A bias current control method for an isolated operational amplifier

Abstract

This invention relates to the field of amplifier bias current control technology, specifically to a method for controlling the bias current of an isolated operational amplifier. The method includes: acquiring output performance characteristics, compensation current, and judgment index values ​​at different judgment times; then analyzing these values ​​to obtain the optimal compensation current; and finally using this optimal compensation current to compensate the amplifier's current. Based on the obtained optimal compensation current, this invention can minimize overcompensation or undercompensation, thereby improving the effectiveness of bias current control for the amplifier.

Description

Technical Field

[0001] The invention relates to the technical field of amplifier bias current control, and in particular to a bias current control method for an isolated operational amplifier. Background Art

[0002] An isolated operational amplifier is an integrated circuit that combines the high gain, linear amplification characteristics and electrical isolation of an operational amplifier. Its main function is to provide electrical isolation between input and output while transmitting signals. It is usually used in situations where high-precision signal processing and isolation of different potentials are required, such as industrial automation, medical equipment, motor control and other fields. Bias current is a small current that flows into or out of the input of an operational amplifier when it is working. Excessive bias current may cause errors in the output signal, such as signal offset or distortion. Excessive bias current may cause the output signal to be sensitive to noise, which in turn causes the amplifier to be unable to work stably and efficiently, especially in the case of high-impedance signal sources. Therefore, during the operation of the amplifier, controlling the bias current of the amplifier is crucial to keep the amplifier working stably and efficiently. Controlling the bias current of the amplifier can also improve signal accuracy and prevent the influence of current interference on the amplified signal, thereby improving the reliability and performance of the overall circuit.

[0003] In the prior art, a traditional compensation current method is usually used to control the bias current of an amplifier. However, when the traditional compensation current method is used to control the bias current of an amplifier, that is, when current compensation is performed on the amplifier, a poor compensation effect may occur. The poor compensation effect may lead to a poor control effect when the bias current of the amplifier is controlled. The reason for the poor compensation effect is that when the traditional compensation current method is used for compensation, over-compensation or under-compensation may frequently occur. Both over-compensation and under-compensation may lead to poor compensation effect. That is, the frequent occurrence of over-compensation or under-compensation may lead to a poor control effect when the bias current of the amplifier is controlled. Therefore, when controlling the bias current of the amplifier, how to improve the control effect is an urgent problem to be solved. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a bias current control method for an isolated operational amplifier, and the technical solution adopted is as follows:

[0005] An embodiment of the present invention provides a bias current control method for an isolated operational amplifier, comprising the following steps:

[0006] During the operation of the isolated operational amplifier, an output effect characterization value at an i-th judgment moment is obtained, where the i-th judgment moment is a current moment;

[0007] According to the preset initial control factor and the output effect characterization value at the i-th judgment moment, the compensation current at the i-th judgment moment is obtained, according to the compensation current at the i-th judgment moment, the output effect characterization value at the i+1-th judgment moment is obtained, and according to the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment, the judgment index value at the i+1-th judgment moment is obtained;

[0008] Determine whether the judgment index value at the i+1th judgment moment is not greater than a preset judgment threshold value, and if so, obtain the control factor at the i+1th judgment moment, obtain the compensation current at the i+1th judgment moment according to the control factor and the output effect characterization value at the i+1th judgment moment, obtain the output effect characterization value at the i+2th judgment moment according to the compensation current at the i+1th judgment moment, and obtain the judgment index value at the i+2th judgment moment according to the output effect characterization values ​​at the i+1th judgment moment and the i+2th judgment moment;

[0009] Determine whether the judgment index value at the i+2th judgment moment is not greater than a preset judgment threshold value, and if so, obtain the control factor at the i+2th judgment moment, obtain the compensation current at the i+2th judgment moment according to the control factor and the output effect characterization value at the i+2th judgment moment, obtain the output effect characterization value at the i+3th judgment moment according to the compensation current at the i+2th judgment moment, and obtain the judgment index value at the i+3th judgment moment according to the output effect characterization values ​​at the i+2th judgment moment and the i+3th judgment moment;

[0010] Continue to determine whether the judgment index value at the i+3th judgment moment is not greater than the preset judgment threshold; if not, use the compensation current at the i+2th judgment moment as the optimal compensation current, and use the optimal compensation current to perform current compensation on the amplifier after the i+3th judgment moment.

[0011] Beneficial effect: The present invention first obtains the output effect characterization value at the i-th judgment moment during the operation of the isolated operational amplifier; then obtains the compensation current at the i-th judgment moment according to the preset initial control factor and the output effect characterization value at the i-th judgment moment, obtains the output effect characterization value at the i+1-th judgment moment according to the compensation current at the i-th judgment moment, and obtains the judgment index value at the i+1-th judgment moment according to the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment; then judges whether the judgment index value at the i+1-th judgment moment is not greater than the preset judgment threshold, and if so, obtains the control factor at the i+1-th judgment moment, obtains the compensation current at the i+1-th judgment moment according to the control factor and the output effect characterization value at the i+1-th judgment moment, obtains the output effect characterization value at the i+2-th judgment moment according to the compensation current at the i+1-th judgment moment, and obtains the judgment index value at the i+1-th judgment moment according to the i+1-th judgment moment and the output effect characterization value at the i+2th judgment moment, to obtain the judgment index value at the i+2th judgment moment; then, determine whether the judgment index value at the i+2th judgment moment is not greater than the preset judgment threshold value, if so, obtain the control factor at the i+2th judgment moment, and obtain the compensation current at the i+2th judgment moment according to the control factor and the output effect characterization value at the i+2th judgment moment, obtain the output effect characterization value at the i+3th judgment moment according to the compensation current at the i+2th judgment moment, and obtain the judgment index value at the i+3th judgment moment according to the output effect characterization values ​​at the i+2th judgment moment and the i+3th judgment moment; finally, continue to determine whether the judgment index value at the i+3th judgment moment is not greater than the preset judgment threshold value, if not, take the compensation current at the i+2th judgment moment as the optimal compensation current, and use the optimal compensation current to perform current compensation on the amplifier after the i+3th judgment moment. Furthermore, the present invention can reduce the occurrence of over-compensation or under-compensation as much as possible based on the obtained optimal compensation current, thereby improving the effect of controlling the bias current of the amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 The present invention is a flow chart of a bias current control method of an isolated operational amplifier. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the embodiments of the present invention.

[0015] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] This embodiment provides a bias current control method for an isolated operational amplifier, which is described in detail as follows:

[0017] like Figure 1 As shown, the bias current control method of the isolated operational amplifier includes the following steps:

[0018] Step S001, during the operation of the isolated operational amplifier, obtaining an output effect characterization value at the ith judgment moment, wherein the ith judgment moment is the current moment.

[0019] When the conventional compensation current method is used to control the bias current of the amplifier, that is, when the amplifier is current compensated, the compensation effect is poor, and the poor compensation effect will lead to the problem of poor control effect when the bias current of the amplifier is controlled, and the reason for the poor compensation effect is that when the conventional compensation current method is used for compensation, over-compensation or under-compensation may frequently occur, and the frequent occurrence of over-compensation or under-compensation will lead to poor compensation effect, that is, the frequent occurrence of over-compensation or under-compensation will lead to the problem of poor control effect when the bias current of the amplifier is controlled, the over-compensation refers to that the compensation current is too large, and the under-compensation refers to that the compensation current is small, and the frequent occurrence of under-compensation or over-compensation will also affect the overall working performance of the amplifier and the stability of the amplifier, so the main purpose of this embodiment is to reduce or reduce the occurrence of over-compensation or under-compensation as much as possible, so as to improve the effect of controlling the bias current of the amplifier, and this embodiment mainly achieves the purpose of reducing the occurrence of over-compensation or under-compensation by finding the optimal compensation current method.

[0020] Because this embodiment mainly determines the optimal compensation current by analyzing the output effect characterization values ​​of different time periods, this embodiment will first obtain the output effect characterization value at the current moment, and the output effect characterization value at the current moment is the basis for obtaining the output effect characterization value corresponding to the subsequent moment; in addition, this embodiment is analyzed by taking any isolated operational amplifier as an example, that is, all isolated operational amplifiers or amplifiers that appear in this embodiment later refer to the same isolated operational amplifier.

[0021] Next, in the process of the isolated operational amplifier working in this embodiment, the output effect characterization value at the i-th judgment moment is first obtained, and the i-th judgment moment is the current moment. In this embodiment, it is necessary to obtain the output effect characterization values ​​at multiple judgment moments, that is, this embodiment not only obtains the output effect characterization value at the i-th judgment moment, and in this embodiment, the method for obtaining the output effect characterization value at each judgment moment is the same. Therefore, for the convenience of description, this embodiment will take the acquisition process of the output effect characterization value at any judgment moment T0 as an example for description, that is, the acquisition process of the output effect characterization value at the judgment moment T0 is:

[0022] First, the monitoring time period corresponding to the judgment moment T0 is obtained, and the monitoring time period corresponding to each judgment moment is the time period formed from the previous judgment moment to the judgment moment, and each monitoring time period corresponding to the judgment moment includes A monitoring moments, A is greater than 0, that is, the monitoring time period corresponding to the judgment moment T0 is the time period formed from the previous judgment moment T0 to the judgment moment T0.

[0023] In specific applications, the implementer needs to set the monitoring time period corresponding to the judgment moment, that is, the time interval between adjacent judgment moments, and the value of A according to actual conditions. For example, in this embodiment, the time length of the monitoring time period corresponding to the judgment moment appearing in the embodiment can be set to 0.5 seconds, that is, the time interval between adjacent judgment moments is 0.5 seconds. In this embodiment, the value of A can also be set to 25, and the time intervals between adjacent monitoring moments are also required to be equal.

[0024] Then, the bias current of the amplifier at each monitoring moment in the monitoring time period corresponding to the judgment time instant T0 is recorded as the bias current corresponding to the corresponding monitoring moment; thereafter, under the bias current corresponding to each monitoring moment in the monitoring time period corresponding to the judgment time instant T0, the input signal and output signal of the amplifier in the monitoring time period corresponding to the judgment time instant T0 are obtained, and are respectively recorded as the first input signal and the first output signal corresponding to the judgment time instant T0, at which time the input signal or the output signal is a time domain signal, and the time interval corresponding to the first input signal or the first output signal corresponding to the judgment time instant T0 is the time interval corresponding to the monitoring time period corresponding to the judgment time instant T0; in addition, this embodiment mainly uses a high-precision current monitoring module to collect the bias current of the amplifier.

[0025] Then, the DTW (dynamic time warping) algorithm is used to obtain the DTW distance between the first input signal corresponding to the judgment time T0 and the first output signal corresponding to it, and recorded as the first characterization value corresponding to the judgment time T0; then, the first difference sequence corresponding to the judgment time T0 is obtained, and the mean of the first difference sequence corresponding to the judgment time T0 is recorded as the second characterization value corresponding to the judgment time T0, and the a-th first difference in the first difference sequence corresponding to the judgment time T0 is the absolute value of the difference between the a-th first amplitude corresponding to the judgment time T0 and the a-th second amplitude corresponding to it, the a-th first amplitude corresponding to the judgment time T0 is the amplitude corresponding to the frequency with the same frequency as the a-th frequency in the first frequency domain signal corresponding to the judgment time T0, and the a-th second amplitude corresponding to the judgment time T0 is the absolute value of the difference between the a-th first amplitude corresponding to the judgment time T0 and the a-th second amplitude corresponding to it. The amplitude corresponding to the frequency with the same frequency as the a-th frequency in the second frequency domain signal corresponding to the judgment time T0, the first frequency domain signal corresponding to the judgment time T0 is the frequency domain signal obtained after the first input signal corresponding to the judgment time T0 is fast Fourier transformed, the second frequency domain signal corresponding to the judgment time T0 is the frequency domain signal obtained after the first output signal corresponding to the judgment time T0 is fast Fourier transformed, the a-th frequency at this time is the a-th frequency in the frequency sequence corresponding to the judgment time T0, and the frequency sequence corresponding to the judgment time T0 is constructed by the frequencies whose amplitudes are not 0 in the second frequency domain signal corresponding to the judgment time T0; then the first characterization value corresponding to the judgment time T0 is multiplied by the corresponding second characterization value, and then the inverse of the result obtained by adding the result to the preset first constant is recorded as the output effect characterization value at the judgment time T0.

[0026] In addition, if the judgment moment T0 is not the i-th judgment moment, then the bias current corresponding to all monitoring moments in the monitoring time period corresponding to the judgment moment T0 refers to the bias current compensated by the compensation current of the previous judgment moment of the judgment moment T0, that is, the compensation current of each judgment moment is mainly used to perform current compensation on the amplifier in the monitoring time period corresponding to the next judgment moment of the judgment moment, and if the judgment moment T0 is not the i-th judgment moment, then the bias current corresponding to all monitoring moments in the monitoring time period corresponding to the judgment moment T0 are equal, and are all the compensation currents of the previous judgment moment of the judgment moment T0, and the previous judgment moment of the judgment moment T0 refers to a judgment moment adjacent to the judgment moment T0 and located before the judgment moment T0 in time; if the judgment moment T0 is the i-th judgment moment, and there is an act of current compensation for the amplifier in the monitoring time period corresponding to the i-th judgment moment, then the bias current corresponding to the monitoring moment described above is also the bias current collected after current compensation, and if there is no act of current compensation for the amplifier in the monitoring time period corresponding to the i-th judgment moment, then the bias current corresponding to the monitoring moment described above is not the bias current after current compensation.

[0027] For ease of understanding, this embodiment will now specifically describe an expression for obtaining the output effect representation value at the i-th judgment moment:

[0028] .

[0029] .

[0030] in, is the output effect representation value at the i-th judgment moment, c1 is the preset first constant, is the first representation value corresponding to the i-th judgment moment, is the second representation value corresponding to the i-th judgment moment, is the total number of data in the first difference sequence corresponding to the i-th judgment moment, is the ath first amplitude, is the ath second amplitude, is the ath first difference in the first difference sequence corresponding to the i-th judgment moment; and in a specific application, the implementer needs to set the value of c1 according to the actual situation. For example, in this embodiment, the value of c1 is set to 0.01, and the purpose of c1 is to prevent the denominator from being 0.

[0031] In addition, the smaller the first characterization value corresponding to the i-th judgment moment is, the smaller the offset between the first input signal corresponding to the i-th judgment moment and the first output signal corresponding thereto is, which also indicates that under the amplifier bias current at each monitoring moment, the output effect of the output signal corresponding to the i-th judgment moment is better; the smaller the second characterization value corresponding to the i-th judgment moment is, the closer the frequency component and intensity in the spectrum signal corresponding to the first output signal corresponding to the i-th judgment moment and the first input signal are, which further indicates that the degree of interference of the first output signal corresponding to the i-th judgment moment by noise may be smaller, and the smaller the degree of interference by noise is, the more it indicates that under the amplifier bias current at each monitoring moment, the output effect of the output signal corresponding to the i-th judgment moment is better; and based on the above analysis, it can be seen that the smaller the first characterization value and the second characterization value corresponding to the i-th judgment moment are, the better the output effect of the output signal corresponding to the i-th judgment moment is. The larger the value of The larger the value of is, the better the output effect of the output signal corresponding to the i-th judgment moment is. On the contrary, when the first characterization value and the second characterization value corresponding to the i-th judgment moment are larger, it indicates that The smaller the value of The smaller the value of , the worse the output effect of the output signal corresponding to the i-th judgment moment.

[0032] Therefore, this embodiment can obtain the output effect representation value at the i-th judgment moment through the above process.

[0033] Step S002, according to the preset initial control factor and the output effect characterization value at the i-th judgment moment, obtain the compensation current at the i-th judgment moment, according to the compensation current at the i-th judgment moment, obtain the output effect characterization value at the i+1-th judgment moment, and according to the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment, obtain the judgment index value at the i+1-th judgment moment.

[0034] After obtaining the output effect characterization value at the i-th judgment moment, the present embodiment obtains the compensation current at the i-th judgment moment according to the preset initial control factor and the output effect characterization value at the i-th judgment moment, and then obtains the output effect characterization value at the i+1-th judgment moment according to the compensation current at the i-th judgment moment, and obtains the judgment index value at the i+1-th judgment moment according to the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment, and the judgment index value is the cutoff condition for determining the optimal compensation current; and based on the above description, it can be seen that if you want to obtain the judgment index value at the i+1-th judgment moment, you need to first obtain the compensation current at the i-th judgment moment according to the preset initial control factor and the output effect characterization value at the i-th judgment moment, so the acquisition process of the compensation current at the i-th judgment moment is:

[0035] First, a preset initial control factor is obtained, and the preset initial control factor is used as the control factor at the i-th judgment moment. The main function of the control factor is to control the adjustment size or adjustment rate of the compensation current, and it is also related to the rate of finding the optimal compensation current. In specific applications, the implementer needs to set the preset initial control factor according to actual conditions, but the value of the preset initial control factor is required to be small. For example, in this embodiment, the preset initial control factor can be set to 0.02.

[0036] In addition, in this embodiment, not only the compensation current at the i-th judgment moment needs to be obtained, but also the compensation currents at multiple judgment moments after the i-th judgment moment need to be obtained. In addition, in this embodiment, the method for obtaining the compensation current at each judgment moment is the same. Therefore, for the convenience of description and understanding, this embodiment will be described later by taking the process of obtaining the compensation current at any judgment moment T0 as an example, that is, the process of obtaining the compensation current at the judgment moment T0 is:

[0037] First, at each monitoring moment in the monitoring time period corresponding to the judgment moment T0, the bias current of the amplifier is obtained, and the average value of all the bias currents of the amplifier obtained in the monitoring time period corresponding to the judgment moment T0 is recorded as the average bias current at the judgment moment T0; then, the result after subtracting the output effect characterization value at the judgment moment T0 from the preset second constant is obtained, and recorded as the first difference operation value at the judgment moment T0, and the product of the average bias current at the judgment moment T0 and the control factor at the judgment moment T0 is obtained, and recorded as the first product value at the judgment moment T0; then, the first difference operation value at the judgment moment T0 is multiplied by the first product value at the judgment moment T0, and the multiplication result is recorded as the first difference operation value at the judgment moment T0 The second product value is obtained, and then the opposite of the second product value at the judgment moment T0 is obtained, and the opposite is used as the compensation current at the judgment moment T0; for example, if the second product value at the judgment moment T0 is S2, then the opposite of the second product value at the judgment moment T0 is -(S2); in addition, the smaller the output effect characterization value at the judgment moment T0 is, the larger the compensation current obtained at the judgment moment T0 is, and the compensation current at the judgment moment T0 is mainly used to compensate for the amplifier in the time period formed by the judgment moment T0 to the next judgment moment of the judgment moment T0, and the next judgment moment of the judgment moment T0 refers to a judgment moment adjacent to the judgment moment T0 and located after the judgment moment T0 in time.

[0038] Therefore, when the control factor and the output effect characterization value at the i-th judgment moment are known, the compensation current at the i-th judgment moment can be obtained according to the above-mentioned method of obtaining the compensation current at the judgment moment T0, and the specific acquisition method will not be described in detail; and after obtaining the compensation current at the i-th judgment moment, the output effect characterization value at the i+1-th judgment moment is obtained according to the compensation current at the i-th judgment moment; and in this embodiment, the method for obtaining the output effect characterization value at the i+1-th judgment moment is the same as the above-mentioned method for obtaining the output effect characterization value at the judgment moment T0, so this embodiment will not be described in detail, and the compensation current at the i-th judgment moment here mainly functions to current compensate the amplifier flow in the monitoring time period corresponding to the i+1-th judgment moment, and when calculating the output effect characterization value at the i+1-th judgment moment, it is necessary to obtain the input and output signals of the amplifier, and the input and output signals of the amplifier obtained at this time are the signals under current compensation using the compensation current at the i-th judgment moment. In addition, after obtaining the compensation current, the microcontroller output analysis module in the compensation circuit of the isolated operational amplifier will also receive the compensation current information, and compensate the bias current of the amplifier according to the received information.

[0039] After obtaining the output effect characterization value at the i+1th judgment moment, the judgment index value at the i+1th judgment moment is obtained according to the obtained output effect characterization values ​​at the i-th judgment moment and the i+1th judgment moment, and the judgment index value at the i+1th judgment moment is the basis for determining the optimal compensation current; in addition, in the present embodiment, not only the judgment index value at the i+1th judgment moment needs to be obtained, but also the judgment index values ​​at multiple judgment moments after the i+1th judgment moment may need to be obtained. Since the method for obtaining the judgment index value at each judgment moment is the same in the present embodiment, for the sake of ease of description and understanding, the following description will be made by taking the process of obtaining the judgment index value at the i+bth judgment moment as an example, where b is a positive integer, i.e., the i+bth judgment moment is not the i-th judgment moment, and therefore the process of obtaining the judgment index value at the i+bth judgment moment is as follows:

[0040] First, the ratio of the output effect characterization value at the i+bth judgment moment to the output effect characterization value at the i-th judgment moment is obtained, and recorded as the first indicator value at the i+bth judgment moment; then, the reciprocal of the result obtained by adding the preset first constant and the first difference absolute value at the i+bth judgment moment is obtained, and recorded as the second indicator value at the i+bth judgment moment; and the first difference absolute value at the i+bth judgment moment refers to the absolute value of the difference between the output effect characterization value at the i+bth judgment moment and the output effect characterization value at the i+(b-1)th judgment moment; then, the normalized value of the result obtained by multiplying the first indicator value at the i+bth judgment moment and its corresponding second indicator value is recorded as the judgment indicator value at the i+bth judgment moment; in addition, the specific expression for obtaining the judgment indicator value at the i+bth judgment moment is:

[0041] .

[0042] in, is the judgment index value at the i+bth judgment moment, Norm() is the normalization function, is the output effect representation value at the i+bth judgment moment, is the output effect representation value at the i-th judgment moment, is the output effect representation value at the i+(b-1)th judgment moment; is the first indicator value at the i+bth judgment moment, is the second indicator of the i+bth judgment moment, is the absolute value of the first difference at the i+bth judgment moment.

[0043] And when the first indicator value and the second indicator at the i+bth judgment moment are larger, it indicates that the judgment indicator value of the i+bth judgment moment is larger, and the larger the judgment indicator value of the i+bth judgment moment is, the greater the possibility that the compensation current at the i+(b-1)th judgment moment is the optimal compensation current. Conversely, it indicates that the possibility that the compensation current at the i+(b-1)th judgment moment is the optimal compensation current is smaller.

[0044] Therefore, when the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment are known, the judgment index value at the i+1-th judgment moment can be obtained according to the above-mentioned method of obtaining the judgment index value at the i+b-th judgment moment, and since the process of obtaining the judgment index value at the i+b-th judgment moment has been described in detail in the above process, this embodiment no longer describes the process of obtaining the judgment index value at the i+1-th judgment moment.

[0045] Step S003, determine whether the judgment index value of the i+1th judgment moment is not greater than the preset judgment threshold value. If so, obtain the control factor of the i+1th judgment moment, and obtain the compensation current of the i+1th judgment moment according to the control factor and the output effect characterization value of the i+1th judgment moment. According to the compensation current of the i+1th judgment moment, obtain the output effect characterization value of the i+2th judgment moment, and according to the output effect characterization values ​​of the i+1th judgment moment and the i+2th judgment moment, obtain the judgment index value of the i+2th judgment moment.

[0046] This embodiment then determines whether the judgment index value of the i+1th judgment moment obtained above is not greater than the preset judgment threshold. If so, it is determined that the compensation current at the i+1th judgment moment is not the optimal compensation current, and the optimal compensation current needs to be further found. That is, when it is determined that the judgment index value of the i+1th judgment moment is less than or equal to the preset judgment threshold, it is necessary to obtain the control factor of the i+1th judgment moment, and then obtain the compensation current of the i+1th judgment moment based on the control factor and the output effect characterization value of the i+1th judgment moment, and then obtain the output effect characterization value of the i+2th judgment moment based on the compensation current at the i+1th judgment moment, and obtain the judgment index value of the i+2th judgment moment based on the output effect characterization values ​​of the i+1th judgment moment and the i+2th judgment moment, and then further determine the optimal compensation current based on the judgment index value of the i+2th judgment moment.

[0047] Therefore, based on the above description, it can be known that if the judgment index value of the i+2th judgment moment is to be obtained, the control factor of the i+1th judgment moment needs to be obtained first; because in this embodiment, it may not only be necessary to obtain the control factor of the i+1th judgment moment, but it may also be necessary to obtain the control factors of multiple judgment moments after the i+1th judgment moment, and because in this embodiment, the method for obtaining the control factor of each judgment moment is the same, so for the convenience of description and understanding, the following will take the acquisition process of the control factor of the i+bth judgment moment as an example for description, that is, the acquisition process of the control factor of the i+bth judgment moment is:

[0048] First, the ratio of the absolute value of the first difference at the i+bth judgment moment to the output effect representation value at the i+(b-1)th judgment moment is recorded as the first ratio, that is, the absolute value of the first difference at the i+bth judgment moment is the absolute value of the difference between the output effect representation value at the i+bth judgment moment and the output effect representation value at the i+(b-1)th judgment moment; then, negative correlation mapping is performed on the first ratio, and the mapping result is recorded as the target mapping value corresponding to the i+bth judgment moment; and the specific expression for obtaining the target mapping value corresponding to the i+bth judgment moment is:

[0049] .

[0050] in, is the target mapping value corresponding to the i+bth judgment moment, exp() is an exponential function with a constant e as the base; and when The smaller the value of The larger the value, the smaller it is.

[0051] Then, it is determined whether the output effect characterization value at the i+bth judgment moment is not less than the output effect characterization value at the i+(b-1)th judgment moment. If so, it indicates that the compensation may not be optimal, and it is necessary to further find and determine the optimal compensation current, that is, when the output effect characterization value at the i+bth judgment moment is greater than or equal to the output effect characterization value at the i+(b-1)th judgment moment, the value after adding the preset second constant to the target mapping value corresponding to the i+bth judgment moment is multiplied by the control factor at the i+(b-1)th judgment moment, and recorded as the control factor at the i+bth judgment moment, and when the output effect characterization value at the i+bth judgment moment is not less than the output effect characterization value at the i+(b-1)th judgment moment and the larger the target mapping value corresponding to the i+bth judgment moment is, it indicates that the current The smaller, and at this time The smaller it is, the less obvious the effect of compensating the monitoring time period corresponding to the i+bth judgment moment based on the compensation current at the i+(b-1)th judgment moment is. The compensation current should be adjusted to a greater extent in the future. The larger the value is, the more obvious the effect of compensating the monitoring time period corresponding to the i+bth judgment moment based on the compensation current at the i+(b-1)th judgment moment is. In order to avoid missing the optimal compensation current, the compensation current should be adjusted to a smaller extent.

[0052] In addition, if the output effect characterization value at the i+bth judgment moment is less than the output effect characterization value at the i+(b-1)th judgment moment, it indicates that over-compensation may have occurred, and it is also necessary to further find and determine the optimal compensation current, that is, when the output effect characterization value at the i+bth judgment moment is less than the output effect characterization value at the i+(b-1)th judgment moment, the value after deducting the target mapping value corresponding to the i+bth judgment moment from the preset second constant is multiplied by the control factor at the i+(b-1)th judgment moment, and the result is recorded as the control factor at the i+bth judgment moment, and when the output effect characterization value at the i+bth judgment moment is less than the output effect characterization value at the i+(b-1)th judgment moment and the larger the target mapping value corresponding to the i+bth judgment moment is, it indicates that over-compensation may have occurred, and it is also necessary to further find and determine the optimal compensation current, that is, when the output effect characterization value at the i+bth judgment moment is less than the output effect characterization value at the i+(b-1)th judgment moment and the larger the target mapping value corresponding to the i+bth judgment moment is, the greater the result is. The smaller, and at this time The smaller it is, the greater the degree of overcompensation is when compensating the monitoring time period corresponding to the i+bth judgment moment based on the compensation current at the i-th judgment moment, and the compensation current should be adjusted to a greater extent in the future; and when The larger it is, the smaller the degree of over-compensation is when compensating the monitoring time period corresponding to the i+bth judgment moment based on the compensation current at the i-th judgment moment. In order to avoid missing the optimal compensation current, the compensation current should be adjusted to a smaller extent.

[0053] Therefore, according to the above method for obtaining the control factor at the i+bth judgment moment, the control factor at the i+1th judgment moment can be obtained in this embodiment, so it will not be described in detail; after obtaining the control factor at the i+1th judgment moment, the compensation current at the i+1th judgment moment is obtained according to the control factor at the i+1th judgment moment and the output effect characterization value, and because the control factor and the output effect characterization value at the i+1th judgment moment are known, according to the above method for obtaining the compensation current at the judgment moment T0, the compensation current at the i+1th judgment moment can be obtained, and the specific acquisition method will not be described in detail; after obtaining the compensation current at the i+1th judgment moment, the output effect characterization value at the i+2th judgment moment is obtained according to the compensation current at the i+1th judgment moment, and according to the above method for obtaining the output effect characterization value at the judgment moment T0, the output effect characterization value at the i+2th judgment moment can be obtained, so this embodiment will not describe the acquisition process of the output effect characterization value at the i+2th judgment moment.

[0054] In a specific application, the implementer needs to set the value of the preset second constant according to the actual situation. For example, in this embodiment, the value of the preset second constant is set to 1.

[0055] After obtaining the output effect characterization value of the i+2th judgment moment, the judgment index value of the i+2th judgment moment is obtained according to the output effect characterization values ​​of the i+1th judgment moment and the i+2th judgment moment; and when the output effect characterization values ​​of the i+1th judgment moment and the i+2th judgment moment are known, the judgment index value of the i+2th judgment moment can be obtained according to the method of obtaining the judgment index value of the i+bth judgment moment. Therefore, this embodiment no longer describes in detail the process of obtaining the judgment index value of the i+2th judgment moment.

[0056] In a specific application, the implementer needs to set the preset judgment threshold according to the actual situation. For example, in this embodiment, the preset judgment threshold can be set to 0.73.

[0057] Step S004, determine whether the judgment index value at the i+2th judgment moment is not greater than the preset judgment threshold value, if so, obtain the control factor at the i+2th judgment moment, obtain the compensation current at the i+2th judgment moment according to the control factor and the output effect characterization value at the i+2th judgment moment, obtain the output effect characterization value at the i+3th judgment moment according to the compensation current at the i+2th judgment moment, and obtain the judgment index value at the i+3th judgment moment according to the output effect characterization values ​​at the i+2th judgment moment and the i+3th judgment moment; continue to determine whether the judgment index value at the i+3th judgment moment is not greater than the preset judgment threshold value, if not, use the compensation current at the i+2th judgment moment as the optimal compensation current, and use the optimal compensation current to perform current compensation on the amplifier after the i+3th judgment moment.

[0058] After obtaining the judgment index value at the i+2th judgment moment, it is immediately judged whether the judgment index value at the i+2th judgment moment is not greater than the preset judgment threshold value. If so, the control factor at the i+2th judgment moment is continued to be obtained, and then the compensation current at the i+2th judgment moment is obtained according to the control factor and the output effect characterization value at the i+2th judgment moment, and then the output effect characterization value at the i+3th judgment moment is obtained according to the compensation current at the i+2th judgment moment, and the judgment index value at the i+3th judgment moment is obtained according to the output effect characterization values ​​at the i+2th judgment moment and the i+3th judgment moment; then it is continued to judge whether the judgment index value at the i+3th judgment moment is not greater than the preset judgment threshold value. If it is judged that the judgment index value at the i+3th judgment moment is greater than the preset judgment threshold value, it is determined that the compensation current at the i+2th judgment moment is the optimal compensation current, and there is no need to continue to search for the optimal compensation current.

[0059] In addition, in the present embodiment, the method for obtaining the control factor at the i+2th judgment moment is the same as the method for obtaining the control factor at the i+bth judgment moment mentioned above, so this embodiment will not be described in detail; the method for obtaining the compensation current at the i+2th judgment moment is the same as the method for obtaining the compensation current at the judgment moment T0 mentioned above, so this embodiment will not be described in detail; the method for obtaining the output effect characterization value at the i+3th judgment moment is the same as the method for obtaining the output effect characterization value at the judgment moment T0 mentioned above, so this embodiment will not be described in detail; the method for obtaining the judgment index value at the i+3th judgment moment is the same as the method for obtaining the judgment index value at the i+bth judgment moment mentioned above, so this embodiment will not be described in detail.

[0060] Therefore, this embodiment can obtain the optimal compensation current through the above process, and after obtaining the optimal compensation current, the optimal compensation current is used to perform current compensation. As described above in this embodiment, if the optimal compensation current is found at the i+3th judgment moment, then the optimal compensation current obtained at this time is subsequently used to perform current compensation on the amplifier after the i+3th judgment moment.

[0061] In addition, after using the optimal compensation current to perform current compensation on the amplifier after the i+3th judgment moment, the following steps are also included: if in the process of using the optimal compensation current obtained above to perform current compensation on the amplifier after the i+3th judgment moment, it is monitored that the bias current change value of the amplifier at the jth monitoring moment is greater than the preset change threshold corresponding to the jth monitoring moment, then at this time, the jth monitoring moment is used as the new i-th judgment moment, and the method of obtaining the optimal compensation current according to the above steps is used to continue to find a new optimal compensation current, and the jth monitoring moment is located after the i+3th judgment moment in time.

[0062] In this embodiment, the method for obtaining the bias current change value of the amplifier at the jth monitoring moment is: first, obtain the historical monitoring time period corresponding to the jth monitoring moment, and record the average of the bias current of the amplifier at all monitoring moments in the historical monitoring time period as the first average, and the bias current at this time is the compensated value; then, record the absolute value of the difference between the bias current of the amplifier at the jth monitoring moment and the first average as the bias current change value of the amplifier at the jth monitoring moment, and the bias current of the amplifier at the jth monitoring moment is also the value after current compensation.

[0063] In addition, in specific applications, the implementer needs to set the preset change threshold corresponding to the j-th monitoring moment and the corresponding historical monitoring time period according to actual conditions. For example, in this embodiment, the product of the bias current of the amplifier at the j-th monitoring moment and 0.1 is used as the preset change threshold corresponding to the j-th monitoring moment. In this embodiment, the time period formed by 0.5 seconds before the j-th monitoring moment is recorded as the historical monitoring time period corresponding to the j-th monitoring moment, and the number of monitoring moments in the historical monitoring time period can be set to 25.

[0064] In summary, in the present embodiment, first, during the operation of the isolated operational amplifier, an output effect characterization value at the i-th judgment moment is obtained; then, according to the preset initial control factor and the output effect characterization value at the i-th judgment moment, a compensation current at the i-th judgment moment is obtained; according to the compensation current at the i-th judgment moment, an output effect characterization value at the i+1-th judgment moment is obtained; and according to the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment, a judgment index value at the i+1-th judgment moment is obtained; then, it is determined whether the judgment index value at the i+1-th judgment moment is not greater than the preset judgment threshold value; if so, a control factor at the i+1-th judgment moment is obtained; according to the control factor at the i+1-th judgment moment and the output effect characterization value, a compensation current at the i+1-th judgment moment is obtained; according to the compensation current at the i+1-th judgment moment, an output effect characterization value at the i+2-th judgment moment is obtained; and according to the i+1-th judgment moment, a judgment index value at the i+1-th judgment moment is obtained. The output effect characterization value at the i+2th judgment moment and the i+2th judgment moment is obtained to obtain the judgment index value at the i+2th judgment moment; then, it is judged whether the judgment index value at the i+2th judgment moment is not greater than the preset judgment threshold value, if so, the control factor at the i+2th judgment moment is obtained, and the compensation current at the i+2th judgment moment is obtained according to the control factor and the output effect characterization value at the i+2th judgment moment, and the output effect characterization value at the i+3th judgment moment is obtained according to the compensation current at the i+2th judgment moment, and the judgment index value at the i+3th judgment moment is obtained according to the output effect characterization values ​​at the i+2th judgment moment and the i+3th judgment moment; finally, it is judged whether the judgment index value at the i+3th judgment moment is not greater than the preset judgment threshold value, if not, the compensation current at the i+2th judgment moment is used as the optimal compensation current, and the optimal compensation current is used to perform current compensation on the amplifier after the i+3th judgment moment. Furthermore, this embodiment can reduce the occurrence of over-compensation or under-compensation as much as possible based on the obtained optimal compensation current, thereby improving the effect of controlling the bias current of the amplifier.

[0065] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A bias current control method for an isolated operational amplifier, characterized in that: The method comprises the following steps: During the operation of the isolated operational amplifier, an output effect characterization value at an i-th judgment moment is obtained, where the i-th judgment moment is a current moment; According to the preset initial control factor and the output effect characterization value at the i-th judgment moment, the compensation current at the i-th judgment moment is obtained, according to the compensation current at the i-th judgment moment, the output effect characterization value at the i+1-th judgment moment is obtained, and according to the output effect characterization values ​​at the i-th judgment moment and the i+1-th judgment moment, the judgment index value at the i+1-th judgment moment is obtained; Determine whether the judgment index value at the i+1th judgment moment is not greater than a preset judgment threshold value, and if so, obtain the control factor at the i+1th judgment moment, obtain the compensation current at the i+1th judgment moment according to the control factor and the output effect characterization value at the i+1th judgment moment, obtain the output effect characterization value at the i+2th judgment moment according to the compensation current at the i+1th judgment moment, and obtain the judgment index value at the i+2th judgment moment according to the output effect characterization values ​​at the i+1th judgment moment and the i+2th judgment moment; Determine whether the judgment index value at the i+2th judgment moment is not greater than a preset judgment threshold value, and if so, obtain the control factor at the i+2th judgment moment, obtain the compensation current at the i+2th judgment moment according to the control factor and the output effect characterization value at the i+2th judgment moment, obtain the output effect characterization value at the i+3th judgment moment according to the compensation current at the i+2th judgment moment, and obtain the judgment index value at the i+3th judgment moment according to the output effect characterization values ​​at the i+2th judgment moment and the i+3th judgment moment; Continue to determine whether the judgment index value at the i+3th judgment moment is not greater than the preset judgment threshold; if not, use the compensation current at the i+2th judgment moment as the optimal compensation current, and use the optimal compensation current to perform current compensation on the amplifier after the i+3th judgment moment.

2. The bias current control method of an isolated operational amplifier according to claim 1, characterized in that: The method for obtaining the output effect characterization value includes: Obtaining a monitoring time period corresponding to each judgment moment, wherein the monitoring time period corresponding to the judgment moment is a time period formed from a previous judgment moment to the judgment moment, and the monitoring time period corresponding to the judgment moment includes A monitoring moments, where A is greater than 0; For any judgment moment T0: the bias current of the amplifier at each monitoring moment in the monitoring time period corresponding to the judgment moment T0 is recorded as the bias current corresponding to the corresponding monitoring moment; under the bias current corresponding to each monitoring moment in the monitoring time period corresponding to the judgment moment T0, the input signal and the output signal of the amplifier in the monitoring time period corresponding to the judgment moment T0 are obtained, and are respectively recorded as the first input signal and the first output signal corresponding to the judgment moment T0; if the judgment moment T0 is not the i-th judgment moment, then the bias current corresponding to all the monitoring moments in the monitoring time period corresponding to the judgment moment T0 refers to the bias current compensated by the compensation current of the previous judgment moment of the judgment moment T0, and the compensation current of the judgment moment is used to perform current compensation on the amplifier in the monitoring time period corresponding to the next judgment moment of the judgment moment; Obtain the DTW distance between the first input signal and the first output signal, and record it as the first characterization value; obtain the first difference sequence corresponding to the judgment time T0, record the mean of the first difference sequence as the second characterization value, the a-th first difference in the first difference sequence is the absolute value of the difference between the a-th first amplitude and the a-th second amplitude, the a-th first amplitude is the amplitude corresponding to the frequency same as the a-th frequency in the first frequency domain signal, the a-th second amplitude is the amplitude corresponding to the frequency same as the a-th frequency in the second frequency domain signal, the first frequency domain signal is the frequency domain signal obtained after Fourier transform of the first input signal, the second frequency domain signal is the frequency domain signal obtained after Fourier transform of the first output signal, the a-th frequency is the a-th frequency in the frequency sequence, and the frequency sequence is constructed by the frequencies whose amplitudes are not 0 in the second frequency domain signal; the inverse of the result obtained by multiplying the first characterization value and the second characterization value and then adding the result to the preset first constant is recorded as the output effect characterization value at the judgment time T0.

3. The bias current control method of an isolated operational amplifier as claimed in claim 2, characterized in that: The method for obtaining the compensation current includes: For the judgment moment T0: the average value of all bias currents of the amplifier obtained in the monitoring time period corresponding to the judgment moment T0 is recorded as the average bias current at the judgment moment T0; the result of subtracting the output effect characterization value at the judgment moment T0 from the preset second constant is recorded as the first difference operation value at the judgment moment T0; the result of multiplying the first difference operation value at the judgment moment T0 and the first product value at the judgment moment T0 is recorded as the second product value at the judgment moment T0, and the opposite of the second product value at the judgment moment T0 is used as the compensation current at the judgment moment T0. The first product value at the judgment moment T0 is the product of the average bias current at the judgment moment T0 and the control factor at the judgment moment T0, and the control factor at the i-th judgment moment is the preset initial control factor.

4. The bias current control method of an isolated operational amplifier according to claim 1, characterized in that: The method for obtaining the control factor at the judgment moment includes: For the i+bth judgment moment, b is a positive integer: The absolute value of the difference between the output effect representation value at the i+bth judgment moment and the output effect representation value at the i+(b-1)th judgment moment is recorded as the first absolute value of the difference at the i+bth judgment moment; the ratio of the first absolute value of the difference to the output effect representation value at the i+(b-1)th judgment moment is recorded as the first ratio; the negative correlation mapping value of the first ratio is recorded as the target mapping value corresponding to the i+bth judgment moment; Determine whether the output effect characterization value at the i+b-th judgment moment is not less than the output effect characterization value at the i+(b-1)-th judgment moment. If so, add the preset second constant to the target mapping value and multiply the result by the control factor at the i+(b-1)-th judgment moment. Record it as the control factor at the i+b-th judgment moment. Otherwise, subtract the target mapping value from the preset second constant and multiply the result by the control factor at the i+(b-1)-th judgment moment. Record it as the control factor at the i+b-th judgment moment. The control factor at the i-th judgment moment is the preset initial control factor.

5. The bias current control method of an isolated operational amplifier as claimed in claim 4, characterized in that: The method for obtaining the judgment index value includes: For the i+bth judgment moment: the ratio of the output effect characterization value of the i+bth judgment moment to the output effect characterization value of the i-th judgment moment is recorded as the first indicator value; the reciprocal of the result obtained by adding the preset first constant and the absolute value of the first difference at the i+b-th judgment moment is recorded as the second indicator value; the normalized value of the result obtained by multiplying the first indicator value by the second indicator value is recorded as the judgment indicator value of the i+b-th judgment moment.

6. The bias current control method of an isolated operational amplifier as claimed in claim 1, characterized in that: After the current compensation of the amplifier after the (i+3)th judgment moment is performed using the optimal compensation current, the following steps are also included: If, during the process of using the optimal compensation current to perform current compensation on the amplifier after the i+3th judgment moment, it is monitored that the bias current change value of the amplifier at the jth monitoring moment is greater than the preset change threshold corresponding to the jth monitoring moment, then the jth monitoring moment is used as the new i-th judgment moment, and the new optimal compensation current is continued to be found according to the method for obtaining the optimal compensation current, and the j-th monitoring moment is located behind the i+3th judgment moment in time.

7. The bias current control method of an isolated operational amplifier as claimed in claim 6, characterized in that: The method for obtaining the bias current change value of the amplifier at the j-th monitoring moment includes: Obtain the historical monitoring time period corresponding to the j-th monitoring moment, and record the average of the bias current of the amplifier at all monitoring moments in the historical monitoring time period as the first average; record the absolute value of the difference between the bias current of the amplifier at the j-th monitoring moment and the first average as the bias current change value of the amplifier at the j-th monitoring moment.

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