Static Timing Analysis Circuit Stage Credit Database
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Solution Overview
Problem
Current static timing analysis (STA) tools face inefficiencies in design optimization due to the time-consuming nature of path-based analysis (PBA), which is often precluded in favor of graph-based analysis (GBA) due to pessimistic results and high resource requirements, leading to suboptimal design processes.
Innovation Solution
The method involves determining GBA delays for multiple timing paths, selecting timing paths with common circuit stages, accessing a circuit stage credit database to predict PBA slack, and updating the database with circuit stage credit values, allowing for the adjustment of GBA delays and reducing the need for actual PBA analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If path-based analysis (PBA) is used for static timing analysis, then measurement precision of timing information is improved, but loss of time and resource consumption increase significantly
Solution Approach 1:
The patent performs PBA in advance on selected timing paths to establish baseline timing information and identify violating paths. These preliminary PBA results are then used to guide subsequent GBA operations, avoiding the need to perform full PBA on all paths during the main analysis phase.
Solution Approach 2:
The patent divides the circuit into different categories of timing paths: violating paths (requiring PBA), non-violating paths (using GBA), and common paths (using hybrid approach). This segmentation allows the system to apply different analysis methods to different path types, optimizing the balance between accuracy and efficiency.
2Manufacturing precision
If path-based analysis (PBA) is used for static timing analysis, then manufacturing precision of timing constraints is improved, but productivity decreases due to high resource requirements
Solution Approach 1:
The patent applies PBA only to the extent necessary - specifically to violating paths and selected common paths - rather than performing it on all timing paths. This partial application of PBA provides sufficient timing accuracy to identify and fix constraint violations without the full resource cost of comprehensive PBA.
Solution Approach 2:
The patent dynamically adjusts the analysis approach based on path characteristics. For example, common paths that appear in multiple timing contexts receive PBA treatment to establish reusable timing information, while unique non-violating paths use faster GBA methods.
3Productivity
If graph-based analysis (GBA) is used instead of path-based analysis, then productivity is improved due to lower resource requirements, but measurement precision of timing information deteriorates due to pessimistic results
Solution Approach 1:
The patent introduces a hybrid analysis framework that acts as an intermediary between pure GBA and pure PBA. The system uses GBA as the default efficient method but introduces PBA as a corrective mechanism for specific paths where GBA produces overly pessimistic results, thereby mediating between speed and accuracy requirements.
Data Source
AI summary
The present embodiments relate to static timing analysis (STA) of circuits. The STA can include determining graph based analysis (GBA) delays of timing paths within the circuit. Path based analysis (PBA) delays of a subset of timing paths can be determined to generate circuit stage credit values for circuit stages in the circuit. The circuit stage credit values can be used to adjust GBA delays of the timing paths. Prediction functions can be utilized to predict or estimate PBA delays of timing paths thereby avoiding the determination of actual PBA delays of the timing paths.