Integrated Circuit Timing Analysis Slack Apportionment
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Solution Overview
Problem
Conventional slack apportionment methods in integrated circuit design provide limited positive slack allocation to downstream macros, leading to power reduction challenges and potential timing budget unfeasibility, especially when applying positive slack to highly positive signal paths.
Innovation Solution
An integrated circuit timing analysis system that applies an even apportionment of slack based on a positive slack threshold, determining a first portion of total slack based on a path ratio and distributing the remaining slack evenly among macros associated with the signal path, thereby increasing positive slack allocation to downstream macros.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional slack apportionment methods are used, then timing analysis can be performed, but positive slack allocation to downstream macros is limited
Solution Approach 1:
The patent segments the total slack into two distinct portions: a first portion allocated based on path ratio (upstream/downstream delay relationship) and a second portion allocated evenly to all macros. This segmentation enables more flexible and effective slack distribution compared to conventional single-method apportionment, thereby increasing positive slack allocation to downstream macros and achieving power reduction.
Solution Approach 2:
The patent applies different allocation strategies to different portions of slack based on local characteristics of the signal path. The first portion is allocated according to the specific path ratio between upstream and downstream delays, while the second portion is distributed evenly. This localized quality approach ensures that slack is allocated where it is most needed and effective, improving both timing feasibility and power reduction.
2Reliability
If conventional slack apportionment methods are used, then timing analysis can be performed, but timing budget feasibility is compromised
Solution Approach 1:
By dividing slack allocation into two structured portions with clear allocation rules (path ratio-based and even distribution), the patent ensures that timing budgets remain feasible while maintaining manageable complexity. The segmented approach provides determinism and predictability in slack distribution, improving timing budget feasibility.
Solution Approach 2:
The patent changes the parameters of slack allocation by introducing a dual-portion methodology with different distribution criteria. This parameter change transforms the slack apportionment from a single-method approach to a multi-parameter approach, ensuring timing budget feasibility while controlling complexity through systematic rules.
3Reliability
If positive slack is applied to highly positive signal paths, then timing may be improved, but power reduction is limited
Solution Approach 1:
The patent applies local quality by allocating the first portion of slack based on the specific path ratio of each signal path. This ensures that slack is applied locally where needed according to the actual timing characteristics of each path, enabling effective timing improvement while optimizing power consumption through targeted rather than blanket slack application.
Solution Approach 2:
By changing the slack allocation parameters to include path ratio calculations and dual-portion distribution, the patent enables more precise control over where and how much slack is applied. This parameter change allows for better optimization of the trade-off between timing requirements and power consumption, achieving greater power reduction compared to conventional methods.
Data Source
AI summary
A system is provided to perform slack apportionment for an integrated circuit. The system includes a time calculation module and a slack apportion module. The time calculation module determines an arrival time corresponding to a target pin in signal communication with a signal path. The slack apportion module determines a total slack associated with the signal path and determines a slack threshold value that is equal to a portion of the total slack. The time calculation module further determines an apportioned arrival time associated with the signal path based on the arrival time and a delay offset value. The slack apportion module further determines a residual slack apportionment value based on a residual slack and the number of macros associated with the signal path. Accordingly, the time calculation module determines a modified apportioned arrival time based on the residual slack apportionment value and the apportioned arrival time.