Threshold voltage control system and control equipment of field effect transistor

Abstract

The invention relates to the technical field of electronic circuits, in particular to a threshold voltage control system and control equipment of a field effect transistor. Comprising a main feedback loop used for obtaining an actual value of a threshold voltage of a field effect transistor, comparing the actual value of the threshold voltage with a set value to obtain a deviation signal, and sending the deviation signal to a control module; the auxiliary feedback loop is used for collecting the current change rate of the field effect transistor and sending the current change rate to the control module; the control module is used for generating a control signal according to the deviation signal and the current change rate and adjusting the grid voltage of the field effect transistor according to the control signal so as to control the threshold voltage of the field effect transistor. According to the invention, the main feedback loop and the auxiliary feedback loop cooperatively collect the voltage deviation signal and the current change rate of the field effect transistor so as to dynamically adjust the grid voltage of the field effect transistor, thereby improving the control precision.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and particularly to a threshold voltage control system and control device for a field effect transistor. Background Art

[0002] In modern semiconductor integrated circuit applications, the precise control of the threshold voltage of a field effect transistor (FET) directly affects the performance and reliability of the chip. As the chip operating frequency increases to several GHz and the operating environment temperature fluctuation range expands to -40°C to 125°C, the traditional single feedback loop threshold voltage control technology gradually exposes significant defects. The existing single feedback system only adjusts the gate voltage to achieve threshold control by collecting the gate-source voltage and comparing it with a preset reference value. However, such a system has two core problems: First, the dynamic response is slow. When the drain current changes rapidly due to a sudden change in the circuit load, the single feedback loop cannot promptly sense the dynamic trend of the current, and the control signal delay reaches 50 - 100 ns, resulting in a lag in the threshold voltage adjustment and causing circuit signal distortion. Second, the control accuracy is insufficient. In the face of interference factors such as temperature drift and process deviation, the single feedback loop is difficult to establish a multivariable compensation mechanism, and the measured threshold voltage fluctuation range can reach ±200 mV, which cannot meet the requirements of high-performance chips for device consistency.

[0003] In summary, the technical problem actually solved by the present invention is how to improve the control accuracy of the threshold voltage of the field effect transistor. Summary of the Invention

[0004] In order to overcome the technical defect of the low control accuracy of the threshold voltage of the above-mentioned field effect transistor, the purpose of the present invention is to provide a threshold voltage control system and control device for a field effect transistor, which cooperatively collect the deviation signal of the voltage and the current change rate of the field effect transistor through the main feedback loop and the secondary feedback loop to dynamically adjust the gate voltage of the field effect transistor, thereby improving the control accuracy.

[0005] The present invention discloses a threshold voltage control system for a field effect transistor, including a main feedback loop, a secondary feedback loop, a field effect transistor, and a control module; wherein, The main feedback loop is connected to the field effect transistor and the control module. The main feedback loop is used to obtain the actual value of the threshold voltage of the field effect transistor, compare the actual value of the threshold voltage with the set value to obtain a deviation signal, and send the deviation signal to the control module; The secondary feedback loop is connected to the field effect transistor and the control module. The secondary feedback loop is used to collect the current change rate of the field effect transistor and send the current change rate to the control module; The control module is used to generate a control signal according to the deviation signal and the current change rate, and adjust the gate voltage of the field effect transistor according to the control signal to control the threshold voltage of the field effect transistor.

[0006] Preferably, the main feedback loop includes an adaptive PID controller; The adaptive PID controller dynamically adjusts the proportional coefficient , integral coefficient , and differential coefficient through a deep learning algorithm and based on the historical threshold voltage and deviation signal; The deep learning algorithm uses a convolutional neural network, preprocesses the historical threshold voltage and deviation signal as inputs, and outputs the dynamically adjusted proportional coefficient , integral coefficient , and differential coefficient .

[0007] Preferably, a first current change rate threshold and a second current change rate threshold are provided in the control module, and the first current change rate threshold is greater than the second current change rate threshold ; The control module dynamically adjusts the control signal according to the relationship between the current change rate and the first current change rate threshold and the second current change rate threshold ; When the current change rate is greater than the first current change rate threshold , when the control module generates a control signal according to the deviation signal and the current change rate, the weight of the current change rate is increased; When the current change rate is less than the second current change rate threshold , when the control module generates a control signal according to the deviation signal and the current change rate, the weight of the current change rate is decreased.

[0008] Preferably, the control module further includes a reinforcement learning unit, and the reinforcement learning unit dynamically adjusts the first current change rate threshold and the second current change rate threshold according to the control signal through a reward mechanism.

[0009] Preferably, the control module further includes a signal processing unit and a driving unit; wherein, The signal processing unit uses a digital signal processor. The signal processing unit is respectively connected to the main feedback loop and the secondary feedback loop to receive the deviation signal and the current change rate, and generates a preliminary control signal according to a preset algorithm. The algorithm calculation formula is: , Among them, is expressed as the preliminary control signal, , , are respectively expressed as the proportional coefficient, integral coefficient, and differential coefficient of the PID algorithm in the signal processing unit, is expressed as the deviation signal, is expressed as the change rate of the deviation signal, is expressed as the feedback coefficient of the secondary feedback loop, is expressed as the temperature compensation coefficient, is expressed as the difference between the current temperature and the reference temperature; The driving unit is used to convert the preliminary control signal into a control signal capable of driving the gate of the field-effect transistor.

[0010] Preferably, it further includes a temperature compensation module and a stress compensation module; among them, A temperature threshold voltage compensation curve is preset in the temperature compensation module, and a stress threshold compensation model is preset in the stress compensation module; The temperature compensation module is connected to the field-effect transistor, and is used to obtain the operating temperature of the field-effect transistor, and correct the set value according to the operating temperature and the temperature threshold voltage compensation curve; and / or, the stress compensation module is connected to the field-effect transistor, and is used to obtain the mechanical stress suffered by the field-effect transistor package, and correct the set value according to the mechanical stress and the stress threshold compensation model; The temperature threshold voltage compensation curve is established by the following formula: , Among them, is expressed as the set value of the corrected threshold voltage, is expressed as the set value of the uncorrected threshold voltage, is expressed as the temperature coefficient, is expressed as the operating temperature obtained by the temperature compensation module, is expressed as the reference temperature; The stress threshold compensation model is established by the following formula: , Among them, is expressed as the set value of the threshold voltage considering stress compensation, is expressed as the stress coefficient, is expressed as the value of the obtained mechanical stress.

[0011] Preferably, the source of the field-effect transistor is grounded, the drain is connected to the load circuit, and the gate is connected to the output terminal of the control module; A variable capacitor is connected in series between the gate of the field-effect transistor and the output terminal of the control module. The variable capacitor is used to adjust the voltage change rate of the gate of the field-effect transistor. The capacitance value of the variable capacitor is dynamically adjusted according to the current change rate, and the adjustment formula is: , where, C represents the capacitance value of the adjusted variable capacitor, represents the initial capacitance value of the variable capacitor, represents the adjustment coefficient.

[0012] Preferably, the main feedback loop further includes a voltage sampling sub-circuit and an analog-to-digital conversion sub-circuit; where, The voltage sampling sub-circuit is used to collect the actual value of the threshold voltage of the field-effect transistor, and the analog-to-digital conversion sub-circuit is used to convert the actual value of the threshold voltage into a digital signal for the control module to process; The voltage sampling sub-circuit adopts a differential sampling method and is provided with an anti-aliasing filter. The cut-off frequency of the anti-aliasing filter is adaptively adjusted according to the operating frequency of the field-effect transistor.

[0013] Preferably, the sub-feedback loop further includes a current sampling sub-circuit and a differential operation sub-circuit; where, The current sampling sub-circuit is used to collect the current of the field-effect transistor, and the differential operation sub-circuit is used to calculate the change rate of the current; The current sampling sub-circuit adopts a Hall current sensor and is provided with an error compensation sub-circuit. The error compensation sub-circuit calculates according to the temperature and the offset characteristics of the Hall element through the calculation formula: to correct the collected current value; where, represents the corrected current value, represents the measured current value, represents the temperature error compensation coefficient, represents the offset error compensation coefficient, O represents the offset of the Hall element.

[0014] The second object of the present invention is to provide a threshold voltage control device for a field-effect transistor. At least one control system as described above is provided on the control device.

[0015] After adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: by cooperatively collecting the deviation signal of the voltage and the current change rate of the field-effect transistor through the main feedback loop and the secondary feedback loop, the gate voltage of the field-effect transistor is dynamically adjusted, thereby improving the control accuracy and the corresponding speed, being able to quickly adapt to complex and changeable working environments, effectively reducing the influence of interference factors such as temperature changes and process deviations on the threshold voltage, and improving the stability and reliability of the operation of the field-effect transistor; the present invention integrates a temperature compensation module and a stress compensation module, combines the dual-loop mechanism of the main feedback loop and the secondary feedback loop, and forms an integrated compensation ability for multi-physical field interference. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the control system of a threshold voltage control system and a control device for a field-effect transistor according to the present invention. Detailed Embodiments

[0017] The advantages of the present invention are further elaborated below in conjunction with the drawings and specific embodiments.

[0018] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0019] The terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0020] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0021] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0022] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0023] In the subsequent description, the use of suffixes such as "module", "component", or "unit" for representing elements is only for the convenience of explaining the present invention, and they have no specific meaning in themselves. Therefore, "module" and "component" can be used interchangeably.

[0024] This embodiment discloses a threshold voltage control system for a field effect transistor, including a main feedback loop, a sub-feedback loop, a field effect transistor, and a control module. Among them, the main feedback loop is connected to the field effect transistor and the control module. The main feedback loop is used to obtain the actual value of the threshold voltage of the field effect transistor, compare the actual value of the threshold voltage with the set value to obtain a deviation signal, and send the deviation signal to the control module. The sub-feedback loop is connected to the field effect transistor and the control module. The sub-feedback loop is used to collect the current change rate of the field effect transistor and send the current change rate to the control module. The control module is used to generate a control signal according to the deviation signal and the current change rate, and adjust the gate voltage of the field effect transistor according to the control signal to control the threshold voltage of the field effect transistor.

[0025] Refer to Figure 1 As shown, this embodiment will describe in detail a threshold voltage control system for a field effect transistor, specifically including a main feedback loop, a sub-feedback loop, a field effect transistor, and a control module.

[0026] The main feedback loop is connected to the field-effect transistor and the control module. The main feedback loop is used to obtain the actual value of the threshold voltage of the field-effect transistor, compare the actual value of the threshold voltage with the set value to obtain a deviation signal, and send the deviation signal to the control module. The secondary feedback loop is connected to the field-effect transistor and the control module. The secondary feedback loop is used to collect the current change rate of the field-effect transistor and send the current change rate to the control module. After passing through the main feedback loop and the secondary feedback loop, there will be a deviation signal and a current change rate in the control module. The control module will generate a control signal based on the deviation signal and the current change rate, so as to adjust the gate voltage of the field-effect transistor according to the control signal to control the threshold voltage of the field-effect transistor.

[0027] Further, the main feedback loop includes an adaptive PID controller; the adaptive PID controller dynamically adjusts the proportional coefficient , integral coefficient , and differential coefficient through a deep learning algorithm and based on the historical threshold voltage and deviation signal; the deep learning algorithm uses a convolutional neural network, preprocesses the historical threshold voltage and deviation signal as inputs, and outputs the dynamically adjusted proportional coefficient , integral coefficient , and differential coefficient .

[0028] In this embodiment, the main feedback loop will be described in detail. The main feedback loop includes an adaptive PID controller. The adaptive PID controller dynamically adjusts the proportional coefficient , integral coefficient , and differential coefficient through a deep learning algorithm and based on the historical threshold voltage and deviation signal; the deep learning algorithm uses a convolutional neural network, preprocesses the historical threshold voltage and deviation signal as inputs, and outputs the dynamically adjusted proportional coefficient , integral coefficient , and differential coefficient . The adaptive PID controller, as a classic control algorithm, consists of three links: proportional (P), integral (I), and differential (D). Through real-time monitoring and adjustment, it ensures precise control of the threshold voltage of the system. The proportional coefficient determines the response speed of the adaptive PID controller to the current deviation. The larger the proportional coefficient , the more rapid the system's response to the deviation signal, but an overly large proportional coefficient may cause system overshoot; the integral coefficient is used to eliminate the steady-state error. Through the integral operation of the deviation signal, the system can also reach the target value after long-term operation; the differential coefficient The change trend of the predicted deviation signal can be predicted, the control amount can be adjusted in advance, overshoot can be suppressed, and the system stability can be enhanced.

[0029] It should be noted that the convolutional neural network includes an input layer, a convolutional layer, a pooling layer, and a fully connected layer. The input layer receives the preprocessed historical threshold voltage, deviation signal, and environmental parameters (such as temperature and stress), and the data dimension is N×M, where N is the length of the time series and M is the number of features. The convolutional layer contains at least 3 two-dimensional convolutional layers, and the size of the convolutional kernel for each layer is 3×3 or 5×5, and the number of channels is 32 / 64 / 128 in sequence, which are extracted through convolutional operations. The pooling layer sets a maximum pooling layer between adjacent convolutional layers, and the size of the pooling window is 2×2, and the stride is 2, which is used for dimensionality reduction and reducing the amount of calculation. The fully connected layer contains 2 fully connected layers, and the number of neurons is 256 and 3 respectively (corresponding to the proportionality coefficient , integral coefficient , differential coefficient ).

[0030] Furthermore, a first current change rate threshold and a second current change rate threshold are provided in the control module, and the first current change rate threshold is greater than the second current change threshold ; the control module dynamically adjusts the control signal according to the relationship between the current change rate and the first current change rate threshold and the second current change rate threshold ; when the current change rate is greater than the first current change rate threshold , when the control module generates a control signal according to the deviation signal and the current change rate, the weight of the current change rate is increased; when the current change rate is less than the second current change rate threshold , when the control module generates a control signal according to the deviation signal and the current change rate, the weight of the current change rate is decreased.

[0031] In this embodiment, the control module will be described in detail. A first current change rate threshold and a second current change rate threshold are preset in the control module, and the first current change rate threshold is greater than the second current change rate threshold , and the control module dynamically adjusts the control signal according to the relationship between the current change rate and the first current change rate threshold and the second current change rate threshold . That is, the secondary feedback loop monitors the current change rate of the field effect transistor in real time, and at the preset first current change rate threshold and the second current change rate threshold Compare to achieve dynamic adjustment of the control signal. More specifically, when the current change rate is greater than the first current change rate threshold , it means that the circuit is in a strong dynamic change working condition. For example, when the load in the power supply circuit suddenly increases, the secondary feedback loop will increase its response weight to the deviation signal to ensure the system responds quickly. For example, originally the main feedback loop and the secondary feedback loop may affect the control signal in a ratio of 7:3. In this working condition, the ratio may be adjusted to 6:4, so that the control module focuses more on adjusting the gate voltage according to the current change trend, and adjusts the threshold voltage in advance to avoid excessive fluctuations in the threshold voltage caused by current mutations and affect the performance of the circuit. When the current change rate is less than the second current change rate threshold , it indicates that the circuit is operating stably. The secondary feedback loop then reduces its response weight to the deviation signal, mainly based on the deviation signal of the main feedback loop based on the threshold voltage, to ensure the stability of the control and reduce unnecessary consumption of computing resources. In the transition interval, the system will adopt algorithms including but not limited to linear interpolation or fuzzy control algorithms to smoothly adjust the weight ratio to prevent sudden changes in the control signal.

[0032] Furthermore, the control module further includes a reinforcement learning unit. The reinforcement learning unit dynamically adjusts the first current change rate threshold and the second current change rate threshold according to the control signal through a reward mechanism.

[0033] In this embodiment, the control module will be described in detail again. The control module includes a reinforcement learning unit. The reinforcement learning unit dynamically adjusts the first current change rate threshold and the second current change rate threshold by real-time monitoring the effect of the control signal and according to the reward mechanism. For example, if the system can stably control the threshold voltage within a certain fluctuation range for a period of time and the response to current changes is rapid and accurate, a positive reward will be given; otherwise, if problems such as serious overshoot of the threshold voltage and response delay occur, a negative reward will be given. By continuously accumulating the reward values, the reinforcement learning unit can independently analyze whether the current threshold setting adapts to the actual working conditions of the circuit. The reinforcement learning unit dynamically fine-tunes the threshold according to the reward value, optimizes the control strategy, and improves the system's adaptive ability.

[0034] Furthermore, the control module further includes a signal processing unit and a driving unit; among them, the signal processing unit uses a digital signal processor. The signal processing unit is respectively connected to the main feedback loop and the secondary feedback loop to receive the deviation signal and the current change rate, and generates a preliminary control signal according to a preset algorithm. The algorithm calculation formula is: . Among them, is represented as the preliminary control signal, , , are respectively represented as the proportional coefficient, integral coefficient and differential coefficient of the PID algorithm in the signal processing unit, is represented as the deviation signal, is represented as the rate of change of the deviation signal, is represented as the feedback coefficient of the secondary feedback loop, is represented as the temperature compensation coefficient, is represented as the difference between the current temperature and the reference temperature; the driving unit is used to convert the preliminary control signal into a control signal capable of driving the gate of the field effect transistor.

[0035] In this embodiment, the control module will be described in detail again. The control module includes a signal processing unit and a driving unit. The signal processing unit uses a digital signal processor. The signal processing unit is respectively connected to the main feedback loop and the secondary feedback loop to receive the deviation signal and the current rate of change in real time, so as to generate a preliminary control signal according to a preset algorithm. The preset calculation formula algorithm is: . Among them, is represented as the preliminary control signal, , , are respectively represented as the proportional coefficient, integral coefficient and differential coefficient of the PID algorithm in the signal processing unit, is represented as the deviation signal, is represented as the rate of change of the deviation signal, is represented as the feedback coefficient of the secondary feedback loop, is represented as the temperature compensation coefficient, is represented as the difference between the current temperature and the reference temperature; the driving unit is used to convert the preliminary control signal generated by the signal processing unit into a control signal capable of driving the gate of the field effect transistor.

[0036] Furthermore, it further includes a temperature compensation module and a stress compensation module; among them, a temperature threshold voltage compensation curve is preset in the temperature compensation module, and a stress threshold compensation model is preset in the stress compensation module; the temperature compensation module is connected to the field effect transistor for obtaining the operating temperature of the field effect transistor and correcting the set value according to the operating temperature and the temperature threshold voltage compensation curve; and / or, the stress compensation module is connected to the field effect transistor for obtaining the mechanical stress suffered by the field effect transistor package and correcting the set value according to the mechanical stress and the stress threshold compensation model; the temperature threshold voltage compensation curve is established by the following formula: . Among them, is represented as the set value of the corrected threshold voltage, is represented as the set value of the uncorrected threshold voltage, Expressed as the temperature coefficient, Expressed as the operating temperature obtained by the temperature compensation module, Expressed as the reference temperature; the stress threshold compensation model is established by the following formula: . Wherein, Expressed as the set value of the threshold voltage after considering stress compensation, Expressed as the stress coefficient, Expressed as the value of the mechanical stress obtained.

[0037] In this embodiment, a threshold voltage control system of a field effect transistor will be described in detail again. The system further includes a temperature compensation module and a stress compensation module. A temperature threshold voltage compensation curve is preset in the temperature compensation module, and a stress threshold compensation model is preset in the stress compensation module. The temperature compensation module is connected to the field effect transistor to obtain the operating temperature of the field effect transistor and correct the set value according to the operating temperature and the temperature threshold voltage compensation curve. The stress compensation module is connected to the field effect transistor to obtain the mechanical stress received by the package of the field effect transistor, so as to correct the set value according to the mechanical stress and the stress threshold compensation model.

[0038] For example, in some embodiments, a high-precision temperature chamber (such as ESPEC SH-241, temperature control accuracy ±0.1 °C, temperature range -70 °C to 180 °C) is used. The field effect transistor is placed on a constant temperature test board inside the temperature chamber to ensure uniform device temperature. A Keithley 2612B source meter is used to provide a stable test bias voltage for the field effect transistor, and a Keysight B1500A semiconductor parameter analyzer is used to collect the threshold voltage in real time, with a sampling accuracy of 0.1 mV. With a temperature decrease of 10 °C, the temperature is gradually increased from -50 °C to 120 °C, and each temperature point is maintained for 30 minutes to make the device reach the thermal equilibrium state. At each temperature point, the gate-source voltage and the drain-source voltage are kept constant, and the threshold voltage is collected every 5 minutes. Six groups of data are obtained at each temperature point. The average value of the six groups of threshold voltage data at each temperature point is taken to obtain the threshold voltage at that temperature. The least squares method is used to fit the temperature T and the threshold voltage to construct a polynomial function, , usually a second-order polynomial (n = 2), which can meet the temperature characteristics and fitting requirements of the field effect transistor, so as to obtain the temperature threshold voltage compensation curve.

[0039] Verification experiments are carried out at untested temperature points (such as -30 °C, 125 °C), and the actual threshold voltage is collected and compared with the predicted value of the compensation curve. If the error exceeds the set threshold (such as 50 mV), the fitting parameters are readjusted or the temperature test point density is increased until the accuracy of the compensation curve meets the requirements.

[0040] In this embodiment, a temperature compensation module and a stress compensation module are further included in the threshold voltage control system of the field-effect transistor to correct the influence of environmental factors on the threshold voltage of the field-effect transistor.

[0041] In practical applications, the working environment of the field-effect transistor is complex and variable, and temperature and stress are important factors affecting the threshold voltage. The temperature compensation module includes, but is not limited to, collecting the working temperature of the field-effect transistor in real time through a temperature sensor. For example, in an automotive engine control module, the ambient temperature around the engine may rapidly rise from normal temperature to over 100 °C when the engine is running. At this time, the temperature compensation module can quickly obtain this temperature change, thereby correcting the set value of the threshold voltage. The threshold voltage of semiconductor devices decreases as the temperature increases. After the set value is adjusted by the temperature compensation module, it is ensured that the threshold voltage of the field-effect transistor can still be maintained within the ideal working range at different temperatures.

[0042] The stress compensation module is responsible for monitoring the mechanical stress on the package of the field-effect transistor. For example, in aerospace equipment, the device will withstand huge vibration and shock stresses during launch, and may also generate stresses due to thermal expansion and contraction during daily operation. The stress compensation module includes, but is not limited to, collecting mechanical stress in real time through a stress sensor. If the detected stress value is 5 MPa, the stress compensation module will correct the set value according to the stress threshold compensation model. The temperature compensation module and the stress compensation module work in coordination with the main feedback loop and the secondary feedback loop. When there is a deviation between the actual value of the threshold voltage collected by the main feedback loop and the set value compensated by the temperature compensation module and the stress compensation module, the control module adjusts the gate voltage based on the deviation signal and the current change rate to achieve more precise control.

[0043] In this embodiment, the establishment of the temperature threshold voltage compensation curve will be described in detail, and its establishment is through the formula: Established. Among them, represents the set value of the corrected threshold voltage, represents the set value of the uncorrected threshold voltage, represents the temperature coefficient, which can be obtained by conducting a large number of experimental tests on the field-effect transistor at different temperatures. The temperature coefficients of field-effect transistors with different materials and processes are different. For example, the temperature coefficient of silicon-based MOSFETs is generally about -2 mV / °C, represents the working temperature obtained by the temperature compensation module, represents the reference temperature.

[0044] It should be noted that the temperature coefficient It can be obtained by placing the field-effect transistor in a programmable high and low temperature test chamber with a temperature control accuracy of ±0.5°C and maintaining the humidity at 20%-80% RH to ensure a stable environment; at the reference temperature =25°C, apply a standard working voltage to the field-effect transistor through a high-precision voltage source (accuracy ±0.1 mV), use a semiconductor parameter analyzer (such as Keysight B1500A) to collect the threshold voltage, and take the average value after repeating the measurement 10 times; with an interval of 10°C, gradually increase the temperature from -55°C to 150°C, and keep the device at each temperature point for 30 minutes to reach thermal equilibrium. During this period, collect the threshold voltage every 5 minutes, and a total of 60 groups of data are obtained; use the least squares method to perform a linear fit on the relationship between temperature T and the threshold voltage, and the obtained value is the temperature coefficient ; conduct verification experiments at non-test temperature points (such as -20°C, 120°C). If the error between the measured value and the fitted value exceeds ±3%, then readjust the test parameters or increase the samples.

[0045] Stress coefficient It is obtained through the following steps. Use a microelectromechanical stress loading platform (accuracy ±1 MPa), and apply a mechanical stress of 0-150 MPa to the field-effect transistor package through the four-point bending method or the thin film deposition stress method; during the stress loading process, keep the device working current constant (such as 100 mA), and synchronously collect the stress value S and the threshold voltage, with a collection frequency of 1 Hz; use polynomial regression analysis for the stress S and the threshold voltage offset relationship, establish a model （ When the higher-order terms can be ignored, it is simplified to a linear model), and take the coefficient of the first-order term as the stress coefficient; apply stress in the axial, radial, and shear directions respectively to verify the universality. If the difference exceeds 5%, then use tensor analysis to construct a three-dimensional stress compensation model.

[0046] In this embodiment, a detailed description of the radial stress threshold compensation model is given. The stress compensation model is established through the following formula: . Among them, represents the set value of the threshold voltage considering stress compensation, represents the stress coefficient, represents the value of the mechanical stress obtained. For example, in some industrial automation equipment, it is known that the mechanical stress of the field-effect transistor is -0.5 mV / MPa. When the stress sensor detects S =8 MPa, it can be calculated that the threshold voltage is reduced by 4 mV due to stress, and the set value is adjusted accordingly.

[0047] Further, the source of the field-effect transistor is grounded, the drain is connected to the load circuit, and the gate is connected to the output terminal of the control module; a variable capacitor is connected in series between the gate of the field-effect transistor and the output terminal of the control module. The variable capacitor is used to adjust the voltage change rate of the gate of the field-effect transistor. The capacitance value of the variable capacitor is dynamically adjusted according to the current change rate, and the adjustment formula is: . Among them, C represents the capacitance value of the adjusted variable capacitor, represents the initial capacitance value of the variable capacitor, represents the adjustment coefficient.

[0048] In this embodiment, the field-effect transistor will be described in detail. The source of the field-effect transistor is grounded, the drain is connected to the load circuit, and the gate is connected to the output terminal of the control module. A variable capacitor is connected in series between the gate of the field-effect transistor and the output terminal of the control module. The variable capacitor is used to adjust the voltage change rate of the gate of the field-effect transistor. The capacitance value of the variable capacitor is dynamically adjusted according to the current change rate. The variable capacitor is not a fixed value, but can dynamically adjust the capacitance value according to the actual operating state of the circuit, especially the current change rate.

[0049] Its working principle is that the role of the variable capacitor is to adjust the change rate of the gate voltage. The capacitor has the characteristic of hindering sudden voltage changes. By changing the capacitance value, the rising or falling speed of the gate voltage can be controlled. In this embodiment, the capacitance value is based on the adjustment formula . Among them, C represents the capacitance value of the adjusted variable capacitor, represents the initial capacitance value of the variable capacitor, represents the adjustment coefficient. For example, in a high-frequency switching power supply circuit, when the load suddenly increases and the current change rate increases sharply. Assuming ， = 2 pF / (A / s) , the circuit change rate reaches 5 A / s. According to the formula calculation, the adjusted capacitance value 。After the capacitance value increases, the change rate of the gate voltage will slow down accordingly, avoiding excessive switching losses of the field-effect transistor and electromagnetic interference caused by voltage mutation, or overshoot of the threshold voltage caused by too rapid voltage change, which affects the stable operation of the circuit. Conversely, when the current change rate is small, the variable capacitance value decreases, and the gate voltage can quickly respond to the change of the control signal, ensuring efficient and stable control of the system under different working conditions. Further, the main feedback loop further includes a voltage sampling sub-circuit and an analog-to-digital conversion sub-circuit; wherein, the voltage sampling sub-circuit is used to collect the actual value of the threshold voltage of the field-effect transistor, and the analog-to-digital conversion sub-circuit is used to convert the actual value of the threshold voltage into a digital signal for the control module to process; the voltage sampling sub-circuit adopts a differential sampling method and is provided with an anti-aliasing filter, and the cut-off frequency of the anti-aliasing filter is adaptively adjusted according to the operating frequency of the field-effect transistor.

[0050] In this embodiment, the main feedback loop will be described in detail again. The main feedback loop further includes a voltage sampling sub-circuit and an analog-to-digital conversion sub-circuit. The voltage sampling sub-circuit therein is used to collect the actual value of the threshold voltage of the field-effect transistor, and the analog-to-digital conversion sub-circuit is used to convert the actual value of the threshold voltage into a digital signal (such as a 12-bit binary value) for the control module to process. The voltage sampling sub-circuit adopts a differential sampling method, simultaneously collects the gate and source voltages through two signal lines (V+ and V-), calculates the difference using a differential amplifier, and is provided with an anti-aliasing filter. The cut-off frequency of the anti-aliasing filter is adaptively adjusted according to the operating frequency of the field-effect transistor. The anti-aliasing filter is used to filter out high-frequency noise above the Nyquist frequency (1 / 2 of the sampling rate) to prevent distortion caused by spectral aliasing.

[0051] Further, the secondary feedback loop further includes a current sampling sub-circuit and a differential operation sub-circuit; wherein, the current sampling sub-circuit is used to collect the current of the field-effect transistor, and the differential operation sub-circuit is used to calculate the change rate of the current; the current sampling sub-circuit adopts a Hall current sensor and is provided with an error compensation sub-circuit. The error compensation sub-circuit calculates according to the temperature and the offset characteristic of the Hall element through the calculation formula: to correct the collected current value; wherein, represents the corrected current value, represents the measured current value, represents the temperature error compensation coefficient, represents the offset error compensation coefficient, O represents the offset of the Hall element.

[0052] In this embodiment, the secondary feedback loop will be explained in detail. The secondary feedback loop includes a current acquisition sub-circuit and a differential operation sub-circuit.

[0053] The function of the current acquisition sub-circuit is to acquire the circuit of the field-effect transistor. The current acquisition sub-circuit includes but is not limited to using a Hall current sensor as the core acquisition component. The Hall current sensor is based on the Hall effect and can achieve non-contact measurement of current, with advantages such as fast response speed and good linearity. At the same time, to solve the problems of temperature drift and inherent offset in the Hall current sensor, an error compensation sub-circuit is added to the circuit, and through a specific calculation formula to correct the acquired current value to ensure the accuracy of the acquired data. Among them, represents the corrected current value, represents the measured current value, represents the temperature error compensation coefficient, represents the offset error compensation coefficient, O represents the offset of the Hall element.

[0054] The differential operation sub-circuit is responsible for processing the current signal acquired by the current sampling circuit, calculating the change rate of the current, and providing key data reflecting the dynamic change trend of the circuit for the control unit, enabling the system to quickly respond to sudden changes in current.

[0055] The second object of this embodiment is to provide a threshold voltage control device for a field-effect transistor, and at least one control system as described above is provided on the control device.

[0056] This embodiment also provides a threshold voltage control device for a field-effect transistor, and a control system provided in the above embodiment is provided thereon.

[0057] It should be noted that the embodiments of the present invention have good implementability and do not impose any form of limitation on the present invention. Any person skilled in the art may use the disclosed technical content to change or modify it into an equivalent effective embodiment. However, as long as it does not depart from the technical content of the present invention, any modification, equivalent change, or modification made to the above embodiments based on the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A threshold voltage control system for a field effect transistor, characterized in that It includes a main feedback loop, a secondary feedback loop, a field effect transistor, and a control module; wherein, The main feedback loop is connected to the field effect transistor and the control module. The main feedback loop is used to obtain the actual value of the threshold voltage of the field effect transistor, compare the actual value of the threshold voltage with a set value to obtain a deviation signal, and send the deviation signal to the control module; The secondary feedback loop is connected to the field effect transistor and the control module. The secondary feedback loop is used to collect the current change rate of the field effect transistor and send the current change rate to the control module; The control module is used to generate a control signal according to the deviation signal and the current change rate, and adjust the gate voltage of the field effect transistor according to the control signal to control the threshold voltage of the field effect transistor.

2. The threshold voltage control system of the field effect transistor according to claim 1, characterized in that, The main feedback loop includes an adaptive PID controller; The adaptive PID controller dynamically adjusts the proportional coefficient, the integral coefficient, and the differential coefficient through a deep learning algorithm and based on the historical threshold voltage and the deviation signal. , the integral coefficient , and the differential coefficient ; The deep learning algorithm uses a convolutional neural network, preprocesses the historical threshold voltage and the deviation signal as inputs, and outputs the dynamically adjusted scale factor , integral coefficient , differential coefficient .

3. The threshold voltage control system of the field effect transistor according to claim 1, characterized in that, The control module is provided with a first current change rate threshold and a second current change rate threshold , and the first current change rate threshold is greater than the second current change rate threshold ; The control module, according to the current change rate and the first current change rate threshold and the second current change rate threshold dynamically adjusts the control signal; When the rate of change of the current is greater than the first rate-of-change-of-current threshold , when the control module generates the control signal according to the deviation signal and the rate of change of the current, the weight of the rate of change of the current is increased; When the rate of change of the current is less than the second rate-of-change-of-current threshold , when the control module generates the control signal according to the deviation signal and the rate of change of the current, the weight of the rate of change of the current is reduced.

4. The threshold voltage control system of the field effect transistor according to claim 3, characterized in that, The control module further includes a reinforcement learning unit, and the reinforcement learning unit dynamically adjusts the first current change rate threshold and the second current change rate threshold according to the control signal through a reward mechanism. and the second current change rate threshold .

5. The threshold voltage control system of the field effect transistor according to claim 1, characterized in that, The control module further includes a signal processing unit and a driving unit; wherein, The signal processing unit adopts a digital signal processor. The signal processing unit is respectively connected to the main feedback loop and the secondary feedback loop to receive the deviation signal and the current change rate, and generate a preliminary control signal according to a preset algorithm. The algorithm calculation formula is: , Among them, is represented as the preliminary control signal, , , are respectively represented as the proportional coefficient, integral coefficient and differential coefficient of the PID algorithm in the signal processing unit, is represented as the deviation signal, is represented as the change rate of the deviation signal, is represented as the feedback coefficient of the secondary feedback loop, is represented as the temperature compensation coefficient, is represented as the difference between the current temperature and the reference temperature; The driving unit is used to convert the preliminary control signal into the control signal capable of driving the gate of the field effect transistor.

6. The threshold voltage control system of the field effect transistor according to claim 1, wherein It further includes a temperature compensation module and a stress compensation module; wherein, A temperature threshold voltage compensation curve is preset in the temperature compensation module, and a stress threshold compensation model is preset in the stress compensation module; The temperature compensation module is connected to the field effect transistor, and is used to obtain the operating temperature of the field effect transistor and correct the set value according to the operating temperature and the temperature threshold voltage compensation curve; and / or, the stress compensation module is connected to the field effect transistor, and is used to obtain the mechanical stress suffered by the package of the field effect transistor and correct the set value according to the mechanical stress and the stress threshold compensation model; The temperature threshold voltage compensation curve is established by the following formula: , Among them, represents the set value of the corrected threshold voltage, represents the set value of the uncorrected threshold voltage, represents the temperature coefficient, represents the operating temperature obtained by the temperature compensation module, represents the reference temperature; The stress threshold compensation model is established by the following formula: , wherein, represents the set value of the threshold voltage after considering stress compensation, represents the stress coefficient, represents the value of the mechanical stress obtained.

7. The threshold voltage control system of the field effect transistor according to claim 1, characterized in that The source electrode of the field effect transistor is grounded, the drain electrode is connected to a load circuit, and the gate electrode is connected to the output end of the control module; A variable capacitor is connected in series between the gate of the field effect transistor and the output terminal of the control module. The variable capacitor is used to adjust the voltage change rate of the gate of the field effect transistor. The capacitance value of the variable capacitor is dynamically adjusted according to the current change rate, and the adjustment formula is: , Among them, C represents the capacitance value of the adjusted variable capacitor, represents the initial capacitance value of the variable capacitor, represents the adjustment coefficient.

8. The threshold voltage control system of the field effect transistor according to claim 1, characterized in that The main feedback loop further includes a voltage sampling sub-circuit and an analog-to-digital conversion sub-circuit; wherein, The voltage sampling sub-circuit is used to collect the actual value of the threshold voltage of the field effect transistor, and the analog-to-digital conversion sub-circuit is used to convert the actual value of the threshold voltage into a digital signal for the control module to process; The voltage sampling sub-circuit adopts a differential sampling method and is provided with an anti-aliasing filter, and the cut-off frequency of the anti-aliasing filter is adaptively adjusted according to the operating frequency of the field effect transistor.

9. The threshold voltage control system of the field effect transistor according to claim 1, wherein The secondary feedback loop further includes a current sampling sub-circuit and a differential operation sub-circuit; wherein, The current sampling sub-circuit is used to collect the current of the field effect transistor, and the differential operation sub-circuit is used to calculate the change rate of the current; The current sampling sub-circuit uses a Hall current sensor and is provided with an error compensation sub-circuit. The error compensation sub-circuit corrects the acquired current value according to the temperature and the offset characteristics of the Hall element through the calculation formula: ​ Among them, is expressed as the corrected current value, is expressed as the measured current value, is expressed as the temperature error compensation coefficient, is expressed as the offset error compensation coefficient, O is expressed as the offset of the Hall element.

10. A threshold voltage control device for a field effect transistor, characterized in that, At least one control system as described in any one of claims 1 to 9 is provided on the control device.

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