Ao amin’ny Tthe EMC famolavolana ny PCB, ny olana voalohany dia ny fametrahana ny sosona; Ny sosona ny solaitrabe dia misy famatsian-kery, sosona amin’ny tany ary sosona famantarana. Amin’ny famolavolana ny vokatra EMC, ankoatry ny fisafidianana ny singa sy ny famolavolana boribory, ny famolavolana PCB tsara dia zava-dehibe ihany koa.

The key to the EMC design of PCB is to minimize the backflow area and make the backflow path flow in the direction we designed. Ny famolavolana sosona no fototry ny PCB, ny fomba fanaovana asa tsara amin’ny famolavolana sosona PCB hahatonga ny vokan’ny EMC amin’ny PCB ho tonga lafatra?

I. Hevitra famolavolana sosona PCB

The core of PCB laminated EMC planning and design is to reasonably plan signal backflow path to minimize the backflow area of signal from the board mirror layer, so as to eliminate or minimize magnetic flux.

Single sosona fitaratra fitaratra

Ny sosona fitaratra dia sosona feno vatan’ny fiaramanidina mifono varahina (sosona famatsiana herinaratra, sosona miorina) mifanila amin’ilay sosona famantarana ao anatin’ny PCB. Ireto no tena lahasa lehibe:

(1) Ahenao ny tabataba miverimberina: ny sosona fitaratra dia afaka manome làlana mivezivezy ambany ho an’ny fihenan-tsofin’ny signal signal, indrindra rehefa misy mikoriana be eo amin’ny rafitra fizarana herinaratra, miharihary kokoa ny anjara asan’ny sosona fitaratra.

(2) EMI fihenam-bidy: ny fisian’ny soson’ny fitaratra dia mampihena ny faritry ny tadivavarana mihidy noforonin’ny famantarana sy ny reflux ary mampihena ny EMI;

(3) mampihena crosstalk: manampy amin’ny fifehezana ny olan’ny crosstalk eo anelanelan’ny tsipika famantarana amin’ny alàlan’ny haingam-pandeha haingam-pandeha, manova ny haavon’ny tsipika famantarana avy amin’ny takelaka fitaratra, azonao atao ny mifehy ny crosstalk eo anelanelan’ny tsipika famantarana, ny kely kokoa ny hahavony, ny kely kokoa ny crosstalk;

(4) Fanaraha-maso imppedance hisorohana ny taratry ny signal.

Selection of mirror layer

(1) Ny famatsian-jiro sy ny fiaramanidina ifotony dia azo ampiasaina ho toy ny fiaramanidina fanovozan-kevitra ary misy fiatraikany amin’ny tariby anatiny;

(2) Relatively speaking, the power plane has a high characteristic impedance, and there is a large potential difference with the reference level, and the high-frequency interference on the power plane is relatively large;

(3) From the perspective of shielding, the ground plane is generally grounded and used as the reference point of the reference level, and its shielding effect is far better than that of the power plane;

(4) Rehefa misafidy ny fiaramanidina fanovozan-kevitra dia tokony aleony ny fiaramanidina ifotony ary ny fiaramanidina herinaratra dia tokony ho voafantina faharoa

Two, magnetic flux cancellation principle

Araka ny filazan’i Maxwell, ny fihetsika elektrika sy andriamby rehetra eo anelanelan’ny vatana na ny onja misaraka, dia ampitaina amin’ny faritra afovoany eo anelanelan’izy ireo, na banga na zavatra matevina io. In a PCB, the flux is always propagated in the transmission line. If the rf backflow path is parallel to the corresponding signal path, the flux on the backflow path is in the opposite direction to that on the signal path, then they are superimposed on each other, and the effect of flux cancellation is obtained.

Ny toetoetran’ny fanafoanana ny flux magnetika

Ny votoatin’ny fanafoanana ny flx dia ny fifehezana ny làlan’ny fiverenan’ny signal, araka ny aseho amin’ity sary manaraka ity:

The right hand rule explains the magnetic flux cancellation effect

How to use the right hand rule to explain the magnetic flux cancellation effect when the signal layer is adjacent to the stratum is explained as follows:

(1) Rehefa mikoriana eo amin’ny tariby ny ony dia hisy sahan’andriamby manodidina ny tariby, ary ny làlan’ny sahan’andriamby dia voafaritry ny fitsipiky ny tanana ankavanana.

(2) rehefa misy roa mifanakaiky ary mifanitsy amin’ny tariby, araka ny aseho eo amin’ny sary etsy ambany, ny iray amin’ireo mpampita herinaratra hivoaka, ny iray kosa mpampita herinaratra hikoriana, raha mandeha amin’ny tariby dia misy ankehitriny ary ny fiverenany ankehitriny, avy eo ny làlana roa mifanohitra amin’ny ankehitriny dia mitovy, ka mitovy ny sahan’andriamby, fa ny lalana kosa mifanohitra,Noho izany dia mifamono izy ireo.

Ohatra amin’ny famolavolana birao dimy, enina

Ho an’ny sosona enina dia aleony ny plan 3

Analysis:

(1) Satria ny sisin’ny signal dia mifanila amin’ny fiaramanidina referow, ary ny S1, S2 ary S3 dia mifanila amin’ny fiaramanidina ambanin’ny tany, dia tratra ny vokatra fanafoanana flux tsara indrindra. Noho izany, S2 no sosona fitaterana tianao, arahin’i S3 sy S1.

(2) Ny fiaramanidina herinaratra dia mifanila amin’ny fiaramanidina GND, ny halavirana eo anelanelan’ny fiaramanidina dia kely dia kely, ary manana ny fiantraikan’ny fanafoanana flux andriamby tsara indrindra sy ny fijanonan’ny fiaramanidina ambany.

(3) Ny famatsiana herinaratra lehibe sy ny lamban’ny gorodona mifanitsy aminy dia hita eo amin’ny sosona 4 sy 5. Rehefa apetraka ny hatevin’ny sosona, tokony hampitomboina ny elanelana misy eo amin’ny S2-P ary tokony hahena ny elanelana misy eo anelanelan’ny P-G2 (ny elanelana misy eo anelanelan’ny sosona Ny G1-S2 dia tokony hahena araka izany), mba hampihenana ny fijanonan’ny fiaramanidina herinaratra sy ny fitaoman’ny herinaratra amin’ny S2.

Ho an’ny sosona enina, safidy 4

Analysis:

Ny Scheme 4 dia mety kokoa noho ny Scheme 3 ho an’ny eo an-toerana, isan’ny fepetra takiana amin’ny signal, izay afaka manome S2 tariby tena tsara.

Vokatry ny EMC ratsy indrindra, drafitra 2

Famakafakana: Amin’ity firafitra ity, ny S1 sy ny S2 dia mifanila aminy, ny S3 sy ny S4 mifanila aminy, ary ny S3 sy ny S4 dia tsy mifanakaiky amin’ny fiaramanidina ambanin’ny tany, noho izany dia ratsy ny vokatra fanafoanana ny flux magnetika.

famaranana

Specific principles of PCB layer design:

(1) There is a complete ground plane (shield) below the component surface and welding surface;

(2) Miezaha hisoroka ny mifanila mivantana amin’ireo sosona famantarana roa;

(3) Ny sosona famantarana rehetra dia mifanila amin’ny fiaramanidina ambanin’ny tany araka izay azo atao;

(4) Ny elakelan’ny tariby misy haavo matetika, haingam-pandeha, famantaranandro ary mari-pamantarana hafa dia tokony hanana fiaramanidina mifanila aminy.