JP2007206943A - Electromagnetic field circuit coupled analysis program, recording medium, analysis method, and analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problematic point that electromagnetic field circuit coupled analysis of an FDTD (finite difference time domain) method and circuit analysis requires interruption of computation in the FDTD method for waiting until a voltage value of a cell is delivered from the circuit analysis, thus resulting in increased analysis time compared with analysis only by performing the FDTD method. <P>SOLUTION: A magnetic field value of a circuit cell, prior to another cell, is computed (S5102) which is necessary for computation of a current value to be delivered to the circuit analysis from the FDTD method, and the current value is delivered to the circuit analysis (S5106). Then, magnetic field computation (S5108) and field computation (S5112) are performed for another cell. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention stores an electromagnetic field circuit linkage analysis program and an electromagnetic field circuit linkage analysis program for causing a computer to execute a linkage analysis combining an electromagnetic field analysis method based on a time domain finite difference method and a circuit analysis method based on a transient electrical circuit analysis. The present invention relates to a recording medium, an analysis method and an analysis apparatus for cooperative analysis.

  In electromagnetic field circuit linkage analysis, analysis is performed while associating an electric field or magnetic field defined in electromagnetic field analysis with a voltage or current defined in circuit analysis. Numerical simulation that combines electromagnetic field analysis and circuit analysis has the characteristic that the characteristics of circuit elements and surrounding electromagnetic field phenomena can be analyzed in a unified manner, which is very useful for analyzing high-frequency signals propagating in a circuit. It is generally known to be useful.

  The time domain finite difference method (hereinafter referred to as FDTD (Finite Difference Time Domain) method), which is one of the methods of electromagnetic field analysis as described above, divides the analysis region into grids and places unknown electromagnetic fields at grid points. To do. In the FDTD method, analysis is performed using a structure called a Yee lattice in which a lattice in which an unknown electric field is arranged and a lattice in which an unknown magnetic field is arranged are shifted by half the width of the lattice. The FDTD method derives a relational expression that works between these unknown electric field and magnetic field and the adjacent unknown magnetic field and electric field by differentiating Maxwell's electromagnetic field equation, and based on that, the unknown electric field and magnetic field are converted to a certain time. This is an analysis method for obtaining the entire electromagnetic field behavior by updating the steps in units. According to this analysis method, the electric field and the magnetic field can be obtained alternately by updating the electric field at a certain time step, updating the magnetic field after ½ time step, and updating the electric field after one time step. .

  Currently, a SPICE (Simulation Program with Integrated Circuit Emphasis) simulator developed by the University of California, Berkeley is known as a transient electrical circuit analysis tool. The tool provides an efficient way to simulate processes in very complex electronic devices.

  Non-Patent Document 1 proposes a method combining a FDTD method and a circuit simulator such as SPICE as a method of simulating a circuit such as an integrated circuit. In the electromagnetic field circuit linkage analysis combining the conventional FDTD method and a circuit simulator (in this case, SPICE), a circuit element is incorporated in a cell of the FDTD, and a current source and a capacitor are connected between terminals corresponding to one side of the cell. A method (current source method) is used in which the FDTD method and the circuit analysis are combined by arranging the FDTD method. Non-Patent Document 2 discloses a voltage source method using a voltage source.

  Patent Document 1 discloses a method for obtaining a stable solution by taking into account the difference between the time in the calculation of the magnetic field in the electromagnetic field analysis and the time in the calculation of the electric field in the electromagnetic field circuit linkage analysis.

  FIG. 7 is a flowchart showing a schematic processing flow of electromagnetic field circuit linkage analysis of the conventional method.

With reference to FIG. 7, the flow of processing in the conventional method will be described. First, the magnetic field values of all cells at the analysis time t are calculated by the FDTD method (step S7102). Based on the result of step S7102, the current value of the cell in which the circuit element is incorporated (hereinafter referred to as a circuit cell) is calculated (step S7104) and transferred to the circuit analysis (step S7106). In the circuit analysis, the current value is received (step S7202), and the voltage value of the circuit cell at the analysis time t is obtained (step S7204). The obtained voltage value is transferred to the FDTD method (step S7206), and the analysis time is advanced by Δt (Δt indicates a time step). In the meantime, in the FDTD method, the electric field value in the region other than the circuit cell at the analysis time t + 1 / 2Δt is obtained (step S7108). Then, the voltage value delivered from the circuit analysis is applied as the voltage value of the circuit cell (step S7110). The electric field value of the circuit cell is calculated based on step S7110 (step S7112), and the analysis time is advanced by 1 / 2Δt. The above processing is repeated until a predetermined condition (for example, whether the analysis time exceeds a predetermined analysis time) is satisfied (steps S7114 and S7208).
Japanese Patent Laid-Open No. 11-153634 A. Thomas, et al .: The use of SPICE lumped circuits as sub-grid models for FDTD analysis, IEEE Microwave Guided Wave Letters, vol. 4, pp. 141-143 (1994). C. Kuo, B. Houshmand, and T. Itoh: Full-wave analysis of packaged microwave circuits with active and nonlinear devices: An FDTD approach, IEEE Transactions on Microwave Theory Techniques, vol. 45, pp. 819-826 (1997) .

  However, in the electromagnetic field circuit linkage analysis by the FDTD method and the circuit analysis, it is necessary to interrupt the calculation in the FDTD method and wait until the cell voltage value is delivered from the circuit analysis. For this reason, there has been a problem that the analysis time increases as compared with the case where the analysis is performed by executing only the FDTD method.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to calculate the magnetic field value of a circuit cell necessary for calculating a current value passed from the FDTD method to circuit analysis to another cell. To provide electromagnetic field circuit linkage analysis program, recording medium, linkage analysis device, and linkage analysis method for performing magnetic field calculation and electric field calculation of other cells after calculating current and passing current value to circuit analysis It is.

  According to one aspect of the present invention, there is provided a program for causing a computer having an arithmetic processing unit to execute electromagnetic field circuit linkage analysis, wherein the arithmetic processing unit is an analysis target divided into a plurality of cells. The step of performing a first electromagnetic field analysis on one of the electric field or magnetic field of the circuit cell in which the circuit element is inserted among the plurality of cells, and the arithmetic processing unit are expressed by a netlist of the circuit element included in the circuit cell A step of setting one of a voltage source or a current source based on one of the electric field or the magnetic field applied by the step of performing the first electromagnetic field analysis on the circuit, and performing a circuit analysis, Of these cells, the second electromagnetic field analysis process for the electric field and magnetic field of cells other than the circuit cell is at least partially in parallel with the circuit analysis process. A step of performing the second electromagnetic field analysis, a step of performing a third electromagnetic field analysis for calculating the other of the electric field or the magnetic field of the circuit cell based on the result of the step of performing the circuit analysis by the arithmetic processing unit, The step of performing one electromagnetic field analysis, the step of performing a circuit analysis, the step of executing in parallel, and the step of performing a third electromagnetic field analysis are repeated until a predetermined condition is satisfied.

  Preferably, in the step of performing the first electromagnetic field analysis, the arithmetic processing unit performs an electromagnetic field analysis on the electric field of the circuit cell, and in the step of performing the circuit analysis, the arithmetic processing unit performs the first operation on the circuit. Based on the electric field applied by the step of performing electromagnetic field analysis, a voltage source is set and circuit analysis is performed, and in the step of performing third electromagnetic field analysis, the arithmetic processing unit is based on the result of the step of performing circuit analysis, Calculate the magnetic field of the circuit cell.

  Preferably, in the step of performing the first electromagnetic field analysis, the arithmetic processing unit performs an electromagnetic field analysis on the magnetic field of the circuit cell, and in the step of performing the circuit analysis, the arithmetic processing unit performs the first operation on the circuit. Based on the magnetic field given by the electromagnetic field analysis step, the current source is set and the circuit analysis is performed. In the third electromagnetic field analysis step, the arithmetic processing unit is based on the result of the circuit analysis step. The electric field of the circuit cell is calculated.

  Preferably, the computer further includes a storage unit, and when the time step Δt is determined in advance, the step of performing the first electromagnetic field analysis includes the step of the arithmetic processing unit generating a magnetic field in the vicinity of the circuit cell at time t. A step of calculating and a step in which the arithmetic processing unit calculates a current in the vicinity of the circuit cell based on the determined magnetic field, and the step of executing in parallel includes the step of the arithmetic processing unit in the cells other than the circuit cell at time t A step of performing a third electromagnetic field analysis, including a step of obtaining a magnetic field, a step of updating time t to t + 1 / 2Δt, and a step of obtaining an electric field of a cell other than the circuit cell at time t by the arithmetic processing unit. The arithmetic processing unit calculates the electric field of the circuit cell based on the result of the circuit analysis step, and the arithmetic processing unit stores the electric field and magnetic field of the region in the storage unit. Storing, and further updating the time t to t + 1 / 2Δt.

  Preferably, in the step of performing the circuit analysis, the arithmetic processing unit sets a current source for the netlist based on the current obtained in the step of performing the first electromagnetic field analysis, and between the two terminals of the circuit element. The step of obtaining the voltage, the operation processing unit storing the voltage between the two terminals in the storage unit, and the step of updating the time t to t + Δt.

  When the other situation of this invention is followed, the computer-readable recording medium which stored the said electromagnetic field circuit cooperation analysis program is provided.

  According to still another aspect of the present invention, there is provided an electromagnetic field circuit cooperation analysis device for performing a cooperation analysis between an electromagnetic field analysis and a circuit analysis, comprising a circuit analysis unit for performing a circuit analysis, wherein the circuit analysis unit includes a plurality of cells. In the region to be analyzed divided into two, the electric field applied by the electromagnetic field analysis or the circuit represented by the netlist of the circuit element included in the circuit cell in which the circuit element is inserted among the plurality of cells. Based on one of the magnetic fields, one of a voltage source and a current source is set, and a circuit analysis unit is included, and an electromagnetic field analysis unit that performs electromagnetic field analysis is further provided. The first electromagnetic field analysis is performed for one of the first, the first means for giving the result of the first electromagnetic field analysis to the circuit analysis unit, and the second electromagnetic field analysis for the electric field and magnetic field of cells other than the circuit cell. And a third electromagnetic field analysis for calculating the other of the electric field or the magnetic field of the circuit cell based on the result of the circuit analysis unit and the means for executing the process in parallel with the process of performing the circuit analysis and at least a part thereof. And an analysis control unit that repeats the means for performing circuit analysis, the first means, the means for executing in parallel, and the means for performing the third electromagnetic field analysis until a predetermined condition is satisfied, including.

  According to still another aspect of the present invention, in a region to be analyzed divided into a plurality of cells, a first electromagnetic field is applied to one of an electric field or a magnetic field of a circuit cell in which a circuit element is inserted among the plurality of cells. A voltage source or a current source based on one of the electric field or the magnetic field applied by the step of performing the analysis and the circuit represented by the net list of the circuit elements included in the circuit cell. A step of performing circuit analysis, a process of performing a second electromagnetic field analysis on the electric field and magnetic field of a cell other than the circuit cell among a plurality of cells, and a process of performing circuit analysis and at least a part thereof Based on the results of the parallel execution step and the circuit analysis step, a third electromagnetic field analysis is performed to calculate the other of the electric field or magnetic field of the circuit cell. Repeating the step of performing the first electromagnetic field analysis, the step of performing the circuit analysis, the step of executing in parallel, and the step of performing the third electromagnetic field analysis until a predetermined condition is satisfied. An electromagnetic field circuit link analysis method comprising steps.

  According to the present invention, the magnetic field value of a circuit cell necessary for passing a current value to circuit analysis by the FDTD method is calculated ahead of other cells. Then, after passing the current value to the circuit analysis, the magnetic field calculation and electric field calculation of other cells are performed, so that these calculations and the voltage calculation of the circuit analysis can be executed in parallel. Therefore, since the time for the magnetic field calculation other than the circuit cell can be included in the overlap time that was only during the electric field calculation in the conventional method, it is possible to prevent an increase in the analysis time due to the execution of the circuit analysis.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As will be apparent from the following description, in the electromagnetic field circuit cooperative analysis program and the cooperative analysis method of the present invention, the electric field and magnetic field in the circuit board are analyzed by electromagnetic field analysis such as the FDTD method, and the electric circuit element is a circuit such as SPICE. When the circuit analysis is performed by the simulator, the magnetic field value of the circuit cell necessary for passing the current value to the circuit analysis in the FDTD method is calculated ahead of other cells. Then, after passing the current value to the circuit analysis, the magnetic field calculation and electric field calculation of other cells are performed, so that these calculations and the voltage calculation of the circuit analysis can be executed in parallel. Therefore, since the time for the magnetic field calculation other than the circuit cell can be included in the overlap time that was only during the electric field calculation in the conventional method, it is possible to prevent an increase in the analysis time due to the execution of the circuit analysis.

(1. System configuration of the present invention)
FIG. 1 is a conceptual diagram showing an example of a computer 100 that executes the cooperation analysis program of the present invention.

  In FIG. 1, a computer 100 for executing a program for cooperative analysis includes an optical disk drive 108 for reading information on an optical disk such as a CD-ROM (Compact Disc Read-Only Memory) 118 and a flexible disk (Flexible Disk). , FD) 116, a computer main body 102 having an FD drive 106 for reading and writing information, a display 104 as a display device connected to the computer main body 102, and an input device also connected to the computer main body 102. A keyboard 110 and a mouse 112 are provided.

FIG. 2 is a block diagram showing the configuration of the computer 100. As shown in FIG.
As shown in FIG. 2, in addition to the optical disk drive 108 and the FD drive 106, the computer main body 102 constituting the computer 100 includes a CPU (Central Processing Unit) 120 connected to the bus 105 and a ROM (Read Only). A memory 122 including a memory (RAM) and a random access memory (RAM), a direct access memory device such as a hard disk 124, and a communication interface 128 for exchanging data with the outside are included. An optical disk such as a CD-ROM 118 is loaded in the optical disk drive 108. An FD 116 is attached to the FD drive 106.

  In the hard disk 124, circuit board data 134 in which parameters representing the physical properties of the board such as the shape of the board, the dielectric constant of the board, etc. are stored for the circuit board to be analyzed, and electromagnetic analysis in the time domain A program 135 for executing FDTD which is one of the techniques for performing the above, a program 136 for executing circuit analysis, and the like are stored. Here, for example, the circuit board data may be supplied from an external database via the communication interface 128. Each program may be supplied by a recording medium such as the FD 116 or the CD-ROM 118, or may be supplied by another computer via a communication line. The execution of FDTD or circuit analysis may be executed by an external computer via the communication interface 128 and the result may be stored in the hard disk 124.

  In addition, in a storage area of the storage device, for example, the hard disk 124, an electric field value storage area for temporarily storing electric field values and magnetic field values as analysis results during the electromagnetic field analysis, and updating those values in the next step. 137 and a magnetic field value storage area 138 are provided.

  Here, the program 135 for executing FDTD and the program 136 for executing circuit analysis are collectively referred to as an electromagnetic field circuit cooperation analysis program.

  Therefore, in the following description, it is assumed that time domain electromagnetic field analysis and circuit analysis are executed in cooperation within one computer device. However, the electromagnetic field analysis and the circuit analysis may be executed by separate computer devices, and data may be exchanged between the separate computer devices via the communication interface 128 to perform the cooperative analysis.

  The CPU 120 functioning as an arithmetic processing unit uses the memory 122 as a working memory to execute processing corresponding to the above-described program 135 for executing FDTD and the program 136 for executing circuit analysis.

  The CD-ROM 118 may be another medium, such as a DVD-ROM (Digital Versatile Disc) or a memory card, as long as it can record information such as a program installed in the computer main body. In this case, the computer main body 102 is provided with a drive device that can read these media.

  The program 135 for executing FDTD and the program 136 for executing circuit analysis are software executed by the CPU 120 as described above. Generally, such software is stored and distributed in a recording medium such as the CD-ROM 118 and the FD 116, read from the recording medium by the CD-ROM drive 108 or the FD drive 106, and temporarily stored in the hard disk 124. Alternatively, when the computer 100 is connected to the network, it is temporarily copied from the server on the network to the hard disk 124. Then, the data is further read from the hard disk 124 to the RAM in the memory 122 and executed by the CPU 120. In the case of network connection, the program may be directly loaded into the RAM and executed without being stored in the hard disk 124.

  The computer hardware itself and its operating principle shown in FIGS. 1 and 2 are general. Therefore, an essential part for realizing the functions of the present invention is software stored in a recording medium such as the FD 116, the CD-ROM 118, and the hard disk 124.

  As a general tendency, various program modules are prepared as a part of a computer operating system, and an application program generally calls a module in a predetermined arrangement to advance processing. . In such a case, the software itself does not include such a module, and the electromagnetic field circuit linkage analysis is possible only when the computer cooperates with the operating system. However, as long as a general platform is used, it is not necessary to distribute software including such modules, and the software itself not including these modules and the recording medium storing the software (and the software distributes on the network). Data signal) can be considered to constitute the embodiment.

(2. Electromagnetic circuit linkage analysis method)
Hereinafter, an electromagnetic field circuit cooperation analysis method according to the present invention will be described.

(2.1 Cooperative analysis method between electromagnetic field analysis and circuit analysis)
First, the FDTD method, which is one of methods for performing electromagnetic field analysis, will be described, and then the current source method used for cooperative analysis will be described.

  The FDTD method is a numerical calculation method by differentiating Maxwell's electromagnetic field equation. First, an analysis region is divided by a lattice, and an electric field is arranged at the center of each side of the lattice, and a magnetic field is arranged at the center of each surface. Then, when Maxwell's equations are differentiated, the electric and magnetic fields are arranged at positions that are spatially shifted by half a cell and temporally by a half time step. Here, the following equations (1) and (2) can be obtained by deriving the unknown electric field to be obtained, the known electric field adjacent to the unknown magnetic field one time step before, and the relational expression that works between the known magnetic fields from the Maxwell equation based on electromagnetism. It becomes like this.

In the formula, bold indicates that the variable is a vector.
Equation (1) is an electric field E (vector) of n time steps, and equation (2) is a relational equation of magnetic field H (vector) of (n + 1/2) time steps. However, Δt, μ, ε, and σ are time step, magnetic permeability, dielectric constant, and conductivity, respectively.

  By updating the unknown electric field and unknown magnetic field in units of a certain time step Δt based on these, the electromagnetic field behavior of the entire analysis region can be obtained in the time domain.

  As described above, in the FDTD method, the time domain electromagnetic field response to be analyzed can be analyzed by sequentially calculating the unknown electric field and the unknown magnetic field in the analysis region by the explicit method.

  Next, the current source method, which is a method for directly combining the FDTD method and circuit analysis, which is used in the electromagnetic field circuit cooperation analysis of the present invention will be described.

  FIG. 3 is a schematic diagram of cooperative analysis by the current source method. FIG. 3A is a diagram showing an FDTD cell including a circuit element to be subjected to circuit analysis, and FIG. 3B shows an equivalent circuit of the current source method corresponding to the cell of FIG. FIG. 3C is a diagram showing a schematic processing flow of the current source method.

  The current source method will be described with reference to FIG. In FIG. 3A, the electric field is assigned along the side of the lattice cell indicated by the solid line, and the magnetic field is assigned along the side of the lattice cell indicated by the dotted line. Δx, Δy, Δz indicate the length of each side of the FDTD cell, and the solid grid cell and the dotted grid cell are shifted from each other by 1 / 2Δx, 1 / 2Δy, 1 / 2Δz. The arrows indicate the directions of the electric field and magnetic field. Here, it is assumed that a circuit element to be subjected to operation analysis by circuit analysis is arranged on a side ab where an electric field is present.

  With reference to FIG. 3C, the flow of processing in the current source method will be described. First, the magnetic field of the cell is calculated by the FDTD method (step S300).

  Then, by applying Ampere's law to the cell including the circuit element and expanding the z component, the following expression (3) is obtained.

However, J _L is the density of the conductive current flowing through the element.
Here, assuming that ε (ΔxΔy) / Δz in the first term on the left side of Equation (3) is equivalently the capacitance C ₀ of the parallel plate capacitor, and the right side is the total current I flowing through the cell, Equation (3) is (4) can be rewritten.

Where V _L is the voltage across the circuit element, and I _L is the total current flowing through the circuit element.
The total current I flowing in the cell can be obtained by circular integration of the magnetic field around the element along the surface 31 using Ampere's law. However, since the magnetic field is constant, I can be considered as a constant current source. . As shown in FIG. 3B, equation (4) can be considered as an equivalent circuit including a current source 32, a capacitor 33, and a network 34.

Returning to FIG. 3C again, the current I is calculated from the magnetic field H obtained by FDTD, and passed to the circuit analysis as the current source value I (step S302), thereby obtaining V _L and I _L by the circuit analysis. I can do it. Then, a V _L by a circuit analysis, passes the V _L to calculate the electric field of the cell sides of the circuit elements in the FDTD method (step S304), in step S306, the electric field E is calculated.

  As described above, the circuit analysis and the FDTD method are directly coupled. Thereby, the coupling with the electromagnetic field can be analyzed considering only the input / output terminals of the circuit.

  Here, although the current source method formulated based on Ampere's law is shown as the cooperative analysis method, the voltage source method, which is a method based on Faraday's law, may be used.

(2.2 Electromagnetic Circuit Cooperative Analysis Method of the Present Invention)
Below, the outline | summary of the cooperation analysis method of this invention is demonstrated.

FIG. 4 is a diagram illustrating an example of a two-dimensional electromagnetic model of a circuit board including an RC network.
With reference to FIG. 4, first, a model of a circuit board that is an object of electromagnetic field circuit linkage analysis of the present invention will be described.

  In order to perform electromagnetic field analysis by the FDTD method, a circuit board is divided into cells and an electromagnetic field model is created. FIG. 4 is a two-dimensional electromagnetic field model in which the circuit board 41 is divided into cells. In the electromagnetic field model, for example, a metal, a dielectric, or the like is set as a substance contained in each cell. Each cell in FIG. 4 includes a conductor 42, a dielectric 44, and a resistor 46a and a capacitor 46b as circuit elements. The substrate 41 also includes a ground 48 indicating a ground electrode and a power source 49.

  The electromagnetic field circuit linkage analysis according to the present invention uses the current source method described in (2.1). At this time, although the magnetic field of all the cells is calculated in step S300 in FIG. 3C, in the present invention, the magnetic field of the circuit cell is calculated prior to other cells. Then, the process of calculating the voltage of the circuit cell by circuit analysis (step S304) and the process of calculating the magnetic field of another cell are performed in parallel.

(3. Implementation on computer 100)
The cooperative analysis method according to the above invention can be implemented as computer software by the following procedure.

The procedure is summarized below.
FIG. 5 is a flowchart showing a specific processing flow of the linkage analysis in the present invention.

  FIG. 6 is a diagram showing calculation target components in the two-dimensional electromagnetic field model. FIGS. 6A to 6D show the transition of the calculation target component, which will be described later in detail.

  With reference to FIG. 5 and FIG. 6, the flow of the cooperative analysis process will be described. Steps S5100 to S5122 are processing according to the program 135 that executes FDTD, and steps S5200 to S5212 are processing according to the program 136 that executes circuit analysis.

The flow of FDTD processing will be described.
First, the CPU 120 reads analysis conditions from the circuit board data 134 stored in the hard disk 124 (step S5100). The analysis conditions include the size of the lattice cell, the time step of FDTD analysis, the time step of circuit analysis, the analysis time, the electric field in the analysis region, the initial value of the magnetic field, the current of the circuit element, the initial value of the voltage, and the analysis region. They are the dielectric, the coordinate value of the conductor, the net list of the circuit element, and the maximum analysis time Tmax.

  Further, the CPU 120 sets the analysis time t to zero, secures a storage area corresponding to the analysis area size and cell size of the analysis condition in the memory 122, and analyzes the coefficients of the analysis area cell based on the arranged conductor and dielectric information. Term calculation is performed (step S5101). The electric field value and magnetic field value are set based on a predetermined electric field and initial magnetic field value. Set time step n to 1.

  In step S5102, the CPU 120 calculates the magnetic field H of the circuit cell at the analysis time Δt (n−1 / 2). In FIG. 6, an electric field is assigned to the side of each cell, and a magnetic field is assigned to the surface of the cell. It is assumed that the circuit element is assigned to the cell side 61. In step S5102, as shown in FIG. 6A, the magnetic field (shaded portion) of the cell including the circuit element is the calculation target component.

  Returning to FIG. 5, in step S <b> 5104, based on the magnetic field calculated in step S <b> 5102, the CPU 120 converts the magnetic field H in the vicinity of the circuit cell into a current value I using the following amperage equation (5).

  Here, the CPU 120 uses the current value I as a current source value to be added to the netlist for circuit analysis.

  The CPU 120 gives the current source value of step S5104 to the circuit analysis (step S5106). The process flow of the circuit analysis that has received the current source value will be described later.

  In step S5108, CPU 120 calculates a magnetic field (shaded portion) for cells other than the cell in which the circuit element is inserted as shown in FIG. 6B. Then, the current analysis time t is advanced by half of the FDTD time step (step S5110).

  In step S5112, the electric field is calculated for cells other than the cell in which the circuit element is inserted as shown in FIG. Here, the electric field indicated by the solid line of each cell is a calculation target component.

  Next, the CPU 120 receives a voltage calculated by circuit analysis (step S5114). However, if it has not been calculated yet, the process is suspended until it is calculated.

  In step S5116, the CPU 120 converts the voltage value received from the circuit analysis into an electric field value of the circuit cell by the following equation (6).

  Δy is the length of the FDTD cell in the Y direction. Although the circuit elements are arranged in the Y direction here, they can be arranged in any direction.

  Then, the CPU 120 sets the electric field value obtained in step S5116 as the electric field value of the cell side 61 into which the circuit element in the electromagnetic field analysis region is inserted as shown in FIG. 6D (step S5118). Let the analysis time be Δt (n + 1/2). The electric field at time Δt (n + 1/2) is stored in the electric field value storage area 137 in the hard disk 124, and the magnetic field is stored in the magnetic field value storage area 138 in the hard disk 124.

  In step S5120, CPU 120 advances current analysis time t by half the time step of FDTD. Let n be n = n + 1. Further, the electric field information in the analysis area at the analysis time t is stored in the electric field value storage area 137 in the hard disk 124, and the magnetic field information is stored in the magnetic field value storage area 138 in the hard disk 124.

  In step S5122, CPU 120 compares current analysis time t with maximum analysis time Tmax. If analysis time t is smaller than maximum analysis time Tmax (No in step S5122), the process returns to step S5102. Otherwise (Yes in step S5122), the storage area of the memory 122 used for analysis is released, and the calculation is terminated.

Next, the flow of circuit analysis processing will be described.
First, the CPU 120 secures a storage area in the memory 122 based on a predetermined net list, and generates a circuit matrix in which a current source and a capacitor are added by a current source method based on element connection information (step S5200). ). The analysis time is set to zero.

  In step S5202, CPU 120 receives the current source value from the electromagnetic field analysis. The process is suspended until the current source value is received.

  Next, the CPU 120 updates the current source value to the current source value received in step S5202 (step S5204), and performs circuit analysis from the analysis time Δt (n−1 / 2) to Δt (n + 1/2). The voltage is obtained (step S5206).

  Further, CPU 120 provides the voltage value at time Δt (n + 1/2) to the electromagnetic field analysis (step S5208). In addition, the CPU 120 stores the current value and voltage value at time Δt (n + 1/2) in the hard disk 124.

  In step S5210, CPU 120 advances current analysis time t by circuit analysis time step Δt, and stores analysis time t and the voltage between circuit element terminals in hard disk 124.

  Then, CPU 120 compares current analysis time t with maximum analysis time Tmax (step S5212). If analysis time t is smaller than maximum analysis time Tmax (No in step S5212), the process returns to step S5202. Otherwise (Yes in step S5212), the storage area of the memory 122 used for analysis is released, and the calculation is terminated.

As described above, the electromagnetic field circuit linkage analysis is performed.
In the above description, the analysis process is terminated on the condition that the maximum analysis time is exceeded. However, the analysis process may be terminated after other conditions such as an electric field and a magnetic field are in a steady state. It is also possible to use whether or not a condition after a predetermined time has passed is satisfied.

  As described above, the electromagnetic field analysis and the circuit analysis are performed by the CPU 120 in accordance with the program 135 for executing the FDTD and the program 136 for executing the circuit analysis, and are executed by a plurality of CPUs connected via the communication interface 128. The result may be exchanged via the computer 100. The electromagnetic field analysis and the circuit analysis may be analyzed using a single CPU, but the analysis area may be divided into a plurality of areas and analyzed using a plurality of CPUs.

  As described above, according to the present invention, the magnetic field value of a circuit cell necessary for passing a current value to circuit analysis by the FDTD method is calculated ahead of other cells. Then, after passing the current value to the circuit analysis, the magnetic field calculation and electric field calculation of other cells are performed, so that these calculations and the voltage calculation of the circuit analysis can be executed in parallel. Therefore, since the time for the magnetic field calculation other than the circuit cell can be included in the overlap time that was only during the electric field calculation in the conventional method, it is possible to prevent an increase in the analysis time due to the execution of the circuit analysis.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a conceptual diagram which shows an example of the computer 100 which performs the cooperation analysis program of this invention. It is a figure which shows the structure of this computer 100 in a block diagram format. It is a schematic diagram of the cooperative analysis by the current source method. It is a figure which shows the example of the two-dimensional electromagnetic field model of a circuit board including RC network. It is the flowchart which showed the flow of the specific process of the cooperation analysis in this invention. It is the figure which showed the calculation object component in a two-dimensional electromagnetic field model. It is a flowchart which shows the flow of the schematic process of the electromagnetic field circuit cooperation analysis of the conventional method.

Explanation of symbols

  31 surface, 32 current source, 33, 46b capacitor, 34 circuit network, 41 circuit board, 42 conductor, 44 dielectric, 46a resistance, 48 ground, 49 power supply, 61 cell side, 100 computer, 102 computer main body, 104 display, 106 FD drive, 108 optical disk drive, 110 keyboard, 112 mouse, 116 FD, 118 CD-ROM, 120 CPU, 122 memory, 124 hard disk, 128 communication interface, 134 circuit board data, 135 FDTD program, 136 circuit analysis 137 Electric field value storage area, 138 Magnetic field value storage area

Claims (8)

A program for causing a computer having an arithmetic processing unit to execute electromagnetic field circuit linkage analysis,
The arithmetic processing unit performs a first electromagnetic field analysis on one of an electric field or a magnetic field of a circuit cell in which a circuit element is inserted among the plurality of cells in a region to be analyzed divided into a plurality of cells. Steps,
Based on one of the electric field or the magnetic field applied by the step of performing the first electromagnetic field analysis on the circuit represented by the net list of the circuit elements included in the circuit cell, the arithmetic processing unit Or setting one of the current sources and performing circuit analysis;
The arithmetic processing unit executes, in parallel with at least a part of the circuit analysis, processing for performing second electromagnetic field analysis on the electric field and magnetic field of cells other than the circuit cell among the plurality of cells. And steps to
A step of performing a third electromagnetic field analysis in which the arithmetic processing unit calculates the other of the electric field or the magnetic field of the circuit cell based on the result of the step of performing the circuit analysis;
The arithmetic processing unit includes a step of performing the first electromagnetic field analysis, a step of performing the circuit analysis, a step of executing in parallel, and a step of performing the third electromagnetic field analysis. An electromagnetic field circuit linkage analysis program for causing a computer to execute an analysis process, comprising: a step of repeating until a condition is satisfied. In the step of performing the first electromagnetic field analysis, the arithmetic processing unit performs an electromagnetic field analysis on the electric field of the circuit cell,
In the step of performing the circuit analysis, the arithmetic processing unit performs a circuit analysis by setting a voltage source based on the electric field applied by the step of performing the first electromagnetic field analysis on the circuit,
The electromagnetic field circuit cooperation analysis program according to claim 1, wherein in the third electromagnetic field analysis step, the arithmetic processing unit calculates a magnetic field of the circuit cell based on a result of the circuit analysis step. In the step of performing the first electromagnetic field analysis, the arithmetic processing unit performs an electromagnetic field analysis on the magnetic field of the circuit cell,
In the step of performing the circuit analysis, the arithmetic processing unit performs a circuit analysis by setting a current source based on the magnetic field given by the step of performing the first electromagnetic field analysis on the circuit,
The electromagnetic circuit integration analysis program according to claim 1, wherein in the third electromagnetic field analysis step, the arithmetic processing unit calculates an electric field of the circuit cell based on a result of the circuit analysis step. The computer further includes a storage unit,
When the time step Δt is predetermined,
The step of performing the first electromagnetic field analysis includes:
The arithmetic processing unit obtaining a magnetic field in the vicinity of the circuit cell at time t;
The arithmetic processing unit includes calculating a current in the vicinity of the circuit cell based on the obtained magnetic field,
The step of executing in parallel includes:
The arithmetic processing unit obtaining a magnetic field of the cell other than the circuit cell at the time t;
Updating the time t to t + 1 / 2Δt;
The arithmetic processing unit includes obtaining an electric field of the cell other than the circuit cell at the time t,
The step of performing the third electromagnetic field analysis includes:
The arithmetic processing unit calculates an electric field of the circuit cell based on a result of the circuit analysis;
The arithmetic processing unit storing the electric field and magnetic field of the region in the storage unit;
The electromagnetic field circuit cooperation analysis program according to claim 3, further comprising a step of further updating the time t to t + 1 / 2Δt. The step of performing the circuit analysis includes:
The arithmetic processing unit sets a current source for the netlist based on the current obtained in the step of performing the first electromagnetic field analysis, and obtains a voltage between the two terminals of the circuit element;
The arithmetic processing unit storing the voltage between the two terminals in the storage unit;
The electromagnetic field circuit cooperation analysis program according to claim 4, further comprising a step of updating the time t to t + Δt.   A computer-readable recording medium storing the electromagnetic circuit cooperation analysis program according to claim 1. An electromagnetic field circuit linkage analysis apparatus for performing linkage analysis between electromagnetic field analysis and circuit analysis,
A circuit analysis unit for performing the circuit analysis;
The circuit analysis unit
In the region to be analyzed divided into a plurality of cells, the electromagnetic field analysis is performed on the circuit represented by the circuit element netlist included in the circuit cell in which the circuit element is inserted among the plurality of cells. Means for setting one of a voltage source or a current source based on one of the electric field or magnetic field applied by
An electromagnetic field analysis unit for performing the electromagnetic field analysis;
The electromagnetic field analysis unit
A first means for performing a first electromagnetic field analysis on one of an electric field or a magnetic field of the circuit cell and providing a result of the first electromagnetic field analysis to the circuit analysis unit;
Means for performing a second electromagnetic field analysis on the electric field and magnetic field of a cell other than the circuit cell in parallel with at least a part of the circuit analysis;
Means for performing a third electromagnetic field analysis for calculating the other of the electric field or magnetic field of the circuit cell based on the result of the circuit analysis unit,
An analysis control unit that repeats the means for performing the circuit analysis, the first means, the means for executing in parallel, and the means for performing the third electromagnetic field analysis until a predetermined condition is satisfied; Including electromagnetic circuit cooperation analysis device. Performing a first electromagnetic field analysis on one of an electric field or a magnetic field of a circuit cell in which a circuit element is inserted among the plurality of cells in a region to be analyzed divided into a plurality of cells;
Based on one of the electric field or magnetic field given by the step of performing the first electromagnetic field analysis on the circuit represented by the net list of the circuit elements included in the circuit cell, one of the voltage source and the current source is Setting and performing circuit analysis;
A process of performing a second electromagnetic field analysis on an electric field and a magnetic field of cells other than the circuit cell among the plurality of cells, and executing the circuit analysis in parallel with the process of performing the circuit analysis;
Performing a third electromagnetic field analysis for calculating the other of the electric field or magnetic field of the circuit cell based on the result of the circuit analysis step;
The step of performing the first electromagnetic field analysis, the step of performing the circuit analysis, the step of executing in parallel, and the step of performing the third electromagnetic field analysis are repeated until a predetermined condition is satisfied. An electromagnetic field circuit linkage analysis method comprising the steps.

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