IPBA-Driven Full-Depth EPBA for Circuit Timing Analysis
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Solution Overview
Problem
Current static timing analysis (STA) methods, particularly path-based analysis (PBA), face challenges in efficiently detecting timing violations in complex digital circuit designs due to pessimistic assumptions, leading to false-positive violations and increased runtime, which hampers circuit performance, cost, and time-to-market.
Innovation Solution
The implementation of an infinite-depth path-based analysis (IPBA) driven full-depth exhaustive path-based analysis (EPBA) system, which uses a breadth-first search traversal technique to propagate phases stage-by-stage, merging signals where possible, to reduce pessimism and enhance coverage, thereby improving the accuracy and efficiency of timing analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If path-based analysis (PBA) is used to perform algorithmic checks on circuit design timing paths, then measurement precision of timing violations is improved, but runtime and processing resources increase
Solution Approach 1:
The patent segments the circuit design into multiple timing paths and processes them in parallel using multi-threading. Each thread independently analyzes specific timing paths, dividing the computational workload to reduce overall runtime while maintaining comprehensive coverage of all timing paths in the circuit design.
Solution Approach 2:
The patent performs preliminary filtering using graph-based analysis (GBA) to identify timing paths that clearly violate timing constraints before applying the more computationally intensive PBA. This preliminary action eliminates obviously violating paths from further analysis, reducing the number of paths requiring full PBA processing and thereby reducing runtime.
2Productivity
If graph-based analysis (GBA) with pessimistic assumptions is used for coarse filtering, then productivity is improved, but measurement precision deteriorates due to false-positive violations
Solution Approach 1:
The patent introduces PBA as an intermediary verification step between GBA and final timing violation confirmation. GBA performs rapid coarse filtering with pessimistic assumptions, then PBA acts as a mediator to verify suspected violations with more accurate path-specific analysis, eliminating false positives while maintaining the productivity benefits of GBA's fast initial filtering.
Data Source
AI summary
A static timing analysis system for finding and reporting timing violations in a digital circuit design prior to circuit fabrication, and associated methods, use exhaustive path-based analysis (EPBA) that is informed by infinite-depth path-based analysis (IPBA) to provide analysis results that are driven full-depth, in contrast to conventional EPBA systems and methods, which can terminate after reaching a maximum depth of analysis as a way of avoiding prolonged or infinite runtimes. The IPBA-driven full-depth EPBA functions for hold-mode as well as setup-mode analysis and achieves reduced pessimism as compared to systems or methods employing IPBA alone, and more complete analysis of designs as compared to systems or methods employing EPBA alone. Improved IPBA signal merging using multidimensional zones for thresholding of signal clustering mitigates the occasional optimism of IPBA.