TopoR

Topor ( Topological Router) - is a Russian CAD ​​program for the design of printed circuit boards that have been previously edited with other programs and saved under the following formats PCAD ASCII PCB, PADS ASCII PCB or DSN.

History

The development of a flexible topological router was started in 1988, when it became clear that traditional unbundling methods, such as regular and irregular network (see grid based router and shape based router ) and sequential Leiterzugverlegung with the fixation of the geometry in the development in a dead end came. A first version of the topological router that has a commercial application, was published in 1996. With this program, the work under MS -DOS and was called FreeStyle router, double-sided PCBs could be unbundled.

This program illustrated the advantages of predominantly fundamentally new approach to the solution of routing tasks: The effectiveness of the developed models and algorithms and also the realization by means of a CAD software. Along with the examples it fit on a floppy disk 1.44 MB of disk space and has the boards faster and higher quality unbundled than comparable programs whose volume was hundreds of times larger than FreeStyle router.

In 2001, the first version of the topological router on Windows, which has received the name Topor appeared. This program not only two-layer, but also multilayer PCBs could be unbundled.

Application

By the use of the CAD program Topór for the design of circuit boards, the overall length of circuit traces and the number of the via as compared to the other programs can be reduced. With the Topor both the single-layer printed circuit boards, as well as the printed circuit boards with a high component density can be successfully disentangled.

The automatic flexible topological unbundling of electrical connections done at any angle, without being limited to only 45 ° and 90 °.

Through effective utilization of the available mounting space and the absence of disentanglement predetermined directions, the level of the electromagnetic crosstalk is substantially reduced.

With the Topor program initially all connections are unbundled, even if it some technological constraints ( constraints) must be violated. In the next step, these errors are eliminated automatically. In the circuit boards with a high component density, this property has a crucial importance because it allows to estimate the fundamental possibility and the workload in a subsequent manual unbundling.

When moving objects ( components, vias ) optimal Leiterzugform will be automatically calculated with the consideration of minimum permissible distances. This leads to a substantial relief of the machining process and freed of the need to comply with the technical limitations.

The user can choose between two methods to calculate the Leiterzugform: with and without the use of circular arcs. First method sets the Leiterzugverlegung ahead with the help of broken lines. In the second method, trace circles around the obstacles along the circular arcs with the maintenance of the necessary clearances and changes between two circular arcs along a short straight line.

When autorouting there is a parallel optimization of several alternative topology variants. The variants in all parameters (total trace length, number of vias ) are worse are removed. This approach allows the use of the mechanism of distributed computations, in order to increase the speed unbundling. According to the authors one of the next versions Topor will include the possibility of a distributed unbundling.

The Topor program has an automatic component placement. This procedure can be used both for all components on a printed circuit board, and only for the components in a selected area. Of course, the quality of automatic component placement can hardly be compared to the quality of the manual placement. However, this step is for an initial component placement with subsequent manual optimization can be used.

In Topor program it is possible to define a minimum permissible and desired distance for each circuit.

The Topor program reduces the line width, if this approximates to a contact who has a smaller width (or if the diameter of the contact pad is smaller than the line width is ) and when laying through tight spaces ( for example, between the contact pads of a component ).

There is the possibility of a teardrop-shaped smoothing the transitions between the conductor lines and contact pads ( teardrops ). The application of this procedure when configuring a circuit board allows the avoidance of constructive and technological constraints ( constraints) in the later addition of teardrops in the CAM editor.

In the automatic disengagement of BGA components with the Topor program such devices are automatically detected and the unbundling a specific strategy is applied. This leads to the reduction of the number of plated-through holes, to reduce the density of contacts and in certain cases also for the reduction of printed circuit board layers.

For the unbundling of single-layer PCBs the program Topor can be used very effectively because it will ensure an absolute minimum of vias ( within the proposed topology). Implementation of effective unbundling is the Topor program either a variant with a layer or alternatively offers a variant with a minimum number of jumpers.