Circuit simulation

• US 5,047,971 A
• Filed: 08/15/1989
• Issued: 09/10/1991
• Est. Priority Date: 06/23/1987
• Status: Expired due to Term

• Current Assignee: Intergraph Software Technologies Company
• Original Assignee: Intergraph Corporation (Hexagon AB)
• Inventors: Horwitz, Lawrence B.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Trans, V. N.
• Application Number:
  US07/394,232
• Time in Patent Office: 756 Days
• Field of Search: 364/488, 364/489, 364/490, 364/578, 364/579, 364/580, 371/23, 371/20, 324/73 AT
• 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 method of simulating the operation of a circuit utilizing voltage or current data obtained from measurements of actual samples of each of the circuit components. The actually measured voltage or current data is employed to mathematically analyze operation of the circuit. In this process, each circuit component is characterized as one or more of a voltage controlled voltage source, voltage controlled current source, current controlled voltage source and current controlled current source. After such characterization, a trial operating point is selected and values of current or voltage between actually measured data points are determined and linearized circuit equations are established with spline equations. The linearized equations are solved. The steps are repeated with a new trial operating point in accordance with a Newton-Rhapson iterative technique until the solution of the linearized equations is within a predetermined range.

Claims

1. A method of simulating operation of a circuit having a plurality of circuit components, at least one of which is an active component, comprising the steps of:

loading characterizing data having been previously actually measured for an actual sample of each individual one of said circuit components, including said at least one active component, in a memory connected to processing means;

loading into said memory data specifying interconnections of said circuit components, including said at least one active component, to form said circuit being simulated; and

causing said processing means to accept said data from both said loading steps and mathematically analyzing the operation of said circuit established in said interconnections loading step to determine operation of said circuit formed by the cooperation of said components, whose characterizing data was loaded said characterizing data loading step, as interconnected in a manner specified in said interconnections loading step by mathematically analyzing interactions of said circuit components.

2. A method as in claim 1 wherein said characterizing data loading step includes the steps of:

characterizing each said circuit component as at least one of a voltage controlled voltage source, a voltage controlled current source, a current controlled voltage source and a current controlled current source; and

loading voltage or current data for said sources corresponding to each said circuit component by measuring and storing voltage and current data for actual samples of each said circuit component.

3. A method as in claim 1 wherein said characterizing data loading step includes the step of storing capacitance or inductance data for at least one said circuit component.

4. A method as in claim 1 wherein said causing step includes the steps of:

causing said processing means to select a trial operating point for said circuit; and

causing said processing means to employ spline equations for determining data values between values of data actually loaded during said characterizing data loading step and linearizing data from said characterizing data loading step around said operating point.

5. A method as in claim 1 further comprising the step of repeating both said loading steps, and said causing step for a series of values of sources in said circuit to perform a DC sweep analysis.

6. A method as in claim 1 further comprising the steps of:

causing said processing means to discretize differential equations in time; and

repeating both said loading steps and said causing step at each incremental time to perform a transient analysis of said circuit.

7. A method as in claim 6 further comprising the step of spectrum analyzing the results of said transient analysis to perform an AC analysis.

8. A method of simulating operation of a circuit having a plurality of circuit components, at least one of which is an active component, comprising the steps of:

(a) characterizing each of said circuit components as at least one of a voltage controlled voltage source, a voltage controlled current source, a current controlled voltage source and a current controlled current source;

(b) loading voltage or current data for said sources corresponding to each of said circuit components by loading voltage and current data having been previously measured for an actual sample of each individual one of said circuit components, including said at least one active component, in a memory connected to processing means;

(c) loading capacitance or inductance data for at least one of said circuit components in said memory;

(d) loading into said memory data specifying interconnections of said circuit components, including said at least one active component, to form said circuit being simulated;

(e) causing said processing means to select a trial operating point for said circuit formed by the cooperation of said components, whose characterizing data was loaded in said loading steps (b) and (c), as interconnected in a manner specified in said loading step (d);

(f) causing said processing means to interpolate data from all of said loading steps around said operating point;

(g) causing said processing means to create linearized circuit equations for said circuit using said interpolated data;

(h) causing said processing means to solve said linearized equations; and

(i) repeating said steps (e) through (h) with other trial operating points until said step (h) produces a solution within a predetermined range to determine operation of said circuit.

9. A method as in claim 8 wherein said repeating step includes the step of causing said processing means to utilize a Newton-Rhapson technique for selecting values for said other trial operating points which produce solutions iteratively closer to said predetermined range.

10. A method as in claim 8 wherein said step f) includes the step of causing said processing means to employ spline functions to determine data values between values actually loaded in said loading step.

11. A method as in claim 10 wherein said repeating step further includes the step of causing said processing means to employ a Newton-Rhapson technique for selecting values for said other trial operating points which produce solutions iteratively closer to said predetermined range.

12. A method as in claim 8 further comprising the step of repeating said steps (a) through (i) for a series of values of sources of said circuit to perform a DC sweep analysis.

13. A method as in claim 8 further comprising the steps of:

causing said processing means to discretize differential circuit equations in time; and

repeating said steps (a) through (i) for a series of incremental times to perform a transient analysis.

14. A method as in claim 13 further comprising the step of spectrum analyzing said transient analysis to obtain an AC analysis.

15. A method of simulating operation of a circuit having a plurality of circuit components, at least one of which is an active component, comprising the steps of:

measuring characteristic data for an actual sample of each individual one of said circuit components, including said at least one active component, by physically testing each said circuit component;

loading into a memory connected to processing means data specifying interconnections of said circuit components, including said at least one active component, to form said circuit being simulated; and

causing said processing means to accept said data from said measuring step and said data from said loading step and mathematically analyzing the operation of said circuit established in said interconnections loading step to determine operation of said circuit formed by the cooperation of said components, whose characterizing data was measured in said measuring step, as interconnected in a manner specified in said interconnections loading step by mathematically analyzing interactions between said circuit components.

16. A method as in claim 15 wherein said measuring step includes the steps of:

characterizing each said circuit component as at least one of a voltage controlled voltage source, a voltage controlled current source, a current controlled voltage source and a current controlled current source; and

measuring voltage or current data for said sources corresponding to each said circuit component by measuring voltage or current data for actual samples of each said circuit component.

17. A method as in claim 15 further comprising the step of measuring capacitance or inductance data for each said circuit component.

18. A method as in claim 15 wherein said causing step includes the steps of:

causing said processing means to select a trial operating point for said circuit;

causing said processing means to interpolate data from said measuring step around said operating points;

causing said processing means to create linearized circuit equations for said circuit using said interpolated data;

causing said processing means to solve said linearized equations; and

repeating said selecting, interpolating, creating and solving steps with other trial operating points until said solving step produced a solution within a predetermined range.

19. A method as in claim 18 wherein said interpolating step causes said processing means to employ spline functions to evaluate said data between data values actually measured.

20. A method as in claim 19 wherein said repeating step includes the step of causing said processing means to employ a Newton-Rhapson technique for selecting values for said other trial operating points which produce solutions iteratively closer to said predetermined range.

21. A method of simulating operation of a circuit having a plurality of circuit components, at least one of which is an active component, comprising the steps of:

(a) characterizing each of said circuit components as at least one of a voltage controlled voltage source, a voltage controlled current source, a current controlled voltage source and a current controlled current source;

(b) measuring characteristic data for said sources corresponding to each of said circuit components by measuring at least one of voltage and current data for an actual sample of each individual one of said circuit components, including said at least one active component;

(c) measuring one of capacitance and inductance data for each of said circuit components;

(d) loading said data from said steps b) and c) into a memory connected to processing means;

(e) loading into said memory data specifying interconnections of said circuit components, including said at least one active component, to form said circuit being simulated;

(f) causing said processing means to select a trial operating point for said circuit formed by the cooperation of said components whose characterizing data was loaded in said step (d), as interconnected in a manner specified in said loading step (e);

(g) causing said processing means to interpolate data from both said measuring steps around said operating point;

(h) causing said processing means to create linearized circuit equations for said circuit using said interpolated data;

(i) causing said processing means to solve said linearized equations; and

(j) repeating said steps f) through i) with other trial operating points until said step i) produces a solution within a predetermined range to determine operation of said circuit.

22. A method as in claim 21 wherein said repeating step includes the step of causing said processing means to employ a Newton-Rhapson technique for selecting values for said other trial operating points which produce solutions iteratively closer to said predetermined range.

23. A methods as in claim 21 wherein said step g) causes said processing means to employ spline functions to evaluate said data between data values actually measured.

24. A method as in claim 23 wherein said repeating step includes the step of causing said processing means to employ a Newton-Rhapson technique for selecting values for said other trial operating points which produce solutions iteratively closer to said predetermined range.