Ekhuluma ngenkinga enzima yokushintshwa kwamandla kagesi, 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: Ukusebenza kukagesi, inqubo yenqubo, izidingo zokuphepha, umthelela we-EMC, njll .; Phakathi kwezinto okufanele zicatshangelwe, ugesi yinto eyisisekelo kunazo zonke, kepha i-EMC inzima kakhulu ukuyiqonda, futhi umgogodla wamaphrojekthi amaningi use-EMC. Okulandelayo kusuka kuzikhombisi-ndlela ezingama-22 zokwabelana ngebhodi le-PCB ne-EMC.

1, isifunda esivuthiwe singaba isikhathi sokuphumula se-PCB design EMI circuit

Umthelela wesifunda esingenhla ku-EMC ungacabanga, izihlungi zokufaka zilapha; Lightning-proof pressure sensitivity; Ukumelana no-R102 ukuvimbela ukushaqeka kwamanje (ngokudlulisela ukunciphisa ukulahleka); Key error mode X capacitance and Y capacitance with inductor filtering; Kunamafusi athinta ibhodi yezokuphepha; Ngayinye yalezi zinsiza ibaluleke kakhulu, futhi ukusebenza nokwenziwa kwedivayisi ngayinye kufanele kuthokozelwe ngokucophelela. 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. Isekethe ne-EMC: (i-topology eyinhloko ejwayelekile kakhulu ye-flyback, bona ukuthi yiziphi izingxenye ezisemqoka zesifunda eziqukethe indlela ye-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. Kepha ukushintsha kwamandla kagesi kukhiqiza amandla kazibuthe aguqukayo, futhi amandla kazibuthe aguqukayo angaveza insimu kagesi (empeleni, lena yiMaxwell equation edumile futhi ngisebenzisa ulimi olulula), futhi inkambu kagesi eguqukayo nayo ingaveza amandla kazibuthe inkambu. Ngakho-ke qiniseka ukuthi unaka izindawo lapho kunezindawo zokucisha / zokucisha, leyo ngenye yemithombo ye-EMC, futhi lo ngomunye wemithombo ye-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! Amanye amaluphu amabili amaluphu okumunca nokulungisa amaluphu, qala uqonde kusengaphambili, bese ukhuluma!

3. Ukuhlangana phakathi kwe-PCB design ne-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. Ingxenye yesakhiwo, isisekelo sokwakhiwa kwe-radiator akukuhle kuzothinta isisekelo senguqulo evikelwe;

4. Uma ingxenye ezwelayo isondele kakhulu emthonjeni wokuphazamiseka, ofana nesekethe le-EMI kanye noshintshi weshubhu, nakanjani kuzoholela ku-EMC empofu, futhi kuyadingeka indawo ecacile yokuhlukaniswa.

5. Intambo ye-RC yokumunca iluphu.

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

Ngizokhuluma ngalokhu, futhi ngizokhuluma ngakho kakhulu, kodwa ngizokunika ukuhola.

Here’s a quick example:

Njengoba kukhonjisiwe ebhokisini elinamachashazi kumfanekiso ongenhla, i-X capacitor pin wiring ifakwe indenti. Ungafunda ukuthi ungayenza kanjani i-capacitor pin wiring yangaphandle (usebenzisa i-wiring wiring yamanje). Ngale ndlela, umphumela wokuhlunga we-X capacitor ungafinyelela esimweni esihle kakhulu.

4. Ukulungiselela ukwakheka kwe-PCB: (uma uzilungiselele ngokuphelele, idizayini ingaba igxathu negxathu ukugwema ukuklanywa nokuqalwa kabusha komklamo)

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.

4. Inqubo yokukhethwa komzila: ukukhethwa kwephaneli elilodwa lephaneli elilodwa, noma ibhodi enezingqimba eziningi, ngokusho komdwebo wesayizi nosayizi webhodi, izindleko nokunye ukuhlolwa okuphelele.

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. Ibanga lephedi yokufaka i-fuse likhulu kuno-3.0mm njengoba kudingwa yimithethonqubo yokuphepha, kanti ipuleti langempela lingu-3.5mm (uma sikhuluma nje, ibanga le-fuse lingu-3.5mm ngaphambili naku-3.0mm ngemuva).

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. Imithethonqubo yokuphepha yesigaba sokuqala idinga u-6.4mm (igebe likagesi), kanti ibanga le-creepage kufanele libe ngu-7.6mm. )

5. Cold ground and hot ground are clearly marked for the first stage; L, N uphawu, INPUT AC INPUT mark, uphawu lokuxhuma lwe-fuse nokunye kufanele kumakwe ngokucacile;

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. Kumithethonqubo yokuphepha, qonda izici zokuhlukanisa indawo eseduze nebhodi le-PCB, okuyindawo yokufaka okuyisisekelo, okuyindawo eqinisiwe, ibanga elihlukile lokuhlukanisa alifani. Kungcono ukuhlola amazinga, futhi ungabala ibanga likagesi, ibanga le-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. Ubudlelwano phakathi kwe-Y capacitance nokuvuza kwamanje nokuxhumana kwamanje.

Njalonjalo, izocacisa ngokuningiliziwe ukuthi ungashiya kanjani ibanga, nokuthi ungazenza kanjani izidingo zokuphepha.

I-6, ukwakheka kwe-PCB kokuhlelwa kokuphakelwa kwamandla

1.Qala ukukala usayizi we-PCB kanye nenani lezinto, ukuze uzuze ukuminyana okuhle, noma okucinene, okuncane kuzoba kubi.

2. Yenza kube lula ukujikeleza isifunda, thatha amadivayisi ayisisekelo njengesikhungo, bese ubeka amadivayisi angukhiye kuqala.

3. Idivayisi imile mpo noma ivundlile ekumiseni ukuma, enye yinhle, enye ilula ukusebenza kwe-plug-in, izimo ezikhethekile zingacabanga ngokutsheka.

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

5. Nciphisa indawo yeluphu ngangokunokwenzeka ngesikhathi sesakhiwo. Amaluphu amane azochazwa ngokuningiliziwe ngokuhamba kwesikhathi.

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

Okulandelayo yi-PCB yokuqala yezintombi engiyidwebile, eminyakeni eminingi edlule, bekunzima kakhulu ukuqeda, kungahle kube nenkinga encane phakathi, kepha ukwakheka okujwayelekile kufanele kufundwe:

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. Okokufaka nokokukhipha kulungisiwe futhi akukwazi ukuhanjiswa. Ibhodi lingunxande.

Lapha ukwakheka kusuka phansi kuye phezulu, kusuka kwesobunxele kuye kwesokudla, futhi ukushabalalisa ukushisa kuncike kugobolondo.

Isifunda se-2.EMI sisekuqondeni kokugeleza okucacile, okubaluleke kakhulu, ngaphandle kwalokho akukuhle futhi akukubi ku-EMC.

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. Isendlalelo esiphezulu samandla aphakeme ngokuvamile siba mbi, bese isendlalelo esingezansi sihamba kahle.

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. Ukwazisa izibonelo ze-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! Ngemuva kuzoba nokuthi leli bhodi lichaze ngokufunda, siqala ukujabulela.

8. Ukuqonda amaluphu amane we-PCB design: (imfuneko eyisisekelo yokwakheka kwe-PCB yindawo encane yamaluphu amane)

Ngaphezu kwalokho, i-loop yokumunca (ukumunca i-RCD, ukumuncwa kwe-RC ye-MOS tube ne-RC ukumunca i-rectifier tube) nayo ibaluleke kakhulu, okuyi-loop edala imisebe ephezulu yemvamisa. Uma unemibuzo mayelana nalesi sibalo esingenhla, wamukelekile ukuxoxa ngaso. Asesabi lutho imibuzo.

9.I-PCB design indawo eshisayo (iphuzu elintantayo elinamandla) nocingo lomhlabathi:

Izinto ezidinga ukunakwa:

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. I-loop eyakhiwe izindawo ezishisayo incane futhi i-wiring ifushane, futhi i-wiring ayinamandla ngangokunokwenzeka, kepha inqobo nje uma i-current yanele.

3. Ikhebula lomhlabathi kufanele ligxilwe endaweni eyodwa. Umhlabathi omkhulu wamandla nomhlabathi wesiginali uhlukile, umhlaba wesampuli uhamba ngokwahlukana.

4. Umhlabathi we-radiator udinga ukuxhumeka endaweni enkulu yamandla.