Numerically modeling inductive circuit elements

• US 7,310,595 B2
• Filed: 06/08/2004
• Issued: 12/18/2007
• Est. Priority Date: 08/19/2002
• Status: Expired due to Fees

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Lowther, Rex, Lin, Yiqun
• Primary Examiner(s): Ferris; Fred
• Assistant Examiner(s): LUU, CUONG V
• Application Number:
  US10/863,542
• Publication Number:
  US 20040225485A1
• Time in Patent Office: 1,288 Days
• Field of Search: 505/210, 336/84.C, 336/200, 336/83, 336/223, 716/1, 716/4, 333/262, 702/75, 257/531
• US Class Current: 703/13
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• 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 determining electrical parameters of inductive elements includes a novel technique of inverting an impedance matrix representative of said inductive circuit element. The method reduces model simulation time by a factor of 3000. In one embodiment, simulation time of a device model was reduced from 1 hour to less than 3 seconds. The method is suitable for use with circuit element modeling tools, circuit simulation environments, and antenna modeling systems. The method may be applied to inductors, transformers, antennas, etc.

Claims

1. A method of modeling a circuit element, the method comprising:

dividing the circuit element into two or more segments;

further dividing each segment into a plurality of filaments;

defining a horizontal plane of symmetry about said circuit element such that a first group of filaments are positioned above said plane of symmetry and a second group of filaments are positioned below said first plane of symmetry;

providing a plurality of filament pairs, wherein each of said plurality of filament pairs comprises one filament in said first group of filaments and one filament in said second group of filaments wherein the one filament in said first group is generally symmetrical to the one filament in the second group; and

using at least one matrix implementing element characteristics representative of the filaments to model the circuit element, wherein the at least one matrix uses the defined horizontal plane of symmetry and filament pairs in generating the model of the circuit element.

2. The method of claim 1, wherein the at least one matrix is an impedance matrix.

3. The method of claim 2, further comprising:

determining elements of the impedance matrix that are representative of the plurality of filament pairs; and

determining elements of an inverse of the impedance matrix.

4. The method of claim 2, wherein said impedance matrix comprises:

a first submatrix a₁₁=R;

a second submatrix a₁₂=−

ω

L;

a third submatrix a₂₁=ω

L;

a fourth submatrix a₂₂=R; and

wherein R is a diagonal filament resistance matrix, L is a filament inductance matrix and ω

is radian frequency.

5. The method of claim 4, further comprising:

evaluating a first matrix equation M1=[ω

²L (1/R) L +R]<sup>−

1</sup>.

6. The method of claim 5, further comprising:

evaluating a second matrix equation M2, wherein said matrix equation M2 comprises M1, L, 1/R, and ω

.

7. The method of claim 6, further comprising:

constructing an inverse of said impedance matrix by setting

a first submatrix of said inverse c₁₁=M1,

a second submatrix of said inverse C₁₂=M2,

a third submatrix of said inverse C₂₁=−

M2, and

a fourth submatrix of said inverse C₂₂=M1.

8. A method of designing an integrated circuit, the method comprising:

modeling of at least one circuit element, wherein the modeling of the at least one circuit element further comprises,

dividing the circuit element into two or more segments,

further dividing each segment into a plurality of filaments,

defining a horizontal plane of symmetry about said circuit element such that a first group of filaments are positioned above said plane of symmetry and a second group of element s are positioned below said first plane of symmetry;

providing a plurality of filament pairs, wherein each of said plurality of filament pairs comprises one filament in said first group of filaments and one filament in said second group of filaments wherein the one filament in said first group is generally symmetrical to the one filament in the second group; and

using at least one matrix implementing element characteristics representative of the filaments to model the circuit element, wherein the at least one matrix uses the defined horizontal plane of symmetry and filament pairs in generating the model of the circuit element.

9. The method of claim 8, wherein one of the at least one matrix is an impedance matrix.

10. The method of claim 9, further comprising:

determining elements of the impedance matrix that are representative of the plurality of filament pairs; and

determining elements of an inverse of the impedance matrix.

11. The method of claim 9, wherein said impedance matrix comprises:

a first submatrix a₁₁=R;

a second submatrix a₁₂32 −

ω

L;

a third submatrix a₂₁=ω

L;

a fourth submatrix a₂₂=R; and

wherein R is a diagonal filament resistance matrix, L is a filament inductance matrix and ω

is radian frequency.

12. The method of claim 11, further comprising:

evaluating a first matrix equation M1=[ω

²L (1/R) L+R]<sup>−

1</sup>.

13. The method of claim 12, further comprising:

evaluating a second matrix equation M2, wherein said matrix equation M2 comprises M1, L, 1/R, and ω

.

14. The method of claim 13, further comprising:

constructing an inverse of said impedance matrix by setting

a first submatrix of said inverse c₁₁=M1,

a second submatrix of said inverse c₁₂=M2,

a third submatrix of said inverse c₂₁=−

M2, and

a fourth submatrix of said inverse c₂₂=M1.

15. A method of designing a circuit element, the method comprising

producing a circuit design;

wherein the circuit design was based on a simulation of the circuit element;

further wherein the simulating simulation of the circuit element was created by, discretizing the circuit element into at least two segments;

dividing each of said at least one segments into a plurality of filaments;

applying an impedance matrix representative of said plurality of filaments, wherein said impedance matrix comprises,

a first submatrix a11=R,

a second submatrix a12=−

ω

L,

a third submatrix a21=ω

L,

a fourth submatrix a22=R, and

wherein R is a diagonal filament resistance matrix, L is a filament inductance matrix and ω

is radian frequency;

evaluating an equation M1=[ω

²L(1/R)L+R]<sup>−

1</sup>;

evaluating a second matrix equation M2, wherein said matrix equation M2 comprises M1, L, 1/R, and ω

.

16. The method of claim 15, wherein simulating the circuit element further comprises:

constructing an inverse of said impedance matrix by setting

a first submatrix of said inverse c₁₁=M1,

a second submatrix of said inverse c₁₂=M2,

a third submatrix of said inverse c₂₁=−

M2,

a fourth submatrix of said inverse c₂₂=M1.

17. The method of claim 15 wherein simulating the circuit element further comprises:

defining a plane of symmetry such that a first group of filaments are positioned above said plane of symmetry and a second group filaments are positioned below said first plane of symmetry, and

providing a plurality of filament pairs, wherein each of said plurality of filament pairs comprises one filament in said first group of filaments and one filament in said second group of filaments.

18. The method of claim 17 wherein said plane of symmetry is oriented horizontally.

19. The method of claim 15 wherein simulating the circuit element further comprises:

defining at least one of said plurality of filaments as having a cross-sectional area greater than remaining filaments within a same said segment.

20. The method of claim 15 wherein simulating the circuit element further comprises:

selecting or defining an equivalent circuit model representative of at least one of said plurality of filaments; and

providing an impedance matrix that is representative of said equivalent circuit model and said plurality of filaments.