Ha re bua ka bothata bo thata ba phepelo ea motlakase, PCB cloth plate problems is not very difficult, but if want to cloth up a refined PCB must be one of the difficulties in switching power supply (PCB design is not good, may cause no matter how to debug parameter debugging cloth out of the situation, so not scaremongering) when reason was the PCB board consideration or a lot of, such as: Ts’ebetso ea motlakase, tsela ea ts’ebetso, litlhoko tsa polokeho, tšusumetso ea EMC, jj .; Har’a lintlha tse lokelang ho tsotelloa, motlakase ke ona oa mantlha ka ho fetesisa, empa EMC ke eona e thata ka ho fetisisa ho e utloisisa, ‘me bothata ba merero e mengata bo ho EMC. Tse latelang ho tsoa litsamaisong tse 22 ho arolelana boto ea PCB le EMC.

1, oa potoloho ba holileng tsebong e ka ba boikhathollo PCB moralo EMI oa potoloho

Kameho ea potoloho e kaholimo ho EMC e ka nahanoa, li-filtara tsa ho kenya li teng mona; Lightning-proof pressure sensitivity; Ho hanyetsa R102 ho thibela tšabo ea hajoale (ka lesokoana ho fokotsa tahlehelo); Key error mode X capacitance and Y capacitance with inductor filtering; Ho na le li-fuse tse amang boto ea polokeho; E ‘ngoe le e’ ngoe ea lisebelisoa tsena e bohlokoa haholo, mme ts’ebetso le ketso ea sesebelisoa ka seng li lokela ho ananeloa ka hloko. The EMC severity level should be considered when designing the circuit, such as the number of filters to be set, the number and location of the y-capacitor quantity. The choice of pressure-sensitive size and quantity is closely related to our requirements for EMC. Welcome to discuss the seemingly simple EMI circuit that actually contains profound truths for each component.

2. Potoloho le EMC: (topology e tsebahalang haholo ea flyback, bona hore na ke likarolo life tsa bohlokoa tsa potoloho tse nang le mekhoa ea EMC)

The circled parts in the circuit in the figure above are very important for EMC (note that the green part is not), such as radiation. It is known that electromagnetic field radiation is spatial, but the basic principle is the change of magnetic flux, which involves the effective cross-sectional area of magnetic field, namely the corresponding loop in the circuit. The electric current can produce a magnetic field, which is stable and cannot be converted into an electric field. Empa matla a fetohang a motlakase a hlahisa matla a khoheli a fetohang, ‘me matla a fetohang a matla a khoheli a ka hlahisa tšimo ea motlakase (ehlile ena ke sebaka se tummeng sa Maxwell mme ke sebelisa puo e hlakileng), mme tšimo e fetohang ea motlakase le eona e ka hlahisa matla a khoheli. tšimo. Kahoo etsa bonnete ba hore u ela hloko libaka tseo ho nang le libaka tsa ho tima / ho tima, ona ke o mong oa mehloli ea EMC, ‘me ona ke o mong oa mehloli ea EMC. For example, the dotted line loop in the circuit is the opening and closing loop of the switch tube. Not only the switching speed can be adjusted during the design of the circuit, but also the area of the wiring loop of the layout board has an important influence on EMC! Li-loops tse ling tse peli ke li-loops tsa ho monya le ho lokisa li-loops, qala ho utloisisa esale pele, ebe u bua!

3. Kamano lipakeng tsa moralo oa PCB le EMC

1.PCB loop has a very important influence on EMC, such as flyback main power loop. If it is too large, the radiation will be poor.

2. Filter wiring effect, filter is used to filter out interference, but if PCB wiring is not good, filter may lose the effect it should have.

3. Karolo ea sebopeho, sebopeho sa radiator ha se hantle se tla ama motheo oa mofuta o sirelelitsoeng;

4. Haeba karolo e hlokolosi e le haufi haholo le mohloli oa tšitiso, joalo ka potoloho ea EMI le switch tube, e tla lebisa ho EMC e futsanehileng, mme sebaka se hlakileng sa ho itšehla thajana sea hlokahala.

5. Wiring ea RC absorption loop.

6.Y capacitor grounding and wiring, and the position of Y capacitor is also critical!

Ke tlo bua ka taba ena, mme ke tlo bua ka yona ho feta, empa ke ya o etella pele.

Here’s a quick example:

Joalokaha ho bontšitsoe lebokoseng le nang le marontho setšoantšong se kaholimo, X wiring pin wiring e kentsoe indent. U ka ithuta ho etsa wiring ea capacitor pin ka ntle (u sebelisa mochini o tobileng oa hona joale). Ka tsela ena, tšusumetso ea X capacitor e ka fihla boemong bo botle.

4. Boitokisetso ba moralo oa PCB: (haeba u itokiselitse ka botlalo, moralo o ka ba mohato o tsitsitseng mohato ka mohato ho qoba ho phethoha ha moralo le ho qala hape)

There are roughly the following aspects, are their own design process to consider, all the content has nothing to do with other tutorials, are just their own experience summary.

1. Appearance structure size, including positioning hole, air channel flow direction, input and output socket, need to match with the customer system, also need to communicate with the customer assembly problems, height limit and so on.

2. Safety certification, products do what kind of certification, where do the basic insulation creepage distance to leave enough, where do strengthen the insulation to leave enough distance or slot.

3. Packaging design: there is no special period, such as preparation for customized packaging.

Khetho ea tsela ea ts’ebetso: khetho e le ‘ngoe ea phanele e habeli, kapa boto ea mekato e mengata, ho latela setšoantšo le boholo ba boto, litšenyehelo le tlhahlobo e ngoe e felletseng.

5. Other special requirements of customers.

The structure and process will be relatively more flexible, safety regulations or relatively fixed part, what certification to do, what safety standards, of course, there are some safety regulations are common in many standards, but there are also some special products such as medical treatment will be more stringent.

For the new entry engineer friends are not dazzled;

Next list some general products general, the following is summarized for IEC60065 specific cloth requirements, for safety needs to keep in mind, encounter specific products will be targeted processing:

1. Sebaka sa sebaka sa fuse ea ho kenya se seholo ho feta 3.0mm joalo ka ha ho hlokoa ke melao ea polokeho, ‘me poleiti ea’ nete ke 3.5mm (ha re bua feela, sebaka sa fuse ke 3.5mm pele le 3.0mm kamora moo).

2. Before and after the rectifier bridge, the safety requirements are 2.0MM, and the plate layout is 2.5MM.

3. After rectification, safety regulations generally do not require, but the distance between high and low voltage is left according to the actual voltage, and 400V high voltage is left above 2.0mm.

4. Melao ea polokeho ea mokhahlelo oa pele e hloka 6.4mm (lekhalo la motlakase), ‘me sebaka sa creepage e lokela ho ba 7.6mm. (Hlokomela hore sena se amana le motlakase oa ho kenya, o hloka ho supa tafoleng bakeng sa lipalo tse ikhethileng, tlhaiso-leseling e fanoeng bakeng sa ts’upiso feela, ho latela maemo a nnete)

5. Cold ground and hot ground are clearly marked for the first stage; L, N letšoao, INPUT AC INPUT letšoao, letšoao la fuse la tlhokomeliso joalo joalo le lokela ho tšoauoa ka ho hlaka;

It is reiterated that the actual safety distance is related to the actual input voltage and the working environment, so it is necessary to refer to the table for specific calculation. The data provided is for reference only and shall prevail in the actual situation.

5. Consider other factors for PCB design safety

1. Understand what certification their products do and what product categories they belong to. For example, medical treatment, communication, electricity, TV and so on are different, but there are also many similarities.

2. Ka melaoana ea polokeho, utloisisa litšobotsi tsa ho koalanya sebaka se haufi le board ea PCB, e leng sebaka sa mantlha sa ho ikoahela, sebaka se tiisitsoeng se koahetsoeng, sebaka se fapaneng sa ho koala ha se tšoane. Ho molemo ho hlahloba maemo, ‘me o ka bala sebaka sa motlakase, sebaka sa creepage.

3. Focus on the safety devices of the product, such as the relationship between the magnetism of the transformer and the original side;

4. Radiator and surrounding distance problem, radiator insulation is not the same as the ground is not the same, the ground is cold, hot insulation is the same cloth.

5. Special attention should be paid to the distance of insurance, requiring the strictest place. The distance between front and rear of the fuse is consistent.

6. Kamano lipakeng tsa Y capacitance le ho dutla hajoale le hajoale ho ikopanya.

Joalo-joalo, e tla hlalosa ka ho qaqileng hore na u ka tloha hole joang, hore na u ka etsa joang litlhoko tsa polokeho.

6, moralo oa PCB oa phepelo ea motlakase

1. Pele lekanya boholo ba PCB le palo ea likaroloana, e le ho fihlela botebo bo botle, kapa botenya, ho tla ba mpe.

2. Etsa potoloho ka mokhoa o itekanetseng, nka lisebelisoa tsa mantlha e le setsi, ‘me u behe lisebelisoa tsa bohlokoa pele.

3. Sesebelisoa se khahlanong le maemo, se setle kapa se otlolohileng, se seng se setle, se seng se sebetsa hantle ka plug-in, maemo a ikhethang a ka nahana ka ho sekama.

4. Take cabling into consideration and arrange the layout in the most reasonable position for subsequent cabling.

5. Fokotsa sebaka sa lupu ka hohle kamoo ho ka khonehang nakong ea moralo. Li-loops tse ‘ne li tla hlalosoa ka botlalo hamorao.

Do the above points, of course, flexible use, more reasonable layout will be born soon.

E latelang ke PCB ea moroetsana ea pele eo ke e takileng, lilemong tse ngata tse fetileng, ho ne ho le thata haholo ho e qeta, ho kanna ha ba le bothata bo bonyenyane bohareng, empa sebopeho se akaretsang se lokela ho ithutoa:

In this figure, the power density is still relatively high. The control part of LLC, the auxiliary source part and the BUCK circuit driver (high-power multi-channel output) part are on the small board, which is not taken out. Let’s take a look at the layout characteristics of the main power:

1. Lisebelisoa tsa ho kenya le ho hlahisa li tsitsitse ‘me li ke ke tsa sisinyeha. Boto e likhutlo li ‘ne.

Mona moralo o tloha tlase ho ea holimo, ho tloha ka letsohong le letšehali ho ea ho le letona, ‘me phallo ea mocheso e ipapisitse le khetla.

Potoloho ea 2.

3. The position of large capacitor should consider PFC loop and LLC main power loop as far as possible;

4. The current of the side side is relatively large. In order to run the current and dissipate the heat of the rectifier tube, this layout is adopted. Karolo e kaholimo ea matla a phahameng ka kakaretso e ea hampe, ‘me e ka tlase e ea ntle.

Each board has its own characteristics, of course, also has its own difficulties, how to reasonably solve the key, we can understand the layout of reasonable selection of meaning?

7. Kananelo ea mehlala ea PCB

I think it is a good place to do it. Of course, there will always be defects, which can also be pointed out. It is not easy for a single panel to be so compact, so you can use this board to learn and discuss! Ka morao hape e tla ba hore boto ena e hlalose thuto, re qala ho e thabela.

8. Kutloisiso ea likonopo tse ‘ne tsa moralo oa PCB: (tlhoko ea mantlha ea sebopeho sa PCB ke sebaka se senyenyane sa likonopo tse’ ne)

Ntle le moo, mokelikeli oa ho monya (RCD absorption, RC absorption ea MOS tube le RC absorption ea rectifier tube) le eona e bohlokoa haholo, e leng leqhubu le hlahisang mahlaseli a phahameng a maqhubu. Haeba u na le lipotso mabapi le setšoantšo se kaholimo, u ka thabela ho li tšohla. Ha re tšabe lipotso leha e le life.

9. PCB e qapa sebaka se chesang (ntlha e ka bang teng e phaphametseng) le terata ea fatše:

Lintlha tse hlokang ho tsotelloa:

1. Pay special attention to hot spots (high-frequency switching points), which are high-frequency radiation points. Cable layout has a great impact on EMC.

2. Lupu e entsoeng ke libaka tse chesang e nyane mme wiring e khuts’oane, ‘me wiring ha e tenya kamoo ho ka khonehang, empa ha feela matla a hona joale a lekane.

3. Thapo ea mobu e tlameha ho theoa ntlheng e le ‘ngoe. Sebaka se ka sehloohong sa motlakase le mobu oa lets’oao o arohane, mehlala ea mobu e ea arohana.

4. Mobu oa radiator o hloka ho hokahanngoa le mochini o moholo oa motlakase.