Kitapo boribory vita pirinty (PCB) dia hita amin’ny ankamaroan’ny karazana fitaovana elektronika. If there are electronic components in a piece of equipment, they are also embedded in various sizes of PCB. In addition to fixing various small parts, the main function of the PCB is to provide electrical connections between the components. As electronic equipment becomes more and more complex, more and more parts are needed, and the wiring and parts on the PCB become more and more dense. A standard PCB looks something like this. Bare Board (without parts on it) is also often referred to as “Printed Wiring Board (PWB).

The substrate of the board itself is made of a material that is insulated and resistant to bending. The small line material that can be seen on the surface is copper foil. Originally, the copper foil is covered on the whole board, and the middle part is etched away in the manufacturing process, and the remaining part becomes a network of small lines. These lines are called conductors or conductors and are used to provide electrical connections to parts on the PCB.

To secure parts to the PCB, we solder their pins directly to the wiring. Amin’ny PCB fototra, ny ampahany dia mifantoka amin’ny lafiny iray ary ny tariby mifantoka amin’ny lafiny iray. So we need to make holes in the board so that the pins can go through the board to the other side, so the pins of the parts are welded to the other side. Because of this, the front and back sides of a PCB are called Component Side and Solder Side respectively.

Raha misy ampahany amin’ny PCB azo esorina na apetraka aorian’ny fanamboarana dia ampiasaina i Socket hametrahana ireo ampahany. Because the socket is directly welded to the board, the parts can be arbitrarily disassembled. A ZIF (Zero InserTIon Force) plug allows parts to be inserted and removed easily. The lever next to the socket can hold the parts in place after you insert them.

To connect two PCBS to each other, an edge connector is commonly used. Ny rantsan-tànana volamena dia misy pads varahina miboridana maromaro izay ampahany amin’ny tariby PCB. Raha ny mahazatra, raha mampifandray dia ampidirintsika ao amin’ny PCB iray ny rantsan-tànana volamena ao amin’ilay Slot mety (antsoina hoe Slots fanitarana) amin’ny PCB hafa. In computers, display cards, sound cards, and similar interface cards are connected to the motherboard by means of a gold finger.

Ny loko maitso na volontany amin’ny PCB dia lokon’ny saron-tava solder. This layer is an insulating shield that protects the copper wire and prevents parts from being welded to the wrong place. Ny efijery landy iray hafa dia hatao pirinty amin’ny sosona fanoherana solder. It is usually printed with words and symbols (mostly white) to indicate the position of the parts on the board. Screen printing surface is also known as icon surface

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Birao tokana

Araka ny efa nolazainay, amin’ny PCB fototra, ny ampahany dia mifantoka amin’ny lafiny iray ary ny tariby mifantoka amin’ny lafiny iray. Because the wire appears on only one side, we call this TYPE of PCB single-sided. Satria ny takelaka tokana dia nisy fameperana henjana be tamin’ny famolavolana ny fizaran-tany (satria ny lafiny iray ihany, ny tariby dia tsy afaka niampita ary tsy maintsy nandeha lalan-kafa), ny boriborintany voalohany ihany no nampiasa takelaka toy izany.

Birao misy lafiny roa

Ny board circuit dia manana tariby amin’ny lafiny roa. But in order to use both wires, there must be proper electrical connections between the two sides. Ity “tetezana” eo anelanelan’ny boriboritany ity dia antsoina hoe lavaka fitarihana (VIA). Ny lavaka torolàlana dia lavaka kely ao amin’ny PCB feno na mifono vy izay azo ampifandraisina amin’ny tariby amin’ny andaniny roa. Because a dual panel has twice the area of a single panel, and because the wiring can be interlaced (it can be wound around to the other side), it is better for more complex circuits than a single panel.

Multi-layer Boards

Mba hampitomboana ny faritra azo tariby dia ampiasaina ny takelaka misy tariby tokana – na misy lafiny roa. Ny tabilao multilayer dia mampiasa takelaka roa sosona, ary apetraka eo anelanelan’ny tontonana tsirairay ary apetaka (tsindriana) ny sosona fisisahana. The number of layers of the board represents several independent wiring layers, usually an even number of layers, including the outermost two layers. Most motherboards are built with four to eight layers, but it is technically possible to build up to 100 layers of PCBS. Ny ankamaroan’ny solosaina lehibe dia mampiasa sosona motherboard vitsivitsy, saingy tsy nampiasaina intsony izy ireo satria afaka soloin’ireo vondron-tsolosaina mahazatra. Because the layers in a PCB are so tightly integrated, it’s not always easy to see the actual number, but if you look closely at the motherboard, you might be able to.

The guide hole (VIA) we just mentioned, if applied to a double panel, must be through the entire board

But in a multilayer, if you only want to connect some of the lines, the guide holes may waste some of the line space in the other layers. Buried vias and Blind vias avoid this problem because they only penetrate a few layers. Blind holes connect several layers of internal PCBS to surface PCBS without penetrating the entire board. Buried holes are only connected to the internal PCB, so light is not visible from the surface.

In a multilayer PCB, the entire layer is directly connected to the ground wire and the power supply. So we classify the layers as Signal, Power or Ground. If the parts on the PCB require different power supplies, they usually have more than two power and wire layers.

Teknolojia fonosana ampahany

Amin’ny alàlan’ny Hole Technology

The technique of placing parts on one side of the board and welding the pins to the other side is called “Through Hole Technology (THT)” encapsulation. This part takes up a lot of space and one hole is drilled for each pin. Ka ny vitran’izy ireo dia tena mandray habaka amin’ny lafiny roa, ary lehibe ny tonon-tany. Etsy ankilany, ny faritra THT dia mifamatotra kokoa amin’ny PCB noho ny Surface Mounted Technology (SMT), izay horesahintsika avy eo. Sockets like wired sockets and similar interfaces need to be pressure-tolerant, so they are usually THT packages.

Surface Mounted Technology

For Surface Mounted Technology (SMT) parts, the pin is welded on the same side with the parts. This technique does not drill holes in the PCB for each pin.

Ny faritra miraikitra amin’ny etona dia azo fehezina amin’ny lafiny roa aza.

SMT koa dia manana faritra kely kokoa noho ny THT. Compared to PCB with THT parts, PCB with SMT technology is much denser. SMT package parts are also less expensive than THT’s. So it’s no surprise that most of today’s PCBS are SMT.

Because the solder joints and pins of parts are very small, it is very difficult to weld them manually. However, given that current assembly is fully automated, this problem will only occur when repairing parts.

The design process

Ao amin’ny famolavolana PCB, dia misy dingana tena lava be aleha alohan’ny tariby ara-dalàna. Ity manaraka ity dia ny fizotry ny famolavolana lehibe:

The system specifications

First of all, the system specifications of the electronic equipment should be planned. It covers system functionality, cost constraints, size, operation and so on.

System function block diagram

Ny dingana manaraka dia ny famoronana tabilao miasa an’ny rafitra. Ny fifandraisana eo amin’ny kianja dia tsy maintsy asiana marika ihany koa.

Divide the system into several PCBS

Dividing the system into several PCBS not only reduces the size, but also gives the system the ability to upgrade and swap parts. The system function block diagram provides the basis for our segmentation. Computers, for example, can be divided into motherboards, display cards, sound cards, floppy disk drives, power supplies, and so on.

Fantaro ny fomba famonosana ampiasaina sy ny haben’ny PCB tsirairay

Once the technology and the number of circuits used for each PCB has been determined, the next step is to determine the size of the board. If the design is too large, then packaging technology will have to change, or re-split the action. Ny kalitao sy ny hafainganam-pandehan’ilay kisary boribory dia tokony hojerena ihany koa rehefa mifantina ny haitao.

Draw schematic circuit diagrams of all PCB’s

The details of the interconnections between the parts should be shown in the sketch. PCB amin’ny rafitra rehetra dia tsy maintsy faritana ary ny ankamaroan’izy ireo dia mampiasa CAD (Computer Aided Design) amin’izao fotoana izao. Here is an example of a CircuitMakerTM design.

Kisary scématique an’ny circuit PCB

Preliminary design of simulation operation

To ensure that the designed circuit diagram works, it must first be simulated using computer software. Such software can read blueprints and show how the circuit works in many ways. This is much more efficient than actually making a sample PCB and then measuring it manually.

Place the parts on the PCB

The way parts are placed depends on how they are connected to each other. Tsy maintsy mifandray amin’ny làlana amin’ny fomba mahomby indrindra izy ireo. Efficient wiring means the shortest possible wiring and fewer layers (which also reduces the number of guide holes), but we’ll come back to this in actual wiring. Here is what the bus looks like on a PCB. Placement is important in order for each part to have perfect wiring.

Test wiring possibilities with correct operation at high speed

Ny sasany amin’ireo rindrambaiko amin’ny solosaina ankehitriny dia afaka manamarina raha toa ka azo ampifandraisina tsara ny fametrahana ny singa tsirairay, na manamarina raha toa ka afaka mandeha tsara amin’ny hafainganana izy. Ity dingana ity dia antsoina hoe mandamina ampahany, saingy tsy handeha lavitra amin’izany isika. Raha misy ny olana amin’ny famolavolana ny faritra dia azo averina alamina ihany koa ny ampahany alohan’ny aondrana any ivelany ilay faritra.

Manondrana faritra amin’ny PCB

The connections in the sketch will now look like wiring in the field. Ity dingana ity dia mazàna mandeha ho azy tanteraka, na dia ilaina aza ny fanovana tanana. Below is the wire template for 2 laminates. Ny tsipika mena sy manga dia maneho ny sosona PCB sy ny sosona welding. The white text and squares represent the markings on the screen printing surface. Ireo teboka mena sy faribolana dia maneho lavaka fandavahana sy fitarihana. Amin’ny farany havanana dia hitantsika ny rantsantanana volamena eo amin’ny tontolon’ny welding amin’ny PCB. The final composition of this PCB is often referred to as the working Artwork.

Each design must conform to a set of rules, such as minimum reserved gaps between lines, minimum line widths, and other similar practical limitations. Ireo famaritana ireo dia miova arakaraka ny hafainganam-pandehan’ny boriborintany, ny tanjaky ny fambara ampitaina, ny fahatsapana ny fizaran-tany amin’ny fanjifana herinaratra sy ny tabataba ary ny kalitaon’ny fitaovana sy ny fitaovana famokarana. If the strength of the current increases, the thickness of the wire must also increase. In order to reduce PCB costs, while reducing the number of layers, it is also necessary to pay attention to whether these regulations are still met. Raha mihoatra ny 2 ny sosona ilaina dia matetika ampiasaina ny elanelan’ny herinaratra sy ny sosona an-tany mba hialana amin’ny famantarana fampitana amin’ny sosona famantarana dia voakitika, ary azo ampiasaina ho ampingan’ny sosona famantarana.

Wire after circuit test

In order to be sure that the line is working properly behind the wire, it must pass the final test. Ity fitsapana ity dia manamarina ihany koa ny fifandraisana tsy marina, ary ny fifandraisana rehetra dia manaraka ny kisary an-tsary.

Mametraha ary manaova rakitra

Satria maro ny fitaovana CAD amin’ny famolavolana PCBS ankehitriny, ny mpanamboatra dia tsy maintsy manana profil mifanaraka amin’ny fenitra alohan’ny ahafahany manamboatra tabilao. There are several standard specifications, but the most common is the Gerber Files specification. A set of Gerber files includes a plan of each signal, power and ground layer, a plan of the solder resistance layer and the screen printing surface, and specified files of drilling and displacing.

Electromagnetic compatibility problem

Ireo fitaovana elektronika izay tsy natao ho an’ny EMC, dia toa mamoaka angovo elektromagnetika ary manelingelina ireo fitaovana manodidina. Ny eMC dia mametraka fetrany ambony indrindra amin’ny fitsabahana elektromagnetika (EMI), saha elektromagnetika (EMF) ary ny fahatapahana matetika amin’ny radio (RFI). Ity lalàna ity dia afaka miantoka ny fiasan’ny fitaovana sy ny fitaovana hafa manodidina azy. Ny EMC dia mametraka fetra henjana amin’ny habetsaky ny angovo azo aparitaka na ampitaina amin’ny fitaovana iray mankany amin’ny iray hafa, ary natao hampihenana ny fahatsapana ho EMF ivelany, EMI, RFI, sns. In other words, the purpose of this regulation is to prevent electromagnetic energy from entering or emanating from the device. This is a very difficult problem to solve, and is usually solved by using power and grounding layers, or putting PCBS into metal boxes. The power and ground layers protect the signal layer from interference, and the metal box works equally well. We won’t go too far into these issues.

The maximum speed of the circuit depends on EMC compliance. EMI anatiny, toy ny fahaverezan’ny mpitondra ankehitriny, dia mitombo rehefa miakatra ny fahita matetika. Raha lehibe loatra ny fahasamihafana misy eo amin’izy roa ankehitriny dia ataovy izay hahalava ny elanelana misy eo amin’izy ireo. This also tells us how to avoid high voltage and minimize the current consumption of the circuit. Ny tahan’ny fahatarana amin’ny tariby dia zava-dehibe ihany koa, ka ny halavan’ny halavany, ny tsara kokoa. Ka ny PCB kely misy tariby tsara dia hiasa tsara kokoa amin’ny hafainganam-pandeha noho ny PCB lehibe.