Liberty File Generation Using Empirical Timing Models
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Solution Overview
Problem
The generation of liberty files for electronic design automation (EDA) tools requires significant computing resources and time due to the need for multiple simulations across various process, voltage, and temperature (PVT) conditions, leading to a large number of .lib files that are time-consuming to produce.
Innovation Solution
A methodology that uses mathematical empirical equations to describe variations in timing data with voltage and temperature, allowing for the reduction of the number of liberty files by generating scaled files for different voltage and temperature values, and extracting parameter values to derive fitting equations, thereby reducing the need for additional simulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple simulations are performed across various PVT conditions to generate liberty files, then the accuracy and completeness of timing data is improved, but the computing resources and time required increase significantly
Solution Approach 1:
The patent performs simulations at selected PVT corner conditions first to establish baseline timing data, then uses mathematical empirical equations to predict timing parameters at intermediate conditions without performing full simulations. This preliminary action at critical points enables subsequent rapid interpolation.
Solution Approach 2:
The patent changes the approach from performing simulations at every PVT condition to performing simulations only at corner conditions and using parameter interpolation for intermediate values. Mathematical empirical equations model the relationship between PVT parameters and timing characteristics, enabling accurate prediction without exhaustive simulation.
2Measurement precision
If multiple simulations are performed across various PVT conditions to generate liberty files, then the accuracy and completeness of timing data is improved, but the computing resources required increase significantly
Solution Approach 1:
The patent performs simulations at selected PVT corner conditions first to establish baseline timing data, then uses mathematical empirical equations to predict timing parameters at intermediate conditions without performing full simulations. This preliminary action at critical points enables subsequent rapid interpolation.
Solution Approach 2:
The patent changes the approach from performing simulations at every PVT condition to performing simulations only at corner conditions and using parameter interpolation for intermediate values. Mathematical empirical equations model the relationship between PVT parameters and timing characteristics, enabling accurate prediction without exhaustive simulation.
3Measurement precision
If liberty files are generated for each variation in parameter settings, then the precision of timing analysis is improved, but the number of files and system complexity increase
Solution Approach 1:
The patent creates a universal timing model that can predict timing parameters across all PVT conditions using a single set of mathematical empirical equations and corner condition data. This universal model replaces the need for multiple separate liberty files, as the same equations can generate accurate timing data for any PVT combination.
Solution Approach 2:
The patent changes the approach from performing simulations at every PVT condition to performing simulations only at corner conditions and using parameter interpolation for intermediate values. Mathematical empirical equations model the relationship between PVT parameters and timing characteristics, enabling accurate prediction without exhaustive simulation.
Data Source
AI summary
Various implementations described herein are directed to a system and methods for generating timing data for an integrated circuit. In one implementation, the method may include generating first timing data for the integrated circuit, and the first timing data may be related to one or more variations of operating conditions for the integrated circuit. Further, the method may include extracting parameter values from the first timing data in association with the one or more variations of operating conditions. Further, the method may include generating second timing data for the integrated circuit, and the second timing data may be based on the extracted parameter values.