CN112231866A

CN112231866A - Capacitance selection method, device, server and medium for power distribution network

Info

Publication number: CN112231866A
Application number: CN201910582701.3A
Authority: CN
Inventors: 蔡步森; 陈欢洋
Original assignee: Zhejiang Uniview Technologies Co Ltd
Current assignee: Zhejiang Uniview Technologies Co Ltd
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2021-01-15
Anticipated expiration: 2039-06-28
Also published as: CN112231866B

Abstract

The embodiment of the invention discloses a method, a device, a server and a medium for selecting a capacitor of a power distribution network, wherein the method comprises the following steps: determining preset parameters including target impedance, lowest cut-off frequency and highest cut-off frequency of a power distribution network; selecting a plurality of different types of decoupling capacitors according to the lowest cut-off frequency and the highest cut-off frequency; determining the capacitance action frequency band of each type of decoupling capacitor according to the working frequency band of each type of decoupling capacitor; determining the number of each type of decoupling capacitors in a plurality of different types of decoupling capacitors according to the target impedance, and determining an actual impedance curve of the power distribution network; determining an anti-resonance point within the range of the lowest cut-off frequency and the highest cut-off frequency; judging whether the actual impedance of the anti-resonance point is greater than the target impedance; if so, increasing the quantity of decoupling capacitors of the capacitive action frequency band where the anti-resonance point is located. The technical scheme provided by the embodiment of the invention can quickly determine the number of the decoupling capacitors, thereby improving the selection efficiency of the decoupling capacitors and shortening the time consumption of the decoupling capacitors.

Description

Capacitance selection method, device, server and medium for power distribution network

Technical Field

The embodiment of the invention relates to the technical field of circuit design, in particular to a method, a device, a server and a medium for selecting a capacitor of a power distribution network.

Background

With the increasing application of high-speed signals (> 10G), electronic systems are developing in the direction of high speed, high density, low voltage and large current, and the problem of power integrity is increasingly highlighted. The fluctuation of the power supply voltage can affect the normal operation of the chip, and the whole system can be hung up in severe cases. Therefore, in the design process of a Power Delivery Network (PDN) system, not only a pure power supply is required to be provided for the circuit, but also a low noise loop is provided for high-speed signals, noise isolation between multiple chips is required, and electromagnetic integrity is ensured. Therefore, the rationality of the PDN system is particularly important.

In general, the design of a PDN system, generally from the frequency domain, uses a target impedance as a reference standard, and adds different kinds of decoupling capacitors to make the impedance of the PDN system lower than the target impedance in a target frequency range, which is at the core of the process to determine the kind and amount of decoupling capacitors. However, in the existing design scheme of the PDN system, the selection process of the decoupling capacitors is inefficient, takes a long time, and an optimal combination scheme of the decoupling capacitors cannot be obtained.

Disclosure of Invention

Embodiments of the present invention provide a method, an apparatus, a server, and a medium for selecting a capacitor of a power distribution network, so as to improve the selection effectiveness of a decoupling capacitor, shorten the time used in the process, and facilitate obtaining an optimal combination scheme of the decoupling capacitor.

In a first aspect, an embodiment of the present invention provides a method for selecting a capacitor of a power distribution network, where the method includes:

determining preset parameters; the preset parameters comprise a target impedance, a lowest cut-off frequency and a highest cut-off frequency of the power distribution network;

selecting a plurality of different classes of decoupling capacitors according to the lowest cut-off frequency and the highest cut-off frequency; wherein the working frequency band of the plurality of different types of decoupling capacitors covers the frequency band range between the lowest cut-off frequency and the highest cut-off frequency;

determining the capacitance action frequency band of each type of decoupling capacitor according to the working frequency band of each type of decoupling capacitor; the capacitance action frequency bands of the decoupling capacitors of different types do not overlap with each other, and the capacitance action frequency bands of the decoupling capacitors of different types cover the frequency band range between the lowest cut-off frequency and the highest cut-off frequency;

determining the number of each type of decoupling capacitor in the plurality of different types of decoupling capacitors according to the target impedance, and determining an actual impedance curve of the power distribution network;

determining an anti-resonance point within the range of the lowest cut-off frequency and the highest cut-off frequency;

judging whether the actual impedance of the anti-resonance point is greater than the target impedance or not;

and if so, increasing the quantity of the decoupling capacitors in the capacitive action frequency band of the anti-resonance point.

In a second aspect, an embodiment of the present invention further provides a capacitance selection apparatus for a power distribution network, where the apparatus includes:

the device comprises a preset parameter determining unit, a parameter setting unit and a parameter setting unit, wherein the preset parameter determining unit is used for determining preset parameters; the preset parameters comprise a target impedance, a lowest cut-off frequency and a highest cut-off frequency of the power distribution network;

a decoupling capacitor selection unit for selecting a plurality of different types of decoupling capacitors according to the lowest cut-off frequency and the highest cut-off frequency; wherein the working frequency band of the plurality of different types of decoupling capacitors covers the frequency band range between the lowest cut-off frequency and the highest cut-off frequency;

the action frequency band determining unit is used for determining the capacitance action frequency band of each type of decoupling capacitor according to the working frequency band of each type of decoupling capacitor;

a capacitance quantity determination unit for determining the quantity of each of the plurality of different classes of decoupling capacitors according to the target impedance and determining an actual impedance curve of the power distribution network;

the anti-resonance point determining unit is used for determining an anti-resonance point in the range of the lowest cut-off frequency and the highest cut-off frequency;

the impedance magnitude judging unit is used for judging whether the actual impedance of each anti-resonance point is greater than the target impedance or not;

and the capacitance number increasing unit is used for increasing the decoupling capacitance of the capacitance action frequency band where the anti-resonance point is located when the judgment result is yes.

In a third aspect, an embodiment of the present invention further provides a server, including:

one or more processors;

a storage device for storing one or more programs,

when executed by the one or more processors, cause the one or more processors to implement a method of capacitance selection for a power distribution network according to any embodiment of the invention.

In a fourth aspect, the embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the capacitance selection method for a power distribution network according to any embodiment of the present invention.

According to the selection method of the power distribution network provided by the embodiment of the invention, the capacitance action frequency band of each type of decoupling capacitor is determined according to the working frequency band of each type of decoupling capacitor; and then, after determining the quantity of the decoupling capacitors of various types to obtain an actual impedance curve of the power distribution network, searching for an anti-resonance point, determining a capacitance action frequency band where the anti-resonance point is located when the actual impedance of the anti-resonance point is greater than the target impedance, and increasing the quantity of the decoupling capacitors of the capacitance action frequency band. Therefore, the actual impedance of the anti-resonance point can be effectively reduced, so that the number of the decoupling capacitors can be determined rapidly, the selection efficiency of the decoupling capacitors can be improved, the time consumption of the process can be shortened, and the optimal combination scheme of the decoupling capacitors can be obtained. The problems that in the prior art, the time consumption is long due to the fact that the efficiency of the selection process of the decoupling capacitor is low, and the optimal combination scheme of the decoupling capacitor cannot be obtained are solved.

Drawings

FIG. 1 is a schematic diagram of an equivalent model of a decoupling capacitor according to an embodiment of the present invention

Fig. 2 is an impedance curve of a decoupling capacitor provided by an embodiment of the present invention;

fig. 3 is an impedance curve of the same type of decoupling capacitor in parallel according to an embodiment of the present invention;

FIG. 4 is an impedance curve of a parallel connection of decoupling capacitors of different types provided by an embodiment of the present invention;

FIG. 5 is an impedance curve of a power distribution network including different types and numbers of decoupling capacitors connected in parallel according to an embodiment of the present invention;

fig. 6 is an impedance curve of two types of decoupling capacitors provided by the embodiment of the present invention;

FIG. 7 is an impedance plot of the decoupling capacitor of FIG. 6 after application to a power distribution network;

FIG. 8 is an impedance curve of the power distribution network after adding a decoupling capacitor to the impedance curve of FIG. 7;

FIG. 9 is an impedance curve of the power distribution network after continuing to add a like decoupling capacitor to the power distribution network of FIG. 8;

FIG. 10 is an impedance curve of the power distribution network after adding a decoupling capacitor in the capacitive action frequency band of the anti-resonance point based on FIG. 7;

fig. 11 is a schematic diagram illustrating a determination method of a capacitive action frequency band of a decoupling capacitor according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of a capacitive test fixture plate according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of a capacitance testing apparatus according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of a capacitive test interface according to an embodiment of the present invention;

FIG. 15 is a schematic diagram of a system model of a power distribution network according to an embodiment of the present invention;

fig. 16 is a flowchart of a capacitance selection method of a power distribution network according to an embodiment of the present invention;

FIG. 17 is a detailed flowchart of S110 in FIG. 16;

FIG. 18 is a detailed flow chart of S130 in FIG. 16;

FIG. 19 is a detailed flow chart of S140 in FIG. 16;

FIG. 20 is a flow chart of another method for selecting capacitance of a power distribution network according to an embodiment of the invention;

fig. 21 is a flowchart of a capacitance selection method for a power distribution network according to another embodiment of the invention;

fig. 22 is a schematic structural diagram of a capacitance selection device of a power distribution network according to an embodiment of the present invention;

fig. 23 is a schematic structural diagram of a server according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Examples

Hereinafter, first, the concepts and models involved in the embodiments of the present invention will be described with reference to fig. 1 to 15; meanwhile, by comparing with the prior art, the beneficial effects of the method for selecting the capacitance (i.e. the decoupling capacitance) of the power distribution network provided by the embodiment of the present invention are exemplified.

Referring to fig. 1, fig. 1 shows a first order equivalent model of a decoupling capacitance, which may also be referred to as an RLC model of the decoupling capacitance. Where ESR represents the equivalent series resistance of the capacitor, ESL represents the equivalent series inductance of the capacitor, C represents the equivalent capacitance of the capacitor, and Lmnt is the mounting inductance (including pad-to-via trace inductance and via-induced inductance).

On this basis, the actual impedance curve of the decoupling capacitor is shown as L004 in fig. 2. With continued reference to FIG. 2, the horizontal axis X represents frequency in Hertz (Hz) and the vertical axis Y represents impedance in Ohms (Ohms, i.e., Ω); the coordinate meanings of the impedance graphs in the following are the same, and can be understood by referring to the coordinate meanings, and the details are not repeated. L001 represents the trend of the equivalent capacitance C of the actual capacitor with frequency, L002 represents the trend of the equivalent inductance ESL of the actual capacitor with frequency, and L003 represents the equivalent series resistance ESR of the actual capacitor. The lowest point of L004 corresponds to the Self-resonant frequency (SRF) of the capacitor, and the impedance at this point is equal to the equivalent series resistance ESR of the capacitor.

Fig. 2 shows the impedance curve of a single decoupling capacitor, and on this basis fig. 3 shows the impedance curve of the same type of decoupling capacitor connected in parallel. Referring to fig. 3, L011 represents an impedance curve of one capacitor, L012 represents an impedance curve of two capacitors connected in parallel, L013 represents an impedance curve of three capacitors connected in parallel, L014 represents an impedance curve of four capacitors connected in parallel, and L015 represents an impedance curve of five capacitors connected in parallel. As can be seen from a comparison of the five impedance curves in fig. 3, with the addition of a decoupling capacitor, the impedance at all frequencies decreases. Therefore, the shunt capacitance can reduce the power supply impedance, which is the basic principle of impedance design of the PDN network.

Referring to fig. 4, fig. 4 shows the impedance curves after connecting two different types of capacitors in parallel. "different classes", i.e. "different types", are to be understood as different SRFs. In fig. 4, L021 represents the equivalent capacitance of the first type capacitor, and L022 represents the equivalent capacitance of the second type capacitor; the equivalent series inductance of the first type of capacitor and the second type of capacitor is represented by L023, and L024 represents an actual impedance curve formed by connecting the first type of capacitor and the second type of capacitor in parallel. Wherein, two minimum value points on L024 are self-resonance points of two capacitors respectively. In addition, there is a Parallel resonance peak, shown as D025, between the two self-resonance points, which is the Parallel resonance frequency of the two capacitors (PRF). When the PDN system is designed, the impedance corresponding to the PRF point needs to be suppressed, so that the actual impedance of the point is smaller than the target impedance.

On the basis of fig. 3 and 4, fig. 5 shows the impedance curves applied to the power distribution network after parallel connection of different classes and different numbers of decoupling capacitors. Referring to fig. 5, L030 represents a target impedance curve, and L031, L032, L033, L034, and L035 represent actual impedance curves of different types of capacitors and the amount of capacitors applied to the PDN system, respectively. Where the actual impedance curve includes several valleys (i.e., minima), the PDN system may correspondingly include several types of capacitances. The PDN system design is also designed to show that the actual impedance corresponding to each anti-resonance point is smaller than the target impedance.

On the basis, in the design process of the PDN system, the actual use situation needs to be considered. For example, the processing efficiency and material management of the production link are affected by excessive selection of the capacitor types; for another example, the number of capacitors is too large, which increases the hardware cost, and increases the layout space and the wiring difficulty of the Printed Circuit Board (PCB). Therefore, in PDN system design, an appropriate type and amount of decoupling capacitors are required to construct a reasonable PDN system.

The main principles of PDN system design are: firstly, calculating target impedance of a corresponding frequency band according to power supply voltage, maximum current and load noise tolerance; secondly, selecting proper types and quantities of capacitors according to the target impedance, so that the impedance of the PDN system is smaller than the target impedance in a corresponding frequency band. The basis for the selection of the capacitance is: the smaller capacitive impedance enables a better reduction of the PDN impedance, resulting in a better improvement of the PDN impedance.

The PDN design method can comprise a table look-up method, specifically, according to the target impedance, the working frequency band and the existing capacitor bank model, the type and the quantity of the capacitors are manually selected by using simulation software, so that the impedance of the PDN system meets the requirement of the target impedance in the corresponding frequency band, and the obtained type and quantity of the capacitors are stored in a database. And selecting a group of proper capacitance types and quantity from the database according to the target impedance and the working frequency band during PDN system design. However, the early-stage database entry workload of the method is large, the determined capacitance types and the determined capacitance numbers are selected through manual judgment and may not be the optimal scheme; when the capacitance model changes, the database needs to be updated from the new one.

The optimization is carried out on the basis of a table look-up method, and the selection of the capacitance can also be realized through programming. Specifically, the self-resonant frequency of the capacitor is used as a capacitor selection basis to obtain a decoupling capacitor required by the PDN system, so that the actual impedance of the PDN system meets the system requirements. For example, fig. 6-9 illustrate the selection process by taking two capacitors as an example. On this basis, fig. 10 shows an impedance curve of the PDN system obtained by applying the capacitance selection method provided by the embodiment of the present invention.

Referring to FIG. 6, L051 represents the impedance curve of 0402 package 10uF capacitor with self-resonance point at 1.2MHz, and L052 represents the impedance curve of 0402 package 1uF capacitor with self-resonance point at 4.0 MHz; the frequency corresponding to the intersection of L051 and L052 is 3.0MHz, which is related to the definition of the frequency band of the capacitor, and is explained in detail later. The frequency band from the resonance point of the 10uF capacitor to the intersection point of the two curves is 1.2MHz-3.0MHz, the frequency range is 1.8MHz, and the impedance of the 10uF capacitor in the frequency band is less than that of the 1uF capacitor; the frequency band from the resonance point of the 1uF capacitor to the intersection point of the two curves is 3.0MHz-4.0MHz, the frequency range is 1.0MHz, and the impedance of the 1uF capacitor in the frequency band is less than 10uF capacitor. It can be seen that within the self-resonance frequency band of 1.2MHz-4.0MHz of the two capacitors, the frequency range of 10uF capacitance action is larger than that of 1uF capacitance.

Illustratively, for a PDN system, the actual impedance is greater than the target impedance at a location corresponding to an antiresonance point, as shown in fig. 7. Where L060 represents a target impedance curve and L061 represents an actual impedance curve, at the location D061, the frequency is 2.801MHz, the target impedance is 0.1 Ω and the actual impedance is 0.187 Ω, i.e., the actual impedance is greater than the target impedance, thus a decoupling capacitance needs to be added to reduce the impedance value at that location.

As can be seen from FIG. 6, the self-resonant point frequency of the 1uF capacitor in 0402 package is 4.0MHz, and the self-resonant point frequency of the 10uF capacitor in 0402 package is 1.2 MHz. Thus, the self-resonance point of the 1uF capacitance is closer to the anti-resonance point. Then, a 1uF capacitor is connected in parallel in the power network of the PDN system, and its impedance curve is shown as L062 in fig. 8, at this time, the impedance at the position D061 decreases, which is shown by D062 in fig. 8, where the actual impedance is 0.039 Ω and is smaller than the target impedance, but there is still a position in the vicinity where the actual impedance is larger than the target impedance.

On the basis of fig. 7, one 1uF capacitor is changed into two 1uF capacitors, and the impedance curve is shown as L063 in fig. 9, where the impedance at the position of D061 is reduced, which is shown by D063 in fig. 9, the actual impedance at the position is 0.020 Ω and is smaller than the target impedance, and there is no position where the actual impedance is larger than the target impedance in the vicinity thereof, that is, the actual impedance at each frequency point is suppressed to be lower than the target impedance in the frequency band range shown in fig. 9.

In the capacitance selection process shown in fig. 7 to 9, only the self-resonance point frequency of the decoupling capacitor is used as the basis for selecting the capacitance. Specifically, near a frequency point D061 where the actual impedance is greater than the target impedance, a capacitance closest to the frequency of the point from the resonance point frequency is selected, and the impedance of the PDN system is reduced by increasing the number of the capacitances. However, the capacitors with different capacitance values, the equivalent series resistance ESR and the equivalent series inductance ESL are not the same, and under the influence of the two parameters, the range of the frequency band of the impedance curve (i.e., the frequency band of the capacitor) and the effect of the impedance curve corresponding to the decoupling capacitor are not the same. In a frequency band range where the actual impedance of the PDN system is greater than the target impedance, a capacitance that is not closest to the self-resonance point frequency can better improve the impedance of the PDN system. The capacitance selecting the capacitance action frequency band of the PDN system can effectively reduce the impedance of the PDN system, so that the type and the number of decoupling capacitors can be quickly selected, the capacitance selection efficiency of the PDN system is improved, the time used in the selection process is shortened, and the optimal combination scheme of the decoupling capacitors cannot be obtained.

Illustratively, fig. 10 is an impedance curve of the PDN system obtained after selecting a decoupling capacitor based on the concept of a capacitive frequency band. Referring to fig. 6, the intersection point of the two curves is used as a boundary, FD051 represents the capacitance action frequency band of 10uF capacitance, and FD052 represents the capacitance action frequency band of 1uF capacitance. Referring to fig. 7 again, the frequency at the position corresponding to D061 is 2.8Hz, and falls within the range of the capacitance operating frequency band of the 10uF capacitor. On the basis, a 10uF capacitor is added to fig. 7, and its impedance curve is shown as L064 in fig. 10, at this time, the impedance at the position of D061 is lowered, which is shown by D064 in fig. 10, where the actual impedance is 0.024uF and is smaller than the target impedance, and there is no position in the vicinity where the actual impedance is larger than the target impedance, that is, the actual impedance of each frequency point is suppressed below the target impedance in the frequency band range shown in fig. 10.

In conjunction with fig. 7-10, on the premise that the same number of decoupling capacitors is selected, the 10uF capacitor is selected to suppress the impedance of the anti-resonance point and the impedance of most frequency points in the operating frequency range more significantly than the 1uF capacitor. Therefore, the decoupling capacitor of the capacitance action frequency band where the anti-resonance point is located is selected, so that the efficiency of capacitor selection is improved, and the optimal combination scheme of the decoupling capacitor is obtained.

Definition of capacitive action frequency band: and sequencing the self-resonance point frequencies of the decoupling capacitors from low to high, searching intersection point frequencies of adjacent capacitance impedance curves, wherein a frequency band between two intersection point frequencies is a capacitance action frequency band of the decoupling capacitor.

The definition of the capacitive action frequency band is exemplarily described below with reference to fig. 11.

Referring to fig. 11, a set of capacitors is selected, the set of capacitors is composed of a capacitor 1, a capacitor 2 and a capacitor 3, impedance curves of the capacitors are respectively represented by L055, L056 and L057, and the lowest point of each impedance curve is the self-resonance point of the decoupling capacitor. The decoupling capacitors corresponding to the self-resonance points from low to high are respectively a capacitor 1, a capacitor 2 and a capacitor 3. The impedance curves of the decoupling capacitors at adjacent self-resonance points have an intersection point, for example, the impedance curves of the capacitors 1 are adjacent to the self-resonance point of the capacitor 2, the impedance curves of the capacitors have an intersection point a, the impedance curves of the capacitors 2 are adjacent to the self-resonance point of the capacitor 3, and the impedance curves of the capacitors have an intersection point B. On this basis, the capacitance of the capacitor 2 acts in a frequency band (i.e., a frequency range) between points a and B. For a capacitor with the lowest self-resonant frequency, such as the capacitor 1, the frequency band of the capacitor is from the lowest cut-off frequency to the frequency of the point A; for the capacitor with the highest self-resonant frequency, such as the capacitor 3, the frequency band of the capacitance action is from the point B frequency to the highest cut-off frequency. The "lowest cut-off frequency" and the "highest cut-off frequency" in this paragraph can be understood as the lowest cut-off frequency and the highest cut-off frequency of the operating frequency band of the PDN system.

It should be noted that fig. 11 only exemplarily takes 3 capacitors as an example, and illustrates the frequency bands of the capacitors. In other embodiments, the number of decoupling capacitors may be set according to requirements of a capacitance selection method of the power distribution network, which is not limited in the embodiment of the present invention.

Optionally, the decoupling capacitor may be tested by a capacitor testing device to obtain an RLC model with accurate decoupling capacitor, so that the selection of appropriate capacitor types and numbers according to the impedance characteristics of the decoupling capacitor is facilitated, the optimization of the capacitor selection process of the PDN system is facilitated, and the design difficulty of the PDN system is simplified.

Illustratively, referring to fig. 12, the capacitive test fixture plate 09 may include: two coaxial connectors SMA092 and one annular transmission line 091; wherein the capacitor to be tested 090 is fixed to the capacitance test fixture plate 09 by means of soldering.

For example, the decoupling capacitor parameter test connection is shown in fig. 13, the device for testing the capacitor is a network analyzer 082, the capacitor test fixture plate 09 is connected to the network analyzer 082 through the test cable 081, and then the network analyzer 082 scans and obtains an impedance curve of the decoupling capacitor in the target frequency band. Illustratively, the target frequency band may range from 100kHz to 500 MHz. Then, the impedance curve obtained by the network analyzer 082 is fitted through simulation software, so that the parameters of the RLC model of the decoupling capacitor can be accurately obtained.

Illustratively, referring to fig. 14, fig. 14 shows the results of a test and fit of a decoupling capacitor. Wherein, L041 represents an impedance curve of the decoupling capacitor obtained by the network analyzer, L042 is an impedance curve drawn by the RLC parameter of the decoupling capacitor, and the fitting degree of the quantity curve is very high, which indicates that the RLC parameter precision of the decoupling capacitor obtained by the network analyzer is also very high.

It should be noted that fig. 14 only illustrates the parameters of an RLC model of decoupling capacitors. In other embodiments, values of ESR, ESL, and ESC displayed by the test interface may be different according to a type of the selected decoupling capacitor, which is not limited in the embodiments of the present invention.

Optionally, before the capacitance selection, a PDN system model may also need to be determined.

A model diagram of the PDN system will be exemplarily illustrated in conjunction with fig. 15 to illustrate the connection relationship between the decoupling capacitor and other components in the PDN system.

Illustratively, referring to fig. 15, power distribution network system model 07 may include: a power module 071, a decoupling capacitor module 072, a power plane 073, a diffusion impedance 074, a via impedance 075, a capacitance mounting inductance module 076, and a load 077; a first end of a power supply module 071 is electrically connected to a first end of a decoupling capacitor module 072, a first end of a power plane 073 and a first end of a load 077, a second end of the power supply module 071 is electrically connected to a second end of a capacitor-mounted inductor module 076, a second end of the power plane 073 and a first end of a diffusion impedance 074, and a second end of the diffusion impedance 074 is electrically connected to a second end of the load 077 through a via impedance 075; decoupling capacitor module 072 comprises a plurality of parallel-connected, heterogeneous decoupling capacitors, and capacitively-mounted inductor module 076 comprises a plurality of capacitively-mounted inductors, each of which is electrically connected to the first terminal of power module 071 via a capacitively-mounted inductor.

The corresponding parameters for each component in the PDN system model 07 need to be obtained before the capacitance selection is performed, as described in detail in the method section below.

Based on the above description, the following describes an exemplary method for selecting a capacitance of a power distribution network according to an embodiment of the present invention with reference to fig. 16 to 21.

Fig. 16 is a flowchart illustrating a method for selecting a capacitor of a power distribution network according to an embodiment of the present invention. Referring to fig. 16, the method includes:

and S110, determining preset parameters.

The preset parameters comprise target impedance, lowest cut-off frequency and highest cut-off frequency of the power distribution network. The frequency range between the lowest cut-off frequency and the highest cut-off frequency is the working frequency band of the power distribution network, and the target impedance is the reference basis for selecting the type and the number of the capacitors in the following. This step provides for the subsequent selection of the capacitor. In this embodiment, the preset parameters may be manually input by a user or automatically obtained by software, which is not limited in the embodiment of the present invention.

And S120, selecting a plurality of different types of decoupling capacitors according to the lowest cut-off frequency and the highest cut-off frequency.

The working frequency band of the plurality of different types of decoupling capacitors covers the frequency band range between the lowest cut-off frequency and the highest cut-off frequency. Specifically, each type of decoupling capacitor can cover a frequency range in the working frequency band of the power distribution network, and the working frequency bands of a plurality of different types of decoupling capacitors are overlapped, so that the complete working frequency band of the power distribution network can be covered. Therefore, in the power distribution network, no matter where the frequency point corresponding to the position where the actual impedance is greater than the target impedance is located in the working frequency band, the actual impedance of the PDN system at the position can be reduced by increasing the number of decoupling capacitors. In this embodiment, the selection of the decoupling capacitors may be manually selected by a user, or may be automatically screened by software in a plurality of different types or different groups of decoupling capacitors, which is not limited in the embodiment of the present invention.

And S130, determining the capacitance action frequency band of each type of decoupling capacitor according to the working frequency band of each type of decoupling capacitor.

The capacitance action frequency bands of each type of decoupling capacitor are not overlapped, and the capacitance action frequency bands of a plurality of different types of decoupling capacitors cover the frequency band range between the lowest cut-off frequency and the highest cut-off frequency.

For example, this step can be performed with reference to the explanation of fig. 11 above, and is not described here again.

S140, determining the number of each type of decoupling capacitors in the multiple different types of decoupling capacitors according to the target impedance, and determining an actual impedance curve of the power distribution network.

Based on the selection of the kind of the decoupling capacitor in S120 and the determination of the capacitance action frequency band of the decoupling capacitor in S130, in this step, the actual impedance of the decoupling capacitor of each kind can be determined according to the capacitance value and the number of the self-resonance points of the decoupling capacitors of each kind. Specifically, by setting the actual impedance to be less than or equal to the target impedance, the number of decoupling capacitors of each type can be determined by rounding up.

Illustratively, when the capacitive action frequency band of a certain type of decoupling capacitor does not overlap with the working frequency band of the power distribution network, the decoupling capacitor of the type does not contribute to reducing the actual impedance of the power distribution network, and the number of the decoupling capacitors can be 0.

When a plurality of selected different types of capacitors are connected in parallel and applied to the power distribution network, the actual impedance curve of the power distribution network can be obtained.

And S150, determining an anti-resonance point in the range of the lowest cut-off frequency and the highest cut-off frequency.

In S140, the actual impedance at the self-resonant point frequency position of each decoupling capacitor is only ensured to be less than or equal to the target impedance. As can be seen from fig. 4, the actual impedance at the anti-resonance point position between two adjacent self-resonance point frequencies may be larger than the target impedance. Therefore, the anti-resonance points are determined to prepare for comparison between the actual impedance and the target impedance in the next step. In this embodiment, each anti-resonance point can be correspondingly determined by determining the position of the maximum value in the actual impedance curve of the power distribution network.

And S160, judging whether the actual impedance of the anti-resonance point is greater than the target impedance.

If the actual impedance corresponding to the anti-resonance point is greater than the target impedance, the number of decoupling capacitors needs to be optimized. That is, if the determination result in this step is yes, S170 is executed.

And S170, increasing the quantity of decoupling capacitors of the capacitance action frequency band where the anti-resonance points are located.

The actual impedance corresponding to each frequency point in the working frequency band of the power distribution network can be effectively reduced through the steps, so that the actual impedance of the anti-resonance point and the actual impedance in the range near the anti-resonance point can be effectively inhibited. The method is favorable for improving the selection efficiency of the decoupling capacitor, shortening the consumed time and obtaining the optimal combination scheme of the decoupling capacitor.

After S170, the process returns to S160, and the process of selecting the decoupling capacitor is ended until the actual impedance of each anti-resonance point is smaller than the target impedance.

Optionally, before S110, the method may further include: a system model of the power distribution network is determined.

For example, a system model of a power distribution network may be as shown in fig. 15.

On this basis, referring to fig. 17, S110 may include:

and S211, determining initial preset parameters.

The initial preset parameters are parameters representing the characteristics of all components of the power distribution network system model; it can also be understood as a parameter that has to be set in order for the power distribution network system model to work. With reference to fig. 15, the initial preset parameters may include a voltage V of the load 077, a maximum working current Imax, a ripple coefficient AR allowed by a working voltage, a ratio TP of a transient current to Imax, a type of the power module 071, values of the capacitor mounting inductors in the capacitor mounting inductor module 076, a size of the power plane 073, a value of the diffusion impedance 074, and a value of the via impedance 075; the PDN impedance cutoff frequency may also be included.

In this embodiment, the initial preset parameters may be set through a human-machine interface.

In this embodiment, the value of the voltage ripple coefficient AR may be 1% to 5%, and the value of the ratio TP of the transient current to Imax may be 30% to 50%; power modules, which may also be referred to as Voltage Regulator Modules (VRMs), may be classified as either switching power supplies or linear power supplies (corresponding to different rvrms and Lvrm); the capacitor mounting inductors (Lmntl, Lmnt2, … … and Lmntn) have different sizes according to the distribution of decoupling capacitors or the form of output (fanout), and the values can be about 0.5nH-2 nH; the power plane can be divided into three conditions of large, medium and small according to the area, and equivalent parameters Rp and Cp can be obtained in advance through simulation software; the values of the PDN impedance cutoff frequency can be 20MHz and 100MHz, and the value of the diffusion impedance 074 is generally small and can be ignored in this embodiment.

S212, determining preset parameters according to the initial preset parameters.

The method mainly comprises the steps of determining target impedance of the power distribution network and an operating frequency band.

Optionally, S212 may include: calculating a target impedance from a target impedance calculation formula, and calculating a class of a power supply moduleThe sizes of the model and power planes determine the lowest cut-off frequency and the highest cut-off frequency; wherein, the target impedance calculation formula is as follows:

in the impedance calculation formula, V is the voltage of a load chip, AR is a ripple factor allowed by the working voltage, Imax is the maximum working current, TP is the proportion of the transient current to Imax, and Z is_TIs the target impedance. Since each parameter on the right side of the equal sign in the calculation formula is determined in S211, the target impedance of the power distribution network can be determined by calculation using the formula.

For example, in a 1-volt power plane (V ═ 1V), the allowable ripple factor of the operating voltage is 5%, the maximum operating current Imax is 10 amperes (Imax ═ 10A), and the ratio TP of the transient current to Imax is 50%; calculable determination of the target impedance Z_TIs 10 milliohm (Z)_T10m Ω). This is merely an exemplary illustration, and in other embodiments, values of the preset parameters may also be set according to actual requirements of a capacitance selection method of the power distribution network, which is not limited in the embodiment of the present invention.

The type of the power module determines the frequency range of the PDN system that can provide power, and the size of the power plane includes the operating frequency range of the load, which is generally within the frequency range of the PDN system that can provide power. Thus, the operating frequency band of the PDN system may be determined by the type of power module and the size of the power plane.

Alternatively, the process of selecting the type of decoupling capacitor, i.e., S120 in fig. 1, may include: selecting a decoupling capacitor group from a preset capacitor bank; the set of decoupling capacitors includes a plurality of different classes of decoupling capacitors.

The preset capacitor bank may include a plurality of decoupling capacitor banks, and each decoupling capacitor bank may be applicable to PDN systems of one or more different operating frequency bands. The term "suitable" in this paragraph means that the working frequency bands of the decoupling capacitors in the decoupling capacitor bank are overlapped to cover the working frequency band of the PDN system.

On this basis, referring to fig. 18, S130 may include:

s231, sequencing the decoupling capacitors of different types in the decoupling capacitor group according to the self-resonance point frequency of the decoupling capacitors of different types from low to high.

And S232, determining the intersection point of the impedance curves of the decoupling capacitors adjacent to the self-resonance point frequency.

S233, determining the capacitance action frequency band of the first decoupling capacitor as the frequency band range between two intersection points on the impedance curve, and determining the capacitance action frequency band of the second decoupling capacitor as the frequency band range between the intersection points on the impedance curve and the boundary cut-off frequency.

Wherein, the first kind of decoupling capacitor is a decoupling capacitor whose self-resonance point frequency in the decoupling capacitor group is in a middle range, for example, the capacitor 2 corresponding to L056 in fig. 11; the second type of decoupling capacitor is the decoupling capacitor with the lowest or highest self-resonance point frequency in the decoupling capacitor bank, such as capacitor 1 and capacitor 3 corresponding to L055 and L057 in fig. 11; the boundary cutoff frequency is the lowest operating frequency of the decoupling capacitor with the lowest frequency from the resonance point, or the boundary cutoff frequency is the highest operating frequency of the decoupling capacitor with the highest frequency from the resonance point.

It should be noted that, when a decoupling capacitor bank only includes two decoupling capacitors, both the two decoupling capacitors are the second type of decoupling capacitor.

Thus, S231-S233 accomplish the division of the frequency band of the capacitive action of the decoupling capacitor.

On this basis, in order to simplify the execution complexity of the subsequent steps, after S130, the method may further include:

and removing the decoupling capacitors in the decoupling capacitor bank, wherein the capacitance action frequency band is not in the frequency band range between the lowest cut-off frequency and the highest cut-off frequency.

The term "the frequency band of capacitive action is not within the frequency band range between the lowest cut-off frequency and the highest cut-off frequency" means that the frequency band of capacitive action of the decoupling capacitor does not overlap with the operating frequency band of the PDN system, i.e. the number of the decoupling capacitors does not affect the actual impedance curve of the PDN, or the number of the decoupling capacitors has little effect on the actual impedance curve of the PDN. Thus, to improve the efficiency of capacitor selection, the decoupling capacitor can be eliminated; and only selecting the decoupling capacitor of the capacitive action frequency band in the working frequency band of the PDN system, and selecting the decoupling capacitor of which the capacitive action frequency band is overlapped with the working frequency band of the PDN system and which is near the lowest cut-off frequency and the highest cut-off frequency of the working frequency band of the PDN system.

Alternatively, referring to fig. 19, S140 may include:

s241, determining the minimum number of decoupling capacitors of each type when the impedance of the self-resonant point of each type of decoupling capacitor is smaller than the target impedance in a mode of impedance parallel connection as the number of the type of decoupling capacitors.

Therefore, on the premise of following the PDN design principle, a small number of decoupling capacitors can be adopted, so that the hardware cost is saved, and the PCB layout space and the wiring difficulty are simplified.

And S242, determining an actual impedance curve of the power distribution network according to the system model of the power distribution network and the type and the number of each type of decoupling capacitor.

Wherein, referring to fig. 15, the type and amount of each type of decoupling capacitor has been determined in the previous steps, and other parameters in the system model of the power distribution network have also been determined in the previous steps, so that the actual impedance curve of the PDN can be determined.

It should be noted that, in the impedance curve, there may be a case where the value of the actual impedance at the position of the partial anti-resonance point is greater than the target impedance, and the number of the decoupling capacitors needs to be further optimized through subsequent steps.

Optionally, after S160 in fig. 1, if the determination result is negative, it is described that the actual impedance at the position of the anti-resonance point is less than or equal to the target impedance, that is, the actual impedance at the position of the anti-resonance point meets the PDN design rule. At this time, the method may further include: and determining the quantity of the decoupling capacitors corresponding to the capacitance action frequency band where the anti-resonance point is positioned as the quantity of the decoupling capacitors.

Therefore, in the capacitance selection process, the number of the decoupling capacitors corresponding to the capacitance action frequency band where the anti-resonance point is located can be determined.

Optionally, if the number of anti-resonance points is multiple, after determining the number of decoupling capacitors corresponding to the capacitance action frequency band where each anti-resonance point is located, the method further includes further optimizing the number of decoupling capacitors, and referring to fig. 20, the method may include:

and S310, determining preset parameters.

And S320, selecting a plurality of different types of decoupling capacitors according to the lowest cut-off frequency and the highest cut-off frequency.

S330, determining the capacitance action frequency band of each type of decoupling capacitor according to the working frequency band of each type of decoupling capacitor.

S340, determining the number of each type of decoupling capacitors in a plurality of different types of decoupling capacitors according to the target impedance, and determining an actual impedance curve of the power distribution network.

And S350, determining an anti-resonance point in the range of the lowest cut-off frequency and the highest cut-off frequency.

And S360, judging whether the actual impedance of the anti-resonance point is greater than the target impedance.

And S370, if the actual impedance of each anti-resonance point is not greater than the target impedance, determining the number of the decoupling capacitors corresponding to the capacitance action frequency band where each anti-resonance point is located as the number of the decoupling capacitors.

At this point, the determination of the type of decoupling capacitor and the number thereof is completed. Because the impedance values corresponding to the frequency points in the actual impedance curve of the PDN system are all reduced to different degrees when the decoupling capacitor of the capacitance action frequency band in which each anti-resonance point is located is added for each anti-resonance point, after S370, it may be tried to reduce the decoupling capacitors added in the previous step corresponding to some anti-resonance points, or the decoupling capacitors preliminarily determined in S340, so as to achieve the purpose of further optimizing the number of decoupling capacitors. Further optimization of the number of decoupling capacitors is exemplarily described below in connection with S380, S390, and S392.

And S380, reducing a decoupling capacitor of a capacitance action frequency band where the anti-resonance point is located.

Wherein this step causes an increase in the actual impedance corresponding to each frequency point in the actual impedance curve of the PDN system. Therefore, the anti-resonance point can be selected based on the anti-resonance point with the actual impedance closest to the target impedance, and the anti-resonance point at a position far away from the anti-resonance point is selected; or after comparing S370, selecting the anti-resonance point corresponding to the smaller actual impedance value; the selection may be performed according to actual requirements of a capacitance selection method of the power distribution network, which is not limited in the embodiment of the present invention.

And S390, judging whether the actual impedance corresponding to each frequency point in the actual impedance curve of the power distribution network is less than or equal to the target impedance.

I.e., after S380, it is determined whether the PDN system still satisfies the design principles (or principles).

If yes, the process continues to step S380, i.e. the decoupling capacitor of the capacitive frequency band where an anti-resonance point is located is continuously decreased. The anti-resonance point selected in this step may be the same as or different from the anti-resonance point selected in the last execution of S380, which is not limited in the embodiment of the present invention.

If not, go to S392.

And S392, adding a decoupling capacitor of the capacitance action frequency band where the anti-resonance point is located again.

By this, the optimization is ended.

This may also include, thereafter, the type of output decoupling capacitance and its corresponding amount, and displaying the PDN impedance curve (which may include the actual impedance curve and the target impedance curve) on a display interface.

Illustratively, referring to fig. 21, the method may include:

and starting.

And S410, acquiring preset parameters.

I.e. determining initial preset parameters.

And S420, calculating target impedance.

I.e. a target impedance of the PDN system is calculated.

And S430, calculating the action frequency band of each capacitance impedance.

Namely, the capacitance action frequency band of each decoupling capacitor is calculated.

And S440, selecting the capacitance in the cut-off frequency range.

Namely, only the decoupling capacitor with the capacitance action frequency band in the working frequency band range of the PDN system is selected, and the decoupling capacitor with the overlap between the capacitance action frequency band and the working frequency band range of the PDN system is selected.

S450, estimating a group of capacitors according to the target impedance.

That is, the number of each type of decoupling capacitor selected in S440 is determined; also included is determining an actual impedance curve for the PDN system.

And S460, searching an anti-resonance point of the impedance curve.

That is, in the actual impedance curve of the PDN system, the antiresonance points are determined. Thereafter, the determination step is performed, i.e., S470 is performed.

And S470, judging whether the anti-resonance point impedance is larger than the target impedance.

That is, for each anti-resonance point, it is determined whether the actual impedance at the position of the anti-resonance point is greater than the target impedance.

If so, the number of decoupling capacitors needs to be increased, i.e., step S472 is performed, and the process returns to step S470.

And S472, increasing the capacitance of the frequency band where the anti-resonance point is located.

Namely, the number of decoupling capacitors corresponding to the capacitance action frequency band where the anti-resonance point is located is increased.

If not, the actual impedance of the anti-resonance point is less than or equal to the target impedance, namely the PDN design principle is met. At this time, S480 is executed.

And S480, optimizing the quantity of the capacitors before and after the anti-resonance point.

That is, it is tried to reduce the number of decoupling capacitors corresponding to the capacitor action frequency band where part of anti-resonance points are located, so that the number of used decoupling capacitors is small on the premise that the actual impedance is smaller than the target impedance.

And S490, determining the used quantity of the capacitors and outputting an impedance curve.

That is, the types of decoupling capacitors and their respective corresponding numbers are determined, and the actual impedance curve of the PDN system is output, and the target impedance curve may also be output simultaneously.

And (6) ending.

According to the selection method of the power distribution network provided by the embodiment of the invention, the capacitance action frequency band of each type of decoupling capacitor is determined according to the working frequency band of each type of decoupling capacitor; and then, after determining the quantity of the decoupling capacitors of various types to obtain an actual impedance curve of the power distribution network, searching for an anti-resonance point, determining a capacitance action frequency band where the anti-resonance point is located when the actual impedance of the anti-resonance point is greater than the target impedance, and increasing the quantity of the decoupling capacitors of the capacitance action frequency band. Therefore, the actual impedance of the anti-resonance point can be effectively reduced, so that the number of the decoupling capacitors can be determined rapidly, the selection efficiency of the decoupling capacitors can be improved, the time consumption of the process can be shortened, and the optimal combination scheme of the decoupling capacitors can be obtained.

Based on the same inventive concept, an embodiment of the present invention further provides a capacitance selection apparatus for a power distribution network, where the apparatus can be used to perform the capacitance selection method for the power distribution network in the foregoing embodiments, and therefore, the apparatus also has the technical effects of the methods in the foregoing embodiments, and the same points can be understood with reference to the foregoing description, and are not described again below.

Illustratively, referring to fig. 22, the apparatus 60 includes: a preset parameter determining unit 610 for determining preset parameters; the preset parameters comprise a target impedance, a lowest cut-off frequency and a highest cut-off frequency of the power distribution network; a decoupling capacitor selection unit 620 for selecting a plurality of different types of decoupling capacitors according to the lowest cut-off frequency and the highest cut-off frequency; wherein the working frequency band of the plurality of different types of decoupling capacitors covers the frequency band range between the lowest cut-off frequency and the highest cut-off frequency; an action frequency band determining unit 630, configured to determine a capacitance action frequency band of each type of decoupling capacitor according to an operating frequency band of each type of decoupling capacitor; a capacitance quantity determining unit 640, configured to determine, according to the target impedance, a quantity of each of the decoupling capacitors in the plurality of different classes, and determine an actual impedance curve of the power distribution network; an anti-resonance point determination unit 650 for determining an anti-resonance point within the lowest cut-off frequency and the highest cut-off frequency range; an impedance magnitude determination unit 660, configured to determine whether an actual impedance of each anti-resonance point is greater than the target impedance; and a capacitance number increasing unit 670 for increasing the decoupling capacitance of the capacitance action frequency band where the anti-resonance point is located when the determination result is yes.

Fig. 22 shows the signal transmission relationship of each unit by way of example, but the signal transmission direction is not limited thereto. In addition, each unit only corresponds to functional division, and in an actual device structure, some units may be integrated into the same component, which is not limited by the embodiment of the present invention.

On the basis of the above embodiments, an embodiment of the present invention further provides a server, including: one or more processors; a storage device for storing one or more programs which, when executed by the one or more processors, cause the one or more processors to implement the method for selecting capacitance of a power distribution network as provided in any of the embodiments above.

Illustratively, and with reference to FIG. 23, FIG. 23 depicts a block diagram of an exemplary server 512 suitable for use in implementing embodiments of the present invention. The server 512 shown in fig. 23 is only an example, and should not bring any limitation to the functions and the scope of use of the embodiments of the present invention.

As shown in fig. 23, the server 512 is represented in the form of a general server. Components of server 512 may include, but are not limited to: one or more processors 516, a storage device 528, and a bus 518 that couples the various system components including the storage device 528 and the processors 516.

Bus 518 represents one or more of any of several types of bus structures, including a memory device bus or memory device controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, such architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MAC) bus, enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

The server 512 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by server 512 and includes both volatile and nonvolatile media, removable and non-removable media.

Storage 528 may include computer system readable media in the form of volatile Memory, such as Random Access Memory (RAM) 530 and/or cache Memory 532. The server 512 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 534 may be used to read from and write to non-removable, nonvolatile magnetic media (not shown in FIG. 23, and commonly referred to as a "hard drive"). Although not shown in FIG. 23, a magnetic disk drive for reading from and writing to a removable, nonvolatile magnetic disk (e.g., a "floppy disk") and an optical disk drive for reading from or writing to a removable, nonvolatile optical disk such as a Compact disk Read-Only Memory (CD-ROM), Digital Video disk Read-Only Memory (DVD-ROM) or other optical media may be provided. In these cases, each drive may be connected to bus 518 through one or more data media interfaces. Storage 528 may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the invention.

A program/utility 540 having a set (at least one) of program modules 542 may be stored, for example, in storage 528, such program modules 542 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each of which examples or some combination thereof may include an implementation of a network environment. The program modules 542 generally perform the functions and/or methods of the described embodiments of the invention.

The server 512 may also communicate with one or more external devices 514 (e.g., keyboard, pointing terminal, display 524, etc.), with one or more terminals that enable a user to interact with the server 512, and/or with any terminals (e.g., network card, modem, etc.) that enable the server 512 to communicate with one or more other computing terminals. Such communication may occur via input/output (I/O) interfaces 522. Further, server 512 may communicate with one or more networks (e.g., a Local Area Network (LAN), Wide Area Network (WAN), and/or a public Network such as the Internet) via Network adapter 520. As shown in FIG. 23, the network adapter 520 communicates with the other modules of the server 512 via the bus 518. It should be appreciated that although not shown, other hardware and/or software modules may be used in conjunction with the server 512, including but not limited to: microcode, end drives, Redundant processors, external disk drive Arrays, RAID (Redundant Arrays of Independent Disks) systems, tape drives, and data backup storage systems, among others.

The processor 516 executes the program stored in the storage device 528 to execute various functional applications and data processing, for example, to implement the method for selecting the power distribution network according to any embodiment of the present invention, and the detailed method may refer to the above, and is not described herein again.

On the basis of the foregoing embodiments, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the method for selecting a capacitor of a power distribution network according to any embodiment of the present invention, and reference may be made to the foregoing specific method, which is not described in detail below.

Computer storage media for embodiments of the invention may employ any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C + +, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or terminal. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for selecting a capacitance of a power distribution network, comprising:

2. The method of claim 1, wherein the inputting preset parameters further comprises: determining a system model of the power distribution network;

wherein the system model of the power distribution network comprises: the device comprises a power supply module, a decoupling capacitor module, a power supply plane, a diffusion impedance, a via hole impedance, a capacitor installation inductance module and a load; a first end of the power module is electrically connected with a first end of the decoupling capacitor module, a first end of the power plane and a first end of the load, a second end of the power module is electrically connected with a second end of the capacitor-mounted inductor module, a second end of the power plane and a first end of the diffused impedance, and a second end of the diffused impedance is electrically connected with a second end of the load through the via impedance; the decoupling capacitor module comprises a plurality of parallel-connected different types of decoupling capacitors, the capacitor mounting inductor module comprises a plurality of capacitor mounting inductors, and each decoupling capacitor is electrically connected with the second end of the power supply module through one capacitor mounting inductor.

3. The method of claim 2, wherein the determining preset parameters comprises:

determining initial preset parameters; the initial preset parameters comprise voltage V of a load, maximum working current Imax, a ripple factor AR allowed by the working voltage, a proportion TP of transient current and Imax, the type of a power supply module, the value of capacitor installation inductance, the size of a power supply plane, the value of diffusion impedance and the value of via impedance;

and determining the preset parameters according to the initial preset parameters.

4. The method of claim 3, wherein determining the preset parameters from the initial preset parameters comprises:

calculating the target impedance according to a target impedance calculation formula, and determining the lowest cut-off frequency and the highest cut-off frequency according to the type of the power supply module and the size of a power supply plane;

wherein, the target impedance calculation formula is as follows:

5. the method of claim 1, wherein selecting a plurality of different classes of decoupling capacitors based on the lowest cutoff frequency and the highest cutoff frequency comprises:

a decoupling capacitor bank is selected from a predetermined capacitor bank.

6. The method of claim 5, wherein determining the capacitive operating frequency band for each type of the decoupling capacitor based on the operating frequency band for each type of the decoupling capacitor comprises:

in the decoupling capacitor group, the plurality of different types of decoupling capacitors are sequenced according to the self-resonance point frequency of each type of decoupling capacitor from low to high;

determining the intersection point of the impedance curves of the decoupling capacitors adjacent to the self-resonance point frequency;

determining the capacitance action frequency band of the first decoupling capacitor as the frequency band range between two intersection points on the impedance curve of the first decoupling capacitor, and determining the capacitance action frequency band of the second decoupling capacitor as the frequency band range between the intersection points on the impedance curve of the second decoupling capacitor and the boundary cut-off frequency;

the first type of decoupling capacitor is the decoupling capacitor with the self-resonance point frequency in the middle range in the decoupling capacitor bank, and the second type of decoupling capacitor is the decoupling capacitor with the lowest or highest self-resonance point frequency in the decoupling capacitor bank; the boundary cut-off frequency is the lowest working frequency of the decoupling capacitor with the lowest self-resonance point frequency, or the boundary cut-off frequency is the highest working frequency of the decoupling capacitor with the highest self-resonance point frequency.

7. The method of claim 6, wherein after determining the capacitive action frequency band of each type of the decoupling capacitor according to the operating frequency band of each type of the decoupling capacitor, the method further comprises:

8. The method of claim 1, wherein determining the number of each of the plurality of different classes of decoupling capacitors based on the target impedance comprises:

and determining the minimum number of the decoupling capacitors of each type when the impedance of the self-resonant point of each type of the decoupling capacitors is smaller than the target impedance in an impedance parallel mode as the number of the decoupling capacitors of the type.

9. The method of claim 8, wherein determining an actual impedance curve for the power distribution network comprises:

and determining an actual impedance curve of the power distribution network according to a system model of the power distribution network and the type and the number of each type of decoupling capacitor.

10. The method of claim 1, wherein determining whether the actual impedance of the anti-resonance point is greater than the target impedance further comprises:

and if not, determining the quantity of the decoupling capacitors corresponding to the capacitance action frequency band where the anti-resonance point is positioned as the quantity of the decoupling capacitors.

11. The method of claim 1, wherein the number of anti-resonance points is plural, and after determining whether the actual impedance of the anti-resonance point is greater than the target impedance, the method further comprises:

if the actual impedance of each anti-resonance point is not greater than the target impedance, determining the number of the decoupling capacitors corresponding to the capacitance action frequency band where each anti-resonance point is located as the number of the decoupling capacitors; and then also comprises the following steps:

reducing the decoupling capacitor of the capacitor action frequency band where the anti-resonance point is located;

judging whether the actual impedance corresponding to each frequency point in the actual impedance curve of the power distribution network is smaller than or equal to the target impedance or not;

if so, continuing to reduce the decoupling capacitor of the capacitive action frequency band where the anti-resonance point is located;

if not, increasing the decoupling capacitor of the capacitance action frequency band where the anti-resonance point is located again;

the capacitance selection and optimization process ends.

12. A capacitance selection device for a power distribution network, comprising:

13. A server, comprising:

one or more processors;

a storage device for storing one or more programs,

when executed by the one or more processors, cause the one or more processors to implement the method for capacitance selection for a power distribution network of any of claims 1-11.

14. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the method for capacitance selection of a power distribution network according to any one of claims 1 to 11.