Accelerated degradation test design and reliability evaluation method and system of operational amplifier

Abstract

The invention provides an accelerated degradation test design and reliability evaluation method and system of an operational amplifier, and relates to the technical field of reliability test and reliability evaluation of the operational amplifier, and the method comprises the steps: carrying out the failure mechanism analysis of the operational amplifier, researching the influence of a stress factor on the performance index of the operational amplifier, and determining the degradation trend of the operational amplifier; testing the degradation behavior of each performance parameter, and determining the most sensitive degradation parameter; setting different temperature stress levels and test intervals, and recording degradation data; an accelerated degradation test scheme is optimized, and a progressive variance is minimized according to a set objective function; performing degradation modeling on the plurality of sensitive parameters by using multiple regression analysis and a Copula function; and an optimal Copula function is selected through an AIC criterion, reliability evaluation of the operational amplifier is completed, and a reliability curve of the operational amplifier is generated based on test data. According to the invention, the problem that the accuracy of test effectiveness and reliability evaluation is difficult to improve is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of reliability testing and reliability evaluation of operational amplifiers, and in particular to an accelerated degradation test design and reliability evaluation method and system for operational amplifiers. Background Art

[0002] With the widespread application of electronic products, especially in high reliability applications (such as aerospace, communications, and medical equipment), higher requirements are placed on the performance and reliability of electronic components. As a key signal processing unit in electronic systems, the performance of operational amplifiers directly affects the stability and reliability of the entire system. Therefore, how to effectively evaluate the reliability of operational amplifiers under different working conditions has become an important research topic.

[0003] Existing operational amplifier life assessment methods usually rely on long-term actual use data. However, this method is time-consuming, costly, and difficult to obtain sufficient failure data in a short period of time, especially in situations with high reliability requirements, where failure data is often insufficient. Therefore, the accelerated degradation test method can obtain degradation data in a shorter period of time by applying higher temperature, stress and other conditions, thereby predicting the long-term reliability of the device.

[0004] However, there are still some deficiencies in the current accelerated degradation test design of operational amplifiers. For example, the stress level and degradation model selection in the test design often lack systematic optimization, resulting in insufficient accuracy and credibility of the degradation results. At the same time, the existing methods are relatively simple for the degradation analysis of multivariate sensitive parameters, which is difficult to accurately reflect the degradation characteristics under actual working conditions. Therefore, there is an urgent need for an improved accelerated degradation test design and reliability assessment method for operational amplifiers to improve the effectiveness of the test and the accuracy of the reliability assessment. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an accelerated degradation test design and reliability assessment method and system for an operational amplifier, which solves the problem that it is difficult to improve the effectiveness of the test and the accuracy of the reliability assessment.

[0006] In order to achieve the above objectives, the technical solution adopted by the present invention is: an accelerated degradation test design and reliability evaluation method for an operational amplifier, comprising:

[0007] Step 1: Analyze the failure mechanism of the operational amplifier, study the influence of stress factors on the performance indicators of the operational amplifier, and determine its degradation trend;

[0008] Step 2: Design a preliminary test, set different stress levels, test the degradation behavior of each performance parameter, and determine the most sensitive degradation parameter;

[0009] Step 3: Develop an accelerated degradation test plan, select a constant stress loading method, use temperature stress as the accelerating stress, set different temperature stress levels and test intervals, and record degradation data;

[0010] Step 4: Reduce the test cost, ensure the quality of degradation data by optimizing the accelerated degradation test scheme, and minimize the asymptotic variance according to the set objective function;

[0011] Step 5: Use multiple regression analysis and Copula function to model the degradation of multiple sensitive parameters and derive the joint reliability model of multiple performance parameters;

[0012] Step 6: Select the optimal Copula function through the AIC criterion to complete the reliability evaluation of the operational amplifier, and generate the reliability curve of the operational amplifier based on the test data.

[0013] The beneficial effects of the present invention are as follows: based on the degradation test data of the operational amplifier, the present invention can efficiently evaluate the reliability of the operational amplifier through multivariate performance parameter degradation modeling, combined with pre-tests and accelerated degradation tests. Under different temperature and electrical stress conditions, the degradation behavior of sensitive parameters is used to establish a reliability model and perform test optimization. The present invention is suitable for reliability evaluation through accelerated degradation tests when there is insufficient operational amplifier failure data, and provides an effective basis for product life prediction in actual use.

[0014] Furthermore, the step 1 is specifically as follows:

[0015] The failure mechanism of the operational amplifier is analyzed, the influence of stress factors on the performance indicators of the operational amplifier is studied, and its degradation trend is determined. The stress type of the sensitive parameters in the preliminary test of step 2 and the accelerated degradation test of step 3 is determined by the degradation trend.

[0016] Furthermore, the step 2 is specifically as follows:

[0017] Design a preliminary test, set different stress levels, and determine the most sensitive degradation parameters based on the determined degradation trend, so as to provide the stress type and level of the accelerated degradation test for step 3 through the preliminary test.

[0018] The beneficial effect of the above further solution is that the analysis of degradation trend can help determine the stress type of sensitive parameters in the preliminary test of step 2 and the accelerated degradation test of step S3.

[0019] Furthermore, the analysis of the most sensitive degradation parameter is as follows:

[0020] The average degradation rate and volatility index are used to analyze the degradation data of each sensitive parameter, where the expression of the average degradation rate is as follows:

[0021]

[0022] Where v represents the average degradation rate of performance parameters, x max represents the maximum degradation value of the performance parameter, x0 represents the initial value of the performance parameter, and t represents the degradation of the performance parameter value from x0 to x max Time taken;

[0023] The expression of volatility indicator is as follows:

[0024]

[0025] Where w represents the volatility of the degradation trajectory, x i represents the i-th data point of the degradation trajectory, y i Indicates that it corresponds to x i The fitted value of , m represents the number of degraded data.

[0026] The beneficial effect of the above further solution is that the present invention further provides the stress type and level of the accelerated degradation test for step 3 through the preliminary test.

[0027] Furthermore, the step 4 is specifically as follows:

[0028] Based on the developed accelerated degradation test plan, it is optimized to reduce the test cost, ensure the quality of degradation data, and minimize the asymptotic variance according to the set objective function.

[0029] Furthermore, the expression of the asymptotic variance in step 4 is as follows:

[0030]

[0031] in, represents the asymptotic variance, express The transpose of Indicates A M,0 The first-order partial derivative of A M,0 represents the acceleration factor for the minimum stress level, express The inverse matrix of express The information matrix, represents the degradation data matrix under multiple stresses, represents the acceleration factor, represents the Boltzmann constant, represents the unknown coefficient, T M represents the highest stress and T0 represents the lowest stress.

[0032] The beneficial effect of the above further scheme is that the present invention reduces the test cost and ensures the quality of degradation data by optimizing the accelerated degradation test scheme.

[0033] Furthermore, the step 5 is specifically as follows:

[0034] After conducting tests based on the optimized accelerated return test scheme, the degradation data of sensitive performance parameters were obtained, and multiple regression analysis and Copula function were used to model the degradation of multiple sensitive parameters, and the joint reliability model of multiple performance parameters was derived.

[0035] Furthermore, the expression of the joint reliability model of the multivariate performance parameters is as follows:

[0036]

[0037] Among them, R 1,...,n (t) represents the joint reliability function under n-dimensional performance parameters, t represents time, R i (t) represents the reliability under the i-th performance parameter, T(g) represents the operator of the sum of g Copula functions, j1,...,j k ,...,j g ∈[1,n],k∈[1,g],R jk (t) represents the jth k Reliability under performance parameters.

[0038] The beneficial effect of the above further solution is that the present invention constructs a joint reliability model under multiple performance parameters, which provides a theoretical basis for the reliability calculation of step 6.

[0039] Furthermore, the step 6 is specifically as follows:

[0040] Based on the joint reliability model of multivariate performance parameters, the model parameters of each multivariate Copula function are solved by the maximum likelihood estimation method;

[0041] Based on the joint reliability model of multivariate performance parameters and the results of solving the model parameters, the optimal Copula function is selected using the AIC criterion;

[0042] Based on the optimal Copula function, the reliability curve of the operational amplifier is generated by obtaining the joint reliability of the operational amplifier which comprehensively considers the degradation process of the performance parameters of the operational amplifier.

[0043] The beneficial effect of the above further solution is that the present invention selects the optimal Copula function through the AIC criterion to achieve reliability evaluation of the operational amplifier under accelerated degradation test data.

[0044] The present invention also provides an accelerated degradation test design and reliability assessment system for an operational amplifier, comprising a processor, wherein the processor is used to execute the accelerated degradation test design and reliability assessment method for the operational amplifier.

[0045] The beneficial effects of the present invention are as follows: based on the degradation test data of the operational amplifier, the present invention can efficiently evaluate the reliability of the operational amplifier through multivariate performance parameter degradation modeling, combined with pre-tests and accelerated degradation tests. Under different temperature and electrical stress conditions, the degradation behavior of sensitive parameters is used to establish a reliability model and perform test optimization. The present invention is suitable for reliability evaluation through accelerated degradation tests when there is insufficient operational amplifier failure data, and provides an effective basis for product life prediction in actual use. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the process of the present invention;

[0047] Figure 2 A simplified connection diagram of the operational amplifier accelerated degradation test equipment of the present invention;

[0048] Figure 3 This is a physical picture of the operational amplifier accelerated degradation test platform of the present invention;

[0049] Figure 4 A schematic diagram showing a comparison of sensitive parameters of the operational amplifier of the present invention;

[0050] Figure 5 A schematic diagram of a joint reliability curve of an operational amplifier that comprehensively considers three performance parameter degradation processes of the present invention;

[0051] Figure 6 It is a schematic diagram of the combined failure distribution function curve of three performance parameters of the operational amplifier of the present invention. DETAILED DESCRIPTION

[0052] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0053] Example 1

[0054] like Figure 1 As shown, the present invention provides an accelerated degradation test design and reliability assessment method for an operational amplifier, and the implementation method thereof is as follows:

[0055] Step 1: Analyze the failure mechanism of the operational amplifier, study the impact of stress factors on the performance indicators of the operational amplifier, and determine its degradation trend, which is specifically:

[0056] The failure mechanism of the operational amplifier is analyzed, the influence of stress factors on the performance indicators of the operational amplifier is studied, and its degradation trend is determined. The stress type of the sensitive parameters in the preliminary test of step 2 and the accelerated degradation test of step 3 is determined by the degradation trend.

[0057] In this embodiment, the failure mechanism of the operational amplifier is analyzed. The performance of the operational amplifier is mainly affected by environmental factors such as temperature and electrical stress. First, through failure mechanism analysis, the influence of different stress sources on performance indicators (such as open-loop gain, input offset voltage, output high level, etc.) is studied. The analysis method includes phenomena such as the destruction of the material structure by thermal effects under temperature stress and electron migration caused by electrical stress. By performing accelerated stress tests on each performance indicator, its degradation trend under different stress levels is observed. Using the laboratory's high temperature test equipment, the temperature and load are gradually increased, and the performance changes of each key parameter are recorded to form a degradation curve. These curves reveal the sensitivity and failure critical point of each performance indicator, and help determine the sensitive parameters in the accelerated stress test.

[0058] Step 2: Design a preliminary test, set different stress levels, test the degradation behavior of each performance parameter, and determine the most sensitive degradation parameter, which is specifically:

[0059] Design a preliminary test, set different stress levels, and determine the most sensitive degradation parameters based on the determined degradation trend, so as to provide the stress type and level of the accelerated degradation test for step 3 through the preliminary test.

[0060] In this embodiment, a preliminary test is designed to determine sensitive parameters. The purpose of the preliminary test is to determine the most sensitive parameter to degradation by testing the degradation behavior of each performance parameter. Different stress levels are set during the design, including temperature (such as 60°C, 80°C, 100°C) and electrical stress (such as overload test under different voltage conditions).

[0061] The equipment used for operational amplifier pre-test and accelerated degradation test includes: operational amplifier tester, signal source, multimeter, power supply, oscilloscope, high temperature test chamber, building block test box, mixed signal test system. The connection logic of each device is as follows: Figure 2 To build, the physical platform diagram is as follows Figure 3 shown.

[0062] Next, a preliminary test is conducted to obtain the degradation data of the operational amplifier's sensitive parameters. The average degradation rate and volatility index are used to analyze the degradation data of each sensitive parameter.

[0063] The average degradation rate is calculated as:

[0064]

[0065] Where v represents the average degradation rate of performance parameters, x max represents the maximum degradation value of the performance parameter, x0 represents the initial value of the performance parameter, and t represents the degradation of the performance parameter value from x0 to x max Time taken.

[0066] The volatility calculation formula is:

[0067]

[0068] Where w represents the volatility of the degradation trajectory, x i represents the i-th data point of the degradation trajectory, y i Indicates that it corresponds to x i The fitted value of , m represents the number of degraded data.

[0069] Input offset voltage parameter V IO , Input bias current parameter I IB and the output fan-out current parameter I SOURCE The degradation performance index results are as follows Figure 4 As shown in the figure, the faster the average degradation rate, the smaller the volatility, the more conducive to data analysis and degradation modeling, and the better the degradation performance of the parameters. Therefore, the selection priority of the three parameters can be obtained as follows: the input offset voltage parameter is the highest, the input bias current parameter is the second, and the output fan-out current parameter is the lowest. In order to ensure the accuracy of reliability evaluation, the subsequent reliability modeling needs to consider the correlation between sensitive parameters.

[0070] Step 3: Develop an accelerated degradation test plan, select a constant stress loading method, use temperature stress as the accelerating stress, set different temperature stress levels and test intervals, and record degradation data;

[0071] In this embodiment, the accelerated degradation test scheme of step 3 is the basis for further optimization of step 4.

[0072] In this embodiment, the design of the accelerated degradation test scheme includes multiple factors (as shown in Table 1, which is a table of accelerated degradation test schemes for operational amplifiers). The constant stress loading method is selected because it is easy to operate, and the temperature stress is determined as the accelerated stress because it has a significant effect on the degradation of the operational amplifier. The stress levels are set to 60°C, 80°C, and 100°C to cover the temperature range from low to high, while being controlled within a reasonable working environment. The number of samples is set to 15 under each stress to balance accuracy and cost. The measurement time interval is set to 100 hours to ensure that key degradation information is captured, and the total test duration is 800 hours to fully demonstrate the degradation law.

[0073] Table 1

[0074] Serial number Design Factors Parameter settings 1 Stress loading method Constant stress accelerated degradation test 2 Accelerated stress type Temperature stress 3 Accelerated stress level 60℃、80℃、100℃ 4 Sample size 15 samples at each stress level 5 Measurement time 100h, 200h, 300h...800h (all stress levels are the same) 6 End time of the test 800 hours

[0075] Step 4: Reduce the test cost, ensure the quality of degradation data by optimizing the accelerated degradation test scheme, and minimize the asymptotic variance according to the set objective function, which is as follows:

[0076] Based on the developed accelerated degradation test plan, it is optimized to reduce the test cost, ensure the quality of degradation data, and minimize the asymptotic variance according to the set objective function.

[0077] In this embodiment, minimizing the asymptotic variance is set as the optimization objective function to optimize the accelerated degradation test scheme, thereby reducing the test cost and ensuring the quality of degradation data. Based on the optimized test scheme, multiple performance degradation data of the operational amplifier are collected to provide data for the performance degradation modeling in step 5.

[0078] In this embodiment, the data in step 2 is a preliminary test, which is generally short-lived and only used to determine the degradation trend. The data in step 4 is a positive test (accelerated degradation test), which is generally long-lived and used for performance degradation and reliability assessment.

[0079] In this embodiment, the purpose of optimizing the accelerated degradation test is to reduce the test cost while ensuring data quality. The degradation process of the product under the maximum stress and minimum stress states is most likely to have inconsistent failure mechanisms. Therefore, the acceleration factor A of the highest stress level relative to the lowest stress level is set to M,0 The asymptotic variance of AVar(A M,0 ) as the objective function, with AVar(A M,0 ) is the minimum value of the optimization target. M,0 The estimation formula is:

[0080]

[0081] Then we can get The calculation formula is:

[0082]

[0083] in, represents the asymptotic variance, express The transpose of Indicates A M,0 The first-order partial derivative of A M,0 represents the acceleration factor for the minimum stress level, express The inverse matrix of express The information matrix, represents the degradation data matrix under multiple stresses, represents the acceleration factor, represents the Boltzmann constant, represents the unknown coefficient, T M represents the highest stress and T0 represents the lowest stress.

[0084] In this embodiment, the total test cost C consists of the following parts:

[0085] Sample fee: C1 = P1N

[0086] Among them, P1 represents the price of a single sample, and N represents the total number of test samples;

[0087] Testing fee: C2 = P2NH

[0088] Among them, P2 represents the single cost of testing the degradation value of the sample, and H represents the total number of measurements, which is equal to the sum of the number of measurements under each stress, that is,

[0089] Other expenses:

[0090] In the formula, H k It represents the price of other test costs such as labor cost, test equipment loss cost, test consumables cost, etc. P3 represents the average cost per unit time of other costs, and f represents the measurement interval.

[0091] The total test cost C is the sum of the above costs and can be expressed as:

[0092]

[0093] In the test, the maximum cost C b The objective function of the accelerated degradation test scheme optimization under the constraint of is:

[0094]

[0095] The constraints are:

[0096] C≤C b ; N k ≥1; f≥1; H k ≥1

[0097] Take the price parameters in the model as: {P1, P2, P3} = {50, 100, 200}, and the objective function The optimal experimental design scheme is obtained by searching for the best solution. The comparison between the optimized scheme and the original scheme is shown in Table 2. Table 2 is a comparison table of the optimized scheme and the original scheme.

[0098] Table 2

[0099]

[0100] Step 5: Use multiple regression analysis and Copula function to model the degradation of multiple sensitive parameters and derive the joint reliability model of multiple performance parameters, which is as follows:

[0101] After conducting tests based on the optimized accelerated return test scheme, the degradation data of sensitive performance parameters are obtained, and multiple regression analysis and Copula function are used to model the degradation of multiple sensitive parameters, and the joint reliability model of multiple performance parameters is derived:

[0102] The expression of the joint reliability model of multiple performance parameters is as follows:

[0103]

[0104] Among them, R 1,...,n (t) represents the joint reliability function under n-dimensional performance parameters, t represents time, R i (t) represents the reliability under the i-th performance parameter, T(g) represents the operator of the sum of g Copula functions, j1,...,jk,...,jg∈[1,n], k∈[1,g], Rj k (t) represents the reliability under the jkth performance parameter.

[0105] In this embodiment, the performance degradation modeling under multiple sensitive parameters is carried out. After the test is carried out according to the optimized accelerated degradation test scheme, the degradation data of the three sensitive performance parameters are obtained, and the degradation model is established using multiple regression analysis and Copula function. For multiple sensitive parameters such as input offset voltage, input bias current and output current, their joint distribution characteristics under different stress conditions are analyzed. Let the degradation amounts of the three sensitive performance parameters be X1, X2, and X3 respectively, then the comprehensive reliability of the product with three performance parameter degradation is derived by the multivariate Copula function, and the expression is:

[0106]

[0107] Among them, T i Indicates the degradation amount X i The corresponding failure time, C(u,v,w) represents the multivariate Copula function, the common ones are: Gumbel Copula, Clayton Copula and Frank Copula.

[0108] Step 6: Select the optimal Copula function through the AIC criterion to complete the reliability evaluation of the operational amplifier, and generate the reliability curve of the operational amplifier based on the test data. The implementation method is as follows:

[0109] Based on the joint reliability model of multivariate performance parameters, the model parameters of each multivariate Copula function are solved by the maximum likelihood estimation method;

[0110] Based on the joint reliability model of multivariate performance parameters and the results of solving the model parameters, the optimal Copula function is selected using the AIC criterion;

[0111] Based on the optimal Copula function, the reliability curve of the operational amplifier is generated by obtaining the joint reliability of the operational amplifier which comprehensively considers the degradation process of the performance parameters of the operational amplifier.

[0112] In this embodiment, according to the joint reliability model, the AIC criterion is used to select the optimal multivariate Copula function to complete the reliability evaluation of the operational amplifier. Let: R1(t) be the reliability of the input offset voltage of the operational amplifier; R2(t) be the reliability of the input bias current of the operational amplifier; R3(t) be the reliability of the output fan-out current of the operational amplifier. The model parameters of each multivariate Copula function are solved by the maximum likelihood estimation method, and then the optimal multivariate Copula function is determined in combination with the Akaike information criterion (AIC). Finally, the joint reliability R of the operational amplifier that comprehensively considers the degradation process of the three performance parameters of the operational amplifier input offset voltage, input bias current and output fan-out current can be obtained. 1,2,3 (t), its reliability curve is as follows Figure 5 As shown. Joint failure distribution function F 1,2,3 (t) Figure 6 As shown. Through the above steps, the design optimization and reliability evaluation of the operational amplifier accelerated degradation test are completed. According to the three performance parameters combined reliability R 1,2,3 The curve analysis of (t) shows that, considering the correlation among the three performance parameters of input offset voltage, input bias current and output fan-out current, the continuous working time (reliable life) of the operational amplifier under normal working stress (T=20℃) with a reliability not less than 0.9 is about 5200 hours, while the specified life of this type of operational amplifier is 5000 hours. The two are relatively close, which verifies the accuracy of the multivariate performance degradation model of the operational amplifier.

[0113] Example 2

[0114] The present invention provides an accelerated degradation test design and reliability assessment system for an operational amplifier, comprising a processor, wherein the processor is used to execute the accelerated degradation test design and reliability assessment method for an operational amplifier described in any one of Embodiment 1, wherein the following is performed:

[0115] The first processing module is used to analyze the failure mechanism of the operational amplifier, study the influence of stress factors on the performance indicators of the operational amplifier, and determine its degradation trend;

[0116] The second processing module is used to design a pre-test, set different stress levels, test the degradation behavior of each performance parameter, and determine the most sensitive degradation parameter;

[0117] The third processing module is used to formulate an accelerated degradation test plan, select a constant stress loading method, use temperature stress as the accelerating stress, set different temperature stress levels and test intervals, and record degradation data;

[0118] The fourth processing module is used to reduce the test cost and ensure the quality of degradation data by optimizing the accelerated degradation test plan, and minimize the asymptotic variance according to the set objective function;

[0119] a fifth processing module, for performing degradation modeling on multiple sensitive parameters using multiple regression analysis and Copula function, and deriving a joint reliability model of multiple performance parameters;

[0120] The sixth processing module is used to select the optimal Copula function through the AIC criterion to complete the reliability evaluation of the operational amplifier and generate the reliability curve of the operational amplifier based on the test data.

[0121] In this embodiment, the present application can divide the functional units according to the accelerated degradation test design and reliability assessment method. For example, each function can be divided into each functional unit, or two or more functions can be integrated into one processing unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. It should be noted that the division of units in the present invention is schematic and is only a logical division. There may be other division methods in actual implementation.

[0122] In this embodiment, the accelerated degradation test design and reliability assessment system includes hardware structures and / or software modules corresponding to the execution of various functions in order to realize the principles and beneficial effects of the accelerated degradation test design and reliability assessment method. It should be easily appreciated by those skilled in the art that, in combination with the schematic units and algorithm steps described in the embodiments disclosed in the present invention, the present invention can be implemented in the form of hardware and / or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software driven manner depends on the specific application and design constraints of the technical solution. Different methods can be used for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

Claims

1. An accelerated degradation test design and reliability assessment method for an operational amplifier, characterized in that: include: Step 1: Analyze the failure mechanism of the operational amplifier, study the influence of stress factors on the performance indicators of the operational amplifier, and determine its degradation trend; Step 2: Design a preliminary test, set different stress levels, test the degradation behavior of each performance parameter, and determine the most sensitive degradation parameter; Step 3: Develop an accelerated degradation test plan, select a constant stress loading method, use temperature stress as the accelerating stress, set different temperature stress levels and test intervals, and record degradation data; Step 4: Reduce the test cost, ensure the quality of degradation data by optimizing the accelerated degradation test scheme, and minimize the asymptotic variance according to the set objective function; Step 5: Use multiple regression analysis and Copula function to model degradation of multiple sensitive degradation parameters and derive a joint reliability model of multiple performance parameters; Step 6: Select the optimal Copula function through the AIC criterion to complete the reliability evaluation of the operational amplifier, and generate the reliability curve of the operational amplifier based on the test data.

2. The accelerated degradation test design and reliability assessment method of an operational amplifier according to claim 1, characterized in that: The step 1 is specifically as follows: The failure mechanism of the operational amplifier is analyzed, the influence of stress factors on the performance indicators of the operational amplifier is studied, and its degradation trend is determined. The stress type of the sensitive parameters in the preliminary test of step 2 and the accelerated degradation test of step 3 is determined by the degradation trend.

3. The accelerated degradation test design and reliability assessment method of an operational amplifier according to claim 1, characterized in that: The step 2 is specifically as follows: Design a preliminary test, set different stress levels, and determine the most sensitive degradation parameters based on the determined degradation trend, so as to provide the stress type and level of the accelerated degradation test for step 3 through the preliminary test.

4. The accelerated degradation test design and reliability assessment method of an operational amplifier according to claim 3, characterized in that: The analysis of the most sensitive degradation parameters is as follows: The average degradation rate and volatility index are used to analyze the degradation data of each sensitive parameter, where the expression of the average degradation rate is as follows: Where v represents the average degradation rate of performance parameters, x max represents the maximum degradation value of the performance parameter, x0 represents the initial value of the performance parameter, and t represents the degradation of the performance parameter value from x0 to x max Time taken; The expression of volatility indicator is as follows: Among them, w represents the volatility of the degradation trajectory, x i represents the i-th data point of the degradation trajectory, y i Corresponding to x i The fitted value of , m represents the number of degraded data.

5. The accelerated degradation test design and reliability assessment method of an operational amplifier according to claim 1, characterized in that: The step 4 is specifically as follows: Based on the developed accelerated degradation test plan, it is optimized to reduce the test cost, ensure the quality of degradation data, and minimize the asymptotic variance according to the set objective function.

6. The accelerated degradation test design and reliability evaluation method of an operational amplifier according to claim 5, characterized in that: The expression of the asymptotic variance in step 4 is as follows: in, represents the asymptotic variance, express The transpose of Indicates A M,0 The first-order partial derivative of A M,0 represents the acceleration factor for the minimum stress level, express The inverse matrix of express The information matrix, represents the degradation data matrix under multiple stresses, represents the acceleration factor, represents the Boltzmann constant, represents the unknown coefficient, T M represents the highest stress and T0 represents the lowest stress.

7. The accelerated degradation test design and reliability evaluation method of an operational amplifier according to claim 1, characterized in that: The step 5 is specifically as follows: After conducting tests based on the optimized accelerated return test scheme, the degradation data of sensitive performance parameters were obtained, and multiple regression analysis and Copula function were used to model the degradation of multiple sensitive parameters, and the joint reliability model of multiple performance parameters was derived.

8. The accelerated degradation test design and reliability evaluation method of an operational amplifier according to claim 7, characterized in that: The expression of the joint reliability model of the multivariate performance parameters is as follows: Among them, R 1,...,n (t) represents the joint reliability function under n-dimensional performance parameters, t represents time, R i (t) represents the reliability under the i-th performance parameter, T(g) represents the operator of the sum of g Copula functions, j1,...,j k ,...,j g ∈[1,n],k∈[1,g],R jk (t) represents the jth k Reliability under performance parameters.

9. The accelerated degradation test design and reliability assessment method of an operational amplifier according to claim 1, characterized in that: The step 6 is specifically as follows: Based on the joint reliability model of multivariate performance parameters, the model parameters of each multivariate Copula function are solved by the maximum likelihood estimation method; Based on the joint reliability model of multivariate performance parameters and the results of solving the model parameters, the optimal Copula function is selected using the AIC criterion; Based on the optimal Copula function, the reliability curve of the operational amplifier is generated by obtaining the joint reliability of the operational amplifier which comprehensively considers the degradation process of the performance parameters of the operational amplifier.

10. An accelerated degradation test design and reliability assessment system for an operational amplifier, characterized in that: It comprises a processor, and the processor is used to execute the accelerated degradation test design and reliability assessment method of the operational amplifier as described in any one of claims 1-9.

Images