A Weighted Directed Graph-Based Algorithm for Group Routing in Printed Circuit Boards

Routing is considered an essential component in the design of printed circuit board (PCB). Current existing PCB designs mostly rely on the process results from electronic design automation tools, and traditional automatic routing research often focuses on only general bus routing without considering bus groups to be determined during the routing process. Due to the absence of general bus grouping, there may be situations where there are more nets in one group than in other groups, resulting in larger line width and line clearance occupied by this group when compared to other bus groups in the original bus routing, thereby posing new challenges to effective and efficient routing. To overcome this drawback, this paper focuses on studying PCB group routing. In this study, a group routing algorithm based on a weighted directed graph is proposed. A Hanan grid graph is constructed, containing only merged edges and their adjacent relationships. Following this, a weighted directed graph is developed using the merged edge information to represent the routing resources on the circuit board. For routing planning, a heuristic search algorithm equipped with multi-wire avoidance features is utilized. The routing situations are then classified into several potential scenarios, with each considered separately, to accomplish detailed routing and obtain a final result of group routing. Results from experiments demonstrate that a 100% routability is consistently achieved by using the algorithm on complex industrial examples that have been previously tested, and that the design rule constraints of all benchmark industrial PCB cases are not violated.