Method, device, medium and program for analyzing conducted electromagnetic interference of operational amplifier

Abstract

The invention provides an operational amplifier conducted electromagnetic interference analysis method and device, a medium and a program. The method comprises the steps that firstly, conducted electromagnetic interference mixed time domain signals of an operational amplifier are collected; converting the time domain signal into a frequency domain signal; substituting the frequency domain signal as an input matrix into a conducted electromagnetic interference mixed frequency domain signal non-negative decomposition model, introducing a time sequence sparse method through spectrum smoothing, separating the conducted electromagnetic interference mixed frequency domain signal, and obtaining each component frequency domain signal of the operational amplifier; the mixed frequency domain signal non-negative decomposition model is constructed based on regularization; and finally, based on each component frequency domain signal, reconstructing a corresponding conducted electromagnetic interference component time domain signal. According to the method, each component frequency domain signal corresponding to each noise source is separated from the mixed frequency domain signal based on the non-negative matrix factorization method, and the defects that a traditional separation method is complex in process and low in precision are overcome.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit electronic information technology, and specifically relates to a method, device, medium, and program for analyzing conducted electromagnetic interference in operational amplifiers. Background Technology

[0002] As integrated circuit technology enters the nanometer era, operational amplifiers, as indispensable signal processing devices in electronic devices, have been widely used in the electronics and information industry due to their advantages such as high input impedance, high open-loop gain, low output impedance, and high common-mode rejection ratio. However, with the increasing operating frequency and integration density of operational amplifiers, the conducted electromagnetic interference (EMI) generated by the multi-stage circuits within them superimposes on the transmission lines, forming a complex conducted EMI noise source. This results in EMI exhibiting mixed, nonlinear, and non-stationary characteristics, leading to increasingly severe electromagnetic compatibility (EMC) problems. Therefore, it is necessary to separate and locate the mixed conducted EMI caused by the input, amplification, and output stages of the operational amplifier to provide an analytical basis for evaluating the impact of different interference components on the operational amplifier and for EMI suppression.

[0003] Traditional operational amplifier conducted electromagnetic interference (EMI) analysis mainly includes principal component analysis (PCA) and independent component analysis (ICA). However, while PCA can identify frequencies exceeding the standard for conducted EMI, it cannot reveal the source and composition of these frequencies, nor can it quantify the contribution ratio of different sources. ICA, although suitable for processing instantaneous linear mixed signals, has limited ability to separate nonlinear mixed signals. Furthermore, as a time-domain analysis method, its computational process is complex and requires approximations, leading to decreased signal separation accuracy. The inevitability and severity of these problems make accurate and efficient analysis of operational amplifier conducted EMI a crucial and valuable technical task requiring significant engineering applications. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for analyzing conducted electromagnetic interference (EMI) in operational amplifiers based on nonnegative matrix decomposition. This method can simply and efficiently solve the problem of separating and locating EMI in operational amplifiers, and provides a diagnostic solution for EMI modeling and design verification of operational amplifiers.

[0005] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0006] A method for analyzing conducted electromagnetic interference in operational amplifiers, comprising:

[0007] S1, Acquire the mixed time-domain signal of conducted electromagnetic interference from the operational amplifier. ;

[0008] S2, time domain signal Convert to frequency domain signal ;

[0009] S3, frequency domain signal Substituting the input matrix into the non-negative decomposition model of the conducted electromagnetic interference mixed frequency domain signal, and introducing the time-series sparsity method through spectral smoothing, the conducted electromagnetic interference mixed frequency domain signal is separated to obtain the frequency domain signals of each component of the operational amplifier. The hybrid frequency domain signal nonnegative decomposition model is constructed based on regularization.

[0010] S4, based on the frequency domain signal of each component The corresponding time-domain signal of conducted electromagnetic interference component is reconstructed. .

[0011] Furthermore, the nonnegative matrix decomposition model of the hybrid frequency domain signal is as follows:

[0012]

[0013] in:

[0014]

[0015]

[0016]

[0017] In the formula, For loss function, and For the first A global regularization function for an interference signal. and For the first A regularization function for an interference signal. and , and All are regularization weight coefficients; input matrix Take mixed frequency domain signal , and for The decomposed basis matrix and coefficient matrix are both non-negative matrices, and each decomposes into a fixed signal. , and variable signals , .

[0018] Furthermore, the component frequency domain signals are separated according to the following separation function. :

[0019]

[0020] in:

[0021]

[0022]

[0023] In the formula, For the first The separated conducted electromagnetic interference frequency domain signal To minimize the function, It is the L2 norm. , , Norm coefficients, and These are the smoothing operators for the basis matrix and the coefficient matrix, respectively; , , In order The first, second, and third column matrices in the matrix. , , In order The first, second, and third row matrices in the matrix.

[0024] Furthermore, the loss function for:

[0025] .

[0026] Furthermore, in S4:

[0027] Calculate the power spectral density of each component of the frequency domain signal:

[0028]

[0029] In the formula, For the first The power spectral density of each component, Sampling frequency, This represents the total number of sampling points;

[0030] The period, sampling frequency, bandwidth, and amplitude parameters of each component frequency domain signal are extracted, and the separated frequency domain signals are transformed into time domain signals using inverse fast Fourier transform:

[0031]

[0032] In the formula, For the first A time-domain signal of a conducted electromagnetic interference component. For window functions The inverse Fourier transform function, This represents the time length of the Hanning window function.

[0033] Furthermore, in S1: the voltage method is used to extract the conducted electromagnetic interference of the operational amplifier through a linear impedance stabilization network;

[0034] In S2:

[0035] Mixed signals Represented in matrix form as follows:

[0036]

[0037]

[0038]

[0039] In the formula, The coefficient matrix, For the reason A vector composed of conducted electromagnetic interference signals , Here is the filter matrix. For time delay;

[0040] The mixed time-domain signal is obtained by performing a short-time Fourier transform on the mixed time-domain signal using the Hanning window function:

[0041]

[0042] In the formula, It is a mixed frequency domain signal. for The short-time Fourier transform signal, for Add Hanning window short-time Fourier transform signal, The duration of the Hanning window function;

[0043] The amplitude and phase of each frequency point contained in the mixed time-domain signal are calculated according to the following formula to obtain the mixed frequency-domain signal composed of multiple sine waves:

[0044]

[0045] In the formula, , ; The number of points in the short-time Fourier transform. Let be the displacement per unit time of the Hanning window function. For window functions.

[0046] Furthermore, based on the following characteristics, the time-domain signals of each conducted electromagnetic interference component are... Noise source localization:

[0047] Input stage: Interference is less than that of the amplifier stage and output stage across the entire frequency band; interference at high frequencies is reduced compared to that at low frequencies.

[0048] Amplification stage: Interference is greater than that of the input stage and output stage across the entire frequency band;

[0049] Output stage: Interference is high at low frequencies and low at high frequencies.

[0050] A computer device, including a memory and a processor;

[0051] The memory is used to store computer programs;

[0052] The processor is used to execute the computer program and, in executing the computer program, implement the above-described operational amplifier conducted electromagnetic interference analysis method.

[0053] A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the above-described operational amplifier conducted electromagnetic interference analysis method.

[0054] A computer program product includes a computer program that, when executed by a processor, implements the above-described operational amplifier conducted electromagnetic interference analysis method.

[0055] The beneficial effects of this invention are as follows:

[0056] (1) This invention provides a method for analyzing conducted electromagnetic interference of operational amplifiers. Based on the non-negative matrix decomposition method, the mixed frequency domain signal is separated into the frequency domain signals corresponding to each noise source, overcoming the defects of traditional separation methods such as complex process and low accuracy.

[0057] (2) By quantifying conducted electromagnetic interference from different sources and combining the circuit characteristics of the operational amplifier input stage, amplification stage and output stage, the present invention can accurately locate the noise source of each component of conducted electromagnetic interference. It does not require a spectrum analyzer and avoids the use of a noise separation network, thereby improving the accuracy and efficiency of conducted electromagnetic interference separation and location while reducing economic costs. Attached Figure Description

[0058] Figure 1 This is a flowchart of the operational amplifier conducted electromagnetic interference analysis method of the present invention;

[0059] Figure 2 A time-domain signal diagram of conducted electromagnetic interference from an operational amplifier;

[0060] Figure 3 Example of conducted electromagnetic interference results for a separate operational amplifier input stage;

[0061] Figure 4 Example of conducted electromagnetic interference results for a separate operational amplifier amplification stage;

[0062] Figure 5 Example of conducted electromagnetic interference results for a separate operational amplifier output stage. Detailed Implementation

[0063] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0064] I. Technical Solution

[0065] Reference Figure 1 As shown, the present invention provides a method for analyzing conducted electromagnetic interference in operational amplifiers based on nonnegative matrix factorization, comprising the following steps:

[0066] Step 1: Acquire the mixed time-domain signal of conducted electromagnetic interference from the operational amplifier.

[0067] Specifically, a voltage method can be used to extract conducted electromagnetic interference (EMI) from the operational amplifier using a linear impedance stabilization network. To ensure the repeatability and comparability of the conducted EMI, the operational amplifier's power supply port is connected to the linear impedance stabilization network. The power supply and RF output terminals of the linear impedance stabilization network are connected to the mains and the EMI receiver, respectively. The 50Ω impedance in the linear impedance stabilization network converts the current signal into a time-domain voltage signal, which is then coupled to the receiver. The mixed time-domain signal of the operational amplifier's conducted EMI includes common-mode conducted EMI and differential-mode conducted EMI, as follows:

[0068]

[0069]

[0070] In the formula, For common-mode conducted electromagnetic interference, For differential-mode conducted electromagnetic interference, The voltage on the live wire. This is the voltage on the neutral line.

[0071] The common-mode and differential-mode conducted electromagnetic interference vectors are superimposed to form a mixed conducted electromagnetic interference signal. Its waveform is as follows Figure 2 As shown, It is a time variable.

[0072] Step 2, time-frequency domain conversion of mixed signal

[0073] By converting the above mixed signal into a time-frequency domain, Converting a time-domain signal into a frequency-domain signal ,include:

[0074] Step 2.1, mix the signals Represented in matrix form as follows:

[0075]

[0076]

[0077]

[0078] In the formula, The coefficient matrix, For the reason ~ this A vector composed of conducted electromagnetic interference signals Its specific value can be set arbitrarily according to actual needs. Here is the filter matrix. For time delay.

[0079] Step 2.2: Perform a short-time Fourier transform on the mixed time-domain signal using the Hanning window function to obtain the mixed frequency-domain signal.

[0080]

[0081] In the formula, It is a mixed frequency domain signal. for The short-time Fourier transform signal, for Add Hanning window short-time Fourier transform signal, The time length of the Hanning window function. For frequency variables.

[0082] The amplitude and phase of each frequency point contained in the mixed time-domain signal are calculated according to the following formula to obtain the mixed frequency-domain signal composed of multiple sine waves:

[0083]

[0084] In the formula, , ; The number of points in the short-time Fourier transform. Let be the displacement per unit time of the Hanning window function. For window functions.

[0085] Step 3: Construct a nonnegative matrix decomposition model for the hybrid frequency domain signal.

[0086] Since the conducted electromagnetic interference spectrum is concentrated in the positive frequency band of 150kHz-30MHz, the signal is non-negative, thus the mixed frequency domain signal... The input matrix for the nonnegative matrix factorization model is:

[0087]

[0088] In the formula, For the input matrix, and Let be the number of rows and columns of the matrix, where Same as the number of conducted electromagnetic interference signals mentioned above.

[0089] Input matrix Decompose it into the product of two nonnegative matrices: the basis matrix and the coefficient matrix.

[0090]

[0091] In the formula, As a basis matrix, The coefficient matrix, This refers to the number of conducted electromagnetic interference noise sources; specifically, operational amplifiers typically consist of three stages: an input stage, an amplification stage, and an output stage. Take 3.

[0092] To avoid external electromagnetic interference from the operational amplifier potentially overshadowing its own weak interference components, and to simplify model computation, a semi-supervised learning approach is adopted for the basis matrix. sum coefficient matrix Decompose:

[0093]

[0094]

[0095] In the formula, For fixed signals in the basis matrix, For the variable signals in the basis matrix, For fixed signals in the coefficient matrix, These are the variable signals in the coefficient matrix.

[0096] Based on regularization, the non-negative matrix decomposition model of conducted electromagnetic interference is established as follows:

[0097]

[0098] In the formula, The value of the nonnegative matrix factorization model function (). For loss function, and For the first Two global regularization functions for the interference signal and For the first A regularization function for an interference signal. Same meaning It is only used in the accumulation formula and the external To differentiate, Corresponding to the location of the interference source (input stage, amplification stage, output stage). and , and All are regularization weight coefficients.

[0099] In this embodiment, the loss function for:

[0100]

[0101] Step 4: Based on spectral smoothing, introduce time-series sparse separation of conducted electromagnetic interference mixed frequency domain signals to obtain the frequency domain signals of each component of the operational amplifier;

[0102] The variable signals in the basis matrix Divide into three groups according to columns:

[0103]

[0104] In the formula, , , In order The first, second, and third column matrices in the matrix.

[0105] The variable signals in the coefficient matrix Divide into three groups by row:

[0106]

[0107] In the formula, , , In order The first, second, and third row matrices in the matrix.

[0108] The separation function based on spectral smoothing and temporal sparsity is established as follows:

[0109]

[0110] In the formula, For the first The separated conducted electromagnetic interference frequency domain signal To minimize the function, It is the L2 norm. , , Norm coefficients, and These are the smoothing operators for the basis matrix and the coefficient matrix, respectively.

[0111] Step 5: Reconstruct the time-domain signals of each component of conducted electromagnetic interference.

[0112] For each component frequency domain signal Calculate the power spectral density :

[0113]

[0114] In the formula, For the first The power spectral density of each component, Sampling frequency, This represents the total number of sampling points.

[0115] The period, sampling frequency, bandwidth, and amplitude parameters of the three frequency domain components are extracted. An inverse fast Fourier transform is then used to convert the three separated frequency domain signals into three time domain signals, thus achieving the separation of the conducted electromagnetic interference mixed time domain signal.

[0116]

[0117] In the formula, For the first A time-domain signal of a conducted electromagnetic interference component. For window functions The inverse Fourier transform function, Indicates the variable and Varying frequency domain signal of conducted electromagnetic interference components .

[0118] Step 6: Based on the characteristics of the multi-stage operational amplifier circuit, locate the noise sources of each component of conducted electromagnetic interference.

[0119] To assess the impact of different interference components on the operational amplifier and to specifically suppress interference exceeding the limits, the three separated conducted electromagnetic interference time-domain signals need to be located to achieve precise matching with the input, amplification, and output stages. The conducted electromagnetic interference of the operational amplifier essentially originates from the non-ideal switching, capacitive coupling, and power supply modulation of transistors in the internal input, amplification, and output stage circuits.

[0120] (1) For the input stage, the bias current flows into the ground port after being filtered by transistors and capacitors, which reduces the differential-mode signal in conducted electromagnetic interference (EMI). Furthermore, since the conducted EMI has not yet been amplified by the amplification stage, the interference is significantly less than that of the amplification stage and the output stage throughout the entire frequency band. In addition, due to the power supply rejection ratio, the interference at high frequencies decreases significantly compared to low frequencies. The conducted EMI at the input stage is as follows: Figure 3 As shown.

[0121] (2) For the amplification stage, the transistor generates a large spike current during rapid switching, which has a very high instantaneous rate of change, directly generating a large amount of conducted electromagnetic interference (EMI). Secondly, the transistor generates displacement current during the charging and discharging of the node capacitor, causing current fluctuations in the amplification stage, indirectly generating EMI. In addition, the EMI generated by the input stage is amplified, further exacerbating the interference. Therefore, across the entire frequency band, the EMI generated by the amplification stage is significantly greater than that generated by the input and output stages. The EMI generated by the amplification stage is as follows: Figure 4 As shown.

[0122] (3) For the output stage, when driving the load, the push-pull branch of the output stage requires a large transient current, which flows into the load through the output stage transistor, generating significant conducted electromagnetic interference in the low-frequency range. At the moment when the output current crosses zero and the transistor switches, there is a brief dead time and nonlinear region. The output current flows directly into the ground port through the load, resulting in a smaller current ripple, which reduces high-frequency interference. Therefore, the conducted electromagnetic interference of the output stage exhibits the characteristics of being large at low frequencies and small at high frequencies, such as... Figure 5 As shown.

[0123] III. Devices, storage media, and software products

[0124] 1. Based on the same inventive concept as the above-described operational amplifier conducted electromagnetic interference analysis method, this application also provides an electronic device, which includes a processor and a memory, wherein computer-readable code is stored in the memory, and when the computer-readable code is executed by the processor, the operational amplifier conducted electromagnetic interference analysis method of the present invention is implemented.

[0125] The memory includes non-volatile storage media and internal memory. The non-volatile storage media can store the operating system and computer-readable code. The computer-readable code includes program instructions that, when executed, cause the processor to perform an operational amplifier conducted electromagnetic interference (EMI) analysis method. The processor provides computational and control capabilities to support the operation of the entire electronic device. The memory provides an environment for the execution of the computer-readable code in the non-volatile storage media, which, when executed by the processor, causes the processor to perform the operational amplifier conducted EMI analysis method.

[0126] It should be understood that a processor can be a central processing unit, other general-purpose processors, digital signal processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, a general-purpose processor can be a microprocessor or any conventional processor.

[0127] 2. This application also provides a readable storage medium, which may be an internal storage unit of the electronic device described in the foregoing embodiments, such as the hard disk or memory of the computer device. The readable storage medium may also be an external storage device of the electronic device, such as a plug-in hard disk, smart memory card, or secure digital card equipped on the electronic device.

[0128] 3. This application also provides a computer program product, including a computer program or instructions, which, when executed by a processor, implements the operational amplifier conducted electromagnetic interference analysis method of the present invention.

[0129] This invention is not limited to the above-described embodiments. Any obvious improvements, substitutions, or modifications that can be made by those skilled in the art without departing from the essence of this invention are within the scope of protection of this invention.

Claims

1. A method for analyzing conducted electromagnetic interference in operational amplifiers, characterized in that: include: S1, Acquire the mixed time-domain signal of conducted electromagnetic interference from the operational amplifier. ; S2, time domain signal Convert to frequency domain signal ; S3, frequency domain signal Substituting the input matrix into the non-negative decomposition model of the conducted electromagnetic interference mixed frequency domain signal, and introducing the time-series sparsity method through spectral smoothing, the conducted electromagnetic interference mixed frequency domain signal is separated to obtain the frequency domain signals of each component of the operational amplifier. The hybrid frequency domain signal nonnegative decomposition model is constructed based on regularization. S4, based on the frequency domain signal of each component The corresponding time-domain signal of conducted electromagnetic interference component is reconstructed. .

2. The operational amplifier conducted electromagnetic interference analysis method according to claim 1, characterized in that: The nonnegative matrix decomposition model for the hybrid frequency domain signal is as follows: in: In the formula, For loss function, and For the first A global regularization function for an interference signal. and For the first A regularization function for an interference signal. and , and All are regularization weight coefficients; input matrix Take mixed frequency domain signal , and for The decomposed basis matrix and coefficient matrix are both non-negative matrices, and each decomposes into a fixed signal. , and variable signals , .

3. The operational amplifier conducted electromagnetic interference analysis method according to claim 2, characterized in that: The component frequency domain signal is separated using the following separation function. : in: In the formula, For the first The separated conducted electromagnetic interference frequency domain signal To minimize the function, It is the L2 norm. , , Norm coefficients, and These are the smoothing operators for the basis matrix and the coefficient matrix, respectively; , , In order The first, second, and third column matrices in the matrix. , , In order The first, second, and third row matrices in the matrix.

4. The operational amplifier conducted electromagnetic interference analysis method according to claim 2, characterized in that: The loss function for: 。 5. The operational amplifier conducted electromagnetic interference analysis method according to claim 1, characterized in that: In S4: Calculate the power spectral density of each component of the frequency domain signal: In the formula, For the first The power spectral density of each component, Sampling frequency, This represents the total number of sampling points; The period, sampling frequency, bandwidth, and amplitude parameters of each component frequency domain signal are extracted, and the separated frequency domain signals are transformed into time domain signals using inverse fast Fourier transform: In the formula, For the first A time-domain signal of a conducted electromagnetic interference component. For window functions The inverse Fourier transform function, This represents the time length of the Hanning window function.

6. The operational amplifier conducted electromagnetic interference analysis method according to claim 1, characterized in that: In S1: the voltage method is used to extract the conducted electromagnetic interference of the operational amplifier through a linear impedance stabilization network; In S2: Mixed signals Represented in matrix form as follows: In the formula, The coefficient matrix, For the reason A vector composed of conducted electromagnetic interference signals , Here is the filter matrix. For time delay; The mixed time-domain signal is obtained by performing a short-time Fourier transform on the mixed time-domain signal using the Hanning window function: In the formula, It is a mixed frequency domain signal. for The short-time Fourier transform signal, for Add Hanning window short-time Fourier transform signal, The duration of the Hanning window function; The amplitude and phase of each frequency point contained in the mixed time-domain signal are calculated according to the following formula to obtain the mixed frequency-domain signal composed of multiple sine waves: In the formula, , ; The number of points in the short-time Fourier transform. Let be the displacement per unit time of the Hanning window function. For window functions.

7. The operational amplifier conducted electromagnetic interference analysis method according to claim 1, characterized in that: Based on the following characteristics, the time-domain signals of each conducted electromagnetic interference component... Noise source localization: Input stage: Interference is less than that of the amplifier stage and output stage across the entire frequency band; interference at high frequencies is reduced compared to that at low frequencies. Amplification stage: Interference is greater than that of the input stage and output stage across the entire frequency band; Output stage: Interference is high at low frequencies and low at high frequencies.

8. A computer device, characterized in that: Including memory and processor; The memory is used to store computer programs; The processor is used to execute the computer program and, in executing the computer program, implement the operational amplifier conducted electromagnetic interference analysis method as described in any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that: The device contains a computer program that, when executed by a processor, causes the processor to perform the operational amplifier conducted electromagnetic interference analysis method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that: It includes a computer program, which, when executed by a processor, implements the operational amplifier conducted electromagnetic interference analysis method as described in any one of claims 1 to 7.

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