Akizungumzia shida ngumu ya kubadili umeme, 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: Utendaji wa umeme, njia ya mchakato, mahitaji ya usalama, athari za EMC, nk; Miongoni mwa mambo ya kuzingatiwa, umeme ndio msingi zaidi, lakini EMC ndio ngumu zaidi kuelewa, na kizingiti cha miradi mingi iko katika EMC. Ifuatayo kutoka kwa maagizo 22 ya kushiriki bodi ya PCB na EMC.

1, kukomaa mzunguko inaweza kuwa burudani PCB kubuni EMI mzunguko

Athari za mzunguko hapo juu kwenye EMC zinaweza kufikiria, vichungi vya kuingiza viko hapa; Lightning-proof pressure sensitivity; Upinzani R102 kuzuia mshtuko wa sasa (na relay ili kupunguza upotezaji); Key error mode X capacitance and Y capacitance with inductor filtering; Kuna fyuzi zinazoathiri bodi ya usalama; Kila moja ya vifaa hivi ni muhimu sana, na utendaji na hatua ya kila kifaa inapaswa kuthaminiwa kwa uangalifu. 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. Mzunguko na EMC: (topolojia kuu inayojulikana zaidi ya kuruka, angalia ni sehemu gani muhimu za mzunguko zina utaratibu wa 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. Lakini mabadiliko ya sasa ya umeme hutoa uwanja unaobadilika wa sumaku, na uwanja unaobadilika wa sumaku unaweza kutoa uwanja wa umeme (kwa kweli, hii ni equation maarufu ya Maxwell na ninatumia lugha nyepesi), na uwanja unaobadilika wa umeme unaweza pia kutoa sumaku uwanja. Kwa hivyo hakikisha unazingatia maeneo ambayo kuna hali ya kuzima / moja, hiyo ni moja wapo ya vyanzo vya EMC, na hii ni moja wapo ya vyanzo vya 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! Matanzi mengine mawili ni matanzi ya kunyonya na kurekebisha vitanzi, kwanza elewa mapema, halafu zungumza!

3. Ushirika kati ya muundo wa PCB na 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. Sehemu ya muundo, muundo wa radiator sio mzuri utaathiri kutuliza kwa toleo lenye ngao;

4. Ikiwa sehemu nyeti iko karibu sana na chanzo cha kuingiliwa, kama mzunguko wa EMI na bomba la kubadili, bila shaka itasababisha EMC duni, na eneo wazi la kutengwa linahitajika.

5. Wiring ya kitanzi cha ngozi cha RC.

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

Nitazungumza juu ya hii, na nitaizungumzia zaidi, lakini nitakupa uongozi.

Here’s a quick example:

Kama inavyoonyeshwa kwenye kisanduku kilichotiwa alama kwenye kielelezo hapo juu, waya ya X capacitor imewekwa ndani. Unaweza kujifunza jinsi ya kutengeneza wiring ya capacitor nje (kwa kutumia wiring ya sasa). Kwa njia hii, athari ya kuchuja ya X capacitor inaweza kufikia hali bora.

4. Maandalizi ya muundo wa PCB: (ikiwa umejiandaa kikamilifu, muundo unaweza kuwa thabiti hatua kwa hatua ili kuepuka muundo kupinduka na kuanza tena)

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. Mchakato wa uteuzi wa njia: jopo moja uteuzi wa paneli mbili, au bodi ya safu nyingi, kulingana na mchoro wa skimu na saizi ya bodi, gharama na tathmini nyingine kamili.

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. Umbali wa pedi ya fuse ya kuingiza ni kubwa kuliko 3.0mm kama inavyotakiwa na kanuni za usalama, na sahani halisi ni 3.5mm (kwa kusema tu, umbali wa fuse ni 3.5mm kabla na 3.0mm baada ya).

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. Kanuni za usalama kwa hatua ya kwanza zinahitaji 6.4mm (pengo la umeme), na umbali wa kutambaa unapaswa kuwa 7.6mm. (Kumbuka kuwa hii inahusiana na voltage halisi ya pembejeo, inahitaji kurejelea jedwali kwa hesabu maalum, data iliyotolewa kwa kumbukumbu tu, kulingana na hali halisi)

5. Cold ground and hot ground are clearly marked for the first stage; L, N alama, INPUT AC INPUT alama, alama ya fuse na kadhalika inapaswa kuwekwa alama wazi;

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. Katika kanuni za usalama, elewa sifa za insulation ya mahali karibu na bodi ya PCB, ambayo mahali ni insulation ya msingi, ni mahali gani ni insulation iliyoimarishwa, umbali tofauti wa kiwango cha kawaida sio sawa. Ni bora kuangalia viwango, na unaweza kuhesabu umbali wa umeme, umbali wa kutambaa.

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. Uhusiano kati ya uwezo wa Y na uvujaji wa sasa na sasa wa mawasiliano.

Na kadhalika, itaelezea kwa kina jinsi ya kuondoka umbali, jinsi ya kufanya mahitaji ya usalama.

6, muundo wa PCB wa mpangilio wa usambazaji wa umeme

1. Kwanza pima saizi ya PCB na idadi ya vifaa, ili kufikia unene mzuri, au mnene, nadra itakuwa mbaya.

2. Badilisha mzunguko, chukua vifaa vya msingi kama kituo, na uweke vifaa muhimu kwanza.

3. kifaa ni wima au usawa kupambana na nafasi, moja ni nzuri, na nyingine ni rahisi kuziba-katika operesheni, hali maalum zinaweza kuzingatia kuteleza.

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

5. Punguza eneo la kitanzi iwezekanavyo wakati wa mpangilio. Vitanzi vinne vitaelezewa kwa undani baadaye.

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

Ifuatayo ni PCB ya bikira ya kwanza niliyochora, miaka mingi iliyopita, ilikuwa ngumu sana kumaliza, kunaweza kuwa na shida ndogo katikati, lakini mpangilio wa jumla unastahili kujifunza:

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. Vituo vya kuingiza na kutoa vimewekwa sawa na haviwezi kusogezwa. Bodi ni mstatili.

Hapa mpangilio ni kutoka chini hadi juu, kutoka kushoto kwenda kulia, na utaftaji wa joto unategemea ganda.

Mzunguko wa EMI bado ni mwelekeo wazi wa mtiririko, ambayo ni muhimu sana, vinginevyo sio nzuri na mbaya kwa 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. Safu ya juu ya nguvu kubwa kwa ujumla huenda hasi, na safu ya chini inakuwa chanya.

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. Kuthamini mifano ya 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! Nyuma pia itakuwa kwa bodi hii kuelezea ujifunzaji, tunafurahiya kwanza.

8. Kuelewa vitanzi vinne vya muundo wa PCB: (mahitaji ya msingi ya mpangilio wa PCB ni eneo dogo la vitanzi vinne)

Kwa kuongezea, kitanzi cha kunyonya (ngozi ya RCD, ngozi ya RC ya bomba la MOS na ngozi ya RC ya bomba la kurekebisha) pia ni muhimu sana, ambayo pia ni kitanzi ambacho hutengeneza mionzi ya masafa ya juu. Ikiwa una maswali yoyote juu ya takwimu hapo juu, unakaribishwa kuyajadili. Hatuogopi maswali yoyote.

9. Ubuni wa PCB mahali pa moto (mahali pa kuelea) na waya wa ardhini:

Mambo yanayohitaji umakini:

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. Kitanzi kinachoundwa na maeneo ya moto ni kidogo na wiring ni fupi, na wiring sio nene iwezekanavyo, lakini kwa muda mrefu kama ya sasa inatosha.

3. Cable ya ardhi lazima iwe chini wakati mmoja. Nguvu kuu ya ardhi na ishara ya ardhi tofauti, ardhi ya sampuli huenda kando.

4. Ardhi ya radiator inahitaji kushikamana na uwanja kuu wa umeme.