Gear switching control method of source meter, source meter, system and medium

Abstract

The invention relates to the technical field of source table control, and discloses a gear switching control method of a source table, the source table, a system and a medium, and the method comprises the steps: detecting a switching action triggered by a current user aiming at the source table; responding to the switching action, determining a switching type, and determining a target electronic device matched with the switching type; and calculating a target control parameter based on the key parameter corresponding to the target electronic device, and performing corresponding control on the source table based on the target control parameter. According to the invention, the source meter is realized in a digital loop mode, the target electronic device matched with the switching type in the digital loop is determined after the gear switching action of the source meter is triggered, and the switching of the voltage gear or the current gear of the source meter is completed through the actions of the target electronic device and the digital loop controller. And the output abrupt change of the source meter is suppressed through the digital loop, stable output of the to-be-tested equipment is kept, the control precision of the source meter is improved to a certain extent, and meanwhile, the test safety is also ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of source meter control, and in particular to a gear switching control method of a source meter, a source meter, a system and a medium. Background Art

[0002] A source meter, also known as a source measurement unit (SMU), is a test instrument that integrates the functions of a voltage source, a current source, a voltmeter, an ammeter, and an electronic load. It can provide accurate DC voltage or DC current output or input, and can simultaneously measure the current, voltage, and other parameters of the components under test (also known as the device under test, DUT, or load). Currently, source meters are usually controlled by a full analog loop. Since the various components of the system including the source meter have cumulative errors, the analog loop control effect is poor, so the corresponding source meter digital loop control is proposed.

[0003] At present, with the important role played by digital loop gear hot-cut technology (including current gear switching and voltage gear switching) in the use scenarios of voltage and current measurement and voltage and current output or input of SMU modules, PMU (Power Measurement Unit) modules, desktop source meters, chip tester power boards, and VI (Voltage / Current) source boards, the corresponding switching requirements generated in different application scenarios should follow the unified gear switching requirements, that is, the load output fluctuation is small and the fluctuation duration is short. However, when the source meter digital loop performs current or voltage gear switching, the switching moment is likely to cause a large sudden change in the load output, and the corresponding output burrs seriously affect the stability of the system, thereby reducing the gear switching efficiency, and it is difficult to achieve efficient control of the source meter digital loop. Summary of the invention

[0004] In view of this, the present invention provides a gear switching control method, source meter, system and medium of a source meter to solve the problem that when the existing source meter switches gears, there is output fluctuation or mutation, and the corresponding output burrs seriously affect the stability of voltage and current on the load, thereby affecting the precise control or test safety of the source meter.

[0005] In a first aspect, the present invention provides a gear switching control method of a source meter, the method comprising: Detect the switching action currently triggered for the source table user; In response to the switching action, determining a switching type, and determining a target electronic device matching the switching type; The target control parameters are calculated based on the key parameters corresponding to the target electronic device, and the source meter is controlled accordingly based on the target control parameters.

[0006] The source meter of the present invention is implemented by means of a digital loop. After detecting a switching action triggered on the source meter, the switching type corresponding to the switching action is determined. At the same time, the target electronic device in the digital loop that matches the switching type is determined, and the voltage range switching or current range switching of the source meter is completed through the corresponding hardware action of the electronic device. This can effectively suppress the output mutation of the source meter, thereby helping to maintain the stable output of the device under test, significantly improving the control accuracy of the source meter to a certain extent, and ensuring the test safety at the same time.

[0007] In an alternative embodiment, in response to the switching action, determining the switching type includes: In response to the switching action, identifying whether the power amplifier module performs output adjustment or whether the voltage conditioning circuit performs switching; If it is identified that the power amplifier module performs output adjustment or the voltage conditioning circuit performs switching, then determine that the switching type is voltage range switching.

[0008] For the specific switching type of the source meter of the present invention, a process of determining whether the power amplifier module performs gain adjustment or determining whether the voltage conditioning circuit switches is designed to determine the switching type of the source meter. When the power amplifier module performs gain adjustment or switches the voltage conditioning circuit, it is determined that the switching type is voltage range switching, which has the significant advantages of simple hardware structure and accurate type determination. In an alternative embodiment, in response to the switching action, determining the switching type includes: In response to the switching action, obtaining the first sampling resistor of the source meter before the switching action is executed; If it is identified that the first sampling resistor or the switching of the current conditioning circuit is instantaneously disconnected after the second sampling resistor is connected in parallel with the first sampling resistor, then determine that the switching type is current range switching, where the second sampling resistor is the sampling resistor corresponding to the preset current range threshold.

[0009] For the specific switching type of the source meter of the present invention, a process of detecting whether the sampling resistor in the digital loop switches or determining whether the current conditioning circuit switches is also designed to determine the switching type of the source meter. When the first sampling resistor is instantaneously disconnected or the current conditioning circuit is switched after the second sampling resistor is connected in parallel with the first sampling resistor, it is determined that the switching type is current range switching, which has the advantages of simple design and safety, and can accurately identify the current range switching of the source meter.

[0010] In an alternative embodiment, if the switching type is voltage range switching, then determine that the target electronic device is the power amplifier module. The power amplifier module is used to adjust the amplitude of the output analog signal of the digital-to-analog converter to the voltage preset range threshold corresponding to the current range. Calculating the target control parameter based on the key parameter corresponding to the target electronic device includes: Acquire a first voltage outputted from the digital-to-analog converter to the power amplifier module, and a gain change before and after output adjustment of the power amplifier module; Determine the second voltage through the first voltage and gain change of the power amplifier module, and check whether the second voltage meets the voltage preset gear threshold corresponding to the current gear; If satisfied, determining whether the second voltage is greater than a preset change threshold; When the second voltage is greater than a preset change threshold, the voltage conditioning circuit is switched; if the source meter is currently in a current source working mode, the preset output current is determined as the target control parameter; if the source meter is currently in a voltage source working mode and the source meter is connected to a device to be tested externally, the output current of the device to be tested is collected using a corresponding current conditioning circuit, and the output current is determined as the target control parameter.

[0011] When the source meter performs voltage gear switching, the present invention determines the second voltage after switching by acquiring the first voltage output by the digital-to-analog converter and the gain change before and after the power amplifier module output is adjusted, and verifies whether the second voltage meets the corresponding range set by the current gear, that is, the voltage preset gear threshold. When the corresponding range is met, a determination is added on the size of the change before and after the voltage gear switching, that is, the size determination of the second voltage and the preset change threshold. When the second voltage is greater than the preset change threshold, the voltage conditioning circuit needs to be switched, and it is determined whether it is necessary to use the corresponding current conditioning circuit to collect the output current of the device under test according to the current source meter working mode, and the output current is determined as the target control parameter. The source meter control parameters can be accurately obtained, and the stable output of the device under test is maintained to a certain extent.

[0012] In an optional implementation, the gear switching control method of the source meter further includes: When the second voltage is not greater than the preset change threshold, the voltage conditioning circuit is not switched; if the source meter is currently in the current source working mode and the device to be tested is connected to the source meter externally, the output current of the device to be tested is collected by the corresponding current conditioning circuit, and the output current is determined as the target control parameter; if the source meter is currently in the voltage source working mode, the preset output voltage is determined as the target control parameter.

[0013] The present invention also takes into account the situation where the output voltage changes little before and after the voltage gear is switched. When the second voltage is not greater than the preset change threshold, the voltage conditioning circuit is not switched. It is only necessary to adjust the output gain of the amplifier module and the target control parameters of the source meter are not changed during the voltage switching process. That is, the corresponding target control parameters are determined according to the current source meter working mode, which effectively suppresses the output mutation of the source meter to a certain extent and helps to maintain the stable output of the device under test.

[0014] In an optional implementation, if the switching type is current gear switching, determining that the target electronic device is a second sampling resistor; and calculating the target control parameter based on the key parameter corresponding to the target electronic device include: Obtain the target current of the source meter before performing the switching action; Calculating the parallel resistance of the second sampling resistor and the first sampling resistor; calculating a third voltage based on the target current and the parallel resistance; When the third voltage meets the preset fluctuation threshold range, if the source meter is currently in the current source working mode and the source meter is connected to the device to be tested externally, the target voltage conditioning circuit is used to collect the output voltage of the device to be tested, and the output voltage is determined as the target control parameter; if the source meter is currently in the voltage source working mode, the preset output voltage is determined as the target control parameter; wherein the target voltage conditioning circuit is determined based on the output adaptability of the power amplifier module after the switching action.

[0015] When the source meter performs current gear switching, the present invention obtains the target current before the switching action is performed, and the parallel resistance values ​​of the corresponding sampling resistors before and after the switching, and then calculates the third voltage according to the target current and the parallel resistance value, and verifies the rationality of the selection of the sampling resistor based on the relationship between the third voltage and the preset fluctuation threshold range, that is, according to the output change reflected by the third voltage, the resistance value of the sampling resistor can be adaptively adjusted based on the reference output change amount in the hardware design stage, thereby reducing the output burrs; at the same time, when the current conditioning circuit is switched, the corresponding target control parameters are determined according to the current source meter working mode, and the source meter control parameters can be accurately obtained, which reduces the output fluctuation or mutation of the source meter to a certain extent, thereby maintaining the stable output of the device to be tested and improving the precise control of the source meter.

[0016] In a second aspect, the present invention provides a source meter, which includes: a controller, a power amplifier module, a resistance selection module, a current conditioning circuit and a voltage conditioning circuit, and the components of the source meter are interconnected to form a digital loop; wherein, the output end of the controller is connected to the input end of the power amplifier module through a digital-to-analog converter, the resistance selection module includes multiple sampling resistors, the output end of the power amplifier module is connected to any sampling resistor selected in the resistance selection module, the output end of each sampling resistor is connected to the current conditioning circuit and the voltage conditioning circuit, the output ends of the current conditioning circuit and the voltage conditioning circuit are connected to the analog-to-digital converter, and the output end of the analog-to-digital converter is connected to the controller.

[0017] The source meter of the present invention is implemented by using a digital loop method, and is specifically composed of a controller, a power amplifier module, a resistance selection module, a current conditioning circuit and a voltage conditioning circuit connected to each other. The output of the source meter can be flexibly adjusted, and the stable output of the device under test is maintained to a certain extent.

[0018] In an optional implementation, the power amplifier module includes a digital potentiometer and an amplifier, which are used to adjust the amplitude of the output analog signal of the digital-to-analog converter to a preset gear threshold corresponding to the current gear.

[0019] The digital potentiometer and amplifier designed in the present invention can realize the continuous numerical adjustment amplification function, help to maintain the continuous and smooth gain change, and thus effectively prevent the gain mutation of the power amplifier module from causing the sudden change of the source meter output voltage, suppress the output mutation of the source meter to a certain extent, and maintain the stable output of the device under test.

[0020] In a third aspect, the present invention provides a gear switching control system, the system comprising a source meter as described in the second aspect or any corresponding embodiment thereof and a device to be tested, wherein the source meter is used to execute a gear switching control method of a source meter as described in the first aspect or any corresponding embodiment thereof.

[0021] The present invention designs a gear switching control system including a source meter and a device under test, wherein the source meter is implemented based on a digital loop, and corresponding control processes of the source meter under voltage gear switching and current gear switching are also designed accordingly, which can greatly suppress the output mutation of the source meter, thereby maintaining the stable output of the device under test, and helping to improve the control accuracy and output stability of the gear switching control system.

[0022] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute a source meter gear switching control method according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 is a structural block diagram of a source table according to an embodiment of the present invention; Figure 2 is a structural block diagram of another source table according to an embodiment of the present invention; Figure 3 is a structural block diagram of a gear switching control system according to an embodiment of the present invention; Figure 4 This is the principle block diagram of the source meter gear switching control system; Figure 5 This is the principle block diagram of the source meter gear switching; Figure 6 is a flow chart of a gear switching control method of a source meter according to an embodiment of the present invention; Figure 7 is a flow chart of a gear switching control method of another source meter according to an embodiment of the present invention; Figure 8 is a flow chart of a gear switching control method of another source meter according to an embodiment of the present invention; Fig. 9 It is a schematic diagram of the result of voltage gear switching with loop control; Fig.10 This is a schematic diagram of the result of voltage gear switching without loop control; Fig.11 It is a schematic diagram of the result of current gear switching with loop control; Fig.12 It is a schematic diagram of the result of current gear switching without loop control. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0026] In this embodiment, a source table is provided. Figure 1 is a structural block diagram of a source table according to an embodiment of the present invention. Figure 1 As shown, the source meter includes: a controller 1, a power amplifier module 3, a resistor selection module 4, a current conditioning circuit 5 and a voltage conditioning circuit 6, and the components of the source meter are interconnected to form a digital loop; wherein, the output end of the controller 1 is connected to the input end of the power amplifier module 3 through a digital-to-analog converter 2, the resistor selection module 4 includes a plurality of sampling resistors, the output end of the power amplifier module 3 is connected to any selected sampling resistor in the resistor selection module 4, the output end of each sampling resistor is connected to the current conditioning circuit 5 and the voltage conditioning circuit 6, the output ends of the current conditioning circuit 5 and the voltage conditioning circuit 6 are connected to the analog-to-digital converter 7, and the output end of the analog-to-digital converter 7 is connected to the controller 1.

[0027] In practical applications, the source meter, as an instrument that integrates signal source and measurement functions, can not only provide driving voltage to the device under test while measuring the current flowing through it, but also provide driving current to the device under test while measuring the voltage across the device under test, making it widely used in the field of detection.

[0028] It should be noted that in this embodiment, a digital loop is used to realize various functional controls of the source meter, wherein the controller 1 is used to respond to the output setting of the user to accurately control the output of the digital-to-analog converter 2, and at the same time receive the feedback output current or voltage data to compare with the corresponding set value, and further adjust the output of the digital-to-analog converter 2 according to the comparison result; the power amplifier module 3 is used to amplify the output of the digital-to-analog converter 2 to the corresponding gear range (that is, the corresponding range of the output voltage or current required by the source meter); the resistor selection module 4 is used to select a suitable sampling resistor, and specifically realize the corresponding connection and disconnection through the gating switch of each sampling resistor, and the specific type of the gating switch is adaptively set based on actual needs; the sampling resistor is used to measure the current flowing through the device under test, and is often connected to the current path of the device under test, and generates a voltage signal proportional to the current for measurement and feedback; the current conditioning circuit 5 and the voltage conditioning circuit 6 are used to process the current and voltage data to ensure the authenticity and reliability of the data, and are respectively connected to the analog-to-digital converter 7 to digitize the processed current and voltage for subsequent analysis by the controller 1.

[0029] It should be noted that in this embodiment, the specific types of each electronic device in the above digital loop are not limited here, and can be adaptively set according to actual needs. For example, the controller 1 is based on a voltage-current digital control loop (Proportional Integral Differential, PID), which is only used as an example.

[0030] The source meter of the embodiment of the present invention is implemented by using a digital loop method, which is specifically composed of a controller, a power amplifier module, a resistance selection module, a current conditioning circuit and a voltage conditioning circuit connected to each other. The current output of the source meter can be flexibly adjusted, greatly meeting the demand for efficient use of the source meter.

[0031] In this embodiment, a source table is provided. Figure 2 is a structural block diagram of another source table according to an embodiment of the present invention. Figure 2 As shown, the power amplifier module 3 includes a digital potentiometer 31 and an amplifier 32, which are used to adjust the amplitude of the output analog signal of the digital-to-analog converter 2 to a preset gear threshold corresponding to the current gear.

[0032] In this embodiment, the preset gear threshold value is the range of the voltage or current corresponding to the gear, and its specific value is adaptively adjusted according to the actual project requirements and is not limited in detail here.

[0033] The digital potentiometer and amplifier designed in the embodiment of the present invention can realize the continuous numerical adjustment amplification function, help to maintain the continuous and smooth gain change, and thus effectively prevent the gain mutation of the power amplifier module from causing the sudden change of the source meter output voltage, suppress the output mutation of the source meter to a certain extent, and maintain the stable output of the device under test.

[0034] In practical applications, the source meter has multiple gear switching requirements in different application scenarios, and the output fluctuation is required to be small and the duration is short during the gear switching. Therefore, it is necessary to design a source meter gear hot switching solution to ensure the output stability of the source meter and the device under test. Therefore, this embodiment also provides a gear switching control system. Figure 3 is a structural block diagram of a gear switching control system according to an embodiment of the present invention. Figure 3 As shown, the system includes: a source meter and a device under test; wherein the source meter is used to implement the subsequent switching control embodiment and preferred implementation. It should be noted that the gear switching control process of the source meter in this embodiment can be found below, and no further explanation is given here.

[0035] The embodiment of the present invention designs a gear switching control system including a source meter and a device under test based on a digital loop, and also designs corresponding control processes of the source meter under voltage gear switching and current gear switching, which can greatly suppress the output mutation of the source meter, thereby maintaining the stable output of the device under test, and helping to improve the control accuracy and output stability of the gear switching control system.

[0036] In a specific embodiment, a source meter gear switching scheme using digital loop control is proposed, which mainly involves the interaction between digital loop control and hardware design to maintain the stability of the source meter gear switching control system. Figure 4 It can be seen from the principle block diagram of the source meter shift control system that the system includes: a load (i.e., the device to be tested) and a source meter (i.e., SMU); wherein, the SMU includes a voltage and current digital control loop PID, a digital-to-analog converter, a PA module (i.e., a power amplifier module, including a digital potentiometer and an amplifier), a sampling resistor, a voltage conditioning circuit, a current conditioning circuit, and an analog-to-digital converter. It should be explained that the digital-to-analog converter of this embodiment outputs a base voltage, and uses a voltage and current digital control loop PID to adjust the output voltage of the digital-to-analog converter, and the voltage value is amplified by the PA module to the required voltage value; after the voltage output by the PA module passes through the sampling resistor, there is a voltage difference at both ends of the sampling resistor, and the loop current is reversely calculated by the aforementioned voltage difference.

[0037] In this embodiment, see Figure 5 From the principle block diagram of the source meter gear switching, it can be seen that the PA module includes a digital potentiometer and an amplifier. It should be noted that in this embodiment, voltage gear switching and current gear switching are considered; wherein, the voltage gear switching is divided into two parts, specifically including: 1. Through the PA module composed of a digital potentiometer and an amplifier, the base voltage output by the digital-to-analog converter is amplified to the target gear range, and the gain can be dynamically adjusted through digital control to achieve precise control of data amplification; 2. Switching the acquisition channel of the voltage conditioning circuit to adapt to the acquisition of voltages of different sizes. When switching the current gear, the sampling resistor's selection switch selects a solid-state relay, which has a faster switching speed than traditional mechanical relays, can achieve microsecond switching, and its lack of mechanical wear can significantly increase the service life of the system. Specifically, when switching the sampling resistor, the loop should be closed, so the current gear switching can be divided into two steps, including: 1. First close the sampling resistor of the target current gear. The solid-state relay is connected in parallel at this time, and the current conditioning circuit is switched to the corresponding target current gear; 2. Then disconnect the corresponding sampling resistor of the previous current gear.

[0038] In summary, in this embodiment, for the voltage gear switching, the digital potentiometer is used to control the multiple relationship between the voltage output of the PA module and the output of the digital-to-analog converter, thereby completing the switching of the voltage gear output part, and at the same time, different voltage conditioning circuits are selected by the relay switch to complete the switching of the voltage acquisition path; for the current gear switching, the corresponding sampling resistor (i.e. Figure 5 Any one of the current sampling resistors R1, R2, R3, etc. included in it) is used to complete the switching of the current gear output part, and different current conditioning circuits are selected through the relay switch to complete the switching of the current acquisition path; in the process of voltage or current gear switching, the voltage and current digital control loop PID is used to eliminate the output burrs generated during gear switching.

[0039] In this embodiment, a method for controlling the gear switching of a source meter is provided. Figure 6 is a flow chart of a method for controlling the gear switching of a source meter according to an embodiment of the present invention. Figure 6 As shown, the process includes the following steps: Step S601: Detect the switching action currently triggered by the source table user.

[0040] It should be noted that the switching action triggered by the source meter in step S601 of this embodiment mainly refers to the user's adjustment operation or setting operation on the source meter output at the software level, specifically, the current gear switching or voltage gear switching of the source meter is flexibly adjusted by the controller.

[0041] Step S602, responding to the switching action, determining the switching type, and determining the target electronic device matching the switching type.

[0042] It should be noted that in step S602 of this embodiment, responding to the switching action and then determining the switching type and its matching target electronic device is mainly implemented at the hardware level; wherein the switching type includes current gear switching and voltage gear switching, and the target electronic device represents any device in the digital loop.

[0043] Step S603, calculating target control parameters based on key parameters corresponding to the target electronic device, and controlling the source meter accordingly based on the target control parameters.

[0044] In this embodiment, the target control parameter is fed back to the controller after passing through the analog-to-digital converter, so that the controller adjusts the corresponding output of the digital-to-analog converter according to the target control parameter.

[0045] It should be noted that when there is no gear switching action on the source meter, the corresponding control process includes: the controller receives the feedback data of the analog-to-digital converter in real time, that is, the voltage and current output by the source meter, and the relevant setting algorithm running inside the controller compares the feedback data with the corresponding values ​​of the voltage or current set by the user, respectively, to obtain the adjusted output data, and converts the adjusted output data into a corresponding analog voltage signal through the digital-to-analog converter, and then outputs it to the power amplifier module for amplification, and then finally outputs it to the output port of the source meter or to the device under test connected to the current sampling resistor through the current sampling resistor, so as to achieve stable control of the device under test. The above process only simply describes a control cycle. In fact, the process is continuously cyclically operated to ensure that the final output value of the source meter is completely equal to the set value.

[0046] The gear switching control method of the source meter in the embodiment of the present invention determines the switching type corresponding to the switching action after detecting the switching action triggered on the source meter, and simultaneously determines the target electronic device matching the switching type in the digital loop, and completes the voltage gear switching or current gear switching of the source meter through the hardware action corresponding to the electronic device. This can effectively suppress the output mutation of the source meter, thereby helping to maintain the stable output of the device under test, significantly improve the control accuracy of the source meter to a certain extent, and thereby ensure the test safety.

[0047] It should be noted that the gear switching in this embodiment includes two modes: voltage gear switching and current gear switching. If the gear switching is voltage gear switching, refer to Figure 7 From the flowchart of voltage gear switching control, it can be seen that the process includes the following steps: Step S701: Detect the switching action currently triggered by the source table user. Figure 6Step S601 of the illustrated embodiment will not be described in detail here.

[0048] Step S702, responding to the switching action, determining the switching type, and determining the target electronic device matching the switching type.

[0049] Specifically, the above step S702 includes: Step S7021, responding to the switching action, identifying whether the power amplifier module performs output regulation or whether the voltage conditioning circuit performs switching.

[0050] It should be noted that, in this embodiment, the output adjustment of the power amplifier module substantially refers to a change in the gain of the power amplifier module.

[0051] In this embodiment, see Figure 5 , assuming that the source meter has two voltage levels, where voltage level I corresponds to a fixed gain of K for the PA module 1 , then the output voltage V2 of the PA module 1 =K 1 ×V1 1 , V1 is the output voltage of the digital-to-analog converter; the fixed gain of the PA module corresponding to voltage level II is K 2 , then the output voltage V2 of the PA module 2 =K 2 ×V1 2 When the source meter triggers the voltage range switch, that is, the voltage range I switches to the voltage range II, the output voltage difference (that is, the voltage difference across the load) is V 1-2 =V2 2 –V2 1 =(K 2 ×V1 2 )-(K 1 ×V1 1 ); Since the output voltage V1 of the digital-to-analog converter 2 and V1 1 Under the real-time control of the digital loop, assuming that the digital loop does not perform real-time control during the voltage range switching process, V1 2 =V1 1 Therefore, the voltage difference across the load is V 1-2 =(K 2 -K 1 )×V1 1 It should be noted that the output voltage of the source meter in the digital loop (i.e., V3) is the same as the voltage across the load. This shows that the change in output voltage when the voltage range is switched is only related to the change in the gain of the PA module. The output voltage of the load can be obtained in real time based on this change and then fed back to the controller.

[0052] It should be noted that with the advancement of technology, when the step size of the digital potentiometer is small enough, the corresponding digital loop can theoretically adjust the output change caused by the gain change of the PA module, and a better voltage level hot-cutting effect can be obtained. Specifically, the PA module containing the digital potentiometer can continuously adjust the resistance value based on a smaller granularity, so that the gain change of the PA module is continuous and smooth, thereby effectively preventing the sudden change of the source meter output voltage caused by the sudden change of the gain.

[0053] Step S7022: If it is identified that the power amplifier module is performing output regulation or the voltage conditioning circuit is switching, it is determined that the switching type is voltage gear switching.

[0054] In this embodiment, when it is not recognized that the power amplifier module is performing output regulation, the process returns to the step of responding to the switching action and determining the switching type.

[0055] Step S7023, determining that the target electronic device that matches the voltage gear switching is a power amplifier module.

[0056] In the embodiment of the present invention, the source meter switching type is determined according to the process of whether the power amplifier module performs gain adjustment or determines whether the voltage conditioning circuit is switched, and when the power amplifier module performs gain adjustment or switches the voltage conditioning circuit, the switching type is determined to be voltage gear switching, which has the significant advantages of simple hardware structure and accurate type determination.

[0057] Step S703, calculating target control parameters based on key parameters corresponding to the target electronic device, and controlling the source meter accordingly based on the target control parameters.

[0058] Specifically, the above step S703 includes: Step S7031, obtaining a first voltage outputted from the digital-to-analog converter to the power amplifier module, and a gain change before and after the output of the power amplifier module is adjusted.

[0059] It should be noted that gain is an important performance indicator of a power amplifier. It indicates the amplification factor of the output signal after the input signal passes through the amplifier. It can reflect the amplifier's signal amplification capability (that is, it determines the size of the signal that the power amplifier can amplify), feedback effect (that is, it affects the feedback effect from the output to the input of the amplifier) ​​and working efficiency (that is, it determines the efficiency of the amplifier and the signal range that can be amplified).

[0060] In this embodiment, the specific method for obtaining the first voltage and the gain change before and after the power amplifier module output is adjusted is not limited here, and can be obtained by referring to the relevant data acquisition method in the art.

[0061] Step S7032, determining a second voltage through the first voltage and gain change of the power amplifier module, and verifying whether the second voltage satisfies a voltage preset gear threshold corresponding to the current gear.

[0062] In this embodiment, the specific value of the voltage preset gear threshold can be adaptively adjusted based on actual project requirements and hardware parameters, and is not limited in detail here.

[0063] Step S7033: if satisfied, determine whether the second voltage is greater than a preset change threshold.

[0064] In this embodiment, if the second voltage does not meet the voltage preset gear threshold corresponding to the current gear, it indicates that the voltage conditioning circuit does not need to be switched during the current voltage gear switching process.

[0065] It should be noted that the preset change threshold in this embodiment is used to characterize the situation where the output changes smoothly before and after the voltage gear is switched, that is, if the output voltage after switching is greater than the preset change threshold, it is considered that the output voltage changes greatly after the voltage gear is switched. In order to ensure that the output of the source meter is stable before and after the gear switch is executed, it is necessary to use the stable current in the loop for corresponding adjustment, that is, it is necessary to switch the voltage conditioning circuit and determine whether it is necessary to use the corresponding current conditioning circuit to collect the output voltage of the device under test according to the current source meter working mode. Specifically, when the source meter is currently in the current source working mode, the output current set by the user is determined as the target control parameter; when the source meter is currently in the voltage source working mode and the source meter is external to the device under test, The output current of the device under test is collected by using the corresponding current conditioning circuit, and the output current is determined as the target control parameter; if the output voltage after switching is not greater than the preset change threshold, it is considered that the voltage conditioning circuit is not switched after the voltage gear is switched. At this time, the output voltage change is small and can be ignored, which indicates that the voltage is stable and can be used for corresponding adjustments to ensure stable output at both ends of the load. Specifically, when the source meter is currently in the current source working mode and the device under test is connected to the source meter externally, the output voltage of the device under test is collected by using the corresponding voltage conditioning circuit, and the output voltage is determined as the target control parameter; when the source meter is currently in the voltage source working mode, the output voltage set by the user is determined as the target control parameter.

[0066] In this embodiment, the specific value of the preset change threshold can be set to a dynamic value, that is, determined by the maximum acquisition voltage of the voltage conditioning circuit. It should be noted that the value determination process of the preset change threshold is completed in the hardware design stage. For example, the preset change threshold is dynamically adjusted according to the maximum voltage output burr of the theoretically calculated source meter to avoid output voltage fluctuations caused by voltage gear switching, thereby avoiding triggering unnecessary current acquisition operations. Specifically, the value determination process of the preset change threshold includes: 1. First, based on the sampling resistor values and the current values at different voltage levels, calculate the maximum voltage output glitch theoretically when switching from one voltage level to another. Then, continuously monitor the voltage level switching operation. Once a switch is detected, read the preset change threshold adjustment coefficient stored in advance related to the current working mode or environmental conditions. Next, make corresponding adjustments to the maximum voltage output glitch based on the preset change threshold adjustment coefficient, compare it with the original preset change threshold, and make adjustments to obtain a new preset change threshold. For example: Based on the sampling resistor values at different voltage levels and the current value, calculate that the maximum voltage output glitch when switching from voltage level A to voltage level B is 5 mV. It is detected that the switching operation from voltage level A to voltage level B occurs, and the preset change threshold adjustment coefficient related to the current working mode (such as high-precision mode) stored in advance is read as 1.2. The original preset change threshold is 4 mV. Based on this preset change threshold adjustment coefficient of 1.2, adjust the maximum voltage output glitch of 5 mV, and the adjusted value is 5 mV × 1.2 = 6 mV. Compare this 6 mV with the original preset change threshold of 4 mV. Since 6 mV is greater than 4 mV, adjust the original preset change threshold to 6 mV, thus obtaining a new preset change threshold of 6 mV.

[0067] 2. During the voltage level switching process, continuously compare the real-time second voltage with the new preset change threshold. Only when the second voltage actually exceeds the adjusted preset change threshold, trigger the switching of the corresponding current conditioning circuit or collect the output current of the device under test. That is, during the voltage level switching process, if it is recognized that the second voltage exceeds the preset change threshold, while switching the voltage conditioning circuit, determine whether to use the current of the current loop as the target control parameter.

[0068] In the embodiments of the present invention, through the dynamic adjustment of the preset change threshold in the hardware design stage, it can effectively ensure the accurate acquisition of the target control parameter when switching voltage levels, thereby improving the control accuracy of the source meter, helping to improve the output stability of the device under test, and at the same time ensuring the test safety.

[0069] Step S7034, when the second voltage is greater than the preset change threshold, switch the voltage conditioning circuit; if the source meter is currently in the current source working mode, determine the preset output current as the target control parameter; if the source meter is currently in the voltage source working mode and the source meter is externally connected to the device under test, use the corresponding current conditioning circuit to collect the output current of the device under test, and determine the output current as the target control parameter.

[0070] It should be noted that the preset output current is the output current set by the user, and its specific value is adaptively adjusted according to the actual user requirements.

[0071] Step S7035, when the second voltage is not greater than the preset change threshold, the voltage conditioning circuit is not switched; if the source meter is currently in the current source working mode and the source meter is connected to the device to be tested externally, the output current of the device to be tested is collected using the corresponding current conditioning circuit, and the output current is determined as the target control parameter; if the source meter is currently in the voltage source working mode, the preset output voltage is determined as the target control parameter.

[0072] It should be noted that the preset output voltage is the output voltage set by the user, and its specific value is adaptively adjusted according to actual user needs.

[0073] In this embodiment, the situation in which the output voltage changes little before and after the voltage gear is switched is also taken into consideration. When the second voltage is not greater than the preset change threshold, there is no need to switch the voltage conditioning circuit. At this time, the output control method of the source meter does not change. It is only necessary to adjust the power amplifier gain to complete the switching of the voltage gear. This effectively suppresses the output mutation of the source meter to a certain extent, and helps to maintain a stable output of the device under test.

[0074] Step S7036: Perform corresponding control on the source table based on the target control parameter.

[0075] In the embodiment of the present invention, when the source meter triggers the voltage gear switching, the second voltage after the switching is determined by obtaining the first voltage output by the digital-to-analog converter and the gain change before and after the power amplifier module output is adjusted, and at the same time, it is verified whether the second voltage meets the corresponding range of the current gear setting, that is, the voltage preset gear threshold. When the corresponding range is met, a judgment is added on the size of the change before and after the voltage gear switching, that is, the size judgment of the second voltage and the preset change threshold is set. When the second voltage is greater than the preset change threshold, the voltage conditioning circuit needs to be switched, and the corresponding target control parameters are determined according to the current source meter working mode. The source meter control parameters can be accurately obtained, and the stable output of the device under test is maintained to a certain extent.

[0076] In this embodiment, if the gear switching is current gear switching, refer to Figure 8 It can be seen from the flow diagram of the current gear switching control that the process includes the following steps: Step S801: Detect the switching action currently triggered by the source table user. Figure 6 Step S601 of the illustrated embodiment will not be described in detail here.

[0077] Step S802, responding to the switching action, determining the switching type, and determining the target electronic device matching the switching type.

[0078] Specifically, the above step S802 includes: Step S8021, in response to the switching action, obtaining the first sampling resistance of the source meter before executing the switching action.

[0079] It should be noted that the current gear switching of this embodiment is essentially as follows: after the gear switching, the corresponding sampling resistor is first connected to the digital loop and connected in parallel with the corresponding sampling resistor before the switching, and then the resistance change process of the corresponding sampling resistor before the gear switching is instantaneously disconnected.

[0080] In this embodiment, see Figure 5 , assuming that the source meter has two current ranges, and the output current corresponding to the source meter in current range I is I, then theoretically, the maximum voltage output glitch when switching from current range I to current range II is V 12 =I×(R2×R1) / (R2+R1), where R1 and R2 are the corresponding current sampling resistors. It should be noted that during the current gear hot-cut process, the actual resistance of the sampling resistor depends on the characteristics of the solid-state relay (i.e., the selection switch of each sampling resistor) to establish a path. According to the characteristics of resistors in parallel, the current mainly passes through the path with smaller impedance. Therefore, the smoother the solid-state relay path is established, the greater the sudden change in the output voltage (i.e., the maximum voltage output burr during the switching process occurs when the two resistors are connected in parallel). In order to ensure the stability of the loop current, the voltage at both ends of the load should be stable, that is, the source meter voltage output should be stable. After selecting a suitable solid-state relay, a certain gear hot-cut processing strategy is required to ensure a stable voltage output, that is, adjust the corresponding parameters according to U=IR to keep U in a stable state.

[0081] Step S8022: if it is identified that the second sampling resistor is connected in parallel with the first sampling resistor and then the first sampling resistor is disconnected instantaneously or the current conditioning circuit is switched, the switching type is determined to be a current range switch, wherein the second sampling resistor is a sampling resistor corresponding to a preset current range threshold.

[0082] In this embodiment, the specific value of the current preset gear threshold is adaptively adjusted based on actual needs and is not limited in detail here.

[0083] Step S8023, determining that the target electronic device that matches the current gear switching is the second sampling resistor.

[0084] In the embodiment of the present invention, for the specific switching type of the source meter, a process is designed to detect whether the sampling resistor in the digital loop is switched or determine whether the current conditioning circuit is switched to determine the switching type of the source meter, and when the first sampling resistor is instantly disconnected or the current conditioning circuit is switched after the second sampling resistor is connected in parallel with the first sampling resistor, the switching type is determined to be current gear switching. This has the advantages of simple and safe design, and can accurately identify the current gear switching of the source meter.

[0085] Step S803, calculating target control parameters based on key parameters corresponding to the target electronic device, and controlling the source meter accordingly based on the target control parameters.

[0086] Specifically, the above step S803 includes: Step S8031, obtaining the target current of the source meter before performing the switching action.

[0087] In this embodiment, the specific method for obtaining the target current is not limited here, and can be obtained by referring to the relevant current acquisition methods in the art, such as using an ammeter to measure the current size, which is only used as an exemplary description.

[0088] Step S8032, calculating the parallel resistance of the second sampling resistor and the first sampling resistor.

[0089] In this embodiment, the parallel resistance of the second sampling resistor and the first sampling resistor can be obtained according to a related formula. For example, the parallel resistance of two resistors R1 and R2 connected in parallel is R=(R1×R2) / (R1+R2).

[0090] Step S8033, calculating the third voltage based on the target current and the parallel resistance.

[0091] Step S8034, when the third voltage meets the preset fluctuation threshold range, if the source meter is currently in the current source working mode and the source meter is connected to the device to be tested externally, the output voltage of the device to be tested is collected by using the target voltage conditioning circuit, and the output voltage is determined as the target control parameter; if the source meter is currently in the voltage source working mode, the preset output voltage is determined as the target control parameter; wherein the target voltage conditioning circuit is determined according to the output adaptability of the power amplifier module after the switching action.

[0092] In this embodiment, the preset fluctuation threshold range is used to characterize the reasonable value range of the sampling resistor, and its specific value can be adaptively adjusted according to actual needs.

[0093] Step S8035: perform corresponding control on the source table based on the target control parameter.

[0094] In this embodiment, the relevant contents of the control in step S8035 are referred to above and will not be repeated here.

[0095] In the embodiment of the present invention, when the source meter triggers the current gear switching, the target current before the switching action is executed and the parallel resistance values ​​of the corresponding sampling resistors before and after the switching are obtained, and then the third voltage is calculated according to the target current and the parallel resistance value, and the rationality of the selection of the sampling resistor is verified based on the relationship between the third voltage and the preset fluctuation threshold range, that is, according to the output change reflected by the third voltage, the resistance value of the sampling resistor can be adaptively adjusted based on the reference output change amount in the hardware design stage, thereby reducing the output burrs; at the same time, when the current conditioning circuit is switched, the corresponding target control parameters are determined according to the current source meter working mode, and the source meter control parameters can be accurately obtained, which reduces the output fluctuation or mutation of the source meter to a certain extent, thereby maintaining the stable output of the device under test and improving the precise control of the source meter.

[0096] In a specific embodiment, considering that in actual applications, the source meter as a signal source includes two working modes: voltage source (output voltage) and current source (output current), so this embodiment correspondingly designs four corresponding gear hot-cut strategies. It should be noted that in different source meter working modes, for the same gear switching type, the switching control process is the same.

[0097] In this embodiment, two switching control processes of the source meter include: 1. Voltage gear switching process: Voltage and current digital control loop PID, referred to as PID, focuses on the voltage output gain and voltage conditioning circuit, that is, the voltage change across the load.

[0098] 2. Current gear switching process: The control parameter that PID focuses on is the voltage across the load (that is, the control parameter that PID focuses on is the current flowing through the load. According to Ohm's theorem, the voltage across the load can also be focused on). The voltage difference value is the "maximum voltage output glitch V when switching from current gear I to current gear II in theory" mentioned above. 12 =I×(R2×R1) / (R2+R1)”.

[0099] Considering that in actual applications, the source meter as a signal source includes two working modes: voltage source (output voltage) and current source (output current), the present embodiment has designed four corresponding gear hot-cut strategies (that is, when the gear is hot-cut, in order to ensure that the output at both ends of the load remains unchanged, the gear hot-cut can be subdivided into four situations based on this as a starting point). It should be noted that in different source meter working modes, for the same gear switching type, the switching control process is the same. The four gear hot-cut strategies specifically include: 1. Consider switching the voltage gear when outputting the voltage (i.e. the voltage output gain is unstable or the voltage conditioning circuit is switched, but the sampling resistor and current conditioning circuit are stable).

[0100] In this embodiment, when the voltage gear is switched, the digital potentiometer is adjusted accordingly, and the output voltage of the PA module changes accordingly. At this time, the PID can output the voltage according to the voltage source; after the digital potentiometer is adjusted, before switching the corresponding voltage conditioning circuit, it can be switched to PID to establish the current of the current loop (that is, the current digital loop is adjusted from a voltage loop to a current loop, and the loop current is collected for corresponding control); or the loop is temporarily opened when the voltage conditioning circuit is switched (that is, the feedback process of feeding back the output voltage at both ends of the load to the controller is terminated).

[0101] In this embodiment, the control result of the voltage gear switching can be referred to Fig. 9 and Fig.10 It needs to be explained that Fig. 9 and Fig.10 The horizontal axis X in the two figures is time, and the vertical axis Y is voltage. It can be seen from the figure that thanks to the smooth and continuous change of the PA module output gain, combined with the gear hot-cut strategy, when mounted and unloaded, there is almost no burr at the output end during the voltage gear hot-cut process (that is, the data trend in the figure is smooth), or the output voltage difference is within the gear accuracy range. This gear hot-cut strategy can significantly improve the test efficiency and ensure the safety of the system. It should be explained that when there is no loop control, the data trend in the figure reflects the output voltage change of the hardware itself. It can be seen that the output voltage changes slowly, and the change process reflects the change in the PA module gain.

[0102] 2. Switch the current gear when considering the output voltage (that is, the current is unstable and the voltage is stable, and the control needs to keep the voltage unchanged so as not to affect the output of the source meter).

[0103] In this embodiment, when the current gear is switched, in order to ensure that the voltage across the load remains unchanged, the PID output voltage (i.e., the maximum voltage output glitch V when switching from current gear I to current gear II in theory) is maintained throughout the current gear switching process. 12 =I×(R2×R1) / (R2+R1)”). The control results of current gear switching can be found in Fig.11 and Fig.12 , Fig.11 and Fig.12 All of them are oscilloscope screenshots. X1 indicates the moment when the switching action starts, X2 indicates the moment when the glitch adjustment is completed during the switching, the difference ΔX between X2 and X1 indicates the duration of the gear switching action, Y1 indicates the voltage when the output is stable, Y2 indicates the maximum output voltage during the switching process, and the difference ΔY between Y2 and Y1 indicates the voltage of the maximum glitch. Fig. 9 and Fig.10 Related indicators can also be found in Fig.11 and Fig.12 Adaptive understanding of the meaning.

[0104] It should be noted that Fig.11 It is a schematic diagram of the result of current gear switching with loop control; Fig.12 This is a schematic diagram of the result of current gear switching without loop control. Fig.11 and Fig.12 Correspondingly, the horizontal axis X in the two figures is time, and the vertical axis Y is voltage. Fig.11 and Fig.12 The two figures are the comparison of the current range thermal effect when the output is 10mA and the external 200Ω resistor is connected. The maximum glitch of the corresponding loop current range switching is 3.75mA (the value is based on Fig.11 It can be seen that the difference ΔY between Y2 and Y1 is 0.75V, and the corresponding maximum loop current switching glitch is 0.75V / 200Ω=3.75mA). The elimination of output glitches is affected by the current regulation strategy. If the current regulation speed is increased, the output glitches will be eliminated faster, and the time can be flexibly modified according to actual needs. The short duration and small amplitude of the glitches can effectively improve the safety of the system and meet a wider range of application scenarios. It can be further seen that when the output voltage suddenly changes during the establishment of the solid-state relay path, the maximum value of the output voltage glitch is lower than that without loop control when there is loop control, and the loop control can quickly adjust the output to stabilize.

[0105] 3. Consider switching the voltage gear when outputting current (i.e. the voltage output gain is unstable or the voltage conditioning circuit is switched, but the sampling resistor and current conditioning circuit are stable).

[0106] In this embodiment, ensuring that the voltage across the load remains unchanged can also be reflected in maintaining the current in the loop unchanged. At this time, the PID output current is maintained throughout the process. For related content, please refer to the first gear hot-cut strategy mentioned above.

[0107] 4. Switch the current gear when considering the output current (that is, the sampling resistor and current conditioning circuit are unstable, but the voltage output gain is stable or there is no need to switch the voltage conditioning circuit).

[0108] In this embodiment, in order to ensure that the voltage across the load remains unchanged, the voltage of the current loop output by PID is maintained throughout the current gear switching process. For related content, please refer to the second gear hot-cut strategy mentioned above.

[0109] In summary, the switching control of the source meter including voltage or current gears in this embodiment is completed according to a single digital loop and in coordination with corresponding hardware actions, wherein the voltage gear switching is the change of the PA module output gain or the switching of the voltage conditioning circuit, and the current gear switching is the switching of the sampling resistor or the current conditioning circuit; at the same time, combined with the working mode of the source meter, four gear hot-cut strategies are designed accordingly, so that the source meter's gear hot-cut output burrs are small and the response is fast, and then the source meter's electrical switching gears can be continuously operated in daily testing, which effectively improves the test efficiency of the equipment under test and protects the equipment under test.

[0110] A computer-readable storage medium is also provided in an embodiment of the present invention. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium and downloaded through a network, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor main control chip or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0111] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for controlling the gear switching of a source meter, characterized in that: The method comprises: Detect the switching action currently triggered for the source table user; In response to the switching action, determining a switching type, and determining a target electronic device matching the switching type; Calculate target control parameters based on key parameters corresponding to the target electronic device, and control the source meter accordingly based on the target control parameters.

2. The gear switching control method of the source meter according to claim 1, characterized in that: The step of responding to the switching action and determining the switching type includes: In response to the switching action, identifying whether the power amplifier module performs output regulation or whether the voltage conditioning circuit performs switching; If it is identified that the power amplifier module performs output regulation or the voltage conditioning circuit performs switching, the switching type is determined to be voltage gear switching.

3. The gear switching control method of the source meter according to claim 1, characterized in that: The step of responding to the switching action and determining the switching type includes: In response to the switching action, obtaining a first sampling resistance of the source meter before performing the switching action; If it is identified that the second sampling resistor is connected in parallel with the first sampling resistor and then the first sampling resistor or the current conditioning circuit is instantly disconnected, the switching type is determined to be current gear switching, wherein the second sampling resistor is a sampling resistor corresponding to a preset current gear threshold.

4. The gear switching control method of the source meter according to claim 2, characterized in that: If the switching type is voltage gear switching, it is determined that the target electronic device is a power amplifier module, and the power amplifier module is used to adjust the amplitude of the output analog signal of the digital-to-analog converter to a voltage preset gear threshold corresponding to the current gear; the target control parameter is calculated based on the key parameters corresponding to the target electronic device, including: Acquire a first voltage outputted by a digital-to-analog converter to the power amplifier module, and a gain change before and after output adjustment of the power amplifier module; Determining a second voltage by using the first voltage and the gain change of the power amplifier module, and verifying whether the second voltage satisfies a voltage preset gear threshold corresponding to a current gear; If satisfied, determining whether the second voltage is greater than a preset change threshold; When the second voltage is greater than a preset change threshold, the voltage conditioning circuit is switched; if the source meter is currently in a current source working mode, the preset output current is determined as the target control parameter; if the source meter is currently in a voltage source working mode and the source meter is externally connected to a device under test, the output current of the device under test is collected using a corresponding current conditioning circuit, and the output current is determined as the target control parameter.

5. The gear switching control method of the source meter according to claim 4, characterized in that: The method further comprises: When the second voltage is not greater than a preset change threshold, the voltage conditioning circuit is not switched; if the source meter is currently in a current source working mode and the source meter is connected to a device under test externally, the output current of the device under test is collected using a corresponding current conditioning circuit, and the output current is determined as a target control parameter; if the source meter is currently in a voltage source working mode, the preset output voltage is determined as a target control parameter.

6. The gear switching control method of the source meter according to claim 3, characterized in that: If the switching type is current gear switching, determining that the target electronic device is a second sampling resistor; The calculating the target control parameter based on the key parameter corresponding to the target electronic device includes: Obtaining a target current of the source meter before performing a switching action; Calculating the parallel resistance of the second sampling resistor and the first sampling resistor; Calculating a third voltage based on the target current and the parallel resistance; When the third voltage meets the preset fluctuation threshold range, if the source meter is currently in the current source working mode and the source meter is connected to the device to be tested externally, the output voltage of the device to be tested is collected by using the target voltage conditioning circuit, and the output voltage is determined as the target control parameter; if the source meter is currently in the voltage source working mode, the preset output voltage is determined as the target control parameter; wherein the target voltage conditioning circuit is determined according to the output adaptability of the power amplifier module after the switching action.

7. A source meter, characterized in that: The source meter includes: a controller, a power amplifier module, a resistance selection module, a current conditioning circuit and a voltage conditioning circuit, and the components of the source meter are interconnected to form a digital loop; wherein the output end of the controller is connected to the input end of the power amplifier module through a digital-to-analog converter, the resistance selection module includes a plurality of sampling resistors, the output end of the power amplifier module is connected to any selected sampling resistor in the resistance selection module, the output end of each sampling resistor is connected to the current conditioning circuit and the voltage conditioning circuit, the output ends of the current conditioning circuit and the voltage conditioning circuit are connected to the analog-to-digital converter, and the output end of the analog-to-digital converter is connected to the controller.

8. The source meter according to claim 7, characterized in that: The power amplifier module includes a digital potentiometer and an amplifier, which are used to adjust the amplitude of the output analog signal of the digital-to-analog converter to a preset gear threshold corresponding to the current gear.

9. A gear switching control system, characterized in that: The system comprises the source meter according to any one of claims 7 to 8 and a device under test, wherein the source meter is used to execute the gear switching control method of the source meter according to any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the gear switching control method of the source meter according to any one of claims 1 to 6.

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