nrog cov teeb liab me me nyob ib puag ncig, lossis yog tias muaj cov khoom sib nqus nyob ze, nws qhov inductance tseem yuav hloov. Lwm cov qauv ntim khoom yog stamped hlau hmoov inductor. Txij li thaum tsis muaj qhov sib txawv hauv qhov inductor thiab cov qauv winding yog cov khoom, qhov teeb meem ntawm magnetic teb dissipation yog me me. Daim duab 10 yog kev siv FFT muaj nuj nqi ntawm RTO 1004 oscilloscope los ntsuas qhov loj ntawm qhov xau magnetic teb ntawm 3 hli saum toj no thiab nyob rau sab ntawm lub stamped inductor. Table 4 teev cov kev sib piv ntawm cov xaim hlau nplaum ntawm cov qauv pob sib txawv inductors. Nws tuaj yeem pom tias cov inductors tsis muaj shielded muaj qhov sib nqus sib nqus loj tshaj plaws; stamped inductors muaj qhov tsawg tshaj plaws sib nqus to, uas qhia qhov zoo tshaj plaws sib nqus shielding nyhuv. . Qhov sib txawv ntawm qhov sib nqus ntawm qhov sib nqus ntawm cov inductors ntawm ob lub qauv no yog hais txog 14dB, uas yog ze li ntawm 5 npaug.

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Daim duab 10. Qhov luaj li cas ntawm qhov sib nqus sib nqus ntsuas ntawm 3mm saum toj no thiab nyob rau sab ntawm lub stamped inductor

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Table 4. Kev sib piv ntawm cov xaim hlau nplaum sib txawv ntawm cov qauv pob sib txawv inductors

8. kev sib txuas

Hauv qee daim ntawv thov, qee zaum muaj ntau yam ntawm DC converters ntawm PCB, uas feem ntau yog teem ib sab ntawm ib leeg, thiab lawv cov inductors coj los kuj tau teem ib sab. Yog tias koj siv hom tsis muaj shielded los yog semi-shielded nrog magnetic kua nplaum Inductors yuav ua ke nrog ib leeg los tsim EMI cuam tshuam. Yog li ntawd, thaum muab lub inductor, nws raug nquahu kom kos lub polarity ntawm lub inductor ua ntej, thiab txuas qhov pib thiab winding point ntawm lub puab txheej ntawm inductor mus rau lub switching voltage ntawm lub converter, xws li VSW ntawm ib tug phaw converter, uas yog qhov txav mus los. Lub qhov hluav taws xob davhlau ya nyob twg txuas nrog cov zis capacitor, uas yog qhov taw tes zoo li qub; tooj liab hlau winding yog li tsim ib tug tej yam degree ntawm hluav taws xob teb shielding. Nyob rau hauv kev teeb tsa ntawm lub multiplexer, kho qhov polarity ntawm inductance pab kho qhov loj ntawm kev sib nrig sib inductance thiab zam qee qhov teeb meem EMI tsis xav txog.

Daim ntawv thov:

Tshooj yav dhau los tau tham txog cov khoom tseem ceeb, cov qauv pob, thiab cov yam ntxwv tseem ceeb ntawm cov inductor. Tshooj lus no yuav piav qhia yuav ua li cas xaiv qhov tsim nyog inductance tus nqi ntawm cov phaw converter thiab cov kev txiav txim siab rau kev xaiv cov khoom lag luam muaj nyob hauv inductor.

Raws li pom nyob rau hauv kab zauv (5), tus nqi inductor thiab qhov zaus hloov ntawm lub converter yuav cuam tshuam rau inductor ripple tam sim no (ΔiL). Lub inductor ripple tam sim no yuav ntws los ntawm cov zis capacitor thiab cuam tshuam rau lub ripple tam sim no ntawm cov zis capacitor. Yog li ntawd, nws yuav cuam tshuam rau kev xaiv ntawm cov zis capacitor thiab txuas ntxiv cuam tshuam rau ripple loj ntawm cov zis voltage. Tsis tas li ntawd, tus nqi inductance thiab cov zis capacitance tus nqi tseem yuav cuam tshuam rau kev tawm tswv yim tsim ntawm lub kaw lus thiab cov lus teb dynamic ntawm lub load. Xaiv tus nqi inductance loj dua muaj kev ntxhov siab tam sim no ntawm lub capacitor, thiab tseem muaj txiaj ntsig los txo cov zis hluav taws xob ripple thiab tuaj yeem khaws ntau lub zog. Txawm li cas los xij, tus nqi inductance loj dua qhia qhov ntim loj dua, uas yog, tus nqi siab dua. Yog li ntawd, thaum tsim lub converter, tus tsim ntawm tus nqi inductance tseem ceeb heev.

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Nws tuaj yeem pom los ntawm cov qauv (5) tias thaum qhov sib txawv ntawm qhov input voltage thiab cov zis voltage ntau dua, qhov inductor ripple tam sim no yuav ntau dua, uas yog qhov phem tshaj plaws ntawm qhov tsim inductor. Ua ke nrog rau lwm yam inductive tsom xam, inductance tsim taw tes ntawm kauj ruam-down converter feem ntau yuav tsum tau xaiv nyob rau hauv tej yam kev mob ntawm siab tshaj plaws input voltage thiab tag nrho load.

Thaum tsim tus nqi inductance, nws yuav tsum ua kom muaj kev sib pauv ntawm qhov inductor ripple tam sim no thiab qhov loj ntawm inductor, thiab qhov cuam tshuam tam sim no (ripple tam sim no yam; γ) tau txhais ntawm no, raws li hauv cov qauv (6).

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Hloov cov mis (6) rau hauv mis (5), tus nqi inductance tuaj yeem qhia tau tias yog mis (7).

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Raws li cov qauv (7), thaum qhov sib txawv ntawm cov tswv yim thiab cov zis voltage loj dua, γ tus nqi tuaj yeem xaiv loj dua; ntawm qhov tsis sib xws, yog tias qhov kev tawm tswv yim thiab cov zis hluav taws xob nyob ze dua, γ tus nqi tsim yuav tsum me dua. Txhawm rau xaiv ntawm inductor ripple tam sim no thiab qhov loj me, raws li kev tsim qauv tsim tus nqi, γ feem ntau yog 0.2 txog 0.5. Cov hauv qab no yog siv RT7276 ua piv txwv los qhia txog kev suav ntawm inductance thiab xaiv cov khoom lag luam muaj nyob hauv inductors.

Tsim qauv: Tsim nrog RT7276 siab tas li ntawm lub sijhawm (Advanced Constant On-Time; ACOTTM) synchronous rectification kauj ruam-down converter, nws hloov zaus yog 700 kHz, input voltage yog 4.5V rau 18V, thiab cov zis voltage yog 1.05V . Tag nrho cov load tam sim no yog 3A. Raws li tau hais los saum toj no, tus nqi inductance yuav tsum tau tsim nyob rau hauv cov xwm txheej ntawm qhov siab tshaj plaws input voltage ntawm 18V thiab tag nrho cov load ntawm 3A, tus nqi ntawm γ yog npaum li 0.35, thiab cov nqi saum toj no yog hloov mus rau hauv kab zauv (7), inductance. tus nqi yog

Siv cov inductor nrog cov pa nominal inductance tus nqi ntawm 1.5 µH. Hloov cov mis (5) los xam cov inductor ripple tam sim no raws li hauv qab no.

Yog li ntawd, lub siab tshaj plaws tam sim no ntawm inductor yog

Thiab qhov txiaj ntsig zoo ntawm inductor tam sim no (IRMS) yog

Vim hais tias cov inductor ripple tivthaiv yog me me, qhov zoo ntawm cov inductor tam sim no feem ntau yog nws cov DC tivthaiv, thiab qhov txiaj ntsig zoo no yog siv los ua lub hauv paus rau kev xaiv cov inductor ntsuas tam sim no IDC. Nrog 80% derating (derating) tsim, inductance yuav tsum yog:

L = 1.5 µH (100 kHz), IDC = 3.77 A, ISAT = 4.34 A

Table 5 teev cov muaj inductors ntawm txawv series ntawm TDK, zoo ib yam li loj tab sis txawv nyob rau hauv pob qauv. Nws tuaj yeem pom los ntawm lub rooj hais tias qhov saturation tam sim no thiab ntsuas tam sim no ntawm cov khoom siv hluav taws xob stamped (SPM6530T-1R5M) yog qhov loj, thiab cov thermal kuj yog me me thiab cov cua kub dissipation zoo. Tsis tas li ntawd, raws li kev sib tham nyob rau hauv tshooj dhau los, cov khoom tseem ceeb ntawm lub stamped inductor yog hlau hmoov core, yog li nws muab piv nrog ferrite core ntawm semi-shielded (VLS6045EX-1R5N) thiab shielded (SLF7055T-1R5N) inductors. nrog hlau nplaum nplaum. , Muaj cov yam ntxwv zoo DC tsis zoo. Daim duab 11 qhia txog kev sib piv ntawm cov inductors sib txawv siv rau RT7276 kev ua haujlwm siab tas li ntawm lub sijhawm synchronous rectification kauj ruam-down converter. Cov txiaj ntsig tau pom tias qhov kev ua tau zoo sib txawv ntawm peb qhov tsis tseem ceeb. Yog tias koj xav txog cov cua kub dissipation, DC bias yam ntxwv thiab magnetic teb dissipation teeb meem, nws raug nquahu kom siv SPM6530T-1R5M inductors.

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Table 5. Kev sib piv ntawm inductances ntawm txawv series ntawm TDK

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Daim duab 11. Kev sib piv ntawm converter efficiency nrog txawv inductors

Yog tias koj xaiv tib lub pob qauv thiab tus nqi inductance, tab sis me me inductors, xws li SPM4015T-1R5M (4.4 × 4.1 × 1.5mm), txawm hais tias nws loj me me, tab sis DC kuj RDC (44.5mΩ) thiab thermal kuj ΘTH ( 51˚C) / W) Loj dua. Rau cov converters ntawm tib yam specifications, qhov zoo ntawm cov tam sim no tolerated los ntawm inductor kuj yog tib yam. Obviously, DC tsis kam yuav txo cov efficiency nyob rau hauv hnyav load. Tsis tas li ntawd, qhov loj thermal kuj txhais tau tias tsis zoo cua sov dissipation. Yog li ntawd, thaum xaiv ib qho inductor, nws tsis yog tsuas yog yuav tsum tau xav txog cov txiaj ntsig ntawm kev txo qhov loj me, tab sis kuj los ntsuas nws cov kev tsis txaus.

Hauv kev xaus

Inductance yog ib qho ntawm cov khoom siv nquag siv hauv kev hloov hluav taws xob hloov hluav taws xob, uas tuaj yeem siv rau lub zog cia thiab lim. Txawm li cas los xij, hauv kev tsim hluav taws xob, nws tsis yog tsuas yog tus nqi inductance uas yuav tsum tau them sai sai rau, tab sis lwm yam tsis muaj xws li AC tsis kam thiab Q tus nqi, kev kam rau siab tam sim no, hlau core saturation, thiab pob qauv, thiab lwm yam, yog txhua yam uas yuav tsum tau ua. raug txiav txim siab thaum xaiv ib qho inductor. . Cov kev ntsuas no feem ntau muaj feem xyuam nrog cov khoom siv tseem ceeb, kev tsim khoom, thiab qhov loj thiab tus nqi. Yog li, tsab xov xwm no qhia txog cov yam ntxwv ntawm cov khoom siv hlau sib txawv thiab yuav ua li cas xaiv qhov tsim nyog inductance raws li kev siv hluav taws xob tsim.