Setup and Hold Time Characterization Using Goal Function Optimization
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Solution Overview
Problem
Conventional methods for characterizing setup and hold times in integrated circuit design are time-consuming, requiring numerous iterations of binary searches to determine the minimum setup and hold times for a design cell to operate within specifications.
Innovation Solution
A method that iteratively adjusts setup and hold times using a goal function, minimizing the number of binary searches by varying the goal function value and testing the design cell until it fails to operate as specified, allowing for the determination of minimum setup and hold times based on relative weights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional binary search methods are used to characterize setup and hold times, then accurate timing values can be determined, but the characterization process becomes time-consuming due to numerous iterations
Solution Approach 1:
The patent changes the approach from fixed iterative binary searches to a goal function-based method that dynamically adjusts timing parameters. By defining a goal function that combines setup and hold time requirements with relative weights, the system can directly determine optimal timing values without extensive iterations, reducing characterization time while maintaining accuracy.
Solution Approach 2:
Instead of performing complete binary searches for both setup and hold times independently (excessive action), the patent uses a goal function to determine timing values more efficiently (partial action). The goal function allows the system to stop searching once sufficient precision is achieved, avoiding unnecessary iterations and reducing overall characterization time.
2Measurement precision
If multiple binary searches are performed to determine minimum setup and hold times, then accurate timing characterization is achieved, but the process complexity and time required increase significantly
Solution Approach 1:
The patent merges the characterization of setup and hold times into a single unified process using a goal function. Instead of performing separate binary searches for each timing parameter, the goal function combines both requirements into one optimization problem, reducing the total number of iterations and improving characterization efficiency while maintaining accuracy.
Solution Approach 2:
The goal function provides feedback about the relative importance of setup and hold times through weighted coefficients. This feedback mechanism allows the system to adjust timing values more intelligently, converging on accurate characterization results faster than traditional binary search methods that treat both parameters equally without feedback guidance.
Data Source
AI summary
A method of characterizing a device under test (DUT) includes determining a goal function associated with a setup and hold time for the DUT. A minimum value for the goal function is determined by iteratively adjusting setup and hold times for input data to the DUT, and determining whether the DUT performs according to specifications. The minimum goal function value will reflect minimum setup and hold time values based on weights associated with the goal function. This allows the minimum setup and hold times for the DUT to be characterized with a small number of binary searches, improving the speed of the characterization process.