Ukuthetha ngengxaki enzima yokutshintsha kombane, 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 kombane, indlela yenkqubo, iimfuno zokhuseleko, impembelelo ye-EMC, njl .; Phakathi kwezinto ezinokuthi ziqwalaselwe, umbane ngowona osisiseko, kodwa i-EMC yeyona nto kunzima ukuyiqonda, kwaye isithintelo seeprojekthi ezininzi silele kwi-EMC. Oku kulandelayo kwimikhombandlela ye-22 yokwabelana ngebhodi yePCB kunye ne-EMC.

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Impembelelo yesekethe engentla kwi-EMC inokucingelwa, iifilitha zokufaka zilapha; Lightning-proof pressure sensitivity; Ukuxhathisa i-R102 ukunqanda umothuko wangoku (ngokudluliswa ukunciphisa ilahleko); Key error mode X capacitance and Y capacitance with inductor filtering; Kukho iifusi ezichaphazela ibhodi yezokhuseleko; Ngasinye kwezi zixhobo zibaluleke kakhulu, kwaye umsebenzi kunye nokusebenza kwento nganye kufuneka kuthathelwe ingqalelo ngononophelo. 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 kunye ne-EMC: (ezona ndawo ziphambili zibuyela umva kwezobuchwephesha, jonga ukuba ngawaphi amalungu aphambili esekethe aqukethe 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. Kodwa ukutshintsha kombane kuvelisa ukutshintsha kwemagneti, kwaye ukutshintsha kwemagneti kunokuvelisa intsimi yombane (enyanisweni, le yindawo yokulinganisa edumileyo kaMaxwell kwaye ndisebenzisa ulwimi olucacileyo), kwaye intsimi yombane eguqukayo inokuvelisa amandla ombane. intsimi. Ke qiniseka ukuba uhoya indawo apho kukho ukucinywa / ukucinywa, yenye yemithombo ye-EMC, kwaye lo ngomnye 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! Ezinye iiluphu ezimbini zeluphu zokufunxa kunye nokulungisa ii-loops, qala uqonde kwangaphambili, emva koko uthethe!

3. Umanyano phakathi koyilo lwe-PCB kunye 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. Inxalenye yesakhiwo, uyilo loyilo lweeradiyetha alulunganga luya kuchaphazela ukuthathwa komhlaba okukhuselweyo;

4. Ukuba icandelo elibuthathaka lisondele kakhulu kumthombo wongenelelo, ofana neesekethe ze-EMI kunye netyhubhu yokutshintsha, ngokuqinisekileyo iya kukhokelela kwi-EMC ehluphekileyo, kwaye indawo ecacileyo yokuzahlula iyafuneka.

5. Ukudibanisa i-RC yokufunxa iluphu.

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

Ndiza kuthetha ngale nto, kwaye ndiza kuthetha ngayo ngakumbi, kodwa ndiza kukukhokela.

Here’s a quick example:

Njengoko kubonisiwe kwibhokisi echokoziweyo kulo mzobo ungasentla, i-X ye-capacitor pin wiring yenziwe indent. Unokufunda indlela yokwenza i-pin ye-capacitor ngaphandle kweentambo (usebenzisa i-wiring yangoku). Ngale ndlela, isiphumo sokucoca i-X capacitor sinokufikelela kwelona lizwe lifanelekileyo.

4. Ukulungiselela uyilo lwe-PCB: (ukuba uzilungiselele ngokupheleleyo, uyilo lunokuba linyathelo elizinzileyo ngenyathelo ukunqanda ukubhukuqa koyilo kunye nokuqala kwakhona)

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.

Inkqubo yokukhethwa kwendlela: Iphaneli enye yokukhetha iphaneli kabini, okanye ibhodi eyahlukeneyo, ngokwedrafti yesayizi kunye nobukhulu bebhodi, indleko kunye nolunye uvavanyo olupheleleyo.

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. Umgama wepali yokufaka i-fuse ungaphezulu kwe-3.0mm njengoko kufunwa yimigaqo yokhuseleko, kwaye eyona mbasa iyi-3.5mm (ngokuthetha nje, umgama wokuhamba wefuse uyi-3.5mm ngaphambili kunye no-3.0mm emva).

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. Imigaqo yokhuseleko yenqanaba lokuqala ifuna i-6.4mm (isikhewu sombane), kwaye umgama wokunyuka kufuneka ubengu-7.6mm. (Qaphela ukuba oku kunxulumene nevolthi yokufaka, kufuneka ubhekise kwitafile yokubala ethile, idatha ebonelelweyo yesalathiso kuphela, ngokuxhomekeke kwimeko eyiyo)

5. Cold ground and hot ground are clearly marked for the first stage; L, N uphawu, INPUT AC INPUT uphawu, uphawu lwesilumkiso njalo njalo kufuneka ziphawulwe ngokucacileyo;

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. Kwimimiselo yokhuseleko, qonda iimpawu zokugquma kwendawo ekufutshane nebhodi yePCB, yeyiphi indawo esisiseko yokugquma, yeyiphi indawo eqinisiweyo yokuqinisa, umgama owahlukileyo wokugquma awufani. Kungcono ukujonga imigangatho, kwaye ungabala umgama wombane, umgama wecrepage.

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.Ubudlelwane phakathi kwamandla e-Y kunye nokuvuza kwangoku kunye nonxibelelwano lwangoku.

Kwaye njalo njalo, iya kuchaza ngokweenkcukacha indlela yokushiya umgama, indlela yokwenza iimfuno zokhuseleko.

I-6, uyilo lwePCB yoyilo lokuhambisa umbane

1. Kuqala yenza umlinganiso wobungakanani bePCB kunye nenani lezinto, ukuze ufezekise uxinano oluluqilima, okanye uxinene, indawo encinci iya kuba mbi.

2. Yenza imodyuli ukuba ibe yimodareyitha, thabatha izixhobo ezingundoqo njengeziko, ubeke izixhobo eziphambili kuqala.

3. Esi sixhobo sithe nkqo okanye tyaba ngokuchasene nokubekwa endaweni, enye intle, enye ilungele ukusebenza kwe-plug-in, iimeko ezizodwa zinokuthi ziqwalasele ukuthambeka.

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

5. Nciphisa indawo yeluphu kangangoko kunokwenzeka ngexesha loyilo. Iziporo ezine ziya kuchazwa ngokweenkcukacha kamva.

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

Oku kulandelayo yi-PCB yokuqala eyintombi endiyizobileyo, kwiminyaka emininzi eyadlulayo, kwakunzima ukuyigqiba, kusenokubakho ingxaki encinci embindini, kodwa ubeko ngokubanzi kufanelekile ukuba lufundwe:

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.Iitheminali zokufaka kunye nezokukhupha zilungisiwe kwaye azinakususwa. Ibhodi yoxande.

Nanku ubeko ukusuka ezantsi ukuya phezulu, ukusuka ekhohlo ukuya ekunene, kwaye ukusasazeka kobushushu kuxhomekeke kwigobolondo.

Isekethe ye-2EMI isacacile ukuba iyahamba na, ebaluleke kakhulu, kungenjalo ayintle kwaye ayilunganga kwi-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. Uluhlu oluphezulu lwamandla aphezulu ngokubanzi luhamba lubi, kwaye umgca ongaphantsi uhamba kakuhle.

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. Ukuxabisa imizekelo ye-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! Ngasemva kuya kubakho ukuba le bhodi ichaze ukufunda, siqala ukonwabela.

8.Ukuqonda iiluphu ezine zoyilo lwePCB: (imfuno esisiseko yoyilo lwePCB yindawo encinci yeeluphu ezine)

Ukongeza, i-loop yokufunxa (ukufunxwa kwe-RCD, ukufunxwa kwe-RC ityhubhu ye-MOS kunye nokufunxwa kwe-RC ityhubhu yokulungisa) nayo ibaluleke kakhulu, ikwayi-loop evelisa imitha yokuhamba rhoqo. Ukuba unemibuzo malunga nomfanekiso ongentla, wamkelekile ukuba uxoxe ngawo. Asoyiki nayiphi na imibuzo.

9. Uyilo lwe-PCB indawo eshushu (indawo edadayo enokubakho) kunye nocingo lomhlaba:

Izinto ezifuna ingqalelo:

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 eyenziwe ngamabala ashushu incinci kwaye i-wiring imfutshane, kwaye i-wiring ayinamandla kangangoko kunokwenzeka, kodwa ngoku nje okwangoku kwanele.

3. Intambo yomhlaba kufuneka ibekwe kwindawo enye. Amandla aphambili komhlaba kunye nomqondiso womhlaba ngokwahlukeneyo, umhlaba wesampulu uyahamba ngokwahlukeneyo.

4. Umhlaba weradiyetha kufuneka uqhagamshelwe kumhlaba ophambili wamandla.