Ngomongkeun masalah sesah pasokan listrik saklar, 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: Kinerja listrik, rute prosés, syarat kaamanan, épék EMC, jst; Diantara faktor anu kedah diperhatoskeun, listrik mangrupikeun anu paling dasar, tapi EMC anu paling hese dipikaharti, sareng hambatan tina seueur proyek aya dina EMC. Ieu ti 22 arah kanggo ngabagi papan PCB sareng EMC.

1, sirkuit asak tiasa janten PCB rarancang sirkuit EMI anu santai

Pangaruh tina sirkuit di luhur kana EMC tiasa dibayangkeun, saringan input di dieu; Lightning-proof pressure sensitivity; Résistansi R102 pikeun nyegah arus kejutan (kalayan relay pikeun ngirangan karugian); Key error mode X capacitance and Y capacitance with inductor filtering; Aya sekering mangaruhan dewan kaamanan; Masing-masing alat ieu penting pisan, sareng fungsi sareng tindakan unggal alat kedah diapresiasi sacara ati-ati. 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. Sirkuit sareng EMC: (topologi utama flyback anu paling dikenal, tingali bagéan konci sirkuit anu ngandung mékanisme 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. Tapi arus listrik anu ngarobah ngahasilkeun medan magnét anu robih, sareng médan magnét anu robih tiasa ngahasilkeun medan listrik (kanyataanna, ieu persamaan Maxwell anu kawéntar sareng kuring nganggo basa polos), sareng medan listrik anu robih ogé tiasa ngahasilkeun magnét sawah. Maka pastikeun anjeun merhatoskeun tempat-tempat anu aya di / off state, éta salah sahiji sumber EMC, sareng ieu mangrupikeun salah sahiji sumber 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! Dua loop anu sanésna nyaéta loop anu nyerep sareng koréksi menerkeun, mimiti ngartos sateuacanna, teras omongan!

3. Asosiasi antara desain PCB sareng 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. Bagian struktur, grounding desain radiator henteu saé bakal mangaruhan grounding tina versi anu dijagaan;

4. Upami bagian sénsitip caket teuing sareng sumber gangguan, sapertos sirkuit EMI sareng tabung saklar, éta pasti bakal nyababkeun EMC anu goréng, sareng daérah isolasi anu jelas diperyogikeun.

5. Kabel loop RC nyerep.

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

Abdi badé nyarioskeun perkawis ieu, sareng kuring badé nyarioskeun langkung seueur, nanging kuring bakal masihan anjeun kalungguhan.

Here’s a quick example:

Sakumaha dituduhkeun dina kotak titik dina gambar di luhur, kabel pin kapasitor X parantos diindénan. Anjeun tiasa diajar kumaha ngadamel kabel pin kapasitor éksternal (ngagunakeun kabel anu ngencet ayeuna). Ku cara kieu, pangaruh nyaring kapasitor X tiasa ngahontal kaayaan anu pangsaéna.

4. Persiapan pikeun desain PCB: (upami anjeun parantos siap, desainna tiasa ajeg saléngkah-saléngkah pikeun nyegah desain ngagulingkeun sareng ngamimitian deui)

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. Pilihan rute prosés: tunggal panel pilihan panel ganda, atanapi multi-layer board, numutkeun diagram skéma sareng ukuran dewan, biaya sareng évaluasi komprehensif sanés.

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. Jarak input fuse pad langkung ageung tibatan 3.0mm sakumaha anu diperyogikeun ku peraturan kaamanan, sareng piring aktualna nyaéta 3.5mm (kantun nyarios, jarak halaman sekering nyaéta 3.5mm sateuacanna sareng 3.0mm saatos).

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. Peraturan kaamanan pikeun tahap kahiji peryogi 6.4mm (celah listrik), sareng jarak creepage kedahna 7.6mm. (Catet yén ieu aya hubunganana sareng tegangan input anu saleresna, kedah ningali kana tabel pikeun itungan khusus, data anu disayogikeun kanggo rujukan hungkul, tunduk kana kaayaan anu saleresna)

5. Cold ground and hot ground are clearly marked for the first stage; L, N mark, INPUT AC INPUT mark, sekering peringatan sareng sanésna kedah jelas ditandaan;

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. Dina peraturan kaamanan, ngartos ciri-ciri insulasi tempat caket sareng papan PCB, tempat anu insulasi dasar, tempat anu dikuatkeun insulasi, jarak insulasi standar anu béda henteu sami. Langkung saé pikeun mariksa standar, sareng tiasa ngitung jarak listrik, jarak 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. Hubungan antara kapasitansi Y sareng arus kabocoran sareng arus kontak.

Sareng terasna, éta bakal ngajelaskeun sacara rinci kumaha ninggali jarakna, kumaha ngalakukeun syarat kaamanan.

6, desain PCB tina perenah catu daya

1. Mimiti ngukur ukuran PCB sareng jumlah komponénna, pikeun ngahontal kapadetan anu saé, atanapi padet, jarang bakal awon.

2. Modulariikeun sirkuit, candak alat inti salaku pusat, sareng tempatkeun konci heula.

3. Alatna nangtung atanapi horizontal anti-posisi, anu hiji saé, anu sanésna merenah operasi plug-in, kaayaan khusus tiasa ngiringan miring.

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

5. Ngurangan area loop saloba mungkin salami perenah. Opat puteran bakal dijelaskeun sacara rinci engké.

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

Ieu mangrupikeun PCB parawan munggaran anu kuring gambar, sababaraha taun ka pengker, éta hésé pisan bérés, panginten aya masalah alit di tengahna, tapi tata ruang umum pantes diajar:

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. Terminal input sareng output tetep sareng teu tiasa dipindahkeun. Papanana segi opat.

Di dieu perenahna ti handap ka luhur, ti kénca ka katuhu, sareng dissipasi panas gumantung kana cangkang.

2. Sirkuit EMI masih arah aliran anu jelas, anu penting pisan, upami éta henteu saé sareng goréng pikeun 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. Lapisan luhur kakuatan luhur umumna négatip, sareng lapisan handapna positip.

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. Aprésiasi conto 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! Di tukangeun ogé pikeun dewan ieu ngajelaskeun diajar, urang mimiti resep.

8. Ngartos kana opat puteran desain PCB: (sarat dasar perenah PCB nyaéta daérah alit tina opat puteran)

Salaku tambahan, loop panyerepan (nyerep RCD, nyerep RC tina tabung MOS sareng nyerep RC tina tabung penyearah) ogé penting pisan, anu ogé loop anu ngahasilkeun radiasi frékuénsi luhur. Upami anjeun ngagaduhan patarosan ngeunaan tokoh di luhur, anjeun wilujeng sumping ngabahasna. Kami henteu sieun kana patarosan.

9. PCB desain titik panas (titik poténsial ngambang) sareng kawat taneuh:

Hal-hal anu peryogi perhatian:

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. Gelung anu diwangun ku titik-titik panas leutik sareng kabelna pondok, sareng kabelna henteu sakumaha kandelna, tapi salami arusna cekap.

3. kabel taneuh kedah di ground dina hiji titik. Taneuh kakuatan utama sareng ground signal misah, sampling ground angkat nyalira.

4. Taneuh radiator kedah disambungkeun kana taneuh kakuatan utama.