JPH11312187A - Equivalent circuit for inductance element, method for analyzing circuit constant, simulator, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a highly accurate equivalent circuit, capable of effectively expressing the characteristics of an inductance element using a ferrite material and to realize an analytical method also. SOLUTION: This equivalent circuit obtained by magnetically coupling a closed circuit, constituted of resistors Rm1, Rm2 and inductors Lm1, Lm2 with an inductor Ls in an LsCpRp parallel circuit by the use of coupling coefficients k1, k2, is used. First, circuit constants Ls, Rp, Cp are determined by utilizing a condition on a resonance point. Then the change in the frequency of a reactance component in the equivalent circuit is calculated, based on the obtained circuit constants Ls, Rp, Cp, and the calculated frequency change is compared with the measured frequency change of the reactance component to determine frequency bands fm1, fm2 for reducing the reactance component. The circuit constants Rm1, Rm2, Lm1, Lm2 and the coupling coefficients k1, k2 are determined based on the determined value, and characteristics with the reduction of inductance taken into consideration due to the magnetic resonance phenomenon of the ferrite material can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for analyzing the circuit constant of an inductance element, and more specifically, an equivalent circuit of an inductance element, a method for analyzing a circuit constant, a simulator, and a method suitable even when a ferrite material is used. And a recording medium.

[0002]

2. Description of the Related Art In order to prevent electromagnetic interference (EMI) on electronic devices, an inductance element using a ferrite material is often incorporated in an electric signal line or a power supply line. FIG. 20A shows an example of the model circuit.
In the figure, an inductance element 12 is connected to the output side of the inverter IC 10 to which a power supply voltage of 5 V is applied, and a transmission line (cable) 14 is connected to the output side of the inductance element 12. . And
Another inverter IC 16 is connected to the output side of the transmission line 14. The frequency characteristic of the inductance element 12 is, for example, as shown in FIG. In the figure, Z indicates impedance, R indicates resistance, and X indicates reactance. As shown in the drawing, as the frequency increases, the reactance X decreases and the resistance R increases. When the pulse signal SA is input to such a signal line from the inverter 10 side, a signal having a waveform as shown in FIG. 20C is measured at the measurement point PD.

In the meantime, operations such as selection of an inductance element and confirmation of an effect by insertion of the element often rely on actual measurement. However, if a result comparable to the actual measurement can be obtained by simulation, it is not necessary to perform the actual measurement, and the study period is advantageously shortened. Therefore, an equivalent circuit that can satisfactorily express the characteristics of the inductance element, which serves as a logical backing, has been studied.

As such an equivalent circuit, an LsCpRp parallel equivalent circuit as shown in FIG. 21A is generally known. This is due to the inductance Ls and the capacitance C
p and a resistor Rp are connected in parallel. When the circuit constant of the inductance element having the frequency characteristic shown in FIG. 20B is selected using such an equivalent circuit, the following is obtained.

First, the impedance Z of the entire equivalent circuit shown in FIG. 21A is represented by Z = R + jX. Here, R is a resistance (real number), X is a reactance (imaginary number), and j is an imaginary unit. The resistance R is expressed by the following equation (1), and the reactance X is expressed by the following equation (2).

[0006]

(Equation 1)

[0007]

(Equation 2)

[0008] In these equations, f is a frequency.
In a low frequency region where the resistance R is small and Z ≒ jX, the following expression 3 is obtained. Since the actual measured value of the reactance component X at a frequency of 1 MHz is X = 85Ω, when this is substituted into Equation 3, Ls = 13.5 μH is selected.

[0009]

(Equation 3)

Next, at the resonance point, the following equation (4) is obtained.

[0011]

(Equation 4) Thus, the measured value Rp of the resistance R at the resonance point is Rp = 640.
Ω is selected. Regarding Cp, the measured value R of resistance at 1 GHz is R = 200Ω, Ls = 13.5 μH,
By substituting Rp = 640Ω into the above equation (1) and solving for Cp, Cp = 0.37 pF is selected. The circuit constants Ls = 13.5 μH and Rp = 64 thus selected.
When 0Ω and Cp = 0.37 pF are applied to the equivalent circuit of FIG. 21A, the impedance characteristic becomes
As shown in FIG.

[0012]

Here, as is apparent from a comparison between FIG. 21 (B), which is a simulation result by an equivalent circuit, and FIG. 20 (B), which is an actually measured value, the two are significantly different. It can be seen that the measured value cannot be accurately analyzed in the equivalent circuit of FIG. In particular, 7.5M
The reactance X near Hz is too large in FIG. Thus, even if a simulator is configured using the equivalent circuit of FIG. 21A, a simulation result with sufficient accuracy cannot be obtained.

Further, using the equivalent circuit of FIG. 21A, a circuit constant of an inductance element having the frequency characteristic of impedance shown in FIG. 22A will be selected. Similarly,
Since the measured value of the reactance X at 10 MHz is X = 60Ω, Ls = 0.96 μH is selected. At the resonance point, 1 = (2πf) ² LsCp and R = Rp, so the actual measured value Rp = 1170Ω of the resistance R at the resonance point is selected.
Further, as for Cp, measured values R of resistance at 1.8 GHz are R = 530Ω, Ls = 0.96 μH, Rp = 1170Ω.
Is substituted into the above equation (1) and solving for Cp, Cp =
0.094 pF is selected.

With respect to the equivalent circuit of FIG.
0.96 μH, Rp = 1170Ω, Cp = 0.094 pF
FIG. 22 shows the impedance frequency characteristics when
As shown in FIG. FIGS. 22A and 22B are significantly different, and the equivalent circuit of FIG. 21A cannot accurately analyze the measured values. In particular, the reactance X near 200 MHz is too large in FIG. Also,
FIG. 22B shows that the reactance X is maximum around 100 MHz and that the resistance R is up to around 40 MHz.
Is also significantly different from FIG. 9A, and the characteristics cannot be approximated well.

[0015] The disadvantage is that the frequency characteristics of the ferrite material used for the inductance element 12 are shown in FIG.
Cannot be handled by the equivalent circuit of Ferrite material has its own resonance frequency,
It is known that a magnetic resonance phenomenon occurs in a frequency region higher than the resonance frequency. Therefore, the permeability decreases (the inductance X decreases when viewed as an inductance element), and the permeability temporarily increases at the natural vibration frequency.

The present invention focuses on these points.
An object of the present invention is to provide a highly accurate equivalent circuit capable of favorably expressing the characteristics of an inductance element, a circuit constant analysis method thereof, and a simulator thereof. Another object is to provide an equivalent circuit of an inductance element, a method of analyzing circuit constants, a simulator, and a recording medium which are particularly suitable for an inductance element using a ferrite material.

[0017]

In order to achieve the above object, an equivalent circuit of the inductance element of the present invention is a parallel circuit in which a first inductance, a first capacitance, and a first resistor are connected in parallel; A second resistor connected in series to either the parallel circuit or the first inductance; a closed circuit magnetically coupled to the first inductance by a mutual inductance and including the resistance and the inductance; It is characterized by having. According to one of the main aspects, a plurality of the closed circuits are provided.

Another equivalent circuit of the present invention is a parallel circuit in which a first inductance, a first capacitance, and a first resistor are connected in parallel; a second capacitance connected in series to the first resistor; In the first inductance,
A closed circuit that is magnetically coupled by mutual inductance and includes a resistance and an inductance. According to one of the main aspects, a plurality of the closed circuits are provided. According to another embodiment, a second resistor is connected in series to either the parallel circuit or the first inductance. According to another embodiment, a second inductance is connected in parallel with the first resistor.

Another equivalent circuit of the present invention is a parallel circuit in which a first inductance, a first capacitance, and a first resistor are connected in parallel; a second capacitance connected in series to the first resistor; A second inductance connected in parallel to the first resistance; a second resistance connected in series to the parallel circuit; magnetically coupled to the first inductance by a mutual inductance; A plurality of closed circuits including an inductance.

Still another invention is characterized in that, in any of the above-described equivalent circuits, the mutual inductance is represented by another circuit element.

The method of analyzing a circuit constant of an inductance element according to the present invention is characterized in that a desired impedance frequency characteristic of the inductance element is obtained by adjusting a circuit constant of the closed circuit in any one of the equivalent circuits.

Another circuit constant analysis method is that a first inductance, a first capacitance, and a first resistance are connected in parallel, and the first inductance is connected to at least one closed circuit by a resistance and an inductance. In the method for analyzing the circuit constant of an inductance element, which analyzes the circuit constant of an equivalent circuit obtained by magnetically coupling the impedance, the impedance of the inductance element is substantially equal to the reactance in the frequency range below the resonance point. Determining the circuit constant of the first inductance; measuring the resistance of the inductance element at the resonance point and determining the circuit constant of the first resistance;
In the frequency range above the resonance point, when the reactance component where the impedance of the inductance element is almost equal to the reactance component is obtained, use the measured value.If the reactance component is not obtained, measure the resistance at that frequency. Determining the circuit constant of the first capacitance using the value and the circuit constant of the first inductance and the first resistor; the equivalent of the inductance element based on the circuit constant obtained in each of the above steps. Calculating a change with respect to the frequency of the reactance in the circuit; comparing the frequency change of the reactance of the equivalent circuit thus obtained with the frequency change of the actually measured reactance of the inductance element; Determining a circuit constant and a coupling coefficient of the closed circuit. It is characterized in.

Still another circuit constant analysis method includes a step of determining a circuit constant of a first inductance from an actually measured impedance value at which the impedance of the inductance element becomes substantially equal to the reactance in a frequency range below the resonance point; Measuring the resistance of the inductance element at the point and determining the circuit constant of the first resistance; in the frequency range above the resonance point, when a reactance is obtained in which the impedance of the inductance element is substantially equal to the reactance. When the reactance component cannot be obtained using the actual measurement value, the circuit constant of the first capacitance is obtained by using the actual measurement value of the resistance at that frequency and the circuit constants of the first inductance and the first resistor. The step of determining the; the circuit constants obtained in each of the above steps Calculating the change in the reactance of the inductance element with respect to the frequency in the equivalent circuit; comparing the frequency change of the reactance of the equivalent circuit with the frequency change of the measured reactance of the inductance element, Determining a circuit constant and a coupling coefficient of the closed circuit so that both are approximated; a step of re-determining a circuit constant of the first resistor using the circuit constant obtained in each of the above steps; an inductance element And the value of the frequency at which the reactance component is maximized is compared with the frequency at which the measured value of the resistance component and the measured value of the reactance component are the same, and the circuit constants of the second inductance and the second capacitance are determined according to the result. Determining a circuit constant of the second resistor. To.

[0024] A simulator for an inductance element according to the present invention is characterized in that a circuit constant is analyzed based on any of the circuit constant analysis methods described above.

The recording medium of the present invention has a function of determining a circuit constant of an inductance element based on any of the above-described methods of analyzing a circuit constant of an inductance element, and obtaining a frequency characteristic of impedance based on the determined circuit constant. It is characterized by having recorded the program including.

A transmission circuit simulator according to the present invention connects an inductance element to a transmission line, and utilizes the circuit constant obtained by the inductance element circuit constant analysis method according to any one of claims 9 to 11. Is characterized by analyzing the characteristics of

The recording medium of the present invention has a function of obtaining a signal waveform of a transmission circuit in which an inductance element is connected to a transmission line by utilizing a circuit constant obtained by any one of the above-described methods for analyzing a circuit constant of an inductance element. The program is recorded.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment First, a first embodiment of the present invention will be described in detail. In this embodiment, a magnetic coupling circuit as shown in FIG. 1A is used as an equivalent circuit of an inductance element using a ferrite material. In the figure, a closed circuit connecting a resistor Rm1 and an inductance Lm1 is magnetically coupled with an inductance Ls of the above-described LsCpRp parallel circuit with a coupling coefficient k1.
, A mutual inductance M1 is formed. M1
= K1√ (LsLm1). Further, a closed circuit connecting the resistor Rm2 and the inductance Lm2 is magnetically coupled to the inductance Ls with a coupling coefficient k2, and a mutual inductance M2 is formed between the inductances Ls and Lm2. M2 = k2√ (LsLm2). Further, an inductance Lr is connected in parallel to the resistor Rp, and a capacitance Cr is connected in series. In addition, a resistor Rs is connected to one end of the circuit.

Next, in this embodiment, the circuit constants of the equivalent circuit of FIG. 1A are selected according to the procedures of the flowcharts shown in FIGS. Hereinafter, a procedure for selecting a circuit constant of the inductance element having the frequency characteristic shown in FIG. 20B will be described.

(1) Determination of Ls (Step S10) First, impedance XL is measured at a frequency fL where Z ≒ jX below the resonance point, and Ls = XL /
(2πfL). In this example, from FIG.
Z ≒ jX at MHz, XL = 85Ω, fL = 1 MHz
Is substituted, Ls = 13.5 μH.

(2) Determination of Rp (Step S12)... Z = j
The actually measured value Ro at the resonance point where X is measured is substituted into the equation (4). In FIG. 20B, the measured value Ro = 64 at the resonance point.
0 Ω, from which Rp = 640 Ω.

(3) Determination of Cp (Steps S14 to S18)
... Frequency f at which Z ≒ jX in the frequency band above the resonance point
c and its measured value Xc are measured. As a result, when they are obtained, they are substituted for Cp = 1 / (2πfcXc). If it cannot be obtained, the Rh at the frequency fh above the resonance point is actually measured.
Calculate p.

[0033]

(Equation 5)

In this example, the measured values Rh = 200Ω, Ls = 13.5 μH, Rp, which are measured values at a frequency fh = 1 GHz.
= 640Ω into the above equation (5), and Cp = 0.37p
Get F.

(4) Determination of Reactance X (Step S)
20)... Substituting the obtained Ls, Rp, and Cp into the above equation (2) to obtain a relational expression representing a change in the reactance X for each frequency f.

(5) Determination of Rm1 and Lm1 (Steps S22 to S22)
S26) With respect to the reactance component X, the graph based on the equation (2) is compared with the graph of the actually measured value. As a result, when the difference between the two is large and it is desired to reduce the reactance X, the frequency fm1 to be reduced most is determined, and Rm1 / Lm1 is determined.
Rm1 and Lm1 are determined so as to satisfy = 2πfm1. Then, the process proceeds to the next step (6).

However, when the difference between the two is small and it is not necessary to reduce the reactance X, Rm1, Lm1, Rm
2, arbitrarily select Lm2. However, Lm1 ≠ 0, Lm2 ≠
0, k1 = 0 and k2 = 0. Note that setting k1 = 0 and k2 = 0 means that the closed circuits of Rm1 and Lm1 and the closed circuits of Rm2 and Lm2 are magnetically coupled with the coupling coefficients k1 and k2, respectively, from the equivalent circuit shown in FIG. Any circuits that do this will be removed. In this case, the process proceeds to the following step (11).

In the example of FIG. 20B, the difference between the calculated value and the actually measured value is large, and the frequency to be reduced most is fm1 = 7.5M
Hz. Therefore, Lm1 = 13.5 μH and Rm1 = 635Ω so as to satisfy Rm1 / Lm1 = 2πfm1.

(6) Determination of k1 (Step S28): Substituting the frequencies fm1, Ls, Cp, and Rp into the following equation (6) to calculate the reactance X1, and measure the target value Xm1 of the actually measured value to be reduced. . Then, X1 and Xm1 are calculated as follows: k1 = √ (2 (1
-Xm1 / X1)) to determine the coupling constant k1.

[0040]

(Equation 6)

In the example of FIG. 20B, the frequency fm1 =
At 7.5 MHz, the value of the reactance in the LsCpRp parallel circuit is X1 = 310Ω, and the target value of the actually measured value to be reduced is Xm1 = 240Ω. From these, the coupling constant k1 = 0.67 is obtained.

(7) Calculation of the reactance of the LsRpCp parallel circuit in which the closed loop is magnetically coupled (step S30): The circuit constants Ls, Cp, Lm1, Rm1, and k1 obtained as described above.
Is substituted into the following Expressions 7 to 9 to obtain RL, XL, and Bc. Then, these RL, XL, Rp, and Bc are substituted into the following equation 10 to calculate a reactance X for each frequency.

[0043]

(Equation 7)

[0044]

(Equation 8)

[0045]

(Equation 9)

[0046]

(Equation 10)

(8) Determination of Rm2 and Lm2 (Steps S32 to S32)
S36) Next, the reactance component X obtained as described above is compared with an actually measured value. As a result, the difference between the two is large,
When it is desired to decrease the reactance X, the frequency fm2 to be reduced most is determined, and R
m2 and Lm2 are determined. Then, the process proceeds to the next step (9).

[0048]

[Equation 11]

However, when the difference between the two is small and the reactance X is not reduced, Rm2 and Lm2 are arbitrarily selected. However, Lm2 ≠ 0, k2 = 0, and the process proceeds to step (10). Here, by setting k2 = 0, FIG.
From the equivalent circuit of (A), a circuit in which a series closed circuit of Rm2 and Lm2 is magnetically coupled with a coupling coefficient k2 is excluded.

In the example of FIG. 20B, as a result of comparing the calculated value and the measured value of the reactance component X, the difference between them is large, and the frequency to be reduced most is fm2 = 30 MHz. Therefore, from the above equation (11), Lm2 = 13.5μ
H, Rm2 = 2600Ω is obtained.

(9) Determination of k2 (step S38) ...
The frequencies fm2, Ls, Cp, Lm1, Rm1, and k1 are substituted into the following equations (12) and (13).
RL, XL and Bc are obtained by substituting into the equations. Then, the reactance X2 is calculated by substituting these RL, XL, Rp, and Bc into the following equation (14). Then, the target value Xm2 of the actually measured value to be reduced is measured, and the measured value is substituted into Expression 15 to determine the coupling constant k2.

[0052]

(Equation 12)

[0053]

(Equation 13)

[0054]

[Equation 14]

[0055]

(Equation 15)

In the example of FIG. 20B, the reactance value X2 = 1 by the LsCpRp parallel circuit at the frequency fm2 is obtained.
85Ω, target value of the measured value to be reduced Xm2 = 170Ω, k
Substituting 1 = 0.67 into Equation 12, the coupling constant k2 = 0.3
Get 0.

(10) Redetermination of Rp (step S40): Next, the frequency fo at the resonance point and the resistance Ro of the impedance
And the circuit constants Ls, Cp, Lm1, Rm1, k1, Lm2, Rm
Substituting 2 and k2 into the following equations (16) and (17) and substituting into equation (9) to obtain RL, XL and Bc, and solving equation (18), Rp is determined again.

[0058]

(Equation 16)

[0059]

[Equation 17]

[0060]

(Equation 18)

In the example of FIG. 20B, RL = 504Ω, XL
= 4830Ω and Bc = 0.283 mS. Also,
Substituting the resistance Ro = 640Ω at the resonance point into equation (18),
Rp = 640Ω was obtained.

(11) Determination of Lr and Cr (Steps S42 to S42)
S46) Next, in FIG. 20B, the frequency at which the resistance R of the impedance Z and the reactance X cross each other is compared with the frequency at which the reactance X becomes maximum.
If they match or the former is on the low frequency side, Lr → ∞, Cr → ∞, and the process proceeds to the next step (12). In this case, the inductance Lr and the capacitance Cr are removed from the equivalent circuit of FIG.

On the other hand, when the former is on the higher frequency side than the latter, the frequency frL and Rp at which it is desired to suppress the rise of the resistance R of the impedance Z are represented by Lr = Rp / (2πf
Lr) to obtain Lr. The frequency frc where the reactance X of the impedance Z should be kept large.
And Rp is substituted for Cr = 1 / (2πfrcRp) to determine Cr.

In the example of FIG. 20B, the frequency at which the resistance R of the impedance Z and the reactance X intersect is 6 MHz.
The frequency at which the reactance X becomes the maximum is about 8 MHz
z. Therefore, r → ｒ and Cr → ∞.

(12) Determination of Rs (Step S48): Next, the DC resistance is actually measured, and its value is set to Rs. FIG.
In the example of (B), since the measured DC resistance value was 0.28Ω, Rs = 0.28Ω.

The circuit constants obtained as described above are shown in FIG.
FIG. 1 shows frequency characteristics when applied to the equivalent circuit of FIG.
(B). Comparing this with FIG. 20 (B), both characteristics are very similar, and it can be seen that the equivalent circuit shown in FIG. 1 (A) is an extremely accurate equivalent circuit of an inductance element.

Further, the equivalent circuit of the circuit constant obtained from the above analysis results was applied to the inductance element 12 shown in FIG. 20A, and the signal waveform of the circuit of FIG. 20A was simulated. FIG. 1C shows the result. As is clear from the comparison with FIG. 20C, it can be seen that the equivalent circuit of FIG. 1A can constitute a simulator with extremely high accuracy.

Next, a method of selecting a circuit constant of a closed loop will be described. FIG. 6A shows a circuit in which one closed loop in which a resistance Rm1 and an inductance Lm1 are connected in series to an inductance Ls by a coupling coefficient k1 is represented as shown in FIG. 6 (A).
It is represented by an equation.

[0069]

[Equation 19]

Here, as described above, Ls = 13.5
μH, k1 = 0.67, Rm1 = 635Ω, Lm1 = 13.
FIG. 6B shows the frequency characteristics of the inductance of the circuit when 5 μH is set. In FIG. 6 (B), the frequency at which the slope of the graph is the largest is obtained by differentiating the equation (19) once using a function that expresses the logarithm of the frequency, and becomes the following equation (20). .

[0071]

(Equation 20)

This is further differentiated once to obtain the condition that the variation becomes “0”. As a result, 2πf = Rm1 /
Lm1. Thus, the relational expression between Rm1 and Lm1 is obtained.

[0073] Also, inductance at this frequency, the Formula 19, by substituting 2 [pi] f = Rm1 / Lm1, obtained as ^{Ls (1-k1 2/2} ). By multiplying the frequency, the reactance X of the impedance Z
When a relational expression of coupling coefficient k1 Xm1 = X1 (1-k1 2 /
2) is obtained.

Incidentally, the magnetic permeability of the ferrite material starts to attenuate at a certain frequency. It is known that it has no lower limit and continues to attenuate until it finally reaches “0”. However, the inductance component X of the impedance Z of the equivalent circuit in which one of the closed loop is magnetically coupled, as shown in FIG. 6 (B), changes to the frequency is gradually dull, converged to the lower limit value Ls (1-k1 ²⁾ Would. In the case of an inductance element using a ferrite material for a magnetic core, there is a concern that an error in characteristics due to an equivalent circuit may increase in a frequency range where the inductance converges to the lower limit.

Therefore, in this embodiment, a second closed loop is prepared, and a circuit constant is selected such that the inductance X decreases in a frequency range where the error increases. The inductance X of the impedance Z of an equivalent circuit in which a second closed loop in which a resistance Rm2 and an inductance Lm2 are connected in series and further magnetically coupled with a coupling coefficient k2 is expressed by the following equation (21).

[0076]

(Equation 21)

From this equation, the frequency at which the slope of the attenuation due to the closed loop becomes the maximum is similarly 2πf = Rm2 / Lm2
Is obtained as Also, the frequency, the closed loop is selected to the frequency range to converge to the lower limit in the case of only one inductance X of the equivalent circuit at that frequency as ^{Ls (1-k1 2 -k2 2} /2) can get.
By multiplying the frequency in this FIG relation Xm2 = X2 of the coupling coefficient and reactance X of the impedance Z of the equivalent circuit of (A) k1 (1-k2 2 / (1-k1 2) / 2) is obtained Can be

The above-mentioned circuit constant Ls = 13.5 μ
H, k1 = 0.67, Rm1 = 635Ω, Lm1 = 13.5
μH, k2 = 0.30, Rm2 = 2600Ω, Lm2 = 1
FIG. 6C shows a frequency characteristic of the inductance X in the equivalent circuit of FIG. 1A when 3.5 μH is set. As is clear from the comparison of FIG.
The frequency that converges to the lower limit is further increased. If necessary, it is possible to further increase the frequency by preparing third and subsequent closed loops. But,
If the frequency can be increased to the resonance point of the inductance element, no further is required. In this embodiment, the resonance point is 120 MH
Since z, the third open loop is not particularly required.

As described above, according to the present embodiment, the characteristics of an inductance element, particularly an inductance element using a ferrite material, can be expressed with high accuracy. Therefore, if the equivalent circuit of FIG. 1A is used for a simulator, a highly accurate simulation can be performed. Also,
If the components having the obtained circuit constants are connected as shown in FIG. 1A, an inductance element having desired characteristics can be obtained.

[0080]

Second Embodiment Next, a second embodiment of the present invention will be described. In this embodiment, the equivalent circuit shown in FIG. 7 is used. FIG. 7 is an equivalent circuit of the above-described circuit of FIG. The equivalent circuit of FIG. 1A has a circuit configuration in which a closed circuit is magnetically coupled with mutual inductance. Here, the value of the mutual inductance is determined as described above, but it is not easy to obtain such a mutual inductance in an actual circuit. On the other hand, in the equivalent circuit shown in FIG. 7, the mutual inductance is expressed as a coil element. Therefore, when components are actually connected, the equivalent circuit of FIG. 7 is simpler and more advantageous than the equivalent circuit of FIG.

Hereinafter, an analysis procedure when the inductance element having the characteristic shown in FIG. 20B is represented by the equivalent circuit of FIG. 7 will be described. The basic procedure is the same as in the first embodiment. FIG. 8 shows the procedure of this embodiment.

First, as in the first embodiment,
The following values are obtained from the data of the graph of FIG.
Ls = 13.5 μH, Cp = 0.37 pF, Lm1 = 13.0.
5 μH, Rm1 = 635Ω, k1 = 0.67, Lm2 = 1
3.5 μH, Rm2 = 2600Ω, k2 = 0.30, Rp =
640Ω, Lr → ∞, Cr → ∞, Rs = 0.28Ω

Next, steps S51 to S6 shown in FIG.
Step 2 is performed in order. Thereby, the next value is determined. Rp = 640Ω, Cp = 0.37 pF, L1 = 4.5
μH, L2 = 9.45 μH, LN1 = 9 μH, LN2 = 4.
05 μH, R1 = 635Ω, R2 = 2600Ω, Lo = −
0.45 μH, Lr → ∞, Cr → ∞, Rs = 0.28Ω

FIG. 1B shows frequency characteristics when the circuit constants obtained as described above are applied to the equivalent circuit of FIG. As is apparent from a comparison between the measured value and FIG. 20B, which is an actually measured value, the two values agree well, and it is understood that this embodiment is also a highly accurate equivalent circuit of an inductor element. Further, the equivalent circuit obtained by the above analysis result is applied to the inductance element 12 shown in FIG. 20A, and the result of simulating the signal waveform of the circuit of FIG. C), and FIG.
As is clear from comparison with (C), a highly accurate simulation can be performed.

Note that steps S53 to S5 shown in FIG.
The relational expression shown in FIG. 9 is obtained as follows. First, a circuit of a magnetic coupling portion is taken out from the equivalent circuit shown in FIG. 1A as shown in FIG. 9A. When the impedance is obtained, it becomes as shown in the following equation (22). By solving this, the following equation (23) is obtained.

[0086]

(Equation 22)

[0087]

(Equation 23)

Next, an equivalent circuit portion of the magnetic coupling portion is extracted from FIG. 7 as shown in FIG. The impedance of this circuit is expressed by the following equation (24). By solving this, the following equation 25 is obtained.

[0089]

(Equation 24)

[0090]

(Equation 25)

The equation (25) obtained in this way is expressed by the equation (2).
When compared with the three equations, the relational equations shown in steps S53 to S59 are derived.

[0092]

Third Embodiment Next, a third embodiment of the present invention will be described. This embodiment shows an analysis method for realizing an inductance element having the characteristics shown in FIG. 22A with the equivalent circuit in FIG. First, according to the characteristics shown in FIG. 22A, since Z ≒ jX at 10 MHz, XL = 60Ω and fL = 10 in Ls = XL / (2πfL) in the equation (3).
By substituting MHz, Ls = 0.96 μH is obtained. next,
From the measured value Ro = 1170Ω at the resonance point, Rp = Ro
Thus, Rp = 1170Ω is determined.

Next, measured values Rh = 530Ω, Ls = 0.96 μH, Rp = 11 at a frequency fh = 1.8 GHz.
By substituting 70Ω into the above equation 5, Cp = 0.09 pF
I got The Ls, Rp, and Cp obtained in this way are substituted into the above equation (5), and the reactance X for each frequency is calculated. Then, the measured value and the calculated value of the reactance component X are compared. As a result, the frequency at which the difference between the two is large and the reactance X needs to be reduced most is fm1 = 1.
It was 60 MHz. Therefore, as in the first embodiment, R
In order to satisfy m1 / Lm1 = 2πfm1, Lm1 = 0.96μ
H, Rm1 = 965Ω.

Further, the value X1 = 580Ω of the reactance component X by the LsCpRp parallel circuit at the above-mentioned frequency and the target value Xm1 = 430Ω of the measured value to be reduced are set as k1 = √ (2 (1- (2) Xm1 / X1)) to obtain a coupling constant k1 = 0.72. Ls, thus obtained,
Cp, Lm1, Rm1, and k1 were calculated using Equations 7 to 10, and the reactance X for each frequency was calculated.
When the calculated value and the measured value of the reactance component X were compared with each other, the difference between them was small, and it was not necessary to particularly reduce the calculated value. Therefore, Rm2 and Lm2 are arbitrarily selected. For example, Rm2 = 965Ω, Lm2 = 0.96 μH, k
1 = 0.

Subsequently, the resonance point frequency fo = 650 MH
z and the circuit constants Ls, Cp, Lm1, Rm1, k1, Lm
Substituting 2, Rm2, k2 into Equations 16 to 18, RL = 47
0 Ω, XL = 2000 Ω, Bc = 0.368 mS. Also, Rp = 1300Ω is obtained from the reactance Ro = 1170Ω at the resonance point.

Next, the frequency at which the graph of the resistance R and the reactance X of the impedance Z intersect with each other and the frequency at which the reactance X is maximized are obtained from FIG. 22A. It is. Therefore, Lr and Cr are obtained as follows using the values of these frequencies.

In FIG. 1A, the inductance Lr is connected in parallel with the resistor Rp. Therefore, the resistance of these parallel circuits is suppressed until the frequency at which the value of the impedance 2πfLr of the inductance Lr exceeds the value of the resistor Rp. That is, the rise of the resistance of the impedance of the parallel circuits is suppressed. Therefore, the frequency frL =
40 MHz, Rp = 1300Ω, Lr = Rp / (2πf
substituting into (rL), Lr = 5.1 μH was obtained.

In the parallel circuit of the inductance Lr and the resistance Rp, a capacitance Cr is connected in series.
Therefore, the impedance of the capacitance Cr is 1 / (2
The resistance sharply increases from the frequency at which the value of (πfCr) falls below the value of the resistor Rp. Therefore, the frequency frC = 100 MHz where the reactance component of the impedance of the LrRpCr circuit is desired to be larger than the resistance component, and Rp = 1300Ω are set to Cr
= 1 / (2πfrC · Rp) to obtain Cr = 1.2 pF. Also, since the measured DC resistance was 0.5Ω,
Rs = 0.5Ω.

The frequency characteristics when the circuit constants obtained as described above are applied to the equivalent circuit of FIG.
As shown in FIG. As is clear from comparison with FIG. 22A, which is an actually measured value, according to the equivalent circuit of the present embodiment,
The frequency characteristics of the inductor element can be expressed with very high accuracy.

[0100]

Embodiment 4 Next, Embodiment 4 of the present invention will be described. In the present embodiment, an inductance element having the characteristics shown in FIG. 22A is obtained by analyzing the equivalent circuit of FIG. 7 according to the procedure shown in FIG. As in the third embodiment, Ls = 0.96 μH, Cp = 0.09 pF, L
m1 = 0.96 μH, Rm1 = 965Ω, k1 = 0.72
Lm2 = 0.96 μH, Rm2 = 965Ω, k2 = 0, Rp =
1300Ω, Lr = 5.1 μH, Cr = 1.2 pF, Rs
= 0.5Ω.

Next, according to steps S51 to S62 in FIG. 8, Rp = 1300Ω, Cp = 0.09pF, L1 =
0.27 µH, L2 = 0.96 µH, LN1 = 0.69 µ
H, LN2 = 0 μH, R1 = 965Ω, R2 = 965Ω, L
o = 0.27 μH, Lr = 5.1 μH, Cr = 1.2 p
F, Rs = 0.5Ω was obtained.

The frequency characteristics when the circuit constants obtained as described above are applied to the equivalent circuit of FIG. 7 match those of FIG. Therefore, even with the equivalent circuit of the present embodiment, the frequency characteristics of the inductor element can be expressed with extremely high accuracy.

[0103]

Embodiment 5 Next, Embodiment 5 of the present invention will be described. In this embodiment, a magnetic coupling circuit as shown in FIG. 11A is used as an equivalent circuit of an inductance element using a ferrite material. This circuit corresponds to FIG.
(A) is a simplified version of the equivalent circuit in which a closed circuit in which a resistance Rm and an inductance Lm are connected to an inductance Ls of an LsCpRp parallel circuit is magnetically coupled with a coupling coefficient k to form a mutual inductance M. It is. Therefore, it exists in the equivalent circuit of FIG.
The analysis may be performed with the circuit constant of the element not existing in the equivalent circuit of FIG.

Next, in this embodiment, the circuit constant of the equivalent circuit is selected according to the procedure of the flowchart shown in FIG. Hereinafter, using the equivalent circuit shown in FIG. 11A and along the procedure shown in FIG. 12, a procedure for selecting a circuit constant of the inductance element having the frequency characteristic shown in FIG. 20B will be described as an example.

(1) Determination of Circuit Constant Ls (Step S1)
... Measure the impedance XL of the entire inductance element. Then, the circuit constant Ls is determined by solving the following equation 26 from the frequency fL that satisfies Z ≒ jX and the measured value XL at frequencies below the resonance point. In the example of FIG.
Since z ≒ ZX and the measured value XL = 17Ω, these values are substituted into the following equation (26) to obtain a circuit constant Ls =
2.7 μH was obtained.

[0106]

(Equation 26)

(2) Determination of Circuit Constant Rp (Step S2)
... The circuit constant Rp is determined from the actual measured value Ro of the resistance at the resonance point of the inductance element as Rp = Ro.
In this example, since the measured value Ro = 260Ω at the resonance point, Rp = 260Ω was obtained from Rp = Ro.

(3) Determination of Circuit Constant Cp (Step S3)
……… At a frequency higher than the resonance point of the inductance element, Z
From the frequency fC that becomes ≒ jX and the actually measured value Xc,
The equation is solved to determine the circuit constant Cp. When the measurement frequency is low and the frequency fc at which Z ≒ jX is equal to or higher than the resonance point and the actual measurement value Xc are not obtained, the frequency at or above the resonance point
Using the frequency fh, the measured value Rh, and the previously determined circuit constants Ls and Rp, the following equation 28 is solved to determine the circuit constant Cp. In this example, the measured value Rh = 124Ω at the frequency fh = 1 GHz, the circuit constant Ls = 2.7 μH, and Rp = 26
0Ω is substituted into the following equation 28 to obtain a circuit constant Cp = 0.
65 pF was obtained.

[0109]

[Equation 27]

[0110]

[Equation 28]

(4) Determination of the reactance X of the whole equivalent circuit (step S4): The circuit constant L thus obtained
Substituting s, Rp and Cp into the following equation (29), the reactance X of the equivalent circuit for each frequency is calculated. As a result, a graph of the change in the reactance component X with respect to the frequency was obtained.

[0112]

(Equation 29)

(5) Determination of Circuit Constants Rm and Lm (Step S5) As described above, when the inductance element is made of a ferrite material, the inductance decreases due to the magnetic resonance phenomenon. Therefore, in the present embodiment, the decrease is compensated for by the coupled equivalent circuits Lm and Rm. That is, the reactance X has a large difference from the measured value, and the frequency f
Rm, Lm so as to satisfy the following equation (30).
To determine. In this example, the frequency to be reduced most is fm
= 15.3 MHz, the circuit constants Lm = 2.7 μH and Rm = 260Ω were obtained from the following equation (30).

[0114]

[Equation 30]

(6) Determination of Coupling Coefficient k (Step S6) ...
... From the value X1 of the reactance X by the LsCpRp parallel circuit at the frequency fm and the target value X2 of the actually measured value to be reduced, the following equation 31 is solved to determine the coupling constant k. In this example, the reactance value X1 = 126 Ω and the target value X2 = 95 Ω of the actually measured value to be reduced were substituted into the above equation 31 to obtain a coupling constant k = 0.70. The mutual inductance M can be obtained from M = k√ (LsLm).

[0116]

(Equation 31)

(7) Re-determination of circuit constant Rp ...
The frequency fo of the resonance point and the circuit constants Ls, Cp, Lm, Rm,
k is substituted into the following Expressions 32 to 34 to obtain RL, X
L and Bc are obtained, and the resistance Ro of the impedance is added.
Is substituted into Expression 35, and Rp is determined again.

[0118]

(Equation 32)

[0119]

[Equation 33]

[0120]

(Equation 34)

[0121]

(Equation 35)

The circuit constants obtained as described above are shown in FIG.
When the frequency characteristics were obtained by applying to the equivalent circuit shown in FIG. 11A, a graph as shown in FIG. 11B was obtained. Comparing this with the measured value shown in FIG. 20 (B), the two graphs are almost the same, indicating that the analysis method according to the present embodiment is extremely accurate.

Next, the equivalent circuit obtained by the above analysis result is applied to the inductance element 12 of the signal line shown in FIG. 20A, and the signal waveform at the measurement point PD when the pulse signal SA is input is shown. As a result of the simulation,
A signal waveform as shown in FIG. 11C was obtained. As is clear from a comparison between FIG. 20C and FIG. 20C, the present embodiment enables extremely accurate simulation.

The equation (30) for selecting the closed-loop circuit constant by the resistance Rm and the inductance Lm.
/ Lm = 2πfm), that is, the relationship between Rm and Lm for maximizing the effect of the closed loop can be derived as follows. First, the closed loop portion is extracted and shown in FIG. 13A, and the inductance L of this circuit is expressed by the following equation (36).

[0125]

[Equation 36]

Here, Ls = 2.7 μH, k = 0.7,
FIG. 13B shows the frequency characteristics of the inductance L when Rm = 260Ω and Lm = 2.7 μH. The largest slope in the graph of FIG.
This can be obtained by differentiating the equation once, and the following equation 37
It is expressed by an equation.

[0127]

(37)

This is further differentiated once, and the condition that the variation becomes “0” is obtained, whereby 2πf = Rm / Lm, which is expressed by the following equation (30), is obtained. Further, the inductance L2 at a frequency satisfying this condition can be obtained as in the following Expression 38 by substituting Expression 30 into Expression 36 representing the inductance L. Further, by multiplying the frequency both sides of the number 38 formula, the number 31 formula is an equation of the coupling coefficient k X2 = X1 (1-k 2/2)
Is obtained.

[0129]

(38)

In the fifth embodiment, when analyzing the DC resistance of the inductance element 12 (see FIG. 20A), the resistance Rs as shown in FIGS. 14A and 14B is connected. What is necessary is just to use the equivalent circuit calculated. When it is necessary to attenuate the reactance X of the impedance Z of the inductance element 12 at a plurality of frequencies, a plurality of inductively-coupled closed circuits as shown in FIG. 14C may be provided.

[0131]

Embodiment 6 Next, Embodiment 6 of the present invention will be described. In this embodiment, an inductance element having the characteristics shown in FIG. 22A is analyzed using the equivalent circuit shown in FIG. This equivalent circuit differs from the equivalent circuit of the fifth embodiment shown in FIG. 11A in that a resistance Cr and a capacitance Cr are connected.

First, since Z ≒ jX at 4 MHz, XL = 14Ω and fL = 4 MHz are substituted into the following expression 39 to obtain L
s = 0.56 μH is obtained.

[0133]

[Equation 39]

Next, since the measured value Ro = 350Ω at the resonance point, Rp = 350Ω is determined from Rp = Ro.

Next, measured values Rh = 150Ω, Ls = 0.56 μH, Rp = 350 at a frequency fh = 1 GHz.
Is substituted into the following equation to obtain Cp = 0.57 pF.

[0136]

(Equation 40)

Next, the Ls, Rp, and Cp obtained in this manner are obtained.
Is substituted into the following Expression 41 to obtain a mathematical expression representing the reactance X for each frequency.

[0138]

[Equation 41]

Next, regarding the reactance X, FIG.
Compared with the measured value of (A), the difference between the two is large and the frequency to be reduced most is determined. In this example, fm = 110M
Hz, Lm = 0.56 μH and Rm = 387Ω so as to satisfy Rm / Lm = 2πfm. Furthermore,
Substituting the value X1 = 169Ω of the reactance of the LsCpRp parallel circuit at the frequency fm and the target value X2 = 128Ω of the actually measured value to k = √ (2-2X2 / X1), and setting the coupling constant k = 0.70 obtain.

Subsequently, the frequency fo = 32 at the resonance point
Substituting 0 MHz and circuit constants Ls, Cp, Lm, Rm, and k into the following equation 42, RL = 170Ω, XL = 632Ω, B
Obtain c = 1.15 mS. Further, the resistance Ro = 350Ω of the impedance Z is substituted into Expression 43, and Rp = 392Ω
Was decided again.

[0141]

(Equation 42)

[0142]

[Equation 43]

Next, in the measured values of FIG. 22A, the frequency at which the reactance X of the impedance Z is maximum is fr = 60 MHz, so that Cr = 1 / (Lsf
By solving r ² ), Cr = 12.5 pF was obtained.

In this embodiment, the capacitance Cr and the inductance Ls connected in series to the resistor Rp resonate in parallel. Therefore, the reactance X near the resonance point is amplified. FIG. 15B shows frequency characteristics when the above circuit constants are applied to the equivalent circuit of FIG. FIG. 22 showing measured values
As is clear from comparison with (A), the characteristics of the inductor element are expressed with high accuracy.

In this embodiment, to analyze the direct current resistance of the inductance element, it is necessary to use FIGS.
An equivalent circuit in which the resistance Rs is connected as shown in FIG. When it is necessary to attenuate the reactance X at a plurality of frequencies, as shown in FIG.
A plurality of closed circuits for inductive coupling may be provided.

[0146]

Seventh Embodiment Next, a seventh embodiment of the present invention will be described. In this embodiment, an inductance element having the characteristics shown in FIG. 22B is analyzed using the equivalent circuit shown in FIG. This equivalent circuit is different from the equivalent circuit of the sixth embodiment shown in FIG. 15A in that an inductor Lr is connected to a resistor Rp.

First, in FIG. 22B, since Z ≒ jX at 100 MHz, Ls = XL / (2πfL) and XL = 66.
Ω, fL = 100 MHz, Ls = 0.105 μH
Get. At the resonance point, the measured value Ro = 380Ω, so Rp = 380Ω is determined from Rp = Ro.

Next, measured values Rh = 260Ω, Ls = 0.105 μH, Rp = 380 at a frequency fh = 1 GHz.
Is substituted into the following equation to obtain Cp = 0.52 pF.

[0149]

[Equation 44]

Next, the Ls, Rp, and Cp obtained as described above are obtained.
Is substituted into Expression 45 to obtain an expression representing a reactance X for each frequency.

[0151]

[Equation 45]

Then, for this reactance component X,
This is compared with the actually measured value in FIG. As a result, when the difference between the two is large, the frequency at which the reactance X is desired to be reduced most is obtained. In this example, since the frequency to be reduced most is fm = 600 MHz, this is Rm / Lm.
= 2πfm, Lm = 0.105 μH, Rm
= 395Ω. LsC at the frequency fm
The value X1 = 47Ω of the reactance of the pRp parallel circuit and the target value X2 = 41Ω of the measured value to be reduced are calculated as k = √ (2-2
X2 / X1) to obtain a coupling constant k = 0.50.

Subsequently, the resonance point frequency fo = 700 MH
z and the circuit constants Ls, Cp, Lm, Rm, and k are substituted into the following equation 46 to obtain RL = 57.1Ω, XL = 339Ω,
Bc = 2.29 mS is obtained. Further, the resistance Ro = 380Ω of the impedance is substituted into Equation 47 to obtain Rp = 445.
Ω was determined again.

[0154]

[Equation 46]

[0155]

[Equation 47]

Next, the frequency frL = 180 MHz at which it is desired to suppress the rise of the resistance of the impedance, and Rp
= 445Ω into Lr = Rp / (2πfrL), and Lr
= 0.39 µH. Finally, the frequency frc = 36 at which the reactance X of the impedance Z is desired to be increased.
0 MHz, Rp = 445Ω, Cr = 1 / (2πfrcR
Substitution into p) gave Cr = 0.99 pF. In this embodiment, since the inductance Lr is connected in parallel to the resistor Rp, the impedance 2πfLr of the inductance Lr
Until the frequency exceeds the value of the resistor Rp, the resistance is suppressed and the rise of the resistance R of the impedance Z is also suppressed.

Further, the value of the impedance 1 / (2πfCr) of the capacitance Cr connected in series is determined by the resistance R
From a frequency below the value of p, the resistance increases rapidly,
Up to that frequency, the reactance X of the impedance Z becomes large.

FIG. 17A shows frequency characteristics when the above-described circuit constants are applied to the equivalent circuit.
(B). This is shown in FIG.
As is clear from comparison with (B), even in the present embodiment, highly accurate analysis of the inductor element is possible.

In this embodiment, to analyze the direct current resistance of the inductance element, it is necessary to use the method shown in FIGS.
An equivalent circuit in which the resistance Rs is connected as shown in FIG. When it is necessary to attenuate the reactance X at a plurality of frequencies, as shown in FIG.
A plurality of closed circuits for inductive coupling may be provided.

[0160]

Eighth Embodiment Next, an eighth embodiment of the present invention will be described. This embodiment is an embodiment of a simulator for frequency characteristics of an inductance element using the above-described analysis method. By using the above-described analysis method, it is possible to simulate the frequency characteristic of the impedance of the inductance element using a computer system or the like.

FIG. 19 shows the configuration of such a simulator. In FIG.
Is an arithmetic processing unit 32 composed of a CPU and the like, and an input unit 3 composed of a keyboard and a mouse.
4, memory 36, display unit 38, CD-ROM drive 4
0, the output unit 37 is provided.

A simulation program for executing the above-described analysis method is stored in a CD-ROM 42, which is one of computer-readable recording media. When the CD-ROM 42 is set in the CD-ROM drive 40, the simulation program is read and executed by the arithmetic processing unit 32. The display 38 has an input data display area 38A and a frequency characteristic waveform display area 38A.
B is set. The user enters the input data display area 3
With reference to 8A, the input unit 34 inputs data such as measured values. The input data is stored in the memory 36 and the input data display area 38A of the display unit 38
Will be displayed.

The arithmetic processing section 32 executes the above-described arithmetic processing based on the input data. As a result, when the frequency characteristics of the impedance Z, the resistance R, and the reactance X of the reactance element are obtained, the graph is displayed in the frequency characteristic graph display area 38B of the display unit 38. The user refers to this graph and, if necessary, further inputs data and corrects the input data.

To explain the case of the first embodiment, the user inputs the measured values in steps S10 to S18 through the input unit 34. The arithmetic processing unit 32 executes the arithmetic processing from step S10 to S20 according to these inputs. As a result, the frequency characteristic of the reactance X is obtained, and this is displayed on the display unit 38.
The user refers to this result and determines in steps S22 to S2
6 is determined, and a corresponding numerical value is input. Based on this input, the arithmetic processing unit 32 determines in steps S28 to S30
Is performed. As a result, the corrected frequency characteristic of the reactance X is obtained, and this is displayed on the display unit 38.

The user determines the steps S32 to S36 by referring to the result, and inputs a corresponding numerical value. Based on this input, the arithmetic processing unit 32 executes the arithmetic processing of steps S38 to S48. Thereby, the frequency characteristics of the impedance Z, the resistance component R, and the reactance component X are finally obtained, and these are displayed on the display unit 38. The finally determined circuit constants are printed out from the output unit 37.

[0166]

Ninth Embodiment Next, a description will be given of a simulator and a simulation method of a signal waveform of a transmission circuit using the above-described equivalent circuit of the inductance element and its analysis method. As a transmission circuit including an inductance element,
Assume a circuit in which impedances ZS and ZL are connected to a transmission line 14 as shown in FIG. In this circuit, V0 is the DC component of the input signal, V is the AC component of the input signal, and εr is the transmission line 14.
, Z0 is the characteristic impedance of the transmission line 14, and L is the line length of the transmission line 14. ZS is the output impedance, and ZL is the input impedance (load impedance).

The relationship between the voltage and the current at the points P and Q of the transmission line 14 is expressed by the following equation (48).
In Equation 48, the potential of the incident wave at point P is Vpf, the current of the incident wave is Ipf, the potential of the reflected wave is Vpr, and the current of the reflected wave is Ipr. The potential of the incident wave at point Q is Vqf, the current of the incident wave is Iqf, the potential of the reflected wave is Vqr,
The current of the reflected wave is Iqr. Further, the voltage of the transmitted wave of the transmission line 14 is Vt, the reflection coefficient at point P is ΔP, the reflection coefficient at point Q is ΔQ, and the phase shift between input and output is A. Here, the transmitted wave voltage Vt is replaced by a relational expression consisting of the output impedance ZS, the characteristic impedance Z0 of the transmission line 14, and the AC component V of the input signal.

[0168]

[Equation 48]

Further, an inductance element is connected to the output impedance ZS in series. The value of the impedance Z1 = R1 + jX1 of the inductance element is obtained in the above-described embodiment. The voltage waveform Vq, voltage spectrum | Va |, current waveform Iq, and current spectrum | Ia | at point Q of the transmission line 14 are expressed by the following equation (49). By using these equations, it is possible to simulate an output waveform on a transmission line to which an inductance element is added.

[0170]

[Equation 49]

FIG. 24 shows the configuration of the simulator according to the present embodiment, and FIG. 25 is a flowchart showing the operation of the simulator according to the present embodiment. The device configuration of the simulator 50 is almost the same as that of FIG. 19 described above. However, in this embodiment, the CD-ROM 5
The simulation program stored in 2 executes the operation shown in FIG. The display unit 54 includes an input data / selection element display area 54A and a waveform display area 5A.
4B is provided.

(1) Initial setting: First, the conditions (R, R) of the impedances ZS, ZL on the input and output sides of the transmission line 14
X), the length L of the transmission line 14, each value of the effective relative permittivity εr and the characteristic impedance Z0, the voltage amplitude, frequency, and rise time of the input pulse are set by the input unit 34 (step S70). The input value is displayed on the display unit 3.
8 is displayed in the input data / selection element display area 54A.

(2) Selection of Insertion Part ... Next, an inductance element to be inserted into the signal wiring is similarly selected by the input unit 34 (step S72). Specifically, an appropriate equivalent circuit and a circuit constant are selected by using the above-described method for analyzing the circuit constant of the inductance element. Alternatively, using the above-described method of analyzing the circuit constant of the inductance element, the circuit constant of each component is stored in the memory 36 in advance as a table, and by referring to this table, the circuit constant corresponding to the inductance element to be inserted is obtained. It may be obtained. The selection result is displayed in the input data / selection element display area 54A of the display unit 54.

(3) Calculation of transmission characteristics... Next, using the values input as described above, the arithmetic processing unit 32 calculates the transmission characteristics according to the equation (48) (step S7).
4). Then, the amplitude and the phase are added by Expression 49 (Step S76). At this time, the circuit constant obtained by the above-described method for analyzing the circuit constant of the inductance element is used. Alternatively, the value of the circuit constant stored in the memory 36 in advance is used.

(4) Display of signal waveform ... The result of the above calculation is substituted into the above equation (53) to obtain a voltage / current waveform or a spectrum waveform. That is, a signal waveform as shown in FIG. 20C is obtained. These waveforms are displayed in the waveform display area 54B of the display unit 54 (Step S58), and are evaluated by the operator (Step S80). And
If there is a problem such as overshoot or undershoot in the signal waveform, the process returns to step S70 or S72, and initialization and inductance element selection are performed again (NG in step S80).

In addition to the evaluation by the operator, evaluation criteria such as overshoot, undershoot, and rise time of the signal waveform are prepared in advance, and the evaluation criteria are compared with the signal waveform obtained by the simulation. Alternatively, the evaluation determination may be performed automatically.

The present invention has many embodiments, and can be variously modified based on the above disclosure.
For example, the following is also included. (1) The numerical values of the frequency, the measured value, and the circuit constant shown in the above embodiment are merely examples, and the present invention is not limited thereto. Further, in order to bring the circuit constants determined in the above-described embodiment closer to the actually measured values, it does not prevent fine adjustment using values in the vicinity thereof. (2) In the above embodiment, two magnetic coupling circuits each including a resistor and an inductance are included in the equivalent circuit. However, if necessary, a plurality of magnetic coupling circuits may be provided. For example,
This is suitable when the inductance component deviates from the actually measured value at a plurality of locations. (3) The present invention is particularly suitable for analyzing the impedance characteristics of an inductance element using a ferrite material, but is generally applicable to an inductance element (coil element). (4) Further, the circuit elements having the circuit constants obtained by the present invention may be connected like an equivalent circuit so that an inductance element having a desired impedance characteristic is obtained in a pseudo manner.

[0178]

As described above, according to the present invention,
Since the decrease in inductance caused by the magnetic resonance phenomenon of the ferrite material is compensated for by taking into account the magnetic coupling circuit, it is possible to analyze the circuit constant of the inductor element with high accuracy, and the frequency of the inductance element formed of the ferrite material is improved. It is possible to accurately simulate the characteristics and the operation characteristics of a circuit including the characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention. (A) is an equivalent circuit, (B) is a characteristic example of an equivalent circuit, and (C) is an example of a signal waveform when an equivalent circuit is used.

FIG. 2 is a flowchart illustrating an analysis procedure according to the first embodiment.

FIG. 3 is a flowchart illustrating an analysis procedure according to the first embodiment.

FIG. 4 is a flowchart showing an analysis procedure in the first embodiment.

FIG. 5 is a flowchart showing an analysis procedure in the first embodiment.

FIG. 6 is a diagram illustrating a closed loop portion extracted from the equivalent circuit of FIG. 1; (A) is a circuit diagram of a closed loop, (B) is a graph showing a frequency change of the inductance in the case of one closed loop, and (C) is a graph showing a frequency change of the inductance in the case of the first embodiment.

FIG. 7 is a circuit diagram showing an equivalent circuit of the second embodiment.

FIG. 8 is a flowchart showing an analysis procedure according to the second embodiment.

9 is a circuit diagram for deriving the relational expression shown in FIG.

FIG. 10 is a graph showing frequency characteristics of the third and fourth embodiments.

FIG. 11 is a diagram showing a fifth embodiment. (A) is an equivalent circuit, (B) is a characteristic example of an equivalent circuit, and (C) is an example of a signal waveform when an equivalent circuit is used.

FIG. 12 is a flowchart showing an analysis procedure in the fifth embodiment.

FIG. 13 is a diagram for deriving the relational expression shown in FIG. (A) is a circuit diagram, and (B) is a graph showing a characteristic example.

FIG. 14 is a circuit diagram showing a modification of the fifth embodiment.

FIG. 15 is a diagram showing a sixth embodiment. (A) is a circuit diagram showing an equivalent circuit, and (B) is a graph showing a characteristic example.

FIG. 16 is a circuit diagram showing a modification of the sixth embodiment.

FIG. 17 is a diagram showing a seventh embodiment. (A) is a circuit diagram showing an equivalent circuit, and (B) is a graph showing a characteristic example.

FIG. 18 is a circuit diagram showing a modification of the seventh embodiment.

FIG. 19 is a block diagram illustrating a configuration of an eighth embodiment.

FIG. 20 is a diagram showing a signal line using an inductance element. (A) is a block diagram showing the configuration, (B)
Is a graph of the frequency characteristic of the impedance, and (C) is a diagram showing an example of a signal waveform.

FIG. 21 is a diagram showing a conventional technique. (A) is a circuit diagram showing an equivalent circuit, and (B) is a diagram showing an example of its impedance frequency characteristic.

FIG. 22A is a graph showing another example of the impedance frequency characteristic of the inductance element, and FIG. 22B is a graph showing an analysis example according to the related art.

FIG. 23 is a circuit diagram illustrating an example of a transmission circuit.

FIG. 24 is a block diagram showing a configuration of a ninth embodiment.

FIG. 25 is a flowchart showing a simulation procedure according to the ninth embodiment.

[Explanation of symbols]

 10, 16 ... inverter IC 12 ... inductance element 14 ... transmission line 30, 50 ... simulator 32 ... arithmetic processing unit 34 ... input unit 36 ... memory 37 ... input unit 38, 54 ... display unit 38A ... input data display area 38B ... frequency Characteristic graph display area 40 CD-ROM drive 42 CD-ROM 54A Input data / selection element display area 54B Waveform display area Cp, Cr Equivalent capacitance Lm, Lm1, Lm2, Lr, Ls, Equivalent inductance M, M1, M2: equivalent mutual inductance Rm, Rm1, Rm2, Rp, Rs: equivalent resistance Z: impedance R: resistance X: reactance

Claims (15)

[Claims] 1. A parallel circuit in which a first inductance, a first capacitance, and a first resistor are connected in parallel; a second resistor connected in series to either the parallel circuit or the first inductance. An equivalent circuit of an inductance element, comprising: a closed circuit including a resistance and an inductance, which is magnetically coupled to the first inductance by a mutual inductance. 2. The equivalent circuit according to claim 1, wherein a plurality of said closed circuits are provided. 3. A parallel circuit in which a first inductance, a first capacitance, and a first resistor are connected in parallel; a second capacitance connected in series with the first resistor; An equivalent circuit of an inductance element, comprising: a closed circuit that is magnetically coupled by a mutual inductance and includes a resistance and an inductance. 4. The equivalent circuit according to claim 3, wherein a plurality of said closed circuits are provided. 5. An equivalent circuit for an inductance element according to claim 3, further comprising a second resistor connected in series to one of said parallel circuit and said first inductance. 6. A second resistor connected in parallel to the first resistor.
6. An inductance according to claim 3, wherein
An equivalent circuit of the inductance element according to any one of the above. 7. A parallel circuit in which a first inductance, a first capacitance, and a first resistor are connected in parallel; a second capacitance connected in series with the first resistor; A second inductance connected in parallel; a second resistance connected in series with the parallel circuit;
An equivalent circuit of an inductance element, comprising: a plurality of closed circuits that are magnetically coupled to the first inductance by a mutual inductance and include a resistance and an inductance. 8. The equivalent circuit of claim 1, wherein the mutual inductance is represented by another circuit element. 9. A method for analyzing a circuit constant of an equivalent circuit of an inductance element according to claim 1, wherein
A method for analyzing a circuit constant of an inductance element, wherein a desired impedance frequency characteristic of the inductance element is obtained by adjusting a circuit constant of the closed circuit. 10. A first inductance, a first capacitance, and a first resistance are connected in parallel, and the first inductance is magnetically coupled to at least one closed circuit formed by a resistance and an inductance. In the method for analyzing the circuit constant of an inductance element, which analyzes the circuit constant of the equivalent circuit, the circuit constant of the first inductance is determined from the measured value of the impedance at which the impedance of the inductance element is substantially equal to the reactance in the frequency range below the resonance point. Determining the resistance of the inductance element at the resonance point and determining the circuit constant of the first resistor; the reactance component in which the impedance of the inductance element is substantially equal to the reactance component in a frequency range equal to or higher than the resonance point. Is obtained, the measured value is Determining the circuit constant of the first capacitance using the measured value of the resistance at that frequency and the circuit constants of the first inductance and the first resistor when the reactance component cannot be obtained. Calculating a change in the equivalent circuit of the inductance element with respect to the frequency based on the circuit constant obtained in each of the above steps; Comparing the frequency change of the measured reactance and determining the circuit constant and the coupling coefficient of the closed circuit so that the two are close to each other. 11. A method for analyzing a circuit constant of an inductance element according to claim 7, wherein the impedance of the inductance element is substantially equal to the reactance in a frequency range below a resonance point. Determining the circuit constant of the first inductance from the actual measurement value; measuring the resistance of the inductance element at the resonance point and determining the circuit constant of the first resistance; When a reactance component in which the impedance of the element is substantially equal to the reactance component is obtained, the measured value is used. Using the circuit constant of the 1st resistor, Determining the circuit constant of the capacitance of the above; calculating the change in the equivalent circuit of the inductance element with respect to the frequency based on the circuit constant obtained in each of the above steps; reactance of the equivalent circuit obtained by this Comparing the change in frequency with the change in frequency of the measured reactance of the inductance element, and determining the circuit constant and coupling coefficient of the closed circuit so that the two are approximated; the circuit obtained in each of the above steps. Re-determining the circuit constant of the first resistor by using the constant; comparing the frequency at which the measured value of the impedance of the inductance element matches the measured value of the reactance with the value of the frequency at which the reactance is maximized; A circuit of the second inductance and the second capacitance according to the result; Determining a constant; determining a circuit constant of the second resistor; and a circuit constant analysis method for the inductance element. 12. A simulator for an inductance element, wherein a circuit constant is analyzed based on the method for analyzing a circuit constant of an inductance element according to any one of claims 9 to 11. 13. A circuit constant of an inductance element is determined based on the method for analyzing a circuit constant of an inductance element according to claim 9, and a frequency characteristic of impedance is obtained based on the determined circuit constant. A computer-readable recording medium on which a program including a function is recorded. 14. A method of connecting an inductance element to a transmission line, and analyzing characteristics of the transmission circuit using a circuit constant obtained by the circuit constant analysis method of the inductance element according to claim 9. Characteristic transmission circuit simulator. 15. A function of obtaining a signal waveform of a transmission circuit in which an inductance element is connected to a transmission line, using a circuit constant obtained by the method for analyzing a circuit constant of an inductance element according to claim 9. A computer-readable recording medium having recorded thereon a program including: