PCB bedradingmetodes word steeds verbeter, en buigsame bedradingstegnieke kan die draadlengte verminder en meer PCB -ruimte vrystel. Konvensionele PCB -bedrading word beperk deur vaste draadkoördinate en die gebrek aan willekeurig gekantelde drade. Die verwydering van hierdie beperkings kan die kwaliteit van die bedrading aansienlik verbeter.

Let’s start with some terminology. Ons definieer willekeurige Hoekbedrading as draadbedrading deur willekeurige Hoeksegmente en radiale te gebruik. Dit is ‘n soort draadbedrading, maar is nie beperk tot die gebruik van slegs 90 grade en 45 grade hoeklynsegmente nie. Topological wiring is wire wiring that does not adhere to grids and coordinates and does not use regular or irregular grids like shape-based wiring. Laat ons die term buigsame bedrading definieer as draadbedrading sonder vaste vorm wat die herberekening van real-time draadvorme moontlik maak om die volgende transformasiemoontlikhede te bereik. Slegs boë van hindernisse en hul gemeenskaplike raaklyne word gebruik om die lynvorm te vorm. (Obstacles include pins, copper foil, forbidden areas, holes and other objects) part of the circuit of two PCB models. Die groen en rooi drade loop op verskillende lae van die PCB -model. The blue circles are the perforations. The red element is highlighted. There are also some red round pins. Use only line segments and models with an Angle of 90 degrees between them. Figuur 1B is ‘n PCB -model met boë en willekeurige hoeke. Wiring at any Angle may seem strange, but it does have many advantages. The way it is wired is very similar to how engineers wired it by hand half a century ago. Toon ‘n regte PCB wat in 1972 ontwikkel is deur ‘n Amerikaanse onderneming genaamd Digibarn vir volledige handbedrading. This is a PCB board based on Intel8008 computer. Die willekeurige hoekbedrading wat in figuur 2 getoon word, is eintlik soortgelyk. Why would they use arbitrary Angle wiring? Omdat hierdie tipe bedrading baie voordele inhou. Arbitrary Angle wiring has many advantages. Eerstens, as u nie die hoeke tussen lynsegmente gebruik nie, spaar u PCB -ruimte (veelhoeke neem altyd meer ruimte in beslag as raaklyne). Traditional automatic cablers can place only three wires between adjacent components (see left and center in Figure 3). By die bedrading van enige hoek is daar egter genoeg ruimte om vier drade op dieselfde pad te lê sonder om die ontwerpreëlkontrole (NGK) te oortree. Gestel ons het ‘n positiewe modus -chip en wil die chippenne aan twee ander penne koppel. Using only 90 degrees takes up a lot of space. Deur willekeurige Hoekbedrading te gebruik, kan die afstand tussen die chip en ander penne verkort word, terwyl die voetspoor verminder word. In this case, the area was reduced from 30 square centimeters to 23 square centimeters. Rotating the chip at any Angle can also provide better results. In this case, the area was reduced from 23 square centimeters to 10 square centimeters. It shows a real PCB. Arbitrary Angle wiring with rotating chip function is the only wiring method for this circuit board. Dit is nie net ‘n teorie nie, maar ook ‘n praktiese oplossing (soms die enigste moontlike oplossing). Shows an example of a simple PCB. Topologiese resultate van kabels, terwyl outomatiese kabelresultate gebaseer op optimale vorm foto’s van die werklike PCB is. An automatic cabler based on optimal shape cannot do this because the components are rotated at arbitrary angles. U benodig meer oppervlakte, en as u nie die komponente draai nie, moet die toestel groter gemaak word. Layout performance would be greatly improved without parallel segments, which are often a source of crosstalk. The level of crosstalk increases linearly as the length of parallel wires increases. As the spacing between parallel wires increases, crosstalk decreases quadratic. Let’s set the level of crosstalk produced by two parallel 1mm wires spaced d to e. As daar ‘n hoek tussen die draadsegmente is, sal die vlak van kruisspraak afneem namate hierdie hoek toeneem. The crosstalk does not depend on the length of the wire, but only on the Angle value: where α represents the Angle between the wire segments. Consider the following three wiring methods. On the left side of Figure 8 (90 degree layout), there is the maximum wire length and the maximum emi value due to parallel line segments. In the middle of Figure 8 (45 degree layout), the wire length and emi values are reduced. On the right-hand side (at any Angle), the wire length is shortest and there are no parallel wire segments, so the interference value is negligible. So arbitrary Angle wiring helps to reduce the total wire length and significantly reduce electromagnetic interference. You also remember the effect on signal delay (conductors should not be parallel and should not be perpendicular to the PCB fiberglass). Advantages of flexible wiring Manual and automatic movement of components does not destroy the wiring in flexible wiring. Die kabel bereken outomaties die optimale vorm van die draad (met inagneming van die nodige veiligheidsafstand). Buigsame bekabeling kan dus die tyd wat nodig is om die topologie te redigeer aansienlik verminder, en ondersteun verskeie herhalings om aan beperkings te voldoen. Dit toon ‘n PCB -ontwerp wat deur gate en takpunte beweeg. Tydens outomatiese beweging word draadtakpunte en deurgate in die optimale posisie aangepas. In most computer-aided design (CAD) systems, the wiring interconnection problem is reduced to the problem of sequentially finding paths between pairs of points in a maze of pads, forbidden areas, and laid wires. As ‘n pad gevind word, word dit reggemaak en word dit deel van die doolhof. Die nadeel van opeenvolgende bedrading is dat die bedradingresultaat kan afhang van die volgorde van die bedrading. As topologiese kwaliteit nog lank nie perfek is nie, kom die probleem van ‘vassteek’ in plaaslik klein gebiede voor. But no matter which wire you rewire, it’s not going to improve the quality of the wiring. This is a serious problem in all CAD systems using sequential optimization. This is where the bending elimination process is useful. Draai buig verwys na die verskynsel dat ‘n draad in een netwerk om ‘n voorwerp op ‘n ander netwerk moet loop om toegang tot ‘n voorwerp te kry. Rewiring a wire will not correct this. ‘N Voorbeeld van buiging word getoon. A lit red wire travels around a pin in the other network, and an unlit red wire connects to this pin. Outomatiese verwerkingsresultate word vertoon. In the second case (on another layer), a lighted green wire is automatically rewired by changing the wiring layer (from green to red). Eliminate wire bending by automatically optimizing wire shape (approximate arcs with line segments just to show any Angle examples without arcs). (top) original design, (bottom) after eliminating bending design. Rooi geboë drade word uitgelig. In ‘n Steiner -boom moet alle lyne as segmente met hoekpunte (eindpunte en byvoegings) verbind word. Bo -aan elke nuwe hoekpunt moet drie segmente bymekaarkom en nie meer as drie segmente moet eindig nie. The Angle between the line segments that converge to the vertex shall not be less than 120 degrees. Dit is nie baie moeilik om ‘n Steiner met hierdie voldoende voorwaardelike eienskappe te bou nie, maar dit is nie noodwendig minimaal nie. Gray Steiner trees are not optimal, but black Steiner trees are. In praktiese kommunikasie -ontwerp moet verskillende soorte hindernisse oorweeg word. Hulle beperk die vermoë om minimum strekbome te bou met behulp van beide algoritmes en Steiner -bome met behulp van meetkundige metodes. The obstacles are shown in gray and we recommend starting at any end vertex. If there is more than one adjacent terminating vertex, you should choose one that allows you to continue using the second vertex. It depends on the Angle. Die belangrikste meganisme hier is ‘n kraggebaseerde algoritme wat die kragte wat op die nuwe hoekpunte inwerk, bereken en dit herhaaldelik na ‘n ewewigspunt beweeg (die grootte en rigting van die kragte hang af van die drade by die aangrensende takpunte). As die hoek tussen ‘n paar lynsegmente wat aan ‘n hoekpunt (eindpunt of optelling) gekoppel is, minder as 120 grade is, kan ‘n vertakkingspunt bygevoeg word, en dan kan ‘n meganiese algoritme gebruik word om die hoekpunt te optimaliseer. It’s worth noting that simply sorting all angles in descending order and adding new vertices in that order doesn’t work, and the result is worse. After adding a new node, you should check the minimum of a subnet consisting of four pins:

1. If a vertex is added to the vicinity of another newly added vertex, check for the smallest four-pin network.

2. If the four-pin network is not minimal, select a pair of “diagonal” (belonging to the quadrilateral diagonal) endpoints or virtual terminal nodes (virtual terminal nodes – wire bends).

3. The line segment that connects the endpoint (virtual endpoint) to the nearest new vertex is replaced by the line segment that connects the endpoint (virtual endpoint) to the distant new vertex.

4. Use mechanical algorithms to optimize vertex positions.

This method does not guarantee to build the smallest network, but compared with other methods, it can achieve the smallest network length without grazing. Dit maak ook voorsiening vir gebiede waar eindpuntverbindings verbied word, en die aantal eindpuntknope kan willekeurig wees.

Flexible wiring at any Angle has some other interesting advantages. For example, if you can automatically move many objects with the help of automatic real-time wire shape recalculation, you can create parallel serpentine lines. This cabling method makes better use of space, minimizes the number of iterations, and allows for flexible use of tolerances. If there are two serpentine lines interlaced with each other, the automatic cabler will reduce the length of one or both, depending on rule priority.

Consider the wiring of BGA components. In the traditional peripheral-to-center approach, the number of channels to the periphery is reduced by 8 with each successive layer (due to a reduction in perimeter). For example, a 28x28mm component with 784 pins requires 10 layers. Some of the layers in the diagram have escaped wiring. Figuur 16 toon ‘n kwart van ‘n BGA. At the same time, when using the “center to periphery” wiring method, the number of channels required to exit to the periphery does not change from layer to layer. Dit sal die aantal lae aansienlik verminder. Vir ‘n komponentgrootte van 28×28 mm is 7 lae voldoende. Vir groter komponente is dit ‘n wen-wen. Figure 17 shows a quarter of the BGA. An example of BGA wiring is shown. When using the “center to periphery” cabling approach, we can complete the cabling of all networks. Arbitrêre hoek topologiese outomatiese kabel kan dit doen. Traditional automatic cablers cannot route this example. Shows an example of a real PCB where the engineer reduced the number of signal layers from 6 to 4 (compared to the specification). In addition, it took engineers only half a day to complete the wiring of the PCB.