Continuous PVT Timing Prediction via Distance-Based Corner Selection

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Solution Overview

Problem

Current PVT corner analysis for integrated circuits is limited by its discrete nature, failing to provide accurate predictive coverage and accuracy for continuous operating conditions, as it relies on a finite set of trained corners.

Innovation Solution

A corner prediction system that selects a subset of trained PVT corners based on a distance-based selection criterion and uses a prediction algorithm to generate performance metric values for target corners, with a validation component modifying the algorithms to refine predictions and improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If discrete PVT corner analysis is used, then the analysis is simpler and requires fewer trained corners, but the predictive coverage and accuracy for continuous operating conditions deteriorates

Engineering Contradiction:
Improveanalysis complexityVSAvoidpredictive accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the discrete PVT corner parameters into a continuous parameter space by introducing distance metrics and interpolation variables. The target corner parameters are continuously adjusted based on weighted combinations of reference corners, enabling continuous prediction across the PVT space rather than discrete corner-by-corner analysis.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary prediction model that acts as a mediator between discrete reference corners and continuous target corners. This model uses distance-based weighting and interpolation algorithms to bridge the gap between discrete training data and continuous prediction requirements, achieving both accuracy and efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If more trained PVT corners are used, then the predictive coverage and accuracy improves, but the computational complexity and data requirements increase

Engineering Contradiction:
Improvepredictive accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential features from the full set of PVT corners by selecting reference corners based on distance criteria. Instead of using all available trained corners, the system extracts and utilizes only those corners that are most relevant to the target prediction, reducing computational overhead while maintaining accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the PVT corner space into regions of influence around each reference corner. By dividing the continuous parameter space into discrete zones and assigning target corners to the nearest reference corners, the system simplifies the prediction process while maintaining local accuracy through targeted analysis.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If distance-based selection criterion is applied, then the prediction accuracy for target corners improves, but the computational overhead for selecting corners increases

Engineering Contradiction:
Improvecorner selection accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by pre-calculating and storing distance metrics between PVT corners before the actual prediction process. Reference corners and their distances are pre-processed and organized, so that during prediction, the system only needs to retrieve and apply pre-computed values rather than calculating distances in real-time, significantly reducing computational overhead.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11295057B1Continuous and discrete corner regularization in multi-PVT timing prediction
Publication Date: 2022.04.05 CADENCE DESIGN SYST INC
  • US11295057B1 patent drawing
  • US11295057B1 patent drawing
  • US11295057B1 patent drawing

AI summary

A corner prediction system applies data generated through discrete process, voltage, and temperature (PVT) corner prediction to achieve highly accurate continuous corner prediction coverage. Embodiments of the corner prediction system can be trained to generate accurate performance metric prediction for a continuous range of PVT corners within a design space given a set of available pre-trained PVT corners. The corner prediction system can address the need to provide accurate continuous timing prediction coverage of design operating conditions (represented by PVT corners) through the availability of discrete PVT corners.