IC PACKAGES TOPOMETRIC MODEL DATABASE WITH PRODUCTION RULES

Abstract

Printed circuit board (PCB) design plays a vital role in the production of radio-electronic devices. While there are several CAD systems available to automate the process, they often fail to consider the scheme topology. To address this, a high-quality automatic system for tracing printed circuit boards is needed. This involves several steps, including the placement of components on the board, the creation of topometric lines, determining the intersection of graph edges with topometric lines, and tracing connections through crosspoints.The creation of topometric lines involves adding additional edges to the graph that connect the outputs of neighboring components. This results in a model consisting of a topological part (connections graph and topometric lines) and a geometrical part (footprints). To facilitate the integration of these parts, a topometric model of a component is introduced.The implementation of a database to store these models is crucial for CAD systems. The database should include information about the package type, geometrical size, conductors' drawing, topology, production rules, and setup scripts for topological lines. Storing production rules in conjunctive-disjunctive form allows for efficient processing and smaller data volume.The topometric database should contain records for each type of IC package, including the package type, footprint image, cycle of the graph, geometrical bindings, production rules, and initialization script for additional poles.To use the IC package topometric models database, the user selects the package type for each element of the circuit. The corresponding record is loaded from the database, including the geometrical and topometric model, which is then copied into the local project base. Additional cases can be initialized and rules for forming conductors under the package can be edited. The application of these rules determines the ability to carry out connections under the package.The author suggests that this approach, utilizing an expert system, can be used for automatic routing of printed circuit boards using a topological approach