Wrth siarad am broblem anodd cyflenwad pŵer switsh, 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: Perfformiad trydanol, llwybr proses, gofynion diogelwch, effaith EMC, ac ati; Ymhlith y ffactorau i’w hystyried, trydanol yw’r mwyaf sylfaenol, ond EMC yw’r anoddaf i’w ddeall, ac mae tagfa llawer o brosiectau yn gorwedd yn EMC. Y canlynol o 22 cyfarwyddyd i rannu’r bwrdd PCB ac EMC.

1, gall cylched aeddfed fod yn gylched EMI dylunio PCB yn hamddenol

Gellir dychmygu effaith y gylched uchod ar EMC, mae’r hidlwyr mewnbwn yma; Lightning-proof pressure sensitivity; Gwrthiant R102 i atal cerrynt sioc (gyda ras gyfnewid i leihau colled); Key error mode X capacitance and Y capacitance with inductor filtering; Mae ffiwsiau sy’n effeithio ar y bwrdd diogelwch; Mae pob un o’r dyfeisiau hyn yn hanfodol bwysig, a dylid gwerthfawrogi swyddogaeth a gweithred pob dyfais yn ofalus. 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. Cylchdaith ac EMC: (y brif dopoleg flyback mwyaf cyfarwydd, gweld pa rannau allweddol o’r gylched sy’n cynnwys mecanwaith 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. Ond mae cerrynt trydan cyfnewidiol yn cynhyrchu maes magnetig cyfnewidiol, a gall maes magnetig cyfnewidiol gynhyrchu maes trydan (mewn gwirionedd, dyma hafaliad enwog Maxwell ac rwy’n defnyddio iaith blaen), a gall maes trydan cyfnewidiol gynhyrchu magnetig hefyd. maes. Felly gwnewch yn siŵr eich bod chi’n talu sylw i’r lleoedd lle mae gwladwriaethau ymlaen / i ffwrdd, dyna un o ffynonellau’r EMC, a dyma un o ffynonellau’r 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! Y ddwy ddolen arall yw dolenni amsugno a dolennau cywiro, deallwch ymlaen llaw yn gyntaf, ac yna siaradwch!

3. Cymdeithas rhwng dyluniad PCB ac 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. Bydd rhan y strwythur, nid yw sylfaen dyluniad y rheiddiadur yn dda yn effeithio ar sylfaen y fersiwn gysgodol;

4. Os yw’r rhan sensitif yn rhy agos at y ffynhonnell ymyrraeth, fel cylched EMI a thiwb switsh, mae’n anochel y bydd yn arwain at EMC gwael, ac mae angen ardal ynysu glir.

5. Gwifrau dolen amsugno RC.

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

Rydw i’n mynd i siarad am hyn, ac rydw i’n mynd i siarad mwy amdano, ond rydw i’n mynd i roi arweiniad i chi.

Here’s a quick example:

Fel y dangosir yn y blwch doredig yn y ffigur uchod, mae’r gwifrau pin cynhwysydd X wedi’u mewnoli. Gallwch ddysgu sut i wneud y gwifrau pin cynhwysydd yn allanol (gan ddefnyddio’r gwifrau cerrynt gwasgu). Yn y modd hwn, gall effaith hidlo cynhwysydd X gyrraedd y cyflwr gorau.

4. Paratoi ar gyfer dyluniad PCB: (os ydych chi’n hollol barod, gall y dyluniad fod yn gyson gam wrth gam er mwyn osgoi gwrthdroi dyluniad a dechrau eto)

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. Dewis llwybr proses: dewis panel dwbl panel sengl, neu fwrdd aml-haen, yn ôl y diagram sgematig a maint y bwrdd, cost a gwerthusiad cynhwysfawr arall.

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. Mae pellter y pad ffiws mewnbwn yn fwy na 3.0mm fel sy’n ofynnol gan reoliadau diogelwch, ac mae’r plât gwirioneddol yn 3.5mm (yn syml, mae pellter ymgripiad y ffiws yn 3.5mm cyn a 3.0mm ar ôl).

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. Mae’r rheoliadau diogelwch ar gyfer y cam cyntaf yn gofyn am 6.4mm (bwlch trydanol), a dylai’r pellter creepage fod yn 7.6mm. (Sylwch fod hyn yn gysylltiedig â’r gwir foltedd mewnbwn, mae angen cyfeirio at y tabl ar gyfer cyfrifiad penodol, y data a ddarperir ar gyfer cyfeirio yn unig, yn amodol ar y sefyllfa wirioneddol)

5. Cold ground and hot ground are clearly marked for the first stage; Dylid marcio’n glir marc L, N, marc INPUT AC INPUT, marc rhybuddio ffiws ac ati;

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. Mewn rheoliadau diogelwch, deallwch nodweddion inswleiddio’r lle agos gyda bwrdd PCB, pa le sy’n inswleiddio sylfaenol, pa le sy’n inswleiddio wedi’i atgyfnerthu, nid yw’r pellter inswleiddio safonol gwahanol yr un peth. Y peth gorau yw gwirio safonau, a gall gyfrifo pellter trydanol, pellter ymgripiol.

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. Y berthynas rhwng cynhwysedd Y a cherrynt gollyngiadau a cherrynt cyswllt.

Ac yn y blaen, bydd yn esbonio’n fanwl sut i adael y pellter, sut i wneud gofynion diogelwch.

6, dyluniad PCB o gynllun cyflenwad pŵer

1. Yn gyntaf, mesurwch faint PCB a nifer y cydrannau, er mwyn sicrhau dwysedd da, neu bydd trwchus, tenau yn hyll.

2. Modiwleiddio’r gylched, cymryd y dyfeisiau craidd fel y canol, a gosod y dyfeisiau allweddol yn gyntaf.

3. Mae’r ddyfais yn gwrth-leoli fertigol neu lorweddol, mae un yn brydferth, a’r llall yn weithrediad plug-in cyfleus, gall amgylchiadau arbennig ystyried gogwyddo.

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

5. Gostyngwch yr ardal dolen gymaint â phosibl yn ystod y cynllun. Esbonnir y pedair dolen yn fanwl yn nes ymlaen.

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

Y canlynol yw’r PCB gwyryf cyntaf i mi ei dynnu, flynyddoedd lawer yn ôl, roedd yn anodd iawn ei orffen, efallai bod problem fach yn y canol, ond mae’n werth dysgu’r cynllun cyffredinol:

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. Mae terfynellau mewnbwn ac allbwn yn sefydlog ac ni ellir eu symud. Mae’r bwrdd yn betryal.

Yma mae’r cynllun o’r gwaelod i’r brig, o’r chwith i’r dde, ac mae’r afradu gwres yn dibynnu ar y gragen.

Mae cylched 2.EMI yn dal i fod yn gyfeiriad llif clir, sy’n bwysig iawn, fel arall nid yw’n brydferth ac yn ddrwg i 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. Mae’r haen uchaf o bŵer uchel yn gyffredinol yn mynd yn negyddol, ac mae’r haen waelod yn mynd yn bositif.

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. Gwerthfawrogi enghreifftiau 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! Y tu ôl hefyd bydd i’r bwrdd hwn egluro dysgu, rydyn ni’n ei fwynhau gyntaf.

8. Dealltwriaeth o’r pedair dolen o ddylunio PCB: (gofyniad sylfaenol cynllun PCB yw ardal fach y pedair dolen)

Yn ogystal, mae’r ddolen amsugno (amsugno RCD, amsugno RC o diwb MOS ac amsugno RC o’r tiwb unioni) hefyd yn bwysig iawn, sef y ddolen sy’n cynhyrchu ymbelydredd amledd uchel hefyd. Os oes gennych unrhyw gwestiynau am y ffigur uchod, mae croeso i chi eu trafod. Nid ydym yn ofni unrhyw gwestiynau.

9. Man poeth dylunio PCB (pwynt potensial fel y bo’r angen) a gwifren ddaear:

Materion sydd angen sylw:

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. Mae’r ddolen a ffurfiwyd gan fannau poeth yn fach ac mae’r gwifrau’n fyr, ac nid yw’r gwifrau mor drwchus â phosibl, ond cyhyd â bod y cerrynt yn ddigon.

3. Rhaid i’r cebl daear gael ei ddaearu ar un pwynt. Prif dir pŵer a daear signal ar wahân, mae tir samplu yn mynd ar wahân.

4. Mae angen cysylltu tir y rheiddiadur â’r prif dir pŵer.