Ngokusekelwe ku PCB ukwakheka kokuphakelwa kwamandla, leli phepha lethula indlela engcono kakhulu yokuhlelwa kwe-PCB, izibonelo namasu wokukhulisa ukusebenza kwemodyuli yamandla eswishi elula.

Lapho uhlela ukwakheka kokuphakelwa kwamandla, okucatshangelwa okokuqala indawo yomzimba ebonakalayo yamaluphu amabili ashintshayo. Although these loop regions are largely invisible in the power module, it is important to understand the respective current paths of the two loops because they extend beyond the module. Ku-loop 1 ekhonjiswe kuMdwebo 1, okokufaka okuzenzekelayo okwenzeka nge-bypass capacitor (i-Cin1) kudlula kwi-MOSFET kuya ku-inductor yangaphakathi nokukhipha i-capacitor (CO1) ngesikhathi esiqhubekayo sokuqhutshwa kweMOSFET ephezulu, futhi ekugcineni ibuyela ku okokufaka kokudlula capacitor.

Schematic diagram of loop in the power module www.elecfans.com

Umdwebo 1 Umdwebo wesikimu we-loop kumodyuli yamandla

Loop 2 is formed during the turn-off time of the internal high-end MOSFEts and the turn-on time of the low-end MOSFEts. Amandla agcinwe ku-inductor yangaphakathi ahamba ngokudlula kokukhipha i-capacitor kanye ne-MOSFEts ephansi ngaphambi kokubuyela ku-GND (bona Umfanekiso 1). Isifunda lapho izihibe ezimbili zingagudluki khona (kufaka phakathi umngcele ophakathi kwamaluphu) yisifunda esinamazinga aphezulu e-DI / DT. Okokufaka kwe-bypass capacitor (i-Cin1) kudlala indima enkulu ekunikezeni imvamisa ephezulu kumguquli futhi ibuyisele imvamisa ephezulu kumthombo wayo.

Okukhiphayo kokudlula capacitor (Co1) akuphathi i-AC yamanje, kepha kusebenza njengesihlungi semvamisa ephezulu yokushintsha umsindo. Ngenxa yezizathu ezingenhla, ama-capacitors wokufaka nawokukhipha kufanele abekwe eduze ngangokunokwenzeka kuzikhonkwane zabo ze-VIN ne-VOUT ezikule mojuli. Njengoba kukhonjisiwe ku-Figure 2, i-inductance eyenziwe yilezi zixhumo ingancishiswa ngokwenza i-wiring phakathi kwama-capacitors okudlula kanye nezikhonkwane zazo ze-VIN ne-VOUT zifushane futhi zibanzi ngangokunokwenzeka.

Umdwebo 2 I-SIMPLE SWITCHER loop

Ukunciphisa ukwehliswa kwesakhiwo ku-PCB kunezinzuzo ezimbili ezinkulu. Okokuqala, thuthukisa ukusebenza kwengxenye ngokukhuthaza ukudluliswa kwamandla phakathi kweCin1 ne-CO1. Lokhu kuqinisekisa ukuthi imodyuli inokudlula okuhle kwe-hf, kunciphisa ukuphakama kwamandla kagesi ngenxa ye-DI / DT ephezulu yamanje. Iphinde inciphise umsindo wedivayisi nokucindezela kwamandla ukuqinisekisa ukusebenza okujwayelekile. Okwesibili, nciphisa i-EMI.

Ama-capacitors axhunywe nge-infasitic inductance encane abonisa izici eziphansi ze-impedance kuma-frequency aphezulu, ngaleyo ndlela anciphisa imisebe eyenziwe. Ama-capacitors e-Ceramic (X7R noma i-X5R) noma amanye ama-capacitor wohlobo lwe-ESR aphansi anconyiwe. Ama-capacitors wokufaka angeziwe angasebenza kuphela uma ama-capacitors angeziwe abekwa eduze kwe-GND ne-VIN. The Power module of the SIMPLE SWITCHER is uniquely designed to have low radiation and conducted EMI. However, follow the PCB layout guidelines described in this article to achieve higher performance.

Ukuhlelwa kwendlela yamanje yesekethe kaningi akunakwa, kepha kudlala indima enkulu ekwandiseni ukwakhiwa kokuphakelwa kwamandla. In addition, ground wires to Cin1 and CO1 should be shortened and widened as much as possible, and bare pads should be directly connected, which is especially important for input capacitor (Cin1) ground connections with large AC currents.

Izikhonkwane ezisisekelo (kufaka phakathi ama-pads angenalutho), okokufaka nokokukhipha ama-capacitors, ama-capacitors okuqalisa okuthambile, nama-resistor empendulo kwimodyuli kufanele konke kuxhunywe kusendlalelo se-loop ku-PCB. Lo ungqimba we-loop ungasetshenziswa njengendlela yokubuyisa enezinga eliphansi kakhulu lokungenisa futhi njengedivayisi yokusabalalisa ukushisa okuxoxwe ngezansi.

ISITHOMBE. 3 Umdwebo wokuhlelwa kwemodyuli ne-PCB njenge-impedance eshisayo

Isiphikisi sempendulo kufanele futhi sibekwe sisondele ngangokunokwenzeka kuphini le-FB (impendulo) yemodyuli. To minimize the potential noise extraction value at this high impedance node, it is critical to keep the line between the FB pin and the feedback resistor’s middle tap as short as possible. Available compensation components or feedforward capacitors should be placed as close to the upper feedback resistor as possible. Ukwenza isibonelo, bona umdwebo wesakhiwo se-PCB kuthebula ledatha yemodyuli efanele.

For AN example layout of LMZ14203, see the application guide document AN-2024 provided at www.naTIonal.com.

Iziphakamiso Zokuklama Ukushisa

Ukuhlelwa okuhlanganisiwe kwamamojula, ngenkathi kuhlinzeka ngezinzuzo zikagesi, kunomthelela omubi ekwakhiweni kokushiswa kokushisa, lapho amandla alinganayo ehlakazeka avela ezikhaleni ezincane. To address this problem, a single large bare pad is designed on the back of the Power module package of the SIMPLE SWITCHER and is electrically grounded. Iphedi isiza ukuhlinzeka nge-impedance yokushisa ephansi ngokweqile evela kuma-MOSFEts angaphakathi, ajwayele ukukhiqiza ukushisa okukhulu, aya kwi-PCB.

I-impedance eshisayo (i-θJC) kusuka ekuhlanganeni kwe-semiconductor kuya ephaketheni elingaphandle lale madivayisi yi-1.9 ℃ / W. Ngenkathi ukufeza inani elihola phambili le-θJC embonini kuyinto enhle, inani eliphansi le-θJC alwenzi mqondo lapho i-impedance eshisayo (θCA) yephakeji langaphandle emoyeni likhulu kakhulu! Uma kungekho ndlela yokuqothula ukushisa kwe-impedance ephansi enikezwa emoyeni oyizungezile, ukushisa kuzoqoqeka kuphedi elingenalutho futhi akunakusakazeka. Manje-ke yini enquma i-θCA? Ukumelana okushisayo kusuka kuphedi elingenalutho kuya emoyeni kulawulwa ngokuphelele ukwakheka kwe-PCB nosinki wokushisa ohambisanayo.

Manje ngokubheka ngokushesha ukuthi ungayakha kanjani i-PCB elula ngaphandle kwamaphiko, isibalo 3 sibonisa imodyuli ne-PCB njenge-impedance eshisayo. Ngoba i-impedance eshisayo phakathi komgwaqo naphezulu kwephakeji elingaphandle iphakeme kakhulu uma iqhathaniswa ne-impedance eshisayo kusuka ekuhlanganeni kuya kuphedi elingenalutho, singayinaka indlela ye-θJA yokushisa ukushisa ngesikhathi sokulinganisa kokuqala kokumelana nokushisa kusuka ekuhlanganeni kuya umoya ozungezile (θJT).

Isinyathelo sokuqala ekwakhiweni kokushiswa kokushisa ukunquma inani lamandla azosakazwa. Amandla adliwe yi-module (PD) angabalwa kalula kusetshenziswa igrafu yokusebenza kahle (η) eshicilelwe kuthebula ledatha.

Sibe sisebenzisa izingqinamba zokushisa kwamazinga okushisa aphezulu ekwakhiweni, i-TAmbient, kanye nethempelesha elinganisiwe elinganisiwe, i-TJuncTIon (125 ° C), ukuthola ukumelana okushisayo okudingekayo kumamojula ahlanganisiwe ku-PCB.

Ekugcineni, sisebenzise ukulinganisa okulula kokudluliswa kokushisa okuphezulu okuphezulu ebusweni be-PCB (enezimpiko zethusi ezingalimalanga ze-1-ounce nezimbobo eziningi zokushisa kokushisa kuzo zombili izitezi ezingaphezulu nezingezansi) ukuthola indawo yepuleti edingekayo ekusakazekeni kokushisa.

Ukuqagelwa kwendawo ye-PCB edingekayo akubheki iqhaza elibanjwe yimigodi yokushiswa kokushisa okudlulisa ukushisa kusuka kungqimba lwensimbi ephezulu (iphakethe lixhunywe ku-PCB) kusendlalelo sensimbi esingezansi. Isendlalelo esingezansi sisebenza njengesendlalelo sesibili esingaphezulu lapho i-convection ingadlulisa khona ukushisa kupuleti. Okungenani izimbobo zokupholisa eziyi-8 kuye kwezi-10 kufanele zisetshenziselwe ukulinganiselwa kwendawo yebhodi ukuze kusebenze. Ukumelana okushisayo kwesinki yokushisa kucatshangelwa yi-equation elandelayo.

Lokhu kusondela kusebenza emgodini ojwayelekile wokungena nge-12 mils ububanzi nge-0.5 oz sidewall yethusi. Izimbobo eziningi zokushisa ngokushisa ngangokunokwenzeka kufanele zakhiwe kuyo yonke indawo engezansi kwephedi elingenalutho, futhi lezi zimbobo zokucisha ukushisa kufanele zenze uhlu olunezikhala ezi-1 kuye ku-1.5mm.

isiphetho

IModyuli yamandla eSIMPLE SWITCHER inikeza enye indlela yokwakhiwa kwamandla kagesi ayinkimbinkimbi nezakhiwo ezijwayelekile ze-PCB ezihambisana nabaguquli beDC / DC. Ngenkathi izinselelo zesakhiwo zisusiwe, omunye umsebenzi wobunjiniyela kusadingeka wenziwe ukwandisa ukusebenza kwemodyuli ngokudlula okuhle nokuklanywa kokushisa kokushisa.