Representative Cell Characterization for Static Timing Analysis
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Solution Overview
Problem
Conventional methods for improving integrated circuit design are inefficient due to the lack of process variation consideration in corner-based analysis and the excessive use of pessimism and resources in methods that account for process variation, leading to suboptimal circuit performance.
Innovation Solution
A system comprising a characterizer component that identifies representative cells based on design criteria, characterizes them, and maps cell-related information to optimize the integrated circuit design by reducing sensitivity to random device variation, using a constructor component to reconstruct and enhance the circuit's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If corner-based analysis through static timing is employed, then the analysis process is simple and fast, but process variation is not taken into account leading to inaccurate timing predictions
Solution Approach 1:
The patent segments the complete set of cells into multiple subsets, with each subset characterized by a representative cell. This segmentation allows the analysis to focus on key representative cells rather than all cells, maintaining analysis speed while capturing process variation effects through the representative cells that embody the characteristics of their respective subsets.
Solution Approach 2:
The patent changes the parameters used in timing analysis by incorporating statistical properties and process variation data into the representative cells. Instead of using fixed corner-based parameters, the system uses dynamically determined representative cells that reflect actual process variation, thereby improving timing prediction accuracy while maintaining computational efficiency.
2Measurement precision
If conventional methods account for process variation with statistical properties of cells, then timing accuracy improves, but undue pessimism is employed and excessive time is required to generate cell-related information
Solution Approach 1:
The patent extracts only the essential characteristics needed for timing analysis from each cell subset and concentrates them into representative cells. By taking out only the relevant statistical properties and process variation data that are necessary for accurate timing prediction, the system avoids the computational burden of analyzing all cells in detail, thus reducing the time required while maintaining accuracy.
Solution Approach 2:
The patent creates representative cells that serve as copies or proxies for groups of similar cells. These representative cells capture the essential behavior and statistical properties of their subsets, allowing the timing analysis to proceed using a smaller set of representative instances rather than all individual cells, thereby reducing computation time while preserving accuracy.
3Reliability
If all cell information is used in timing analysis, then comprehensive coverage is achieved, but the amount of information and computational resources required becomes undesirable
Solution Approach 1:
The patent divides the complete cell set into multiple subsets and assigns a representative cell to each subset. This segmentation strategy ensures that all cells are covered comprehensively through their representatives, maintaining analysis reliability while reducing the total amount of information that needs to be processed by working with the smaller set of representative cells rather than all individual cells.
Solution Approach 2:
The representative cells serve multiple functions: they represent their respective subsets, capture process variation effects, and enable timing analysis. This multi-functionality allows a single representative cell to stand in for multiple individual cells, reducing the overall information processing complexity while maintaining comprehensive coverage of all cell types in the design.
Data Source
AI summary
Techniques efficiently improve circuit design to reduce its sensitivity to random device variation. A characterizer component can identify a subset of cells for an integrated circuit that can be representative of respective other cells of a set of cells. The characterizer component can analyze the representative cells of the subset to generate a variation profile, and can map the representative cells to physical cells used in the design of the circuit. A cell library comprising cells that are usable, have limited usage, and/or have general usage can be generated based on analysis results from the mapped cells. The circuit can be reconstructed based on the list of available cells using the cell library. The reconstructed circuit can be analyzed, and in case of a cell(s) violating a constraint, the cell(s) can be modified or enhanced to achieve target performance criteria.