Malingana ndi PCB Kapangidwe ka magetsi, pepalali limakhazikitsa njira zabwino kwambiri za PCB, zitsanzo ndi maluso othandizira kukonza magwiridwe antchito osavuta a switcher.

Mukamakonza dongosolo lamagetsi, choyambirira ndi malo olumikizira matumba awiri akusinthaku. 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. Mzere wa 1 womwe ukuwonetsedwa mu Chithunzi 1, zomwe zikuyenda pakadutsa capacitor (Cin1) zimadutsa MOSFET kupita mkati mwa zotulutsa ndi zotuluka polowera capacitor (CO1) panthawi yopitilira kumapeto kwa MOSFET, ndipo pamapeto pake imabwerera ku kulowetsa kulambalala capacitor.

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

Chithunzi 1 Chithunzi chojambulidwa cha loop mu module yamagetsi

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. Mphamvu zomwe zimasungidwa mkati mozungulira zimadutsa potuluka polowera capacitor ndi MOSFEts otsika asanabwerere ku GND (onani Chithunzi 1). Dera lomwe malupu awiri samalumikizana (kuphatikiza malire pakati pa malupu) ndi dera lokhala ndi DI / DT yayikulu. Kulowetsa kopyola capacitor (Cin1) kumachita gawo lofunikira pakufotokozera mafupipafupi amtundu wa wotembenuza ndikubwezeretsanso pafupipafupi njira yake.

Zotsatira zake zimadutsa capacitor (Co1) sizikhala ndi ma AC ambiri pano, koma imakhala ngati fyuluta yayikulu kwambiri yosinthira phokoso. Pazifukwa zomwe zili pamwambapa, zolowetsera ndi zotulutsa zoyika ziyenera kuikidwa pafupi kwambiri ndi zikhomo zawo za VIN ndi VOUT pagawolo. Monga momwe tawonetsera pa Chithunzi 2, kulowerera komwe kumapangidwa ndi kulumikizaku kumatha kuchepetsedwa ndikupanga kulumikizana pakati pazodutsa ma capacitors ndi mapini awo a VIN ndi VOUT mwachidule momwe zingathere.

Chithunzi 2 SIMPLE SWITCHER loop

Kuchepetsa kuchepa kwa mapangidwe a PCB kuli ndi maubwino awiri akulu. Choyamba, sinthani magwiridwe antchito polimbikitsa kusamutsa mphamvu pakati pa Cin1 ndi CO1. Izi zimatsimikizira kuti gawoli lili ndi hf yodutsa bwino, yochepetsera kukwera kwamphamvu kwamagetsi chifukwa chakumapeto kwa DI / DT. Amachepetsanso phokoso lamagetsi ndi kupsinjika kwamagetsi kuti zitsimikizike kuti zimayendera bwino. Chachiwiri, chepetsani EMI.

Ma capacitor olumikizidwa ndi kuchepa kwa parasitic inductance amawonetsa kuchepa kwa ma impedance pama frequency apamwamba, motero amachepetsa ma radiation. Ceramic capacitors (X7R kapena X5R) kapena ma low capacitors ena a ESR amalimbikitsidwa. Zowonjezera zowonjezera ma capacitors atha kugwiritsidwa ntchito ngati ma capacitors owonjezera ayikidwa pafupi ndi GND ndi VIN itha. 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.

Kukonzekera njira zamakono zamakono nthawi zambiri kumanyalanyazidwa, koma kumathandiza kwambiri pakukonzekera kapangidwe ka magetsi. 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.

Zikhomo zokhazikika (kuphatikiza mapiritsi opanda kanthu), zolowetsa ndi zotulutsa ma capacitors, zoyambira zoyambira, ndi zoyikira mayankho mu gawoli zonse ziyenera kulumikizidwa ndi lupu wosanjikiza pa PCB. Chingwe cholumikizira ichi chitha kugwiritsidwa ntchito ngati njira yobwererera ndi njira yotsika kwambiri komanso ngati chida chodziwitsira chomwe chatchulidwa pansipa.

CHITH. 3 Chithunzi chojambulidwa cha module ndi PCB ngati impedance wamafuta

Otsutsa mayankho akuyeneranso kuikidwa pafupi kwambiri ndi pini ya FB (mayankho) ya gawoli. 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. For an example, see the PCB layout diagram in the relevant module data table.

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

Malingaliro Akutulutsa Kutentha

Kapangidwe kabwino ka ma module, pomwe kumapereka maubwino amagetsi, kumakhudza kusintha kwakapangidwe kazotentha, komwe mphamvu yofananira imachotsedwa m’malo ang’onoang’ono. 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. Padiyo imathandizira kutulutsa kutsika pang’ono kwamphamvu kuchokera ku MOSFEts mkati, komwe kumapangitsa kutentha kwambiri, kupita ku PCB.

Kutentha kwamatenthedwe (θJC) kuchokera pamphambano ya semiconductor kupita phukusi lakunja lazida izi ndi 1.9 ℃ / W. Ngakhale kukwaniritsa kutsogola kwa θJC kotsogola ndikwabwino, mtengo wotsika wa θJC umakhala wopanda tanthauzo pamene mpweya wamagetsi (θCA) wa phukusi lakunja mlengalenga ndiwokulirapo! Ngati palibe njira yotsitsa yozimitsa kutentha yomwe imaperekedwa kwa mpweya wozungulira, kutentha kumadzipezera pamiyala yopanda kanthu ndipo sikungathe kuzimiririka. Nanga nchiyani chimatsimikizira θCA? The thermal resistance from bare pad to air is completely controlled by the PCB design and associated heat sink.

Tsopano kuti muwone mwachidule momwe mungapangire PCB yosavuta yopanda zipsepse, chithunzi 3 chikuwonetsa gawoli ndi PCB ngati impedance yotentha. Chifukwa kutentha kwamphamvu pakati pa mphambano ndi pamwamba phukusi lakunja ndikokwera kwambiri poyerekeza ndi kutenthetsa kwamphamvu kuchokera pamphambano kupita padeti yopanda kanthu, titha kunyalanyaza njira ya heatJA yotaya kutentha pakuyerekeza koyamba kwa kukana kwamphamvu kuchokera pamphambano kupita mpweya wozungulira (θJT).

Gawo loyamba pakupanga kutentha ndikutanthauzira kuchuluka kwa mphamvu kuti ithe. Mphamvu yogwiritsidwa ntchito ndi module (PD) imatha kuwerengedwa mosavuta pogwiritsa ntchito graph graph (η) yofalitsidwa pagome lazidziwitso.

Kenako timagwiritsa ntchito zovuta za kutentha kwambiri pamapangidwe, TAmbient, ndi kutentha kwa mphambano, TJuncTIon (125 ° C), kuti tidziwe kukana kwamphamvu komwe kumafunikira ma module omwe ali pa PCB.

Pomaliza, tidagwiritsa ntchito kuyerekezera kwaposachedwa kutentha kwakukulu pamtundu wa PCB (wokhala ndi zipsepse za 1-ounce zamkuwa zosasunthika ndi mabowo ambiri otenthetsera pamwamba komanso pansi) kuti adziwe malo omwe amafunikira kutentha.

Kufunika kwa dera la PCB sikulingalira mbali yomwe mabowo amatulutsa otentha omwe amasamutsa kutentha kuchokera pazitsulo zazitsulo (phukusi limalumikizidwa ndi PCB) mpaka pansi pazitsulo. Mzere wapansi umakhala ngati wachiwiri wosanjikiza womwe convection imatha kusamutsa kutentha kuchokera m’mbale. Mabowo ozizira osachepera 8 mpaka 10 ayenera kugwiritsidwa ntchito kuti kuyerekezera kwa bolodi kukhale kovomerezeka. Kutentha kwamadzi otentha kumayesedwa ndi equation yotsatirayi.

Kuyerekeza kumeneku kumagwira ntchito pobowoleza mamililita 12 mulitali ndi 0.5 oz zammbali zamkuwa. Mabowo ambiri otenthetsera kutentha amayenera kupangidwa m’dera lonse pansi pa pedi, ndipo mabowo otenthetsera kutenthawa ayenera kukhala pakati pa 1 mpaka 1.5mm.

mapeto

Module yamagetsi ya SIMPLE SWITCHER imapereka njira ina yamagetsi yamagetsi yovuta komanso mawonekedwe a PCB omwe amagwirizanitsidwa ndi otembenuza DC / DC. Ngakhale zovuta zakapangidwe zidachotsedwa, ntchito ina ya uinjiniya ikufunikirabe kuchitidwa kuti ikwaniritse magwiridwe antchito modutsa ndikudutsa koyipa.