Timing-Sensitive Circuit Extraction for Statistical Margin Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional timing margin checks for custom circuit designs are overly pessimistic or optimistic, leading to sub-optimal circuit designs due to inadequate handling of on-chip variations and complexity, particularly in scenarios involving races between multiple signal paths, and existing statistical approaches are impractical for large designs.
Innovation Solution
A novel system for automatic timing-sensitive circuit extraction and statistical timing margin simulation that generates a timing-sensitive netlist, performs parallelized simulations, and flags design errors, considering both global and local variations, to provide accurate and practical timing margin distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deterministic analysis with severe guard-bands is used, then functionality is ensured under worst-case conditions, but the circuit design becomes overly pessimistic and sub-optimal
Solution Approach 1:
The patent transforms the deterministic worst-case parameter approach into a statistical parameter distribution approach. Instead of using fixed guard-band parameters based on worst-case assumptions, the system employs statistical analysis with parameter distributions that capture actual variation behavior, enabling more accurate and less pessimistic timing margin assessment while maintaining reliability
Solution Approach 2:
The patent creates extracted timing-sensitive circuit models that replicate the critical timing behavior of the full design. These simplified copies allow statistical timing analysis to be performed on representative subsets rather than the complete design, reducing computational complexity while preserving the essential timing characteristics needed for accurate margin assessment
2Measurement precision
If statistical analysis is performed on large full-block designs, then more accurate timing representations are obtained, but the runtime becomes impractical (weeks or months)
Solution Approach 1:
The patent segments the large full-block design into smaller, manageable timing-sensitive circuit extracts. By dividing the complete design into discrete timing paths and extracting only the relevant portions for statistical analysis, the system maintains measurement precision on critical paths while reducing overall analysis time from weeks/months to practical durations
Solution Approach 2:
The patent extracts timing-sensitive circuits from the larger design context, isolating the critical timing paths that need statistical analysis. This extraction process removes unnecessary circuit elements from the analysis scope, allowing accurate statistical timing assessment to be performed on reduced models rather than the complete design, thereby achieving both precision and practical runtime
3Ease of manufacture
If conventional corner methodologies are used for timing checks, then simple single-path checks can be performed, but they fail to accurately handle races between multiple signal paths
Solution Approach 1:
The patent introduces dynamic stimulus application and temporal sequencing capabilities that allow the timing analysis system to handle multiple signal paths and their interactions. By dynamically applying stimuli and observing temporal relationships between multiple paths, the system can accurately assess races and conflicts that static corner methodologies cannot detect, while maintaining practical complexity through automated extraction and analysis
Data Source
AI summary
Embodiments include systems and methods for automatic timing-sensitive circuit extraction for statistical timing margin analysis of custom designs. A timing-sensitive circuit extractor system can take pre- or post-layout netlists for integrated circuits and can automatically generate a timing-sensitive netlist. For example embodiments can generate a connectivity graph from the netlist and can traverse the graph with constraints defined according to measurement nodes to extract the timing-sensitive circuit. Memory timing checks and corresponding stimuli can generally be pre-defined, and a test-bench generator can generate appropriate parameters, stimuli, etc. Statistical simulations can then be performed to quickly generate results, which can be post-processed to obtain timing margin distributions and to flag out design errors.