Da lori PCB ipilẹ ti ipese agbara, iwe yii ṣafihan ọna ipilẹ PCB ti o dara julọ, awọn apẹẹrẹ ati awọn imuposi lati jẹ ki iṣẹ ṣiṣe ti modulu agbara switcher rọrun.

Nigbati o ba gbero ipilẹ ipese agbara, iṣaro akọkọ ni agbegbe lupu ti ara ti awọn meji yiyi awọn lupu lọwọlọwọ. 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. Ni lupu 1 ti o han ni Nọmba 1, kapasito fori ifilọlẹ ti ara ẹni lọwọlọwọ (Cin1) kọja nipasẹ MOSFET si inductor inu ati kapasito fori kaakiri (CO1) lakoko akoko adaṣe lemọlemọ ti MOSFET giga-giga, ati nikẹhin pada si kapasito fori input.

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

Nọmba 1 Aworan atọka ti lupu ni module agbara

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. Agbara ti a fipamọ sinu inductor inu n ṣàn nipasẹ kapasito fori ti o wujade ati MOSFEts opin kekere ṣaaju ki o to pada si GND (wo olusin 1). Ekun nibiti awọn lupu meji ko ni papọ ara wọn (pẹlu ala laarin awọn lupu) jẹ agbegbe ti o ni DI/DT lọwọlọwọ lọwọlọwọ. Kapasito fori titẹ sii (Cin1) ṣe ipa pataki ninu ipese ipese igbohunsafẹfẹ giga si oluyipada ati ipadabọ ipo igbohunsafẹfẹ giga si ọna orisun rẹ.

Agbara kaakiri iṣelọpọ (Co1) ko gbe lọwọlọwọ AC pupọ, ṣugbọn ṣe bi àlẹmọ igbohunsafẹfẹ giga fun yiyi ariwo. Fun awọn idi ti o wa loke, titẹ sii ati awọn kapasito iṣelọpọ yẹ ki o wa ni isunmọ bi o ti ṣee ṣe si awọn pinni VIN wọn ati VOUT lori modulu naa. Gẹgẹbi o ti han ni Nọmba 2, inductance ti ipilẹṣẹ nipasẹ awọn isopọ wọnyi le dinku nipasẹ ṣiṣe wiwọn laarin awọn kapasito fori ati awọn pin wọn VIN ati VOUT bi kukuru ati jakejado bi o ti ṣee.

Olusin 2 SIMPLE SWITCHER lupu

Dindinku inductance ni ipilẹ PCB ni awọn anfani pataki meji. Ni akọkọ, ilọsiwaju iṣẹ paati nipa igbega gbigbe agbara laarin Cin1 ati CO1. Eyi ṣe idaniloju pe modulu naa ni ifasita hf ti o dara, idinku awọn gaasi foliteji inductive nitori giga DI/DT lọwọlọwọ. O tun dinku ariwo ẹrọ ati aapọn foliteji lati rii daju iṣẹ ṣiṣe deede. Keji, dinku EMI.

Awọn agbara ti o ni asopọ pẹlu inductance parasitic to kere ṣe afihan awọn abuda ikọlu kekere si awọn igbohunsafẹfẹ giga, nitorinaa dinku itankalẹ ti a ṣe. Awọn agbara seramiki (X7R tabi X5R) tabi awọn kapasito iru ESR kekere miiran ni a ṣe iṣeduro. Afikun awọn kapasito igbewọle le wa sinu ere nikan ti a ba gbe awọn kapasito afikun nitosi GND ati VIN pari. 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.

Iṣeto ọna lọwọlọwọ lọwọlọwọ jẹ igbagbe nigbagbogbo, ṣugbọn o ṣe ipa pataki ni imudarasi apẹrẹ ipese agbara. 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.

Awọn pinni ti ilẹ (pẹlu awọn paadi igboro), titẹ sii ati awọn kapasito iṣelọpọ, awọn kapasitẹrẹ ibẹrẹ, ati awọn alatako esi ninu modulu yẹ ki gbogbo wa ni asopọ si fẹlẹfẹlẹ lupu lori PCB. Ipele lupu yii le ṣee lo bi ọna ipadabọ pẹlu lọwọlọwọ inductance kekere pupọ ati bi ẹrọ itusilẹ ooru ti jiroro ni isalẹ.

EEYA. 3 Aworan atọka ti modulu ati PCB bi ikọlu igbona

Alatako esi yẹ ki o tun wa ni isunmọ bi o ti ṣee ṣe si PIN FB (esi) ti module naa. 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. Fun apẹẹrẹ, wo aworan apẹrẹ PCB ninu tabili data module ti o yẹ.

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

Awọn imọran Apẹrẹ Itanna Ooru

Ifilelẹ iwapọ ti awọn modulu, lakoko ti o n pese awọn anfani itanna, ni ipa odi lori apẹrẹ imukuro ooru, nibiti agbara deede ti tuka lati Awọn aaye kekere. 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. Paadi naa ṣe iranlọwọ lati pese aibikita igbona kekere ti o kere pupọ lati MOSFEts inu, eyiti o ṣe ina pupọ julọ igbona, si PCB.

Idena igbona (θJC) lati isunmọ semikondokito si package ita ti awọn ẹrọ wọnyi jẹ 1.9 ℃/W. Lakoko ti o ṣaṣeyọri iye θJC ti ile-iṣẹ jẹ apẹrẹ, iwọn kekere θJC ko ni oye nigbati ifura igbona (θCA) ti package lode si afẹfẹ tobi pupọ! Ti ko ba si ọna ifasita igbona kekere-kekere si afẹfẹ agbegbe, ooru yoo kojọpọ lori paadi igboro ati pe ko le tuka. Nitorina kini ipinnu θCA? Idaabobo igbona lati paadi igboro si afẹfẹ jẹ iṣakoso patapata nipasẹ apẹrẹ PCB ati ifọwọkan ooru ti o somọ.

Bayi fun wiwo ni iyara bi o ṣe le ṣe apẹrẹ PCB ti o rọrun laisi awọn imu, eeya 3 ṣe afihan modulu ati PCB bi ikọja igbona. Nitori ikọlu igbona laarin isunmọ ati oke ti package ita jẹ jo ga ni akawe si ikọlu igbona lati ibi isunmọ si paadi igboro, a le foju foju ọna disJA igbona ooru lakoko iṣiro akọkọ ti resistance igbona lati ibi ipade si afẹfẹ agbegbe (θJT).

Igbesẹ akọkọ ninu apẹrẹ itusilẹ ooru ni lati pinnu iye agbara lati tuka. Agbara ti o jẹ nipasẹ modulu (PD) le ṣe iṣiro ni rọọrun nipa lilo iwọn ṣiṣe (η) ti a tẹjade ninu tabili data.

Lẹhinna a lo awọn idiwọn iwọn otutu ti iwọn otutu ti o pọ julọ ninu apẹrẹ, TAmbient, ati iwọn otutu idapo ti a ti sọ, TJuncTIon (125 ° C), lati pinnu idiwọ igbona ti o nilo fun awọn modulu ti o wa lori PCB.

Lakotan, a lo isunmọ isọdọtun ti gbigbe ooru ti o pọju lori oju PCB (pẹlu awọn imu idẹ 1-haunsi ti ko bajẹ ati ọpọlọpọ awọn iho ifibọ ooru lori mejeji awọn ilẹ oke ati isalẹ) lati pinnu agbegbe awo ti o nilo fun itusilẹ ooru.

Isunmọ agbegbe PCB ti a beere ko ṣe akiyesi ipa ti awọn iho imukuro ooru ti o gbe ooru lati fẹlẹfẹlẹ irin oke (package ti sopọ si PCB) si isalẹ irin irin. Ipele isalẹ n ṣiṣẹ bi fẹlẹfẹlẹ oju -aye keji nipasẹ eyiti convection le gbe ooru lati awo naa. O kere ju 8 si 10 awọn iho itutu yẹ ki o lo fun isunmọ agbegbe igbimọ lati wulo. Idaabobo igbona ti iwẹ ooru jẹ isunmọ nipasẹ idogba atẹle.

Isunmọ yii kan si iho-aṣoju aṣoju ti iwọn mil mil 12 pẹlu ogiri idẹ 0.5 oz. Bi ọpọlọpọ awọn ihò jijin ooru bi o ti ṣee ṣe yẹ ki o ṣe apẹrẹ ni gbogbo agbegbe ni isalẹ paadi igboro, ati awọn ihò jijin ooru wọnyi yẹ ki o ṣe akojọpọ pẹlu aye kan ti 1 si 1.5mm.

ipari

Module agbara SIMPLE SWITCHER n pese yiyan si awọn apẹrẹ ipese agbara eka ati awọn ipilẹ PCB aṣoju ti o ni nkan ṣe pẹlu awọn oluyipada DC/DC. Lakoko ti awọn italaya akọkọ ti yọkuro, diẹ ninu iṣẹ imọ -ẹrọ tun nilo lati ṣee ṣe lati mu iṣẹ ṣiṣe modulu ṣiṣẹ pẹlu irekọja ti o dara ati apẹrẹ imukuro ooru.