CN112668275B

CN112668275B - Method for searching optimal substitute target capacitance in given capacitance set

Info

Publication number: CN112668275B
Application number: CN202011639451.1A
Authority: CN
Inventors: 蒋历国; 凌峰; 王刚; 代文亮
Original assignee: Xinhe Semiconductor Technology Shanghai Co ltd
Current assignee: Xinhe Semiconductor Technology Shanghai Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2023-12-19
Anticipated expiration: 2040-12-31
Also published as: CN112668275A

Abstract

The method for searching the optimal substitute target capacitance in the given capacitance set comprises the following steps of S1, selecting a target capacitance combination; step S2: calculating the parallel impedance of the target capacitance combination: step S3: selecting a substitute capacitor combination; step S4: setting a combination condition: step S5: generating a combination condition candidate combination step S6: calculating a parallel impedance curve for each candidate combination: and S7, comparing the obtained product with a target impedance curve, S8, sorting all the combinations meeting the conditions according to the difference value, and finding an alternative combination scheme, S9, and generating a curve comparison graph according to the selection. The specific combinations of the impedance parameters closest to a specific capacitor or a capacitor combination can be quickly found out in a specific capacitor set by setting the limiting condition of the capacitor, so that the design efficiency is greatly improved, reference is provided for the design, and the method has extremely high practical value.

Description

Method for searching optimal substitute target capacitance in given capacitance set

Technical Field

The invention belongs to the field of electronic design automation, and particularly relates to a method for searching an optimal substitute target capacitor in a given capacitor set.

Background

Such problems are often encountered in chip design work because of space constraints, price constraints, manufacturing constraints, etc. that require multiple capacitors to be substituted for a capacitor or combination of capacitors of a certain characteristic.

Disclosure of Invention

1. Technical problem to be solved by the invention

The invention aims to solve the technical problems, and can quickly find out specific combinations of impedance parameters closest to a specific capacitor or a capacitor combination in a specific capacitor set by setting the limiting condition of the capacitor, thereby greatly improving the design efficiency, providing reference for the design and having extremely high practical value.

2. Technical proposal

In order to achieve the above purpose, the technical scheme provided by the invention is as follows:

a method of finding an optimal surrogate target capacitance in a given set of capacitances, comprising the steps of:

s1, selecting a target capacitor combination;

step S2: calculating the parallel impedance of the target capacitance combination:

step S3: selecting a substitute capacitor combination;

step S4: setting a combination condition:

step S5: generating a combination condition candidate combination:

step S6: calculating a parallel impedance curve for each candidate combination:

step S7, comparing with a target impedance curve:

step S8, sorting all the combinations meeting the conditions according to the difference value, and finding an alternative combination scheme:

and S9, generating a curve comparison graph according to the selection.

Preferably, in the step S1, the target capacitance combination may be one or more, and the parallel impedance of the multiple combinations is taken as the final target impedance.

Preferably, the replacing capacitor in step S2 is selected from a capacitor bank to use the candidate capacitors to form a new capacitor combination to replace the target capacitor.

3. Advantageous effects

Compared with the prior art, the technical scheme provided by the invention at least comprises the following beneficial effects:

the invention can quickly find out the specific combination of impedance parameters closest to a specific capacitor or combination of capacitors in a specific capacitor set by setting the limiting condition of the capacitor.

Drawings

FIG. 1 is a schematic flow chart of the present invention.

Detailed Description

In order that the invention may be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which, however, the invention may be embodied in many different forms and are not limited to the embodiments described herein, but are instead provided for the purpose of providing a more thorough and complete disclosure of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention; the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, a method for quickly finding an optimal alternative to a target capacitance in a given set of capacitances is implemented, comprising the steps of:

step S1, selecting a target capacitor combination

The target capacitance combination may be one or more, and the parallel impedance of the plurality is taken as the final target impedance.

Step S2, calculating the parallel impedance of the target capacitor combination

And calculating an impedance curve of the target capacitance combination according to the parallel impedance calculation method.

Step S3, selecting a substitute capacitor combination

The substitute capacitor is selected from a capacitor bank, and the candidate capacitors are used to form a new capacitor combination to replace the target capacitor.

Step S4, setting up combination conditions

Each capacitor within the substitute capacitor combination may be set to meet the condition, such as the number of capacitors a being greater than a certain value or less than a certain value. And the final total capacitance may also be limited, for example, the total capacitance is less than 10.

And S5, generating a combination condition candidate combination.

And (3) sorting and combining the combinations according to the set candidate conditions, and screening out the combinations meeting the conditions in 4) to form candidate combinations.

Step S6, calculating the parallel impedance curve of each candidate combination

The parallel impedance is calculated for each combination that occurs.

Step S7, comparing with the target impedance curve

The impedance curve of each candidate combination is compared with the target impedance curve, so that the impedance curve is ensured to fall below the target impedance curve, the impedance curve is discarded if the impedance curve is not in accordance with the condition, and the difference value is accumulated if the impedance curve is in accordance with the condition.

And S8, sorting all the combinations meeting the conditions according to the difference value, and finding out an alternative combination scheme.

Step S9, generating a curve comparison graph according to the selection

And when a certain candidate combination is selected, displaying the graph of the candidate combination and the target curve in real time, and supporting simultaneous display of a plurality of curves to check the coincidence degree of the curves.

Description of specific algorithm:

the conditions are known: the frequency range, the target capacitance list (and Y parameter information of each capacitor in the frequency range), the candidate capacitance list (and Y parameter information of each capacitor in the frequency range), the allowable number of a certain capacitor in the candidate capacitance list is limited, and the total number is limited by a specific algorithm:

1. assuming that the number of candidate capacitor combination selections is limited to [ <2, =2, <5], the total number is less than 6

Any combination of candidate capacitors is obtained through DFS recursive algorithm enumeration

2. Then, all combinations of [ <2, =2, <5] are screened according to the conditions of less than or equal to sum and the like, and those combinations which finally meet the conditions are obtained.

3. Traversing these combinations meeting basic constraints, for each combination, for example, the combination meeting the conditions is [1,2,3], we need to find a combination with parallel impedance smaller than the target parallel impedance according to the requirement, because the Y parameter is the inverse of the Z impedance parameter, and it is easy to know according to the parallel impedance formula:

|k1*Ya+k2*Yb+....|>＝|Ytarget|

the formula is:

|1*Ya+3*Yb+3*Yc|>＝|Ytarget|

and (3) performing traversal comparison on all Y parameters, if the Y parameters are not matched, exiting, and continuing to perform comparison on the next combination, wherein the matched combination is added into a list, and the sum of differences of |1×ya+3×Yb+3×Yc| - |Ytarget| is accumulated in the comparison process

4. And (3) carrying out difference value sequencing on all the combinations meeting the conditions to obtain the best candidate combination in all the combinations.

The foregoing examples merely illustrate certain embodiments of the invention and are described in more detail and are not to be construed as limiting the scope of the invention; it should be noted that it is possible for a person skilled in the art to make several variants and modifications without departing from the concept of the invention, all of which fall within the scope of protection of the invention; accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A method of finding an optimal surrogate target capacitance in a given set of capacitances, comprising the steps of:

step S1: selecting a target capacitance combination;

step S2: calculating the parallel impedance of the target capacitor combination;

step S3: selecting a substitute capacitor combination, wherein the substitute capacitor is selected from a capacitor bank, and the candidate capacitors are used for forming a new capacitor combination to substitute a target capacitor;

step S4: setting a combination condition;

step S5: generating a combination condition candidate combination;

step S6: calculating a parallel impedance curve of each candidate combination;

step S7: comparing with a target impedance curve;

step S8: sorting all the combinations meeting the conditions according to the difference value, and finding out an alternative combination scheme;

step S9: generating a curve comparison graph according to the selection; and the following steps are performed according to known conditions,

the known conditions are: the frequency range, the target capacitance list and Y parameter information of each target capacitance in the frequency range, the candidate capacitance list and Y parameter information of each candidate capacitance in the frequency range, the allowable number of a certain capacitance in the candidate capacitance list is limited, and the total capacitance number is limited;

enumeration is carried out through a DFS recursive algorithm to obtain any combination of candidate capacitors;

screening all the obtained candidate capacitor combinations according to the allowable number limit and the total capacitor number limit of a certain capacitor in the candidate capacitor list to obtain the combinations which finally meet the conditions;

traversing the combinations meeting the limiting conditions, finding out a combination with parallel impedance smaller than that of the target capacitor combination for each combination, and obtaining a difference value, wherein the difference value is the difference between the sum of Y parameters of all capacitors in the combination in the frequency band and the sum of Y parameters of the capacitors corresponding to the target capacitor combination in the frequency band, and the Y parameters are the inverse of the Z impedance parameters.

2. The method of claim 1, wherein in step S1, the target capacitance combination may be one or more, and the parallel impedance is taken as the final target impedance.