Statistical Uncertainty Feedback in Circuit Simulation

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Solution Overview

Problem

Current sampling and characterization tools for analog, mixed-signal, and custom digital circuit design face challenges such as lengthy processing times, uncertainty in results due to limited data, and inability to display statistical uncertainty, leading to potential false positives and negatives in evaluating circuit designs.

Innovation Solution

A method and system that analyze electrical circuit designs by obtaining simulation data, processing it to determine characteristic values and statistical uncertainty, and dynamically updating results, allowing users to assess quality and halt processing based on pre-determined criteria, thereby providing early and continually improving results with uncertainty reporting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sufficient number of circuit simulations are performed to reduce statistical uncertainty, then measurement precision improves, but loss of time increases

Engineering Contradiction:
Improvestatistical uncertaintyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by calculating and displaying intermediate statistical results during the simulation process. It computes characteristic values and their statistical uncertainties after each batch of simulations, allowing early assessment of result quality without waiting for all simulations to complete. This enables users to stop simulations early if uncertainty requirements are met, reducing total processing time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring and displaying the statistical uncertainty of characteristic values during the simulation process. Users receive real-time feedback on the quality of results, allowing them to make informed decisions about whether to continue or stop simulations. This feedback mechanism resolves the contradiction by making the trade-off between precision and time explicit and controllable.

Inventive Principle:
Principle #23Feedback

2Reliability

If statistical uncertainty is displayed to users, then reliability of interpretation improves, but device complexity increases

Engineering Contradiction:
Improveinterpretation reliabilityVSAvoidtool complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses statistical uncertainty values as an intermediary to bridge the gap between raw simulation data and reliable interpretations. By calculating and presenting uncertainty metrics (such as confidence intervals) alongside characteristic values, the tool mediates between the complexity of statistical analysis and the user's need for reliable conclusions. This intermediary representation simplifies interpretation while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If simulation processing continues until maximum precision is achieved, then measurement precision improves, but productivity decreases

Engineering Contradiction:
Improveresult precisionVSAvoiddesign throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system applies dynamics by making the simulation process adaptive rather than static. It allows users to define target uncertainty thresholds and automatically stops simulations when these thresholds are met, rather than running a fixed number of simulations. This dynamic approach optimizes the balance between precision and productivity by performing only the necessary amount of simulation work required to achieve satisfactory results.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS8589138B2On-the-fly improvement of certainty of statistical estimates in statistical design, with corresponding visual feedback
Publication Date: 2013.11.19 SIEMENS INDUSTRY SOFTWARE INC
  • US8589138B2 patent drawing
  • US8589138B2 patent drawing
  • US8589138B2 patent drawing

AI summary

A system and method to analyze analog, mixed-signal, and custom digital circuits. The system and method displays to a user characteristic values of a circuit and statistical uncertainty values of the characteristic values early in a sampling or characterization run of the circuit. The characteristic values and their statistical uncertainties are updated as the sampling or characterization run progresses. The user can halt the sampling or characterization run once a desired level of uncertainty is attained. The system can automatically halt the sampling or characterization run, once the statistical uncertainty lie within a pre-determined range.