Compact Physical Models for Passive Structures

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Solution Overview

Problem

Existing methods for generating simulation models of passive electrical circuit structures, such as inductors and transmission lines, often result in bulky models that are unsuitable for long transient simulations, leading to non-converging simulations, run-time crashes, and inaccurate results due to non-physical components like negative capacitances and voltage-controlled-voltage-sources.

Innovation Solution

A multi-step methodology is employed to generate compact physical models by optimizing impedance values and parameters, ensuring convergence and accuracy through analytical frameworks and simulation-based optimization, while preserving low-frequency resistance and inductance, and refining parameters based on the intended use context.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If full extraction is used to generate source models, then model accuracy is improved, but model size increases and becomes bulky

Engineering Contradiction:

Improvemodel accuracyVSAvoidmodel size

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential impedance characteristics from the full extraction source model, separating the critical low-frequency resistance and inductance parameters from the complete frequency-dependent model. This selective extraction creates a compact representation that retains accuracy for transient simulations while removing unnecessary complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the frequency-dependent impedance parameters into time-domain equivalent circuit parameters (resistance and inductance values) that are suitable for transient simulation. By changing the parameter representation from frequency-domain to time-domain equivalents, the model becomes compact while preserving the essential electrical characteristics needed for accurate simulation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If source models with non-physical elements are used, then model completeness is improved, but simulation reliability deteriorates

Engineering Contradiction:

Improvemodel completenessVSAvoidsimulation reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent converts the potentially harmful non-physical elements (negative capacitances, negative resistances, VCVS) into beneficial physical equivalents. By transforming these problematic elements into physically realizable RLC circuit components with positive values, the model maintains completeness in representing impedance characteristics while ensuring simulation convergence and reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the parameter values and signs to eliminate non-physical characteristics. Negative capacitances and resistances are transformed into positive-valued physical components through parameter transformation, and controlled sources are replaced with passive RLC elements, making the model suitable for reliable transient simulation.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If full extraction is used to generate source models, then impedance accuracy is improved, but CPU processing time increases

Engineering Contradiction:

Improveimpedance accuracyVSAvoidCPU processing time

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using the complete frequency-domain extraction model directly for transient simulation, the patent inverts the approach by creating an equivalent time-domain RLC circuit model that reproduces the impedance characteristics. This inversion allows the model to run efficiently in transient simulation mode with reduced CPU time while maintaining impedance accuracy.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11568117B2Generating simulation-friendly compact physical models for passive structures

Publication Date: 2023.01.31 SYNOPSYS INC

AI summary

A system and method for generating simulation-friendly compact physical models for passive structures is disclosed. The method includes generating an impedance map specifying impedances at a plurality of frequencies corresponding to one or more port-pairs of a circuit component using a processor to extract a plurality of impedance values between the one or more port-pairs based on a first value for each parameter of a plurality of parameters of the circuit component. The method includes generating a second circuit representation model based on updating the plurality of impedance values between the one or more port-pairs based on a second value for one or more parameters of the plurality of parameters of the circuit component, and updating the second circuit representation model by tuning the updated plurality of impedance values of the between the one or more port-pairs based on a predetermined use context of the circuit component in a circuit.