Global equivalent circuit modeling system for substrate mounted circuit components incorporating substrate dependent characteristics

• US 7,269,810 B1
• Filed: 10/18/2005
• Issued: 09/11/2007
• Est. Priority Date: 04/18/2003
• Status: Expired due to Term

• Current Assignee: University of South Florida (State University System of Florida)
• Original Assignee: University of South Florida (State University System of Florida)
• Inventors: Weller, Thomas, Lakshminarayanan, Balaji, Gordon, Horace, Capwell, John
• Primary Examiner(s): Lin; Sun James
• Application Number:
  US11/163,408
• Time in Patent Office: 693 Days
• Field of Search: 716/5, 716/4, 716/1
• US Class Current: 716/115
• CPC Class Codes: G06F 30/30 Circuit design
• CPC Class Codes: G06F 30/33 Design verification, e.g. functional simulation or model checking
• CPC Class Codes: G06F 30/3308 using simulation

Abstract

The present invention is a substrate dependent circuit modeling system for substrate-mounted components. The height and dielectric constant of a substrate have a significant impact on the frequency response of such components, and these effects cannot be treated independently from the circuit model. The equivalent circuit parameters in the model must be made to vary in accordance with changes in the substrate. The invention includes the steps of selecting a substrate mounted electrical circuit component for which an equivalent circuit model is desired, determining equivalent circuit model input parameters, wherein some of which are dependent upon characteristics of the substrate upon which the component is mounted, for the selected component, representing the selected electrical circuit component mounted upon the substrate as an equivalent electrical circuit, formulating mathematical expressions based upon the input parameters, and creating a unique equivalent circuit model for the component mounted upon the given substrate, the unique equivalent circuit model representing the mounting of the component upon the given substrate wherein the equivalent circuit model provides behavior and performance predictions of the component based upon the given substrate characteristics.

Claims

1. A method for generating a global equivalent circuit model to represent a family of electrical circuit components to be mounted upon a given substrate, the global equivalent circuit model incorporating substrate-dependent parameters, the method comprising the following steps:

selecting a plurality of electrical circuit components from a family of electrical circuit components for which a global equivalent circuit model is desired, the family of electrical circuit components comprising a plurality of electrical circuit components having values within a predetermined range of values and wherein the plurality of electrical circuit components selected does not include all of the electrical circuit components in the family;

measuring electrical response of each of the plurality of selected electrical circuit components;

extracting variable values and circuit element values from a measured electrical response for each of the plurality of selected electrical circuit components;

selecting an unmeasured electrical circuit component from the family of selected electrical circuit components, wherein the unmeasured electrical circuit component is not one of the plurality of selected electrical circuit components for which an electrical response has been measured;

identifying the variable values for the measured electrical circuit component of the plurality of selected electrical circuit components that has a value above the value of the unmeasured electrical circuit component and determining the corresponding circuit element values for the measured electrical circuit component of the plurality of electrical components that has a value above the value of the unmeasured electrical circuit component;

identifying the variable values for the measured electrical circuit component of the plurality of selected electrical circuit components that has a value below the value of the unmeasured electrical circuit component and determining the corresponding circuit element values for the measured electrical circuit component of the plurality of selected electrical circuit components that has a value below the value of the unmeasured electrical circuit component; and

performing linear interpolation between the identified circuit element values for the measured electrical circuit component of the plurality of selected electrical circuit components that has a value above the value of the unmeasured electrical circuit component and the identified circuit element values for the measured electrical circuit component of the plurality of selected electrical circuit components that has a value below the value of the unmeasured electrical circuit component resulting in an approximation of the electrical circuit component value for the unmeasured electrical circuit component from the family of selected electric circuit components.

2. The method of claim 1, wherein the step of measuring the electrical response of the plurality of selected electrical circuit components further comprising steps of:

determining input parameters of the global equivalent circuit model for a selected electrical circuit component, wherein some of said input parameters are dependent upon characteristics of a given substrate upon which the electrical circuit component is mounted, for the selected electrical circuit component;

representing the selected electrical circuit component mounted upon the substrate as an equivalent electrical circuit;

formulating mathematical expressions based upon the input parameters; and

creating a unique equivalent circuit model for the selected electrical circuit component mounted upon the given substrate, the unique equivalent circuit model representing mounting of the selected electrical circuit component upon the given substrate wherein the unique equivalent circuit model provides behavior and frequency performance predictions of the selected electrical circuit component based upon characteristics of the given substrate.

3. The method of claim 2 wherein the step of determining input parameters of the global equivalent circuit model comprises steps of measuring geometric properties of said given substrate and defining equation variables.

4. The method of claim 1 further comprising a step of incorporating the equivalent circuit model into a circuit simulation tool.