Ngokusekelwe kulo PCB ubeko lonikezelo lwamandla, eli phepha lazisa eyona ndlela yokuyilwa kwePCB, imizekelo kunye neendlela zokuphucula ukusebenza kwemodyuli yamandla eswitshi elula.

Xa ucwangcisa ubeko lonikezelo lwamandla, into yokuqala ethathelwa ingqalelo yindawo yeluphu ebonakalayo kwezi zimbini zitshintshayo zangoku. 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. Kwi-loop 1 eboniswe kumzobo 1, igalelo lokuzilawula lokuzidlula ngoku (i-Cin1) elidlula kwi-MOSFET ukuya kwi-inductor yangaphakathi kunye nakwimveliso ye-bypass capacitor (CO1) ngexesha lokuqhubeka ngokuqhubekayo kweMOSFET ephezulu, kwaye ekugqibeleni ibuyela igalelo lokudlula kwi-capacitor.

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

Umzobo 1 Umzobo weskimu welogo kwimodyuli 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 kwi-inductor yangaphakathi ihamba ngokuphuma kwe-capacitor kunye nesiphelo esisezantsi se-MOSFEts ngaphambi kokubuyela kwi-GND (jonga umfanekiso 1). Ummandla apho iiluphu ezimbini zingadibaniyo (kubandakanywa umda phakathi kweziporo) ngummandla one-DI / DT ephezulu ngoku. Igalelo lokudlula kwi-capacitor (i-Cin1) lidlala indima ephambili ekuboneleleni ngesantya esiphakamileyo sangoku kwisiguquli kunye nokubuyisela imeko yangoku ephezulu kumthombo wayo.

Imveliso yokudlula kwi-capacitor (Co1) ayiphathi i-AC yangoku, kodwa isebenza njengecebo lokucoca isantya esiphakamileyo sokutshintsha ingxolo. Ngenxa yezi zizathu zingasentla, igalelo kunye neziphumo zeekhabnitha kufuneka zibekwe kufutshane kangangoko kwi-VIN kunye ne-VOUT yezikhonkwane kwimodyuli. Njengoko kubonisiwe kumzobo 2, ukungafakwanga okuveliswe koku kunxibelelana kunokuncitshiswa ngokwenza i-wiring phakathi kwe-bypass capacitors kunye ne-VIN kunye ne-VOUT yezikhonkwane ezimfutshane nezibanzi kangangoko kunokwenzeka.

Umzobo 2 SIMPLE SWITCHER loop

Ukucutha inductance kulwakhiwo lwePCB kunezibonelelo ezimbini eziphambili. Okokuqala, phucula ukusebenza kwecandelo ngokukhuthaza ukuhanjiswa kwamandla phakathi kweCin1 kunye ne-CO1. Oku kuqinisekisa ukuba imodyuli ine-hf yokudlula elungileyo, ukunciphisa iincopho zamandla ombane ngenxa ye-DI / DT ephezulu yangoku. Iyanciphisa nengxolo yesixhobo kunye noxinzelelo lwevolthi ukuqinisekisa ukusebenza kwesiqhelo. Okwesibini, ukunciphisa i-EMI.

I-Capacitors edityaniswe ne-infasas infucation inductance ibonakalisa iimpawu eziphantsi ze-impedance kwii-frequency eziphezulu, oko ke kunciphisa i-radiation eqhutyiweyo. Iiceramic capacitors (i-X7R okanye i-X5R) okanye ezinye ii-capacitors ezisezantsi ze-ESR ziyacetyiswa. Ii-capacitors zokufaka ezongezelelweyo zinokudlala kuphela ukuba ii-capacitors ezongezelelweyo zibekwe kufutshane ne-GND kunye neVIN. 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.

Ukucwangciswa kwendlela yangoku kuhlala kungakhathalelwanga, kodwa kudlala indima ephambili ekuphuculeni uyilo lonikezelo lwamandla. 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 ezisisiseko (kubandakanya iiphedi ezingenanto), igalelo kunye neziphumo zokuthintela, ukuqala kokuthamba, kunye neempendulo ezichasayo kwimodyuli kufuneka zonke zidityaniswe kumaleko e-loop kwi-PCB. Lo maleko wokujikeleza unokusetyenziswa njengendlela yokubuyela kunye ne-inductance yangoku ephantsi kakhulu kwaye njengesixhobo sokuhambisa ubushushu esixoxwe ngezantsi.

IKHIWANE. 3 Umzobo obonisa imodyuli kunye nePCB njengempembelelo ye-thermal

Isichaso sokuphendula kufuneka sibekwe kufutshane kangangoko kunokwenzeka kwi-FB (ingxelo) isikhonkwane semodyuli. 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.

Iingcebiso zoyilo lobushushu

Ubume beemodyuli ezixineneyo, ngelixa zibonelela ngezibonelelo zombane, zinefuthe elibi kuyilo lokusasaza ubushushu, apho amandla alinganayo apheliswa kwizithuba ezincinci. 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 inceda ukubonelela nge-impedance esezantsi kakhulu kwi-MOSFEts yangaphakathi, ethi ivelise ubukhulu bobushushu, kwi-PCB.

I-impedance ye-thermal (θJC) ukusuka kwi-semiconductor junction ukuya kwiphakheji yangaphandle yezi zixhobo yi-1.9 ℃ / W. Ngelixa ukufezekisa ishishini elikhokelela kwi-θJC kufanelekile, ixabiso eliphantsi le-CJC alwenzi ngqondo xa i-impedance ye-thermal (θCA) yephakheji yangaphandle emoyeni inkulu kakhulu! Ukuba akukho ndlela yokutshutshisa ubushushu ephantsi inikwa umoya ojikelezileyo, ubushushu buya kuqokeleleka kwibala elingenanto kwaye abunakupheliswa. Ke yintoni egqiba i-θCA? Ukuxhathisa kobushushu ukusuka kwindawo engenanto ukuya emoyeni kulawulwa ngokupheleleyo kuyilo lwePCB kunye nesinki yokufudumeza enxulumene nayo.

Ngoku ukujonga ngokukhawuleza indlela yokuyila iPBB elula ngaphandle kwamaphiko, umzobo 3 ubonakalisa imodyuli kunye nePCB njengempembelelo ye-thermal. Ngenxa yokuba i-impedance ye-thermal phakathi kwesiphambuka kunye nomphezulu wepakeji yangaphandle iphakame kakhulu xa kuthelekiswa ne-thermal impedance ukusuka kwisiphambuka ukuya kwi-pad engenanto, sinokuyihoya indlela ye-θJA yokusasaza ubushushu ngexesha loqikelelo lokuqala lokuchasana nobushushu ukusuka kwindibano ukuya umoya ojikelezileyo (θJT).

Inyathelo lokuqala kuyilo lokusasaza ubushushu kukuqinisekisa ubungakanani bamandla anokuchithwa. Amandla asetyenziswa yimodyuli (PD) anokubalwa ngokulula kusetyenziswa igrafu yokusebenza (η) epapashwe kwitafile yedatha.

Sisebenzisa ke ubunzima obubobona buthi buninzi kuyilo, i-TAmbient, kunye nobushushu be-junction, TJuncTIon (125 ° C), ukumisela ubushushu obufunekayo kwiimodyuli ezipakishwe kwi-PCB.

Okokugqibela, sisebenzise ulungelelwaniso olwenziwe lula lokuhambisa ubushushu obuninzi kwindawo yePCB (kunye ne-1-ounce yamaphiko obhedu angonakaliswanga kunye nemingxunya yokuntywila kobushushu kwimigangatho ephezulu kunye nezantsi) ukumisela indawo yeplate efunekayo ukusasaza ubushushu.

Indawo yePCB yokuqikelelwa ayiyithatheli ngqalelo indima edlalwe yimingxunya yokunyusa ubushushu ehambisa ubushushu ukusuka kumaleko aphezulu esinyithi (iphakheji iqhagamshelwe kwi-PCB) kumaleko wentsimbi ongezantsi. Umaleko osezantsi usebenza njengomaleko womgangatho wesibini apho ukuhambisa kungadlulisa ubushushu kwisitya. Ubuncinci i-8 ukuya kwi-10 imingxunya yokupholisa kufuneka isetyenziselwe ukuqikelela kwendawo yebhodi ukuba isebenze. Ukuxhathisa kobushushu besinki yokufudumeza kuqikelelwa yile nxaki.

Olu hlobo lusondela kumngxuma oqhelekileyo we-12 mils enobubanzi obuyi-0.5 oz yodonga lobhedu. Mininzi imingxunya esinki yokufudumeza kangangoko kufanele ukuba yenzelwe kwindawo engaphantsi kwephedi engenanto, kwaye le mingxunya yokuntywila kobushushu kufuneka yenze uluhlu olunezithuba ezi-1 ukuya kwi-1.5mm.

siphelo

Imodyuli yamandla ESIMPLE SWITCHER ibonelela ngenye indlela yoyilo olunzima lokuyilwa kwamandla kunye nolungelelwaniso lwePCB oluhambelana neziguquli zeDC / DC. Ngelixa imiceli mngeni yoyilo isusiwe, umsebenzi wobunjineli kusafuneka wenziwe ukwandisa ukusebenza kwemodyuli ngokudlula okuhle kunye noyilo lokusasaza ubushushu.