System and method of providing additional circuit analysis using simulation templates

• US 7,110,929 B1
• Filed: 11/12/1999
• Issued: 09/19/2006
• Est. Priority Date: 11/12/1999
• Status: Expired due to Fees

• Current Assignee: Intusoft, Co.
• Original Assignee: Intusoft, Co.
• Inventors: Meares, Lawrence G.
• Primary Examiner(s): Knight, Anthony
• Assistant Examiner(s): Craig, Dwin M.
• Application Number:
  US09/438,856
• Time in Patent Office: 2,503 Days
• Field of Search: 703/14, 703/13, 345/22, 716/3
• 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

Abstract

A simulation template and method therefor is disclosed that modifies a SPICE netlist that describes a circuit in order to provide customized or pre-installed additional analysis. More specifically, a simulation template is an interactive command language (ICL) script that has embedded instructions telling a netlist where to insert information and which options are to be provided. It is used to expand SPICE beyond the traditional limitations of the basic alternating current (AC), direct current (DC), and transient analysis by allowing parameter variations and multiple simulations passes to be run under one analysis umbrella. Such additional analysis employing parameter variations and multiple analysis passes include sensitivity analysis, root means square (RSS) analysis, extreme value analysis (EVA) and worst case sensitivity (WCS), to name a few. The simulation template includes a routine to add to a netlist for altering circuit parameter values of the circuit design in a pre-determined manner, a routine to add to the netlist for performing simulations of the circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements, and a routine to add to the netlist for manipulating at least one of the vector measurements in accordance with the pre-determined analysis.

Claims

1. A method of modifying a SPICE netlist of a circuit design using a simulation template to perform a pre-determined analysis involving circuit parameter perturbations, the method comprising:

adding a first simulation routine to said SPICE netlist to perform a reference simulation of said SPICE netlist to arrive at nominal values for selected vector measurements;

adding a perturbing routine to said SPICE netlist for altering circuit parameter values of said circuit design in a pre-determined manner;

adding a second simulation routine to said SPICE netlist for performing simulations of said circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements; and

adding an analysis routine to said SPICE netlist for manipulating at least one of said selected vector measurements in accordance with said pre-determined analysis.

2. The method of claim 1, further including

adding tolerances in the SPICE netlist for said circuit parameters.

3. The method of claim 1, further including

removing parameter and vector save statements in said SPICE netlist.

15. The method of claim 1, wherein

said circuit parameter values of said circuit design are one of resistance of a resistor, capacitance of a capacitor, and inductance of an inductor.

16. The method of claim 1, wherein

said at least one selected vector measurement is voltage at a node of said circuit design.

17. The method of claim 1, wherein

said at least one selected vector measurement is current along a branch of said circuit design.

18. The method of claim 1, wherein

said at least one selected vector measurement is power dissipation in a component of said circuit design.

19. The method of claim 18, wherein

said component of said circuit design is one of a resistor, a capacitor, and an inductor.

20. The method of claim 1, wherein

only one circuit parameter value of said circuit design is altered at a time by the perturbing routine.

36. The method of claim 1, wherein

said circuit parameter value of said circuit design is one of impedance, admittance, gain, and trans-impedance of an electronic component.

37. The method of claim 36, wherein

said electronic component is an active electronic component.

38. The method of claim 36, wherein

said electronic component is a passive electronic component.

4. A method of modifying a SPICE netlist of a circuit design using a simulation template to perform a pre-determined analysis involving circuit parameter perturbations, the method comprising:

adding a first simulation routine to said SPICE netlist to perform a reference simulation of said SPICE netlist to arrive at nominal values for selected vector measurements;

adding a perturbing routine to said SPICE netlist for altering circuit parameter values of said circuit design in a pre-determined manner;

adding a second simulation routine to said SPICE netlist for performing simulations of said circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements; and

adding an analysis routine to said SPICE netlist for manipulating at least one of said selected vector measurements in accordance with said pre-determined analysis, wherein said pre-determined analysis includes

a sensitivity analysis involving determining a difference between said respective selected vector measurements and said nominal values for said selected vector measurements.

6. The method of claim 4, wherein

said pre-determined analysis further includes

an extreme value analysis involving a determination of a maximum of said difference between said respective selected vector measurements and said nominal values for said selected vector measurements when said circuit parameter values are at their extreme tolerance values.

7. The method of claim 4, wherein

said pre-determined analysis further includes

a worst case by sensitivity analysis involving a maximum of an absolute value of said difference between said respective selected vector measurements and said nominal values for said selected vector measurements.

5. A method of modifying a SPICE netlist of a circuit design using a simulation template to perform a pre-determined analysis involving circuit parameter perturbations, comprising:

adding a first simulation routine to said SPICE netlist to perform a reference simulation of said SPICE netlist to arrive at nominal values for selected vector measurements;

adding a perturbing routine to said SPICE netlist for altering circuit parameter values of said circuit design in a pre-determined manner;

adding a second simulation routine to said SPICE netlist for performing simulations of said circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements; and

adding an analysis routine to said SPICE netlist for manipulating at least one of said selected vector measurements in accordance with said pre-determined analysis;

wherein said pre-determined analysis includes

a sensitivity analysis involving determining a difference between said respective selected vector measurements and said nominal values for said selected vector measurements, and

a root summed square analysis involving a sum of the square of said difference between said respective selected vector measurements and said nominal values for said selected vector measurements.

8. A computer readable medium having stored therein a simulation template for modifying a SPICE netlist of a circuit design to perform a pre-determined analysis involving parameter perturbations, comprising:

a routine to add to said SPICE netlist for performing a reference simulation of said SPICE netlist to arrive at nominal values for selected vector measurements;

a routine to add to said SPICE netlist for altering circuit parameter values of said circuit design in a pre-determined manner;

a routine to add to said SPICE netlist for performing simulations of said circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements; and

a routine to add to said SPICE netlist for manipulating at least one of said selected vector measurements in accordance with said pre-determined analysis.

9. The computer readable medium of claim 8, wherein

said simulation template further includes

a command to add tolerances in the SPICE netlist for said circuit parameters.

10. The computer readable medium of claim 8, wherein

said simulation template further includes

a command to remove parameter and vector save statements in said SPICE netlist.

21. The computer readable medium of claim 8, wherein

said circuit parameter values of said circuit design are one of resistance of a resistor, capacitance of a capacitor, and inductance of an inductor.

22. The computer readable medium of claim 8, wherein

said at least one selected vector measurement is voltage at a node of said circuit design.

23. The computer readable medium of claim 8, wherein

said at least one selected vector measurement is current along a branch of said circuit design.

24. The computer readable medium of claim 8, wherein

said at least one selected vector measurement is power dissipation in a component of said circuit design.

25. The computer readable medium of claim 24, wherein

said component of said circuit design is one of a resistor, a capacitor, and an inductor.

26. The computer readable medium of claim 8, wherein

only one circuit parameter value of said circuit design is altered at a time by the perturbing routine.

39. The computer readable medium of claim 8, wherein

said circuit parameter value of said circuit design is one of impedance, admittance, gain, and trans-impedance of an electronic component.

40. The computer readable medium of claim 39, wherein

said electronic component is an active electronic component.

41. The computer readable medium of claim 39, wherein

said electronic component is a passive electronic component.

11. A computer readable medium having stored therein a simulation template for modifying a SPICE netlist of a circuit design to perform a pre-determined analysis involving parameter perturbations, comprising:

a routine to add to said SPICE netlist for performing a reference simulation of said SPICE netlist to arrive at nominal values for selected vector measurements;

a routine to add to said SPICE netlist for altering circuit parameter values of said circuit design in a pre-determined manner;

a routine to add to said SPICE netlist for performing simulations of said circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements; and

a routine to add to said SPICE netlist for manipulating at least one of said selected vector measurements in accordance with said pre-determined analysis, wherein said pre-determined analysis includes

a sensitivity analysis involving determining a difference between said respective selected vector measurements and said nominal values for said selected vector measurements.

13. The computer readable medium of claim 11, wherein

said pre-determined analysis further includes

an extreme value analysis involving a determination of a maximum of said difference between said respective selected vector measurements and said nominal values for said selected vector measurements when said circuit parameter values are at their extreme tolerance values.

14. The computer readable medium of claim 11, wherein

said pre-determined analysis further includes

a worst case by sensitivity analysis involving a maximum of an absolute value of said difference between said respective selected vector measurements and said nominal values for said selected vector measurements.

12. A computer readable medium having stored therein a simulation template for modifying a SPICE netlist of a circuit design to perform a pre-determined analysis involving parameter perturbations, comprising:

a routine to add to said SPICE netlist for performing a reference simulation of said SPICE netlist to arrive at nominal values for selected vector measurements;

a routine to add to said SPICE netlist for altering circuit parameter values of said circuit design in a pre-determined manner;

a routine to add to said SPICE netlist for performing simulations of said circuit design for respective altered circuit parameter values to arrive at respective selected vector measurements; and

a routine to add to said SPICE netlist for manipulating at least one of said selected vector measurements in accordance with said pre-determined analysis;

wherein said pre-determined analysis includes

a sensitivity analysis involving determining a difference between said respective selected vector measurements and said nominal values for said selected vector measurements, and

a root summed square analysis involving a sum of the square of said difference between said respective selected vector measurements and said nominal value for said selected vector measurements.

27. A method of analyzing a SPICE netlist of a circuit design, the method comprising:

(a) providing a SPICE netlist of a circuit design;

(b) selecting a selected vector measurement of the circuit design;

(c) simulating the SPICE netlist of the circuit design using nominal circuit parameter values to determine a nominal vector measurement associated with the selected vector measurement;

(d) altering at least one circuit parameter value of a component in the SPICE netlist in a pre-determined manner to generate at least one altered circuit parameter value;

(e) simulating the SPICE netlist of the circuit design with the at least one altered circuit parameter value to determine an altered vector measurement associated with the selected vector measurement;

(f) repeating steps (d) and (e) with the at least one circuit parameter value to generate a plurality of altered circuit parameter values and to determine a plurality of altered vector measurements of the circuit design; and

(g) determining a difference between the plurality of altered vector measurements and the nominal vector measurement to generate a sensitivity in the vector measurement of the circuit design in response to alterations in the at least one circuit parameter value of the component in the SPICE netlist.

28. The method of claim 27, wherein

a simulation template is used to perform steps (b)–

(g).

29. The method of claim 27, wherein

the at least one circuit parameter value of the component in the SPICE netlist is altered within a tolerance of the component.

30. The method of claim 27, wherein

the at least one circuit parameter value of a component is one of resistance of a resistor, capacitance of a capacitor, and inductance of an inductor.

31. The method of claim 27, wherein

the vector measurement of the circuit design is one of voltage at a node, current along a branch, and power dissipation in the component.

32. The method of claim 27, wherein

only one circuit parameter value of said circuit design is altered at a time.

34. The method of claim 27, wherein

the at least one circuit parameter value is altered to a maximum value and the SPICE netlist of the circuit design is simulated to determine a first altered vector measurement, and

the at least one circuit parameter value is altered to a minimum value and the SPICE netlist of the circuit design is simulated to determine a second altered vector measurement,

and the method further comprises

determining a maximum of a first absolute value of the first altered vector measurement less the nominal vector measurement and a second absolute value of the second altered vector measurement less the nominal vector measurement to determine an extreme value analysis (EVA) for the vector measurement of the circuit design.

35. The method of claim 27, further comprising:

determining scalar differences between the plurality of altered vector measurements and the nominal vector measurement,

taking the absolute value of the scalar differences to generate absolute scalar differences,

determining a maximum value of the absolute scalar differences to determine a worst case by sensitivity (WCS) for the selected vector measurement of the circuit design.

42. The method of claim 27, wherein

the at least one circuit parameter value of a component is one of impedance, admittance, gain, and trans-impedance of an electronic component.

43. The method of claim 42, wherein

the electronic component is an active electronic component.

44. The method of claim 42, wherein

the electronic component is a passive electronic component.

33. A method of analyzing a SPICE netlist of a circuit design, the method comprising:

(a) providing a SPICE netlist of a circuit design;

(b) selecting a selected vector measurement of the circuit design;

(c) simulating the SPICE netlist of the circuit design using nominal circuit parameter values to determine a nominal vector measurement associated with the selected vector measurement;

(d) altering at least one circuit parameter value of a component in the SPICE netlist in a pre-determined manner to generate at least one altered circuit parameter value;

(e) simulating the SPICE netlist of the circuit design with the at least one altered circuit parameter value to determine an altered vector measurement associated with the selected vector measurement;

(f) repeating steps (d) and (e) with the at least one circuit parameter value to generate a plurality of altered circuit parameter values and to determine a plurality of altered vector measurements of the circuit design;

(g) determining a difference between the plurality of altered vector measurements and the nominal vector measurement to generate a sensitivity in the vector measurement of the circuit design in response to alterations in the at least one circuit parameter value of the component in the SPICE netlist; and

(h) determining a sum of the differences between the plurality of altered vector measurements and the nominal vector measurement, squaring the sum of the differences, and taking the square root of the squared sum of the differences to determine a root summed square (RSS) for the vector measurement of the circuit design in response to alterations in the at least one circuit parameter value of the component in the SPICE netlist.