EDA Testbench Coverage Convergence via Random Variable Correlation

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Solution Overview

Problem

Conventional methods for achieving high coverage point coverage in electronic circuit verification are time-consuming and require complex modifications to existing verification tools, as well as computationally expensive processes and extensive training data.

Innovation Solution

An improved testbench for EDA software tools that uses a data analysis engine to identify initial random variables corresponding to sampled coverage point solutions through a time-based association process, generating revised constraint parameters to produce focused random variables that systematically tune stimulus data to achieve higher coverage without requiring fundamental changes to existing configurations or extensive memory resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to achieve high coverage point coverage, then coverage completeness is improved, but verification time and complexity increase significantly

Engineering Contradiction:
Improvecoverage point coverageVSAvoidverification time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements feedback by analyzing simulation results to identify uncovered coverage points, then automatically generating new random variables and stimulus data targeted at those specific gaps. This closed-loop approach uses coverage metrics to guide subsequent simulation iterations, efficiently directing verification efforts toward remaining uncovered areas rather than random exploration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes parameters by dynamically adjusting random variable distributions and constraint parameters based on coverage analysis. When coverage gaps are identified, the system modifies the statistical parameters of random variable generation to bias toward stimulus patterns more likely to exercise uncovered functionality, thereby accelerating coverage convergence.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If manual analysis and test generation are used to achieve coverage convergence, then coverage completeness is improved, but device complexity and operational complexity increase

Engineering Contradiction:
Improvecoverage completenessVSAvoidverification tool complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The verification system performs self-service by automatically analyzing its own simulation results, identifying coverage gaps, and generating targeted test stimuli without external intervention. The data analysis engine autonomously processes coverage metrics and directs subsequent verification efforts, eliminating the need for manual analysis and reducing operational complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces a data analysis engine as an intermediary between the simulator and testbench. This intermediary automatically processes simulation results, correlates random variables with coverage points, and generates refined constraint parameters, thereby automating the complex analysis task and reducing the complexity burden on users.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If extensive simulation runs are performed to achieve coverage goals, then coverage completeness is improved, but computational cost and memory resources increase

Engineering Contradiction:
Improvecoverage completenessVSAvoidcomputational cost
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

Instead of performing exhaustive simulation runs to achieve complete coverage, the patent applies partial action by targeting only the specific coverage gaps identified through analysis. The system generates stimulus data focused on uncovered areas rather than uniformly exploring all possible scenarios, reducing computational effort while maintaining coverage effectiveness.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs preliminary analysis of simulation results to identify coverage gaps before launching subsequent simulation runs. This preliminary action allows the system to pre-target specific uncovered functionality, avoiding wasteful computational expenditure on already-covered areas and reducing overall computational cost.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10831961B2Automated coverage convergence by correlating random variables with coverage variables sampled from simulation result data
Publication Date: 2020.11.10 SYNOPSYS INC
  • US10831961B2 patent drawing
  • US10831961B2 patent drawing
  • US10831961B2 patent drawing

AI summary

A data analysis engine is implemented in a testbench to improve coverage convergence during simulation of a device-under-validation (DUV). During a first simulation phase initial stimulus data is generated according to initial random variables based on user-provided constraint parameters. The data analysis engine then uses a time-based technique to match coverage variables sampled from simulation response data with corresponding initial random variables, determines a functional dependency (relationship) between the sampled coverage variables and corresponding initial random variables, then automatically generates revised constraint parameters based on the functional dependency. The revised constraint parameters are then used during a second simulation phase to generate focused random variables used to stimulate the DUV to reach additional coverage variables. In one embodiment, the functional dependency is determined by cross-correlating sampled coverage variables and corresponding initial random variables.