Scan Chain Optimization via Constrained Single-Linkage Clustering
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Solution Overview
Problem
Current design-for-test systems using k-means clustering do not optimize the total wire length of scan chains, leading to increased complexity in signal routing and power consumption in circuit testing.
Innovation Solution
The implementation of constrained single-linkage clustering by a physical design tool to identify and redistribute latch clusters, minimizing total wire length across scan chains while adhering to constraints such as maximum latch count and cluster distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If k-means clustering is used to form scan chains, then scan chains can be generated, but total wire length is not optimized leading to increased routing complexity and power consumption
Solution Approach 1:
The patent changes the clustering approach from k-means to constrained single-linkage clustering, which fundamentally alters how latches are grouped. This parameter change in the clustering algorithm enables optimization of total wire length while reducing routing complexity, as single-linkage clustering naturally groups spatially adjacent latches more effectively for scan chain formation.
Solution Approach 2:
The patent segments the latch population into multiple clusters using constrained single-linkage clustering, where each cluster represents a spatially coherent group of latches. This segmentation strategy groups latches that are physically close together, which directly reduces the total wire length required for scan chain routing and simplifies the overall routing complexity.
2Use of energy by stationary object
If k-means clustering is used to form scan chains, then scan chains can be generated, but power consumption increases due to non-optimized wire length
Solution Approach 1:
The patent changes the clustering methodology from k-means to constrained single-linkage clustering, which optimizes the spatial arrangement of latches in scan chains. This parameter change reduces the total wire length required, which directly lowers power consumption since shorter wires consume less power during signal transitions in the scan chains.
3Length of moving object
If latch clusters are formed without redistribution, then clustering is simpler, but total wire length is not minimized
Solution Approach 1:
The patent performs preliminary clustering using constrained single-linkage clustering to create initial latch clusters based on spatial proximity. This preliminary action establishes a foundation of spatially coherent groups that can then be optimized through redistribution, ensuring that the final scan chain configuration minimizes total wire length while maintaining clustering efficiency.
Solution Approach 2:
The patent introduces dynamic redistribution of latches between clusters after the initial clustering phase. This dynamic adjustment allows the system to optimize total wire length by moving latches to their most appropriate clusters, improving the overall efficiency of the scan chain formation process without sacrificing the initial clustering structure.
Data Source
AI summary
Scan chain optimization utilizing constrained single linkage clustering is disclosed. In an embodiment, a physical design tool identifies a placement of a plurality of latches in a circuit layout; generates, based on the placement, a set of latch clusters by applying constrained single-linkage agglomerative clustering to the plurality of latches; optimizes the set of latch clusters by redistributing latches across clusters; and generates a set of scan chains corresponding to the optimized set of latch clusters.