Component-based analog and mixed-signal simulation model development

• US 5,963,724 A
• Filed: 02/16/1996
• Issued: 10/05/1999
• Est. Priority Date: 02/16/1996
• Status: Expired due to Term

• Current Assignee: Synopsys Incorporated
• Original Assignee: Analogy, Inc. (Synopsys Incorporated)
• Inventors: Mantooth, H. Alan, Wolff, Christopher M.
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Fiul, Dan
• Application Number:
  US08/602,223
• Time in Patent Office: 1,327 Days
• Field of Search: 395/500, 364/578
• US Class Current: 703/14
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods
• CPC Class Codes: G06F 8/34 Graphical or visual programming

Abstract

The Model Editor (106) makes simulation modeling easier and more intuitive by extracting essential information and presenting it to the user, and by providing tools to investigate simulation and model robustness, in an interactive, graphical environment. Using the model editor, the user enters relationships or formulas in the equation editor (200), enters symbols in the topology editor (202), and interconnects them (1804). Relationships can be hidden for screen efficiency (1806). Selecting a symbol highlights the corresponding relationships in the equation editor through cross-coupling, and conversely selecting an equation or instance highlights the corresponding symbol in the topology editor (1808). The model editor includes parameter management tools (206) to manage equation parameters. Models or portions thereof that are reused donate the parameter management data to the new model (1810). Following editing and parameter management, the user can perform model robustness and verification. Sample point manager, newton step manager and matrix element stamp analysis are all new, interactive, graphical, intuitive tools. Finally, the user can perform a simulation on the model.

Claims

1. A computer-readable medium encoded with a model editor software tool for creating and revising a representation of a simulation model for modeling analog and mixed-signal physical circuits and systems, the model editor comprising:

an equation editor for defining one or more relationships within the model and for displaying the defined relationships in an equation editor screen display;

a topology editor for defining a set of symbols and for displaying the defined set of symbols in a topology editor screen display, and further for interconnecting the symbols in the topology editor screen display so as to define a topology of the model, each of the symbols being associated with a corresponding one of the relationships defined in the equation editor; and

means for cross-linking the equation editor and the topology editor so as to identify and highlight the corresponding symbol in the topology editor screen display in response to a user selection of a model instance in the equation editor screen display; and

, conversely, so as to identify and highlight a corresponding model instance in the equation editor screen display in response to a user selection of a symbol in the topology editor screen display.

2. A computer-readable medium encoded with a model editor software tool according to claim 1 wherein the model editor includes means for model parameter management, the model parameter management means including means for displaying valid operating regions, default values and parameter descriptions of the model.

3. A computer-readable medium encoded with a model editor software tool according to claim 2 wherein the model parameter management tool further includes means for defining a parameter transformation and means for mapping a selected parameter into a transformed parameter according to a user-defined parameter transformation, thereby allowing the user to present the selected parameter in a preferred form.

4. A computer-readable medium encoded with a model editor software tool according to claim 2 wherein the model parameter management tool includes means for displaying in a display screen window, for each parameter in the model, a parameter name, a default value and a description.

13. A computer-readable medium encoded with a model editor software tool according to claim 1 wherein the equation editor screen displays a model name and a list of instances of the model identified by the model name.

14. A computer-readable medium encoded with a model editor software tool according to claim 13 wherein the model name is displayed at a first hierarchical level, the list of model instances is displayed at a second hierarchical and the equation editor screen further displays an equation that describes one of the relationships in the model.

15. A computer-readable medium encoded with a model editor software tool according to claim 13 wherein each of the hierarchical levels of the equation editor screen display is selectively expandable and collapsible by the user to manage use of the display screen.

16. A computer-readable medium encoded with a model editor software tool according to claim 13 wherein all of the circuit elements that are instances of a particular model are identified and highlighted in the topology editor screen display in response to user selection of the said particular model in the equation editor screen display.

17. A model editor software tool according to claim 1 wherein the model editor implements differential-algebraic equations for continuous-time modeling in a hardware description language independent fashion.

18. A model editor software tool according to claim 1 wherein the model editor implements event schedulers and handlers for discrete-time modeling in a hardware description language independent fashion.

5. A computer-readable medium encoded with a suite of software tools for interactively creating and revising a simulation model for modeling analog and mixed signal digital-analog physical circuits and systems, the software tools comprising:

a model editor for interactive creation and revision of the simulation model, the model editor including a topology editor and an equation editor, cross-linked to one another and providing a graphical user interface so as to allow said creation and revision of the simulation model;

a model database coupled to the model editor for storing a representation of the simulation model; and

the model editor further including at least one model robustness tool for assisting the user in creating and revising the simulation model without having to repeat execution of the simulation model.

6. A computer-readable medium encoded with a suite of software tools according to claim 5 wherein the model robustness tool includes a sample point assistant.

7. A computer-readable medium encoded with a suite of software tools according to claim 5 wherein the model robustness tool includes a Newton step manager.

20. A computer-readable medium encoded with a suite of software tools according to claim 5 wherein the model robustness tool includes a process for analyzing a matrix element stamp.

8. A computer-readable medium encoded with a software system for modeling analog and mixed signal digital-analog physical circuits and systems, comprising:

a model editor for interactive creation and revision of a simulation model, the model editor including a topology editor and an equation editor, cross-linked to one another and providing a graphical user interface so as to allow said creation and revision of the simulation model without the user writing or editing the simulation model in a hardware description computer programming language;

a model database coupled to the model editor for storing a representation of the simulation model;

a hardware description language code generator coupled to the model database for generating a hardware description language representation of the stored simulation model; and

a simulator arranged to receive the hardware description language representation of the simulation model and execute the simulation model.

9. A computer-readable medium encoded with a software system for modeling according to claim 8 and further comprising:

means for capturing intermediate results during said execution of the simulation model; and

means for displaying said intermediate results to the user in a graphical interface independent of the hardware description language thereby assisting the user in further development of the simulation model.

10. A computer-readable medium encoded with a model editor software tool for creating and revising a representation of a simulation model for modeling analog and mixed-signal physical circuits and systems, the model editor comprising:

an equation editor for defining one or more relationships within the model and for displaying the defined relationships in an equation editor screen display;

a topology editor for defining a set of symbols and for displaying the defined set of symbols in a topology editor screen display, and further for interconnecting the symbols in the topology editor screen display so as to define a topology of the model, each of the symbols being associated with a corresponding one of the relationships defined in the equation editor;

means for cross-linking the equation editor and the topology editor so as to identify and highlight the corresponding symbol in the topology editor screen display in response to a user selection of a model instance in the equation editor screen display; and

, conversely, so as to identify and highlight a corresponding model instance in the equation editor screen display in response to a user selection of a symbol in the topology editor screen display; and

means for model parameter management, the model parameter management means including means for displaying valid operating regions, default values and parameter descriptions of the simulation model.

11. A computer-readable medium encoded with a model editor software tool according to claim 10 wherein the model parameter management tool further includes means for defining a parameter transformation and means for mapping a selected parameter into a transformed parameter according to a user-defined parameter transformation, hereby allowing the user to present the selected parameter in a preferred form.

12. A computer-readable medium encoded with a model editor software tool according to claim 10 wherein the model parameter management tool includes means for displaying in a display screen window, for each parameter in the model, a parameter name, a default value and a description.

19. A model editor software tool according to claim 10 wherein the model parameter management means is coupled to the equation editor for invoking the parameter manager in response to an equation selected in the equation editor screen display to view or modify parameters of the selected equation.