Integrated Circuit Timing Closure via Selective Path Optimization
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Solution Overview
Problem
Integrated circuits (ICs) face challenges in achieving timing closure due to delays in signal paths, which are not adequately addressed by existing design flows, leading to potential degradation of circuit performance.
Innovation Solution
A method is introduced that processes circuit designs through a late stage of the design flow, calculating baseline delays and slacks for paths, selecting paths for physical optimization, and applying optimizations only if they result in reduced delays, thereby ensuring improved timing without degrading performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical optimization is applied to all paths in the circuit design, then timing closure is improved, but computational complexity and processing time increase significantly
Solution Approach 1:
The patent applies physical optimization selectively only to critical paths identified by slack analysis, rather than uniformly to all paths. This local approach focuses computational resources on areas where timing closure is most needed, reducing overall computational complexity while maintaining timing closure effectiveness.
Solution Approach 2:
The patent segments the circuit design into multiple paths and identifies critical paths based on slack values. By dividing the optimization task into path-specific segments rather than treating the entire circuit as one unit, the computational complexity is reduced while still achieving timing closure for the most critical sections.
2Loss of time
If physical optimization is applied early in the design flow, then timing issues are addressed sooner, but the accuracy of delay calculations is insufficient
Solution Approach 1:
The patent performs preliminary processing through synthesis, mapping, placement, and routing to establish accurate baseline delays before applying physical optimization. This preliminary action ensures that when optimization is applied, the delay calculations are based on accurate, up-to-date information from the complete design flow.
Solution Approach 2:
The patent implements a feedback mechanism where baseline delays are calculated, slack is determined, and physical optimization is applied only if it improves timing. The optimized path delays are compared against baseline delays to ensure actual improvement, creating a feedback loop that ensures both timing closure and calculation accuracy.
3Manufacturing precision
If aggressive physical optimization is applied to meet timing requirements, then timing closure is achieved, but circuit performance may be degraded
Solution Approach 1:
The patent uses feedback to verify that optimized paths actually improve timing before incorporation. The system calculates baseline delays, applies optimization, then compares optimized path delays against baselines. Only optimizations that demonstrably improve timing are accepted, ensuring reliability is not compromised while achieving timing closure.
Solution Approach 2:
The patent changes physical parameters such as routing and placement only when it results in reduced delay. By conditioning parameter changes on actual timing improvement verification, the system achieves timing closure without introducing harmful changes that could degrade overall circuit performance or reliability.
Data Source
AI summary
Physical optimization for timing closure for an integrated circuit includes processing a circuit design at least partially through a design flow to a late stage of the design flow. Using a processor, a baseline delay is calculated for each of a plurality of paths of the circuit design. A slack for each of the plurality of paths is determined. Physical optimization further includes selecting a path of the circuit design that meets a selection criterion according, at least in part, to the slack of the path, applying, using the processor, a physical optimization to the selected path resulting in an optimized path, and calculating a delay of the optimized path. The optimized path is incorporated into the circuit design only responsive to determining that the delay of the optimized path is less than the baseline delay of the selected path.