N’ikwu okwu banyere nsogbu siri ike nke inye ọkụ ọkụ ọkụ, 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: Ọrụ eletriki, ụzọ usoro, ihe nchekwa, mmetụta EMC, wdg; N’ime ihe ndị a ga -atụle, eletriki bụ ihe kachasị mkpa, mana EMC bụ ihe kacha sie ike nghọta, na ngọngọ nke ọtụtụ ọrụ dị na EMC. Ihe ndị a sitere na ntuziaka 22 ịkekọrịta bọọdụ PCB na EMC.

1, sekit tozuru oke nwere ike bụrụ ihe ntụrụndụ PCB EMI sekit

Enwere ike icheta mmetụta nke sekit dị n’elu nwere na EMC, ihe nzacha ntinye dị ebe a; Lightning-proof pressure sensitivity; Nguzogide R102 iji gbochie ujo ugbu a (yana iji ọsọ agbapụta iji belata mfu); Key error mode X capacitance and Y capacitance with inductor filtering; There are fuses affecting the safety board; Nke ọ bụla n’ime ngwa ndị a dị oke mkpa, ekwesịrị iji nlezianya ghọta ọrụ na omume nke ngwaọrụ ọ bụla. 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. Circuit na EMC: (topology isi ụgbọ elu ama ama nke ọma, lee akụkụ igodo sekit nwere usoro 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. Mana ọkụ eletrik na -agbanwe agbanwe na -emepụta ike ndọta na -agbanwe agbanwe, na ndọta na -agbanwe agbanwe nwere ike imepụta ọkụ eletrik (n’eziokwu, nke a bụ akara Maxwell a ma ama na m na -eji asụsụ dị larịị), na ọkụ eletrik na -agbanwe agbanwe nwekwara ike imepụta ndọta. ubi. Yabụ gbaa mbọ hụ na ị na -elebara anya ebe steeti gbanyụrụ/gbanyụọ, nke ahụ bụ otu isi mmalite EMC, nke a bụkwa otu n’ime isi mmalite 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! Loops abụọ ndị ọzọ bụ loops absorption na loops na -edozi, buru ụzọ ghọta tupu oge ahụ, wee kwuo okwu!

3. Mmekọrịta dị n’etiti imebe 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. The structure part, the radiator design grounding is not good will affect the grounding of the shielded version;

4. Ọ bụrụ na akụkụ ahụ dị nro dị nso na isi nnyonye anya, dị ka okirikiri EMI na ọkpọ ọkpọ, ọ ga -eduga EMC na -adịghị mma, yana mpaghara nkewapụ doro anya.

5. Wiring nke RC absorption loop.

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

I’m going to talk about this, and I’m going to talk about it more, but I’m going to give you a lead.

Here’s a quick example:

Dị ka egosiri na igbe ntụpọ dị na ọnụ ọgụgụ dị n’elu, etinyela eriri igwe X capacitor. Ị nwere ike mụta ka esi eme wiwi capacitor ka ọ bụrụ mpụga (site na iji wiwi ugbu a). N’ụzọ dị otu a, mmetụta nzacha nke X capacitor nwere ike iru steeti kacha mma.

4. Nkwadebe maka imebe PCB: (ọ bụrụ na ị kwadebere nke ọma, imewe ahụ nwere ike kwụ otu ebe site na nzere iji zere ịtụgharị ma malite ọzọ)

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. Nhọrọ usoro nhazi: otu panel otu nhọrọ ọnụọgụ abụọ, ma ọ bụ bọọdụ nwere ọtụtụ akwa, dị ka eserese atụmatụ na nha bọọdụ, ọnụ ahịa na nyocha ndị ọzọ zuru oke.

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. Anya nke fuse fuse dị ukwuu karịa 3.0mm dị ka iwu nchekwa siri chọọ, na efere n’ezie bụ 3.5mm (na -ekwu okwu naanị, ebe mgbaba nke fuse bụ 3.5mm tupu na 3.0mm mgbe).

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. Iwu nchekwa maka ọkwa nke mbụ chọrọ 6.4mm (oghere eletriki), na anya creepage kwesịrị ịbụ 7.6mm. (Rịba ama na nke a metụtara voltaji ntinye, ọ dị mkpa ka ị na -arụtụ aka na tebụl maka ngụkọta oge akọwapụtara, data enyere maka ntụnyere naanị, dabere n’ọnọdụ ahụ n’ezie)

5. Cold ground and hot ground are clearly marked for the first stage; L, N akara, akara ntinye AC ntinye, akara ịdọ aka na ntị fuse na ihe ndị ọzọ kwesịrị ka akara nke ọma;

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. Na ụkpụrụ nchekwa, ghọta njirimara mkpuchi ebe dị nso na bọọdụ PCB, ebe bụ mkpuchi mkpuchi, ebe a na -eme ka mkpuchi sie ike, ịdị anya mkpuchi dị iche iche abụghị otu. Ọ kacha mma ịlele ụkpụrụ, yana nwee ike gbakọọ anya eletriki, anya 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. Mmekọrịta dị n’etiti Y capacitance na mwepu mmiri ugbu a na kọntaktị ugbu a.

Na ndị ọzọ, ọ ga -akọwa nke ọma otu esi ahapụ ebe dị anya, ka esi eme ihe nchekwa.

6, imepụta PCB nke okirikiri nhọrọ ọkụ ọkụ

1. Buru ụzọ tụọ nha PCB na ọnụ ọgụgụ ihe mejupụtara ya, iji nweta njupụta dị mma, ma ọ bụ nke dị okirikiri, ga -adị njọ.

2. Gbanwee sekit, were ngwaọrụ ndị bụ isi dị ka etiti, wee buru ụzọ debe ngwaọrụ igodo.

3. Ngwaọrụ kwụ ọtọ ma ọ bụ kwụ kwụ ọtọ, otu mara mma, nke ọzọ dị mma nkwụnye ọrụ, ọnọdụ pụrụ iche nwere ike ịtụle tilt.

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

5. Belata mpaghara akaghị ka enwere ike n’oge nhazi. A ga -akọwa nko anọ ahụ n’ụzọ zuru oke ma emechaa.

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

Ndị na -esonụ bụ PCB na -amaghị nwoke nke mbụ m sere, ọtụtụ afọ gara aga, ọ siri ike ịmecha, enwere ike inwe obere nsogbu n’etiti, mana nhazi izugbe bara uru ịmụ:

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. A na -edozi ọnụ mbubata na mbubata na enweghị ike imegharị ya. Bọọdụ ahụ bụ akụkụ anọ.

N’ebe a, okirikiri nhọrọ ukwuu bụ site na ala ruo n’elu, site n’aka ekpe gaa n’aka nri, na ikposa ọkụ na -adabere na shei.

2.EMI sekit ka bụ ntụzịaka doro anya, nke dị ezigbo mkpa, ma ọ bụghị na ọ maghị mma ma dịkwa njọ maka 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. N’elu oyi akwa nke ike dị elu na -adịkarị njọ, na ala ala na -aga nke ọma.

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. Ịghọta ihe atụ 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! Behind will also be for this board to explain learning, we first enjoy.

8. Understanding of the four loops of PCB design :(the basic requirement of PCB layout is the small area of the four loops)

In addition, the absorption loop (RCD absorption, RC absorption of MOS tube and RC absorption of rectifier tube) is also very important, which is also the loop that generates high frequency radiation. If you have any questions about the above figure, you are welcome to discuss them. We are not afraid of any questions.

9. PCB chepụta ebe na -ekpo ọkụ (ebe nwere ike na -ese n’elu mmiri) na waya ala:

Ihe ndị chọrọ nlebara anya:

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. Loop nke ntụpọ ọkụ kpụpụtara dị ntakịrị yana wiwi dị mkpụmkpụ, na wired adịghị oke ka o kwere mee, mana ọ bụrụhaala na nke ugbu a ezuola.

3. Ekwesịrị ịtọba eriri ala n’otu ebe. Ala ike isi na ala mgbaama dị iche, ala nlele na -aga iche iche.

4. Ekwesịrị ijikọ ala radiator na ala ike isi.