Circuit board design system, design data analysis method and recording medium with analysis program recorded thereon

• US 20060070015A1
• Filed: 09/28/2005
• Published: 03/30/2006
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Iwaki, Hideki, Furukawa, Yukinobu
• Granted Patent: US 7,350,175 B2
• Time in Patent Office: Days
• US Class Current: 716/115
• 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

The design system, which is equipped with capability to analyze circuit board design data, comprises a storing section for recording design data, including structure data, circuit data, and element data; a selection section for selecting a pair of circuit elements subject to interference analysis among circuit elements placed on a circuit board, represented by the structure data; a substitution section for acquiring element data concerning circuit elements selected by the selection section from the design data and, based on element data, generating equivalent circuit data representing electromagnetic coupling within the pair of circuit elements with the help of an equivalent circuit; and an analysis section for calculating an amount of interference within the pair of circuit elements by analyzing data produced by combining the equivalent circuit data with the circuit data.

Claims

1. A design system equipped with capability to analyze design data for a circuit board having circuit elements and wiring placed thereon, comprising:

a storing section that stores the design data, including structure data representing a structure of the circuit elements and wiring placed on the circuit board, circuit data representing circuits built from the circuit elements and the wiring, and element data concerning the circuit elements;

a selection section that selects a pair of circuit elements subject to interference analysis among the circuit elements placed on the circuit board represented by the structure data;

a substitution section that acquires element data concerning the circuit elements selected by the selection section from the design data and generating, based on the element data, equivalent circuit data representing electromagnetic coupling within the pair of circuit elements using an equivalent circuit; and

an analysis section that calculates an amount of interference within the pair of circuit elements by analyzing data obtained by combining the equivalent circuit data with the circuit data.

2. The design system according to claim 1, further comprising a model storing section that stores an equivalent circuit model of electromagnetic coupling occurring within a pair of circuit elements,

wherein the substitution section acquires the equivalent circuit model from the model storing section and generates the equivalent circuit data using the acquired equivalent circuit model.

3. The design system according to claim 1, wherein the substitution section uses the element data acquired from the design data to calculate values representing characteristics of the equivalent circuit and generate the equivalent circuit data.

4. The design system according to claim 1, further comprising a setup file section that stores, as condition data, data representing a region subject to analysis on the circuit board,

wherein the selection section selects a pair of circuit elements located within the region represented by the condition data.

5. The design system according to claim 1, further comprising a setup file section that stores, as condition data, data representing assessment criteria for the amount of interference between circuit elements, and

an assessment section that provides an assessment of the presence/absence of interference within the pair of circuit elements by comparing the assessment criteria with the amount of the interference within the pair of circuit elements calculated by the analysis section.

6. The design system according to claim 1, further comprising a setup file section that stores, as condition data, a maximum value of a distance between the circuit elements subject to analysis,

wherein the selection section selects a pair of circuit elements that are spaced at a distance not greater than the maximum value.

7. The design system according to claim 3, further comprising a setup file section that stores, as condition data, data representing maximum and minimum values of values representing the characteristics of the equivalent circuit,

wherein the substitution section generating the equivalent circuit data by considering the equivalent circuit as an open circuit when the value representing the characteristics of the equivalent circuit is greater than the maximum value and considering the equivalent circuit as a short circuit when the value representing the characteristics of the equivalent circuit is smaller than the minimum value.

8. The design system according to claim 7, further comprising a setup file section that stores, as condition data, data comprising data representing a frequency domain subject to analysis and a range of an amount of interference between circuit elements that are to be taken into consideration, and

a characteristic value range determination section that obtains the maximum value and the minimum value of the value representing the characteristics of the equivalent circuit based on the frequency domain and the range of the amount of interference.

9. The design system according to claim 1, further comprising a setup file section that stores condition data representing the conditions of processing at least in either one of the selection section, the substitution section, and the analysis section, and

a user interface accepting information input from users and recording the condition data in the setup file section based on the information input.

10. The design system according to claim 1, further comprising an output section that displays information representing an amount of interference within the pair of circuit elements obtained by the analysis section in association with a configuration of a circuit board represented by the design data.

11. The design system according to claim 1, wherein the design data includes data representing net groups obtained by grouping similar nets among nets contained in the circuits of a circuit board into a single group, and,

in a case where there is a plurality of net groups, the selection section selects a circuit element connected to a certain net group and a circuit element connected to another net group as the pair of circuit elements.

12. The design system according to claim 1, wherein the selection section selects an inductor pair as the pair of circuit elements, and

the substitution section acquires, as the element data, at least information representing coordinates of the elements of the inductors, information representing a direction of placement of the inductors, information representing electrical connections of the terminals of the inductors, and information representing the characteristics of the inductors.

13. A design system equipped with capability to analyze design data for a circuit board having circuit elements placed thereon, comprising:

a storing section that stores design data representing the circuit board and circuit elements placed thereon,

a display section that displays a configuration of the circuit board and circuit elements represented by the design data on screen,

an updating section that updates a configuration of the circuit elements displayed by the display section based on information input from outside,

a selection section that selects a pair of circuit elements subject to interference analysis among circuit elements placed on the circuit board represented by the design data when the configuration of the circuit elements is updated by the updating section,

a substitution section that acquires element data concerning the circuit elements selected by the selection section from the design data and generates equivalent circuit data produced by substitution with an equivalent circuit for electromagnetic coupling within the pair of circuit elements based on the element data,

an analysis section that obtains an amount of interference within the pair of circuit elements by analyzing circuits obtained by reflecting the equivalent circuit data in the circuits of the circuit board represented by the design data, and

the display section displays data representing the interference amount obtained by the analysis section along with the updated circuit elements when the configuration of the circuit elements is updated by the updating section.

14. A design system for a circuit board containing a plurality of inductors, comprising:

a storing section that records design data for the circuit board,

a selection section that selects a first inductor connected to one of the terminals of a circuit element placed on the circuit board and a second inductor connected to another terminal corresponding to said terminal from the design data,

a polarity assessment section that provides an assessment as to whether a mutual inductance between the first inductor and the second inductor is positive or negative, and

a correction section that applies corrections to the design data when the mutual inductance is negative such that an orientation of the first inductor or the second inductor is modified in order to render said mutual inductance positive.

17. The design system according to claim 14, wherein the winding direction of the first inductor and the winding direction of the second inductor are the same.

15. A design system for a circuit board having a plurality of inductors placed thereon, comprising:

a storing section that stores design data for the circuit board,

a selection section that selects a first inductor connected to one of the terminals of a circuit element with at least two terminals placed on the circuit board and a second inductor connected to an other terminal corresponding to said terminal from the design data,

a capacitance calculation section that calculates parasitic capacitance between the first inductor and the second inductor,

a mutual inductance calculation section that calculates a mutual inductance between the first inductor and the second inductor,

a frequency calculation section that obtains a resonance frequency of the first inductor and the second inductor, expressed using the parasitic capacitance and the mutual inductance, and

a correction section that applies corrections to the design data so as to modify a distance between the first inductor and the second inductor in order to match the resonance frequency to the frequency characteristics required for the circuit elements.

16. The design system according to claim 15, wherein the frequency calculation section obtains the resonance frequency using the Expression 1 below, in which L1 is the self-inductance of the first inductor, L2 is the self-inductance of the second inductor, M is the mutual inductance between the first inductor and the second inductor, C is the parasitic capacitance, and α

is a constant

$\begin{array}{cc}f=\frac{\mathrm{\alpha <br><br>}}{2<br><br>\mathrm{\pi <br><br>}}\times <br><br>\frac{1}{\sqrt{\mathrm{L1}·<br><br>\mathrm{L2}}}\times <br><br>\sqrt{\frac{<br><br>M<br><br>}{C}}.& \mathrm{Expression}<br><br>\text{\hspace{1em}<br><br>}<br><br>1\end{array}$

18. An analysis method for, utilizing a computer, analyzing design data, including structure data representing a structure of circuit elements and wiring placed on a circuit board, circuit data representing circuits built from the circuit elements and the wiring, and element data concerning the circuit elements, the analysis method comprising:

a selection step, in which a selection section provided in the computer selects a pair of circuit elements subject to interference analysis from among circuit elements located on the circuit board represented by the structure data;

a substitution step, in which a substitution section provided in the computer acquires element data concerning the circuit elements selected in the selection step from the design data and, based on the element data, generates equivalent circuit data representing electromagnetic coupling within the pair of circuit elements using an equivalent circuit; and

an analytical step, in which an analysis section provided in the computer analyzes data obtained by combining the equivalent circuit data and the circuit data in order to calculate an amount of interference within the pair of circuit elements.

19. A recording medium storing an analysis program directing a computer to carry out processing to analyze design data including structure data representing a structure of circuit elements and wiring placed on a circuit board, circuit data representing circuits built from the circuit elements and the wiring, and element data concerning the circuit elements, the program directing a computer to carry out:

selection processing, during which a pair of circuit elements subject to interference analysis is selected from among the circuit elements placed on the circuit board represented by the structure data;

substitution processing, during which element data concerning the circuit elements selected during the selection processing is acquired from the design data and, based on the element data, equivalent circuit data is generated that represents electromagnetic coupling within the pair of circuit elements using an equivalent circuit; and

analytical processing, during which data obtained by combining the equivalent circuit data with the circuit data is analyzed to calculate an amount of interference within the pair of circuit elements.