Pin Clustering for Power-Ground Network via Nearest Neighbor Graph
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Solution Overview
Problem
Traditional routing algorithms in electronic design automation (EDA) often connect circuit design pins to arbitrary power-ground network access points, leading to violations of connection constraints, resulting in suboptimal wirelength, via count, and bounding box size.
Innovation Solution
A method that clusters pins by constructing a nearest neighbor graph, evaluating edge costs, and merging pin clusters based on constraints such as pin count, radius, and wirelength to minimize wirelength and vias while satisfying connection constraints, connecting pins in each cluster to the nearest power-ground access point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional routing algorithms connect pins to arbitrary power-ground network access points, then the routing process is simple, but connection constraints are violated and wirelength is suboptimal
Solution Approach 1:
The patent segments the pin connection problem into two distinct phases: (1) pin clustering phase where pins are grouped into clusters with associated access points, and (2) routing phase where standardized net definitions are used. This segmentation allows constraint satisfaction to be handled separately from routing execution, resolving the contradiction between precision and complexity.
Solution Approach 2:
The patent performs preliminary pin clustering and access point assignment before the actual routing process. By pre-establishing pin clusters and their associated power-ground access points, the system ensures constraint satisfaction is determined in advance, allowing the routing phase to proceed with simplified net definitions without re-evaluating constraints.
2Productivity
If pins are connected to arbitrary access points, then the routing process is fast, but wirelength and via count are suboptimal
Solution Approach 1:
The patent separates the optimization problem (pin clustering to minimize wirelength and via count) from the routing execution phase. By pre-optimizing pin cluster assignments and access point selections, the system achieves wirelength optimization without sacrificing routing speed in the actual routing phase.
Solution Approach 2:
The patent changes the representation parameters from individual pin-to-access-point connections to pin cluster-to-access-point connections. This parameter change allows the system to evaluate and optimize wirelength and via count at the cluster level, achieving better metrics while reducing the computational complexity of the routing phase.
3Manufacturing precision
If pins are clustered to minimize wirelength and vias, then connection quality improves, but the clustering process becomes complex
Solution Approach 1:
The patent introduces pin clusters as intermediary structures between individual pins and power-ground access points. These clusters serve as mediators that group pins with similar access point requirements, simplifying the optimization problem while maintaining placement quality through constrained cluster formation based on geometric and electrical criteria.
4Device complexity
If traditional routing is used, then the process is simple, but bounding box size is suboptimal
Solution Approach 1:
The patent performs preliminary pin clustering with bounding box constraints before routing. By evaluating and optimizing pin cluster bounding boxes in advance, the system determines feasible cluster formations that minimize area usage, allowing the routing phase to proceed with simplified processes while achieving optimal bounding box sizes.
Data Source
AI summary
Various embodiments provide for clustering pins of a circuit design for connection to a power-ground network (PG) of the circuit design using a nearest neighbor graph. Pin clustering, according to some embodiments, can minimize wirelength, minimize a number of vias, satisfy constraints relating to a pin count (e.g., maximum number of pins per power-ground access point), and satisfy constraints relating to a bounding box size.