JPH0512325A - Circuit analytic simulation system - Google Patents

Abstract

PURPOSE:To shorten a computation time to half and evade the divergence of computation by dividing electric characteristics into areas, performing polynomial approximation, section by section, and distinctively using the polynomial according to an area at the time of circuit analytic simulation. CONSTITUTION:The electric characteristics and the number of area divisions are inputted from an electric characteristic file 4 and an area division number file 5, the electric characteristics are divided into the area by using the number of area divisions, and the border points of the respective areas are found. Then data in the area-divided sections are stored and used to find the coefficient of the polynomial by a method of the least squares, and the coefficient is stored. Further, an area to be calculated is retrieved according to data to be simulated and the coefficient is substituted in the polynomial corresponding to the retrieved area to calculate the characteristics of an element. Then the calculated element characteristics are used to set the circuit equation of the whole circuit, which is solved to obtain a solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breakage simulation method, and more particularly to a circuit breakage simulation method for an electronic circuit that handles active elements.

[0002]

2. Description of the Related Art Conventionally, in this type of circuit analysis simulation method, the characteristics of active elements are calculated using physical equations.

FIG. 3 is a flow chart of a circuit analysis simulation for explaining such a conventional example. As shown in FIG. 3, the conventional simulation method inputs the electric characteristics based on the electric characteristics file 4. This input data uses a physical equation, and all parameters of the equation are obtained by the method of least squares. . This parameter is stored. The program up to this point may be different from the program described below.

Next, the solution of the physical equation is obtained by repeating the above calculation until it converges. That is, here, element characteristics are calculated. Furthermore, by calculating the circuit equation,
It is determined whether or not it has converged. If it has converged, the process proceeds to the next step, but if it has not converged, it returns to the above-mentioned repeating step and repeats the same operation.

FIG. 4 is a voltage / current characteristic diagram of the bipolar transistor using the flow shown in FIG. As shown in FIG. 4, the characteristic transistor base-emitter voltage V _B E Is a logarithmic display of the relationship between the collector current IC and the base current IB.
C and the base current IB are expressed by the following equations (1) and (2).

[0006]

As described above, the equation obtained by the physical method is used in the circuit analysis. The equation has many parameters and uses a non-linear function.

[0008]

The conventional circuit analysis simulation method described above uses the equation obtained by the physical method. Since the equation has many parameters and uses a non-linear function, divergence and oscillation are likely to occur at the time of calculation, and there is a drawback that it takes a lot of time to converge (calculate a solution).

An object of the present invention is to provide a circuit analysis simulation method which shortens the calculation time and prevents the calculation from diverging.

[0010]

A circuit analysis simulation method according to the present invention comprises a step of dividing electric characteristics into a plurality of areas, and a step of approximating data of each section divided into the plurality of areas to a polynomial. , And using the polynomial for each of the sections.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a flow chart of a circuit analysis simulation for explaining an embodiment of the present invention. As shown in FIG. 1, in the present embodiment, an area dividing step (first step) 1 for dividing an inputted electric characteristic into n areas,
It includes an approximation step (second step) 2 for approximating the divided data of each section into a polynomial, and a calculation step (third step) 3 for selectively calculating the data until convergence in each section. First, in the first step 1, the electric characteristic and the area division number are input from the electric characteristic file 4 and the area division number file 5, respectively. Here, the electrical characteristic is divided into regions using the number of divided regions, and the boundary points of the respective regions are obtained by a countermeasure. Next, in the second step 2, the data of each section divided into areas is stored. The data of each of these sections is used to find the coefficient of the polynomial by the least-squares method, and the coefficient is stored. These operations are repeated for the number of area divisions. It should be noted that the work up to this point (up to the point where polynomial coefficients are obtained) can be set as one program, and the coefficient of the polynomial in the calculation step 3 which is the third step described later can be transferred. Further, in the third step, the area to be calculated is searched from the data to be simulated. Moreover, the above-mentioned coefficient is applied to the polynomial corresponding to the searched area to calculate the characteristic of the element. Then, a circuit equation for the entire circuit is established using the calculated element characteristics, and the solution is obtained by calculating it. Finally, it is judged whether or not the calculated solution is within the error range. If it is outside the error range, it is considered that the solution has not converged, and the above process is repeated. If it is within the error range, it is determined that the solution has converged. The processing is ended with regard to this.

FIG. 2 is a voltage / current characteristic diagram of the bipolar transistor using the flow shown in FIG. As shown in FIG. 2, this characteristic is also a logarithmic representation of the relationship between the base-emitter voltage V _{BE of the} transistor and the collector current IC and the base current IB. The difference from the conventional one is that the voltage V _BE is n. It is divided and each section n is calculated as in the following equations (3) and (4).

[0014]

As described above, since the polynomial used for each of the n-divided sections is used for the calculation, the equation can be simplified and the calculation time can be reduced to about half. Moreover, the calculation does not diverge and does not converge.

[0016]

As described above, the present invention divides the electrical characteristics into regions, approximates polynomials in each section, and uses the polynomials differently depending on the regions in the circuit analysis simulation to calculate the equations to be calculated. Since it can be simplified, the calculation time is halved, and it is possible to prevent the calculation from diverging and not converging.

[Brief description of drawings]

FIG. 1 is a flow diagram of a circuit analysis simulation for explaining an embodiment of the present invention.

FIG. 2 is a voltage / current characteristic diagram of a bipolar transistor using the flow shown in FIG.

FIG. 3 is a flow chart of a circuit analysis simulation for explaining an example of the related art.

FIG. 4 is a voltage / current characteristic diagram of a bipolar transistor using the flow shown in FIG.

[Explanation of symbols]

 1 Electrical characteristic region division step 2 Data polynomial approximation step 3 Calculation step 4 Electrical characteristic file 5 Region division number file

Claims (1)

Claim: What is claimed is: 1. Dividing an electrical characteristic into a plurality of areas, approximating data of each section divided into the plurality of areas to a polynomial, and setting the polynomial to each of the sections. And a step of performing a calculation according to the method used in step S1.