System and method to facilitate simulation

• US 20050288918A1
• Filed: 06/24/2004
• Published: 12/29/2005
• Est. Priority Date: 06/24/2004
• Status: Abandoned Application

• Current Assignee: Eugene Berta, Thomas W. Chen
• Original Assignee: Eugene Berta, Thomas W. Chen
• Inventors: Chen, Thomas W., Berta, Eugene
• Application Number:
  US11/089,582
• Publication Number:
  US 20050288918A1
• Time in Patent Office: Days
• US Class Current: 703/22
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

One disclosed embodiment may comprise a system to facilitate simulation that includes a mapping system that converts parameter data having a first form corresponding to a first frequency distribution for at least one parameter to a second form, the second form corresponding to a modified frequency distribution for the at least one parameter that is functionally related to the first form and that exhibits an increased variation in the at least one parameter relative to the first form.

Claims

13. An apparatus for performing simulation of a system, comprising

a converter that modifies original parameter data for at least one parameter of the system to a modified form of the parameter data that is functionally related to the original parameter data and that exhibits increased variation in the at least one parameter;

a simulator that performs a plurality of simulations on a model of the system which varies in the at least one parameter for each of the plurality of simulations by selecting the at least one parameter from the modified form of the parameter data, the simulator providing an indication of reliability for the system based on the modified form of the parameter data; and

a mapping system that determines an actual indication of reliability for the system by mapping the indication of reliability provided by the simulator to the original parameter data.

14. The apparatus of claim 13, wherein the converter applies a spread factor to the original parameter data to provide the modified parameter data.

15. The apparatus of claim 14, wherein the original parameter data comprises a first normalized frequency distribution for the least one parameter, the converter applying the spread factor to the first normalized frequency distribution to provide the modified form of parameter data as a second normalized frequency distribution.

16. The apparatus of claim 15, wherein the spread factor comprises a constant value, the converter multiplying a standard deviation of the first normalized frequency distribution by the spread factor to provide the second normalized frequency distribution.

17. The apparatus of claim 15, wherein the mapping system further comprises:

an integration function that integrates a portion of the second normalized frequency distribution to provide a corresponding sigma value based on the indication of reliability of the system provided by the simulator; and

a re-mapping component that employs the sigma value relative to the first normalized frequency distribution to provide a probability of reliability for the system.

18. The apparatus of claim 13, wherein the simulator performs monte carlo simulation on the model of the system to determine the indication of reliability for the system in terms of the modified form of the parameter data.

19. The apparatus of claim 13, wherein the system comprises at least a portion of an integrated circuit.

20. The apparatus of claim 19, wherein the at least a portion of the integrated circuit further comprises at least one static random access memory (SRAM) cell.

21. The apparatus of claim 13, further comprising a sample size function that determines a number of the plurality of simulations to perform on the model with the modified form of parameter data sufficient to achieve a given confidence level.

22. An apparatus to facilitate simulation comprising:

means for converting parameter data representing at least one parameter of a system from a first form of the parameter data to a second form of the parameter data, the second form of the parameter data being functionally related to the first form of the parameter data and exhibiting a wider distribution for the at least one parameter relative to the first form of the parameter data;

means for performing simulations of the system based on the second form of the parameter data and for providing results for the simulations; and

means for mapping results of the simulations to the first form of the parameter data to provide a corresponding probability for at least one operating characteristic of the system.

23. The apparatus of claim 22, further comprising means for determining a number of simulations to be performed by the means for performing simulations.

24. The apparatus of claim 22, wherein the first form of the parameter data and the second form of the parameter data are corresponding normalized frequency distributions for the at least one parameter of the system.

25. The apparatus of the claim 24, wherein the system is at least a portion of an integrated circuit.

26. The apparatus of claim 25, wherein the corresponding probability comprises a probability of failure for the at least a portion of the integrated circuit.

27. A method comprising:

converting a first functional form of parameter data representing at least one parameter of a system to a second functional form of the parameter data, the second functional form of the parameter data being functionally related to the first functional form and exhibiting increased variation in respect to the at least one parameter relative to the first functional form; and

employing simulation results to determine an indication of reliability for the system, the simulation results resulting from simulations performed for the system based on the second functional form.

1. A system to facilitate simulation comprising:

a mapping system that converts parameter data having a first form corresponding to a first frequency distribution for at least one parameter to a second form, the second form corresponding to a modified frequency distribution for the at least one parameter that is functionally related to the first form and exhibiting an increased variation in the at least one parameter relative to the first form.

2. The system of claim 1, wherein the mapping system applies a spread factor to the first frequency distribution to provide the modified frequency distribution as a widened frequency distribution.

3. The system of claim 2, wherein the spread factor comprises a constant, the mapping system multiplying a standard deviation of the first frequency distribution by the spread factor to produce the widened frequency distribution.

4. The system of claim 2, wherein the first frequency distribution and the modified frequency distribution comprise respective normalized frequency distributions.

5. The system of claim 1, further comprising a simulator that employs the modified frequency distribution to provide at least one value indicative of an operating characteristic of a real system based on results of a number of simulations performed on a model of the real system according to the least one parameter selected from the modified frequency distribution.

6. The system of claim 5, wherein the simulator comprises a monte carlo simulation component.

7. The system of claim 5, wherein the operating characteristic comprises an indication of reliability for the real system.

8. The system of claim 5, wherein the real system comprises at least a portion of an integrated circuit, and the simulator employing the modified frequency distribution to provide an indication of reliability for the at least a portion of the integrated circuit.

9. The system of claim 8, wherein the at least a portion of the integrated circuit further comprises at least one static random access memory (SRAM) cell.

10. The system of claim 5, further comprising a sample size function that determines the number of simulations to be performed on the model to achieve a given confidence level.

11. The system of claim 1, wherein the mapping system is a first mapping system, the system further comprising a second mapping system that converts simulation results derived from simulation performed based on the modified distribution to a corresponding indication of reliability associated with the first frequency distribution.

12. The system of claim 11, wherein the second mapping system further comprises:

an integration function that integrates a portion of the modified frequency distribution to provide a sigma value based on the simulation results; and

a re-mapping component that employs the sigma value relative to the first frequency distribution to determine a probability under the first frequency distribution.

28. The method of claim 27, further comprising performing a plurality of the simulations on a model of the system based on substantially randomly selecting the at least one parameter from the second functional form.

29. The method of claim 27, further comprising determining a sample size for the simulations sufficient to achieve a given confidence level for the indication of reliability for the system.

30. The method of claim 29, wherein the system comprises at least a portion of an integrated circuit, and the indication of reliability for the system comprising a failure probability for the at least a portion of the integrated circuit with respect to the at least one parameter.

31. The method of claim 27, wherein the converting further comprising applying a spread factor to the first functional form of the parameter data so that the second functional form of parameter data has a wider distribution relative to the first functional form of the parameter data.

32. The method of claim 27, further comprising aggregating the indication of reliability for the system for a plurality of parameters.

33. A computer programmed to perform the method of claim 27.

29-1. The method of claim 27, wherein each of the first functional form and the second functional form comprises a first frequency distribution and a second frequency distribution for the at least one parameter, the method further comprising:

integrating a portion of the second frequency distribution to provide a corresponding sigma value based on the simulation results; and

determining the indication of reliability for the system as a probability value associated with the first frequency distribution based on the sigma value.

34. A computer readable medium having computer executable instructions for performing a method comprising:

converting a first frequency distribution for at least one parameter of a system to a second frequency distribution for the at least one parameter, the second frequency distribution being functionally related to the first frequency distribution and exhibiting increased variation in respect to the at least one parameter relative to the first frequency distribution; and

mapping results of simulation performed with the second frequency distribution to a corresponding indication of reliability for the system associated with the first frequency distribution.