Method of determining characteristic of device under test, and test and measurement system

Abstract

To accurately obtain a target measurement with a small number of times that measurement is carried out.SOLUTION: In a step 704, a test and measurement instrument obtains three first measurements. In a step 706, a mathematical model representative of operation of a device under test (DUT) is determined based on the three first measurements. The test and measurement instrument then determines a plurality of second measurements of the characteristic of the DUT that are different from the three first measurements (a step 708). The mathematical model is verified based on the plurality of second measurements, and the behavior of the test and measurement instrument is adjusted based on the verified mathematical model (a step 710).SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure generally relates to a test measurement system, and more specifically, to a function for searching for characteristics of a device under test in a test measurement system.

Background Art

[0002] In device testing, a search function is used to find specific device parameters. Examples of search functions include finding the threshold voltage of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), which is the voltage between the gate and source of the MOSFET required for the MOSFET to turn "on" and conduct (defined by a specific current level). This search function is given a target current and voltage range, and at this time, it searches for the threshold voltage at which the MOSFET conducts the target current (search: explore, investigate). For any approach to finding this parameter, it is necessary to repeatedly supply a voltage to adjust the conducting current to approach the target current, so that the final current reading value is close enough to the target current and the search can be completed in a timely manner.

[0003] One solution is to use a binary search algorithm. The binary search algorithm repeatedly performs measurements at the center position between the lower and upper limits of the previous measurement. When using the binary search algorithm, the first measurement is performed at the threshold voltage at the center position between the lower and upper limits of the threshold voltage. If the measured current is lower than the target current, the threshold voltage needs to be higher than the previous center position value. Then, by setting the voltage value at this previous center position as the lower limit, the range of possible result variation is halved. The next measurement is again performed at the center position, and the variation range is halved again. Since the variation range is halved in each iteration, the number of possible results for a binary search is 2 N (N is the number of iterations), and the variation range becomes the reciprocal 1 / (2 N ).

Prior Art Documents

[0004] [Patent Document 1] JP 2017-027637 A [Non-patent literature]

[0005] [Non-Patent Document 1] "Binary search" article, Wikipedia (Japanese version), [online], [Retrieved January 7, 2025], Internet<https: / / ja.wikipedia.org / wiki / 二分探索> [Non-Patent Document 2] Article on "curve fitting", also referred to as "curve fitting", "best fit", and "curve regression", Wikipedia (Japanese version), [online], [Retrieved January 9, 2025], Internet<https: / / ja.wikipedia.org / wiki / 曲線あてはめ> Summary of the Invention [Problem to be solved by the invention]

[0006] The binary search algorithm is very robust and has the advantages of being simple and easy to calculate. Therefore, it is easier to achieve a higher sampling frequency. However, in the measurements required in these applications to overcome noise, the measurement time for the binary search algorithm is relatively long (on the order of milliseconds), so the calculation time is relatively very short. Furthermore, since accuracy is important, if another measurement is added to further narrow down the variable range, the search will take even more time. Also, among the assumptions in the binary search algorithm, there are some that are not highly regarded in one application but are important in another application. The binary search algorithm assumes that the value of the supplied voltage is the accurate measured value in the device under test (DUT), but this is not the case. The binary search algorithm has no way to consider this error. Furthermore, if the binary search algorithm erroneously obtains a result voltage that is lower or higher than the specific voltage it intended to test, the binary search algorithm cannot converge to the correct side of the specific voltage it was going to test. That is, the error cannot be made normal.

[0007] Functionally, the binary search algorithm is a one-dimensional algorithm that shifts the voltage left or right along the x-axis depending on whether the state of the result measurement is above or below the target. An accurate current measurement in a continuous range of values is rendered as a binary value based on whether it is above or below the target. In an example of the execution of a binary search, the process is simply shown on a single x-axis of the control variable of the voltage. This example of the execution of a binary search functions well under the assumption that there is no functional relationship between the input variable and the output variable, apart from the fact that it is an injective (one-to-one) function. Means for Solving the Problem

[0008] The system according to the present invention is composed of devices having one or more computer functions. During operation, by installing software, firmware, hardware, or a combination thereof that causes the system to perform specific processes or operations into the system, these specific processes or operations can be configured to be executed. One or more computer programs according to the present invention can be configured to execute these specific processes or operations by including instructions that cause a data processing device to perform specific processes or operations when executed by the data processing device.

[0009] In a general aspect, the method may have a process of obtaining a plurality of first measurement values regarding a device under test (DUT). In this case, the test measurement device is not set using the characteristics of the DUT, and the plurality of first measurement values may include measurement values regarding the characteristics of the DUT. The method may also have a process of obtaining an exponential function model of the DUT based on the plurality of first measurement values. At this time, this exponential function model represents the operation (behavior) of the DUT. The method may further have a process of obtaining a plurality of second measurement values different from the plurality of first measurement values. At this time, the plurality of second measurement values may include measurement values regarding the characteristics of the DUT. The method may further have a process of verifying the exponential function model based on the plurality of second measurement values. Furthermore, the method may have a process of adjusting the operation of the test measurement device based on the verified exponential function model of the DUT. Another embodiment of this aspect includes a corresponding computer system, device, and computer program, each of which is configured to execute the operation of this method.

[0010] In a general aspect, the test measurement system may include a test measurement device, which may have one or more ports for connecting the test measurement device to a device under test (DUT). The test measurement system may have a memory. The test measurement system may also have one or more processors configured to execute a program (code) stored in the memory. In this case, the program causes the one or more processors to perform processes of obtaining a plurality of first measurement values regarding parameters of the DUT that are not used to set the test measurement device, obtaining an exponential function model of the DUT parameters based on the plurality of first measurement values, obtaining a plurality of second measurement values regarding the DUT parameters, verifying the exponential function model based on the plurality of second measurement values when the plurality of second measurement values are different from the plurality of first measurement values, and adjusting the operation of the test measurement device based on the verified exponential function model of the DUT. Other embodiments of this aspect include corresponding computer systems, devices, and computer programs, each configured to perform the operations of the method.

[0011] In a general aspect, the test measurement system may include a test measurement device having one or more ports for connecting the test measurement device to a device under test (DUT). The test measurement system may have a memory. The test measurement system may also have one or more processors configured to execute a program (code) stored in the memory. The program causes the one or more processors to perform processes of obtaining a model of the DUT parameters based on three measurement values of the parameters by the test measurement device, verifying the model based on a fourth measurement value and a fifth measurement value of the parameters by the test measurement device, and adjusting the operation of the test measurement device regarding the parameters based on the verified model of the DUT. Another embodiment of this aspect includes corresponding computer systems, devices, and computer programs, each configured to perform the operations of the method.

[0012] These and other aspects will be understood by reference to the following detailed description.

Brief Description of the Drawings

[0013]

Figure 1

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Figure 7

Modes for Carrying Out the Invention

[0014] To enable a detailed understanding of the above features, the following will more specifically describe what was briefly summarized above with reference to examples of embodiments, and some of these are shown in the accompanying drawings. However, note that the accompanying drawings show only examples of typical embodiments and are not intended to limit the scope thereto.

[0015] For ease of understanding, the same reference numerals are used as much as possible to indicate the same elements common to multiple drawings. This assumes that it may be beneficial to incorporate the elements of one example into other examples.

[0016] Hereinafter, various features will be described with reference to the drawings. Note that these drawings may or may not be drawn to the same scale, and elements having the same structure or function are denoted by the same reference numerals throughout all the drawings. Note that the drawings are only intended to briefly explain the functions. They are not intended to provide an exhaustive description or to limit the scope of the claims.

[0017] Furthermore, the illustrated embodiments do not show all aspects and advantages. Aspects or advantages described in connection with a particular embodiment are not necessarily limited to that embodiment and can be implemented in any other embodiment even if not so illustrated or explicitly described.

[0018] FIG. 1 shows a test measurement system 100 according to an embodiment of the disclosed technology, which includes a user device 108 having a user interface (UI) 110 and a test measurement device 102 connected via a network 104. Measurement data generated by the test measurement device 102 is communicated via the network 104 and is accessible by the user device 108. Access to the measurement data includes streaming, displaying, and analyzing the data using the user interface 110 of the user device 108 to set and change measurement settings, including various data conversions of the measurement data from the test measurement device 102. In some embodiments, the user can use the user device 108 to change parameters and any settings related to the search function described in this application. In further embodiments, the user can visualize models of device characteristics and parameters using the user device 108 as further described in this application.

[0019] In the test measurement system 100 of FIG. 1, the test measurement device 102 has one or more processors 114, a memory 116, a display unit 118, and a user interface (UI) 120. The user interface (UI) 120 may exist as part of a touch screen display or may take the form of an operation knob or other user input device. The one or more main processors 114 are configured to execute instructions from the memory 116 and perform any method and related steps defined by such instructions to control the overall operation of the test measurement device 102. One or more measurement units 122 within the test measurement device 102 perform the main function of measuring parameters and other characteristics of signals from a device under test (DUT) 124 that is tested or analyzed by the test measurement system 100. Some of the measurements performed by the one or more measurement units 122 include measurements of the voltage, current, and power of an input signal in the time domain, as well as measurements of the characteristics of a signal in the frequency domain. The one or more measurement units 122 typically represent any component or function for performing any measurement executed by the test measurement device 102. The test measurement device 102 is coupled to the DUT 124 via a connection (e.g., one or more cables or other suitable type of electrical connection) 126.

[0020] In some embodiments, the memory 116 includes instructions for implementing a search function 128 and a model derived from the search function 128. Thereby, the one or more main processors 114 of the test measurement device 102 are configured to execute instructions from the memory 116 to implement the search function 128. Further details regarding the search function 128 and the corresponding model are described in this application.

[0021] The test measurement device 102 obtains and generates measurement values by testing the DUT 124, and these measurement values may be transmitted to the user device 108 through the network 104. For these transmissions, the network port 138 of the test measurement device 102 is coupled to the network 104 via the connection part 130 and further coupled to the user device 108 via the network connection part 132. In this way, the network port 138 enables the test measurement device 102 to transmit the obtained measurement values to the user device 108 via the network 104. In some embodiments, the test measurement device 102 is directly coupled to the user device 108, and thus the test measurement device 102 directly transmits the obtained measurement values to the user device 108.

[0022] When the measurement values obtained from the test measurement device 102 are transferred or uploaded to the user device 108, the user can access the obtained measurement values and other information related to the obtained measurement values according to the settings of the user device 108 to investigate and analyze various characteristics of the obtained measurement values. The user device 108 is coupled to the test measurement device 102 via the network connection part 132, the network 104, and the network port 134. The user interface 110 of the user device 108 may be configured to access, display, and share the obtained measurement values.

[0023] As described above, although the user device 108 is the only one illustrated in FIG. 1 among the plurality of user devices, the test measurement system 100 can include any number of user devices having similar components and corresponding user interfaces 110. The user device 108 has one or more processors 140, a memory 142, a display unit 144, and a user interface (UI) 110. The one or more processors 140 are configured to execute instructions from the memory 142 and implement the methods defined by such instructions, thereby controlling the overall operation of the user device 108. The display unit 144 can be any suitable type of digital screen such as an LED display or an LCD, or any other suitable type of display. The display unit 144 renders or displays the window generated by the user interface 110 for the user of the user device 108 to view. The user interface 110 may have a keyboard, a mouse, a touch screen, or any other suitable operating device that can be used by the user to interactively operate the user device 108.

[0024] In the test measurement system 100, the network 104 can be a closed network (i.e., a network available only to users of a specific company, building, or private network), an open network (including, for example, the Internet), a virtual private network (VPN), a combination of these, or any other suitable type of network architecture. The network connections 130 and 132 between the components of the test measurement system 100 can be any suitable type of wired or wireless network, including a near field communication (NFC) connection, an infrared (IR) connection, a Bluetooth® connection, a Wi-Fi connection, an Ethernet® connection, and the like.

[0025] The present disclosure describes a search function (e.g., the search function 128 in FIG. 1) for device characteristic evaluation. Device characteristic evaluation or characteristic measurement is performed to find parameters used in the circuit design process and model the operation. In the manufacturing process, a device under test (DUT) is tested to confirm compliance with the published specifications. When the test starts, the exact operating characteristics of the DUT are unknown. However, its general or approximate operating pattern is unique to that DUT. For example, in a MOSFET (metal oxide semiconductor field effect transistor), when the gate-source voltage (Vgs) is low, as Vgs increases, the drain-source current (Ids) increases exponentially. The current does not increase significantly until Vgs exceeds its threshold voltage (Vth). That is, the threshold voltage (Vth) is an important parameter. The value of Vth varies as a result of process non-uniformity and impurities.

[0026] The present disclosure is that when it is found that the general or approximate relationship between Vgs and Ids is exponential, preliminary measurement values can be used as data points for defining an exponential function curve that models the device. Next, this model is used to obtain an approximate value of Vth, and then Vth is measured and used to further improve the model. In the present disclosure, although it is an exponential function, the present disclosure is not limited to the exponential function and can be applied to other mathematical functions such as polynomial functions representing the characteristics of the DUT.

[0027] The process of fitting an exponential function curve to data points (curve fitting) is a type of statistical curve regression. However, unlike linear regression or higher-order polynomial regression, an exact equation cannot be easily derived. The present disclosure uses regression and approximation to fit the provided data points, such that f(x) = A + Be CxIt includes continuously evolving an exponential function curve of the form. Initial approximations of parameters A, B, and C can be determined using linear approximation. However, for a nearly exact fit to the data points required in this process, the exponential function curve is further adjusted by repeatedly adjusting the parameters to minimize the error between the model and the data points.

[0028] The disclosed technology has a search function that improves accuracy by modeling a device using multiple data points instead of using data for a single point to determine the next measurement point. Since the model disclosed in the present disclosure is a continuous function, the next measurement determined can be made at any value and is not limited to a list of possible discrete values such as in a binary search. This improvement in accuracy also reduces the number of measurement iterations required to reach the target point of the parameter. Although the present disclosure is described using a continuous function, the present disclosure can also be applied to other types of functions.

[0029] Since three points are required for one curve, the search function of the present disclosure generates its first three measurement points in the same way as a binary search function. Next, an exponential function curve is fitted to these data. This curve is used to determine the fourth measurement point. The measured value is in the region generally possible for that device as the target value. To make the next approximation as accurate as possible towards that target, a curve is created using only the three nearest data pairs so that the approximation is localized to the target region. This process, i.e., measuring at a location as close as possible to the target, creating a model of local data points, and measuring again until the target is approached sufficiently closely, is repeated.

[0030] As described above, a DUT (e.g., DUT 124) can be coupled to a test measurement device (e.g., test measurement device 102) for testing. Before the test measurement device performs measurements, the test measurement device does not have information regarding the exact individual characteristics of that particular DUT. In some embodiments, the test measurement device may obtain general or approximate information about the DUT, such as the device type of the DUT (diode, MOSFET, etc.) from the user. In some embodiments, the test measurement device may have desired characteristics or parameters to be measured for the DUT. For example, when the DUT is a MOSFET, it may be desired to determine the threshold value of Vgs of the DUT. Therefore, some information about the DUT is not known to the test measurement device, and the user desires to obtain more accurate information about the DUT (and that particular individual) using the test measurement device. Accordingly, the test measurement device needs further information regarding the desired characteristics and parameters of the DUT to perform further testing of the DUT. However, once the test measurement device obtains information related to the desired characteristics and parameters of the DUT, the test measurement device adjusts its operation based on the desired characteristics and parameters and based on a model of the desired characteristics and parameters to continue testing the DUT.

[0031] Since the test measurement device does not have information regarding the characteristics and parameters of the DUT, the test measurement device starts a process of determining the characteristics and parameters of the DUT by means of the search function described in the present application (e.g., search function 128 in FIG. 1). The test measurement device starts using the search function by generating three measurement values regarding the desired device characteristics and parameters. For each of these three measurement values, the test measurement device executes the search function by searching for specific characteristics and parameters of the device based on a desired result within a lower limit and an upper limit based on previous iterative measurements. In some embodiments, the test measurement device uses a predetermined lower limit and upper limit when it determines that it has not performed measurements previously. In some embodiments, the user can set the lower limit and the upper limit before starting the search function.

[0032] Figures 2 to 6 show parameter values for measurements for measuring the characteristics of a device using the search function as described in the present application according to some embodiments. As an example, when performing the search function of the present disclosure on an exemplary device such as a diode, the search function looks for a first measured value of the voltage between 0.00 volts (i.e., the lower limit) and 1.00 volts (i.e., the upper limit) when the diode conducts 10 mA. Thus, for Measurement 1 of the search function of the present disclosure, when the search function by the test measurement device uses a supply voltage of 500 mV, the resulting measured current was 0.503 mA (i.e., the first measured value is 500 mV and 0.503 mA).

[0033] Since the result of the first measured value is different from the desired value, the test measurement device adjusts the lower and upper limits of the next measurement based on this previous measurement. For example, since the measured current of Measurement 1 was less than the target current of 10 mA, the test measurement device determines that the required voltage is greater than 500 mV and less than 1.00 V (shown on the x-axis of FIG. 2). Therefore, the test measurement device sets the lower limit of the next measurement to 500 mV and the upper limit of the next measurement to 1.00 V.

[0034] The test measurement device adjusts the supply voltage of the next measurement to the midpoint of the adjusted lower and upper limits of the next measurement, i.e., 750 mV. Thus, for Measurement 2 of the search function of the present disclosure, when using a supply voltage of 750 mV, a measured current of 121 mA occurred (i.e., the second measured value is 750 mV and 121 mA).

[0035] Since the result of Measurement 2 is still different from the desired value, the test measurement device adjusts the lower and upper limits of the next measurement based on the previous measurement. Since the measured current of Measurement 2 was greater than the target current of 10 mA, the required voltage is 500 mV or more and less than 750 mV as shown on the x-axis of FIG. 3. That is, the variable range is adjusted to 250 mV (half of the previous 500 mV). Therefore, as shown in FIG. 3, the test measurement device sets the lower limit of the next measurement to 500 mV and the upper limit of the next measurement to 750 mV.

[0036] The test measurement device adjusts the supply voltage for the next measurement to the central position between the adjusted lower limit and the upper limit of the next measurement, that is, 625 mV. Therefore, when Measurement 3 of the search function of the present disclosure uses a supply voltage of 625 mV, a measurement current of 8.5 mA is obtained (that is, the third measurement value is 625 mV and 8.5 mA).

[0037] At this point, since the search function of the present disclosure has three data points, a curve can be fitted to the three data points (curve regression). Therefore, the test measurement device determines a model based on the three data points (the first measurement value, the second measurement value, and the third measurement value). In some embodiments, the model is a mathematical model, and more specifically, an exponential function model. In further embodiments, the exponential function is based on f(x)=A + Be Cx Based on this, the test measurement device determines the model so as to fit a mathematical model (in this example, an exponential function model) to the given data points using regression and approximation. In such embodiments, the test measurement device determines the coefficients A, B, and C of the exponential function.

[0038] To verify the accuracy of the model, the test measurement device performs additional measurements. Since a result different from the desired result was obtained in the third measurement, the test measurement device adjusts the lower and upper limits of the next measurement based on the previous measurements. Since the measurement current of Measurement 3 was less than the target current of 10 mA, the required voltage is between 625 mV and less than 750 mV as shown on the x-axis of FIG. 4. Therefore, the variable range is adjusted to 125 mV (half of the previous 250 mV). Thus, the test measurement device determines the lower limit of the next measurement to be 625 mV and the upper limit of the next measurement to be 750 mV.

[0039] The test measurement device adjusts the supply voltage for the next measurement (i.e., Measurement 4) to a point between the adjusted lower limit and the upper limit of the next measurement. At this point, the test measurement device uses a different range for the next measurement compared to the ranges used for the previous three measurements. In some embodiments, the test measurement device uses a range for determining the next measurement point based on the resolution of the test measurement device. Thus, as shown in FIG. 5, based on the above embodiments, using three points (indicated by white circles) and linear approximation, based on the exponential function model and the resolution of the test measurement device, the next measurement point can be approximated to 632.6 mV (indicated by a black circle) for a desired current of 10 mA. The search function of the present disclosure performs Measurement 4 with a supply voltage of 632.58 mV, and as a result, the measured current is 9.79 mA. That is, in this example, the fourth measurement values are 632.58 mV and 9.79 mA.

[0040] The test measurement device further adjusts the exponential function curve using the result of Measurement 4 to match the current result of the search function. In some embodiments, the test measurement device adjusts the values of A, B, and C in the exponential function formula f(x) = A + Be Cx considering Measurement 4. Accordingly, the test measurement device adjusts the model (curve) of the device parameters to fit (curve fit) the measurement values (data points) obtained so far. For example, when the test measurement device is searching for the threshold voltage (Vth), which is an example of a device parameter of a transistor, the model represents the measured drain current (Ids) of the device as a function of the gate-source voltage (Vgs). In such an example, the threshold voltage is the amount of Vgs applied to obtain a specific Ids such that the device is considered to be "on" and conducting. Thus, the model representing Ids as a function of Vgs is used to find the threshold voltage for a specific Ids, and for that purpose, the test measurement device adjusts the model representing Ids as a function of Vgs. As a result, the test measurement device can accurately find the desired device parameter (Vth in this example) using the model and change its operation based on the model.

[0041] As described above, starting from after the first verification measurement, the test measurement device determines whether to continue the search. In some embodiments, the test measurement device can use the difference from the latest measurement value with respect to a desired target as a basis for determining whether to continue the search. For example, the test measurement device calculates the difference of 0.21 mA between the measured current of 9.79 mA in Measurement 4 and the target current of 10 mA. In some embodiments, a difference threshold for continuing the search can be set in advance or can be set by the user.

[0042] In this example, the difference between the measured current and the target current is 0.21 mA, which is greater than the difference threshold for this model. Therefore, the test measurement device determines to continue the search and further verification of the model is required to ensure the accuracy of the model. Thus, the search function searches for another value of the supply voltage at which the target current becomes 10 mA. Since the result of the previous measurement is different from the desired result, the test measurement device adjusts the lower and upper limits of the next measurement based on the previous measurement. Similar to the previous measurement, the test measurement device uses a variation range for determining the next measurement point based on the resolution of the test measurement device. Since the measured current in Measurement 4 was less than the target current of 10 mA, the required voltage variation range is 632.58 mV or more and less than 750 mV.

[0043] Therefore, based on the above example, as shown in FIG. 6, based on the exponential function model and the resolution of the test measurement device, the next measurement point can be approximated to 633.8 mV (indicated by the black circle) for the desired current of 10 mA. The search function performs Measurement 5 using a supply voltage of 633.8 mV, and the measured current becomes 10.017 mA. That is, in this example, the fifth measurement value is 633.8 mV and 10.017 mA.

[0044] As described above, each time the search function is iterated, the test measurement device determines whether to continue the search. When the target current is 10 mA and the reading is 10.017 mA, the error in the fifth iteration of the search function remains at 17 μA. If the search function of the present disclosure is iterated one more time, it may result in a measurement result that is numerically closer to the target, but it is important to keep in mind the accuracy of the test measurement device itself. In the 100 mA range, the specification of the current measurement accuracy of the test measurement device used to perform these measurements is 12 μA for a reading of approximately 10 mA.

[0045] In this embodiment, since the measured current in Measurement 5 was greater than the target current of 10 mA, the search function further adjusts the exponential curve to match the current result of the search function using the result of Measurement 5. In this way, the search function can perform another measurement based on the resolution of the test measurement device and the exponential function model. In such a case, Measurement 6 uses a supply voltage of 633.53 mV and the measured current becomes 9.997 mA.

[0046] The adjustment of 0.270 mV between Measurement 5 and Measurement 6 can be evaluated as significantly better based on the resolution of 16.25 mV achieved in its sixth iteration in the case of binary search.

[0047] FIG. 7 is a flowchart of a process 700 of the search function described in the present application according to some embodiments. This process 700 can be performed by a test measurement device (e.g., the test measurement device 102 of FIG. 1).

[0048] Process 700 begins with step 702. Process 700 includes a step 704 of obtaining (i.e., measuring) three measurement values. In some embodiments, for the first measurement, the test measurement device selects a measurement point between a predetermined upper limit and a predetermined lower limit. In such examples, the predetermined upper limit and the predetermined lower limit can be provided by the user or be based on the limits of the DUT. In some embodiments, the test measurement device selects a measurement point (e.g., the midpoint between the lower limit and the upper limit) between an upper limit based on the previous measurement and a lower limit based on the previous measurement. For the first measurement point, since the test measurement device has not performed a measurement previously, the test measurement device may use the lower limit and the upper limit specified by the lower limit and the upper limit based on the DUT's specifications. For example, when the test measurement device is looking for the threshold voltage of a transistor, at the first measurement point, a lower limit of 0V and an upper limit of 1V are used. The three measurements performed during step 704 can be used to determine any characteristic or parameter of the DUT as long as the measurements made by the test measurement device on the DUT relate to the same characteristic or parameter.

[0049] Process 700 includes a step 706 of obtaining a model of the device's parameters based on the three measurement values. As described above, when obtaining a model of the device characteristics or device parameters, the test measurement device uses the three measurement values to generate a continuous function representing the operation of the DUT. In some embodiments, the model is based on an exponential function representing the device characteristics or device parameters of the DUT. As this exponential function, for example, the formula of f(x)=A + Be Cx may be used. In such examples, the test measurement device may obtain the values of A, B, and C.

[0050] Process 700 includes a step 708 of obtaining a fourth measurement value of the device parameters. As described above, the fourth measurement value adjusts the device characteristics and variable parameters used in the three measurements of step 704. In some embodiments, the test measurement device selects measurement points based on the resolution of the test measurement device. For example, the resolution of the test measurement device can be defined by the specification of the measurement accuracy of the current. In a further example, the test measurement device selects measurement points between an upper limit based on a previous measurement and a lower limit based on a previous measurement.

[0051] Process 700 includes a step 710 of adjusting a model of the device parameters based on available measurement values. In some embodiments, the test measurement device may adjust the values of A, B, and C in the formula f(x)=A + Be Cx for a model representing device characteristics and device parameters. In some embodiments, before adjusting the model, the test measurement device determines whether the fourth measurement value deviates significantly from the model. In such an example, the model has a deviation range assumed for the measured values of the device parameters. If the test measurement device determines that the fourth measurement value deviates from the model by more than a specific amount, the test measurement device performs further measurements, which are repetitions of the fourth measurement. If the measured value from this repeated measurement still deviates from the model by more than a specific amount, the test measurement device displays an error warning to the user.

[0052] Process 700 includes a step 712 of determining whether to continue searching for the device parameters. If the test measurement device determines not to continue searching for the device parameters, process 700 continues to step 726.

[0053] If the test measurement device determines to continue searching for the device parameters, process 700 then proceeds to step 714 to obtain a fifth measurement value of the device parameter. In some embodiments, the test measurement device selects a measurement point based on the resolution of the test measurement device. In a further example, the test measurement device selects a measurement point between an upper limit based on the previous measurement and a lower limit based on the previous measurement.

[0054] Process 700 continues to step 716 where it adjusts the model of the device parameter based on the available measurement values. In some embodiments, step 716 is similar to step 710 and adjusts the model of the device parameter based on the available measurement values, including the fifth measurement value obtained in step 714. The test measurement device may adjust the values of A, B, and C in the formula f(x) = A + Be Cx In some embodiments, prior to adjusting the model, the test measurement device determines whether the fifth measurement value deviates significantly from the model. In such an example, the model has an expected deviation range for the measured values of the device parameter. If the test measurement device determines that the fifth measurement value deviates (is off) from the model by more than a certain amount, the test measurement device performs another additional measurement, which is a repetition of the fifth measurement. If the measurement value from this repeated measurement still deviates from the model by more than a certain amount, the test measurement device displays an error warning to the user.

[0055] Process 700 continues to step 718 where it determines whether to continue searching for the device parameter. If the test measurement device determines not to continue searching for the device parameter, process 700 proceeds to step 726.

[0056] When the test measurement device determines to continue the search for the device parameters, process 700 then proceeds to obtain another measured value of the device parameters in step 720. In some embodiments, the test measurement device selects the measurement point based on the resolution of the test measurement device. In a further example, the test measurement device selects the measurement point between the upper limit based on the previous measurement and the lower limit based on the previous measurement.

[0057] Process 700 then proceeds to step 722 of adjusting the model of the device parameters based on the available measured values. In some embodiments, step 722 is similar to steps 710 and 716, and adjusts the model of the device parameters based on the available measured values, including the latest measured value obtained in step 720. The test measurement device may adjust the values of A, B, and C in the formula of f(x)=A + Be Cx In some embodiments, before the test measurement device adjusts the model, it determines whether the latest measured value deviates significantly from the model. In such an example, the model has a deviation range (range of deviation) assumed for the measurement of the device parameters. If the test measurement device determines that the latest measured value deviates from the model by more than a specific amount, the test measurement device performs another separate measurement. This is a repetition of the latest measurement. If the measured value from this repeated measurement deviates from the model by more than a specific amount, the test measurement device displays an error warning to the user.

[0058] Process 700 then proceeds to step 724 of determining whether to continue the search for the device parameters. If the test measurement device determines not to continue the search for the device parameters, process 700 proceeds to step 726.

[0059] If the test measurement device determines to continue the search for the device parameters, process 700 repeats steps 720, 722, and 724 described above.

[0060] Process 700 includes a step 726 of adjusting the operation of the test measurement device based on a model of the parameters of the device. In some embodiments, the test measurement device considers the model of the device parameters when making further measurements, when measuring another parameter of the DUT, or when analyzing the model for detailed information about the DUT.

[0061] In some embodiments, when determining whether the test measurement device continues the search, the test measurement device may determine whether the latest measured values of the characteristics or parameters deviate from the model of the characteristics or parameters by a specific amount (there is a deviation). The amount of deviation of the measured value from the model can be set in advance or set based on the model. In some embodiments, the deviation amount (amount of deviation) based on the model may be based on the predicted range given by the model within which the measured values converge. If the measured value is outside the predicted range given by the model, subsequent adjustment of the model based on that measured value may cause the model to change significantly, which is not desirable. In some embodiments, when the test measurement device determines that the latest measured value deviates from the model by a specific amount, without adjusting the model, the test measurement device performs a new different measurement, and if this new measured value still deviates from the model, the test measurement device displays an error. In some embodiments, the deviation between the measured value and the model may be applied to any measurement by the test measurement device after the test measurement device generates the model.

[0062] When using a continuous function to obtain measured values, measurements can be made at any value within a continuous range rather than from a list of pre-determined discrete values as used in binary search. Using a continuous range of values improves accuracy by measuring at a position as close as possible to the target rather than at the next value in the list of discrete values.

[0063] Using binary search and its list of discrete values also generates quantization error. This quantization error occurs when the measured value is close to the target and determines whether the values independent of noise increase or decrease. This quantization error appears as a multimodal distribution in the data and indicates a problem with the process where only the problems of the algorithm exist. This error would be corrected and the accuracy would be improved if there were an algorithm that was evaluated with very high precision and continuously, but it is accompanied by difficulties.

[0064] The accuracy of the source measure unit (SMU) is highest when the measurement is performed in the smallest possible range. In binary search, since an approximation of the next measurement cannot be obtained, the SMU cannot set the optimal range and needs to set a range with the highest possible probability. In contrast, the search function of the present disclosure can optimally use the SMU by adaptively setting the range for the highest accuracy.

[0065] When the measurement returns a measured value that deviates significantly from the model, the search function of the present disclosure can determine whether the measurement should be performed again or, ultimately, return an error indicating that the circuit connection is damaged. In the case of binary search, since it depends on one measurement, binary search will continue to adjust that one independent variable and return an incorrect value.

[0066] Usually, the creation of a device model is performed for design work using fully measured parameters to predict the operation of the device in the designed circuit. Furthermore, the approximations made for design work are usually linear, quadratic, or polynomial and are optimized locally only in the designed operating region. The use of exponential functions is more suitable for the overall operation of these devices, which is important for a search function that does not depend on exact operation.

[0067] The present disclosure further refines the model of the device used to find the target measurement value. By utilizing preliminary measurements, the curve regression of the exponential function is repeatedly used on the test measurement device, improving the accuracy and precision of the overall search function and reducing the number of measurements. Furthermore, by improving the model of the device to find the target measurement value, the operation of the test measurement device can be adjusted, making further measurements by the test measurement device more accurate and highly precise.

[0068] In the present disclosure, the term "or" is meant to be inclusive and means any, some, several, or all of the listed items. Relative terms such as "about," "approximately," "substantially," "generally," etc. are used to indicate the possibility of a variation of ±10% of the value being described or understood.

[0069] Aspects of the present disclosure can take various modifications and alternative forms. Specific aspects are illustrated in the drawings and described in detail herein. However, it should be noted that the examples disclosed herein are presented for the purpose of clarifying the description and are not intended to limit the scope of the general concepts disclosed to the specific aspects described herein, unless explicitly limited. Accordingly, the present disclosure is intended to cover all modifications, equivalents, and alternatives of the described aspects in light of the appended drawings and the claims.

[0070] References to aspects, examples, etc. in the specification indicate that the described items may include certain features, structures, or characteristics. However, all disclosed aspects may or may not include those specific features, structures, or characteristics, and, unless otherwise specified, do not necessarily refer to the same aspect. Further, if the description relates to a specific aspect and describes a specific feature, structure, or characteristic, such feature, structure, or characteristic can be employed in relation to another disclosed aspect, whether or not such feature is explicitly described in relation to such other disclosed aspect.

[0071] Aspects of the disclosed technology can operate on a specially programmed general purpose computer including specially created hardware, firmware, a digital signal processor, or a processor operating in accordance with programmed instructions. The terms "controller" or "processor" as used herein are intended to include microprocessors, microcomputers, ASICs, and dedicated hardware controllers, among others. Aspects of the disclosed technology can be realized by computer-usable data and computer-executable instructions such as one or more program modules executed by one or more computers (including monitoring modules) and other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., which, when executed by a processor within a computer or other device, perform a particular task or implement a particular abstract data type. The computer-executable instructions may be stored on a computer-readable storage medium such as a hard disk, optical disk, removable storage medium, solid state memory, RAM, etc. As will be understood by those skilled in the art, the functions of the program modules may be combined or distributed as necessary in various embodiments. Further, such functions may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGAs), etc. One or more aspects of the disclosed technology can be implemented more effectively using a particular data structure, and such data structures are considered to be within the scope of the computer-executable instructions and computer-usable data described herein.

[0072] The disclosed embodiments may, in some cases, be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may be implemented as instructions carried or stored by one or more computer-readable media that can be read by and executed by one or more processors. Such instructions may be referred to as a computer program product. As used herein, a computer-readable media means any media that can be accessed by a computing device. By way of example, and not limitation, a computer-readable media may include computer storage media and communication media.

[0073] Computer storage media means any media that can be used to store computer-readable information. By way of example, and not limitation, computer storage media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, and any other removable or non-removable media implemented with any technology. Computer storage media excludes signals per se and transient forms of signal transmission.

[0074] Communication media means any media that can be used to communicate computer-readable information. By way of example, and not limitation, communication media may include coaxial cable, fiber optic cable, air, or any other media suitable for communicating electrical, optical, radio frequency (RF), infrared, sound, or other forms of signals.

[0075] The disclosed embodiments may, in some cases, be implemented in hardware, firmware, software, or any combination thereof. The above references to other integrated circuits such as FPGAs and voltage regulators can be replaced with any component that can perform the same function. The disclosed embodiments may also be implemented as instructions carried or stored by one or more non-transitory computer-readable media, which may be read and executed by one or more processors. Such instructions may sometimes be referred to as a computer program product. As used herein, computer-readable media means any media that can be accessed by a computing device. By way of example and not limitation, computer-readable media may include computer storage media and communication media. Examples

[0076] The following presents examples that are useful for understanding the technology disclosed in this application. Embodiments of this technology may include one or more of the examples described below and any combination thereof.

[0077] Example 1 is a method for measuring the characteristics of a device under test (DUT) coupled to a test measurement device, acquiring a plurality of first measurement values of the DUT including measurement values of the characteristics in a state where the test measurement device is not set using the characteristics of the DUT; obtaining a mathematical model representing the operation of the DUT based on the plurality of first measurement values; acquiring a plurality of second measurement values of the DUT including measurement values of the characteristics, which are different from the plurality of first measurement values; verifying the mathematical model based on the plurality of second measurement values; and adjusting the operation of the test measurement device based on the verified mathematical model of the DUT. comprising.

[0078] Example 2 is the method of Example 1, wherein the mathematical model is f(x) = A + Be CxIt is based on the mathematical formula of the exponential function.

[0079] Example 3 is the method of Example 2, wherein A, B, and C are determined based on the plurality of first measurement values.

[0080] Example 4 is the method of any one of Examples 1 to 3, wherein the mathematical model is a continuous function.

[0081] Example 5 is the method of any one of Examples 1 to 4, wherein the plurality of first measurement values may include current measurement values, each of which is associated with a corresponding voltage measurement value.

[0082] Example 6 is the method of any one of Examples 1 to 5, wherein the plurality of second measurement values have a resolution based on the test measurement device.

[0083] Example 7 is the method of any one of Examples 1 to 6, wherein the process of obtaining the plurality of second measurement values includes a process of repeatedly measuring at points based on the resolution of the test measurement device.

[0084] Example 8 is the method of any one of Examples 1 to 7, wherein the process of obtaining the plurality of second measurement values includes a process of determining points to be measured based on the mathematical model.

[0085] Example 9 is the method of any one of Examples 1 to 8, wherein the process of obtaining the plurality of first measurement values includes a process of repeatedly measuring at intermediate points between the lower limit and the upper limit.

[0086] Example 10 is the method of any one of Examples 1 to 9, wherein the resolution of each measurement when repeatedly measuring is half of the resolution of the previous measurement.

[0087] Example 11 is any one of Examples 1 to 10, and the process of verifying the mathematical model based on the plurality of second measurement values includes: determining at least one of the plurality of second measurement values that deviates from the mathematical model by a given amount based on the mathematical model; obtaining a plurality of third measurement values; and when the plurality of third measurement values deviate from the mathematical model by a given deviation amount, displaying an error to the user.

[0088] Example 12 is a test measurement system, a test measurement device having one or more ports for connecting to a device under test (DUT); a memory; one or more processors configured to execute a program stored in the memory and comprising: When the program is executed, the one or more processors are caused to: obtain a plurality of first measurement values of the parameters of the DUT in a state where the test measurement device is not set using the parameters of the DUT; obtain a mathematical model of the parameters of the DUT based on the plurality of first measurement values; obtain a plurality of second measurement values of the parameters of the DUT that are different from the plurality of first measurement values; verify the mathematical model based on the plurality of second measurement values; and adjust the operation of the test measurement device based on the verified mathematical model of the DUT.

[0089] Example 13 is the test measurement system of Example 12, wherein the plurality of second measurement values have a resolution based on the test measurement device.

[0090] Example 14 is the test measurement system of Example 12 or Example 13, and the program for causing the one or more processors to perform the process of obtaining the plurality of second measurement values includes a program for causing the one or more processors to perform a process of repeatedly measuring at points based on the resolution of the test measurement device.

[0091] Example 15 is the test measurement system of any one of Examples 12 to 14, and the program for causing the one or more processors to perform the process of obtaining the plurality of second measurement values includes a program for causing the one or more processors to perform a process of determining measurement points based on the mathematical model.

[0092] Example 16 is the test measurement system of any one of Examples 12 to 15, and the program for causing the one or more processors to perform the process of obtaining the plurality of first measurement values includes a program for causing the one or more processors to perform a process of repeatedly measuring at intermediate points between the lower limit and the upper limit.

[0093] Example 17 is the test measurement system of any one of Examples 12 to 16, and the resolution of each measurement when repeatedly measuring is half of the resolution of the previous measurement.

[0094] Example 18 is a test measurement system, a test measurement device having one or more ports for connecting to a device under test (DUT), a memory, one or more processors configured to execute a program stored in the memory, and comprising: When the program is executed, it causes the one or more processors to obtain a model of the parameter based on three measurement values of the parameter of the DUT obtained by the test measurement device, verify the model based on a fourth measurement value and a fifth measurement value of the parameter of the DUT obtained by the test measurement device, A process of adjusting the operation of the test measurement apparatus regarding the parameters based on the verified model of the DUT, and causing it to be performed.

[0095] Example 19 is the test measurement system of Example 18, and the program that causes the one or more processors to perform the process of obtaining the fourth measurement value and the fifth measurement value includes a program that causes the one or more processors to perform a process of repeatedly measuring at points based on the resolution of the test measurement apparatus.

[0096] Example 20 is the test measurement system of Example 18 or Example 19, and the model is based on the formula f(x)=A + Be Cx of the formula.

[0097] The above versions of the subject matter of the present disclosure have many effects that have been described or will be apparent to those skilled in the art. Nevertheless, in all versions of the disclosed apparatus, system or method, not all of these effects or features are required.

[0098] In addition, the description of the present application refers to specific features. It should be understood that the disclosure herein includes all possible combinations of all of these specific features. When a particular feature is disclosed in relation to a particular aspect or embodiment, that feature can be used in relation to other aspects and embodiments as far as possible.

[0099] Also, in the present application, when referring to a method having two or more defined steps or processes, these defined steps or processes may be executed in any order or simultaneously, as long as the circumstances do not exclude their possibilities.

[0100] For convenience of explanation, specific embodiments of the present invention have been illustrated and described, but it will be understood that various changes can be made without departing from the gist and scope of the present invention. Therefore, the present invention should not be limited except by the appended claims.

Explanation of Reference Numerals

[0101] 100 Test Measurement System 102 Test Measurement Device 104 Network 108 User Device 110 User Interface (UI) 114 One or More Processors 116 Memory 118 Display Unit 120 User Interface (UI) 122 Measurement Unit 124 Device Under Test (DUT) 126 Connection Unit 128 Search Function 130 Connection Unit 132 Network Connection Unit 134 Network Port 138 Network Port 140 One or More Processors 142 Memory 144 Display Unit

Claims

1. A method for measuring the characteristics of a device under test (DUT) coupled to a test measurement apparatus, comprising: acquiring a plurality of first measurement values of the DUT including measurement values of the characteristics, in a state where the test measurement apparatus is not set using the characteristics of the DUT; obtaining a mathematical model representing the operation of the DUT based on the plurality of first measurement values; acquiring a plurality of second measurement values including measurement values of the characteristics of the DUT, different from the plurality of first measurement values; verifying the mathematical model based on the plurality of second measurement values; adjusting the operation of the test measurement apparatus based on the verified mathematical model of the DUT A method for measuring the characteristics of a device under test comprising the above steps.

2. The characteristic measurement method of the test device according to claim 1 based on the formula of f(x)=A + Be Cx of the above formula.

3. The method for measuring the characteristics of a device under test according to claim 2, wherein A, B, and C are determined based on the plurality of first measurement values.

4. The method for measuring the characteristics of a device under test according to claim 1, wherein the process of acquiring the plurality of second measurement values includes a process of determining a measurement point based on the mathematical model.

5. The method for measuring the characteristics of a device under test according to claim 1, wherein the process of acquiring the plurality of first measurement values includes a process of repeatedly measuring at an intermediate point between a lower limit and an upper limit.

6. The process of verifying the mathematical model based on the plurality of second measurement values includes: determining at least one of the plurality of second measurement values that deviates from the mathematical model by a given amount based on the mathematical model; acquiring a plurality of third measurement values; and displaying an error to the user if the plurality of third measurement values deviate from the mathematical model by a given deviation amount. The method for measuring the characteristics of a device under test according to claim 1.

7. A test measurement system, comprising: a test measurement apparatus having one or more ports for connecting to a device under test (DUT); a memory; one or more processors configured to execute a program stored in the memory wherein, when the program is executed, the one or more processors are caused to: acquire a plurality of first measurement values of the parameters of the DUT in a state where the test measurement apparatus is not set using the parameters of the DUT; obtain a mathematical model of the parameters of the DUT based on the plurality of first measurement values; acquire a plurality of second measurement values of the parameters of the DUT, different from the plurality of first measurement values; ​ A process of verifying the mathematical model based on the plurality of second measurement values, and a process of adjusting the operation of the test measurement apparatus based on the verified mathematical model of the DUT A test measurement system that causes these processes to be performed.

8. The program that causes the one or more processors to perform the process of obtaining the plurality of second measurement values includes the program according to claim 7 of the test measurement system that causes the one or more processors to perform the process of repeatedly measuring at points based on the resolution of the test measurement apparatus.

9. The program that causes the one or more processors to perform the process of obtaining the plurality of second measurement values includes the program according to claim 7 of the test measurement system that causes the one or more processors to perform the process of determining measurement points based on the mathematical model.

10. A test measurement system, A test measurement apparatus having one or more ports for connecting to a device under test (DUT), A memory, One or more processors configured to execute a program stored in the memory Comprising, When the program is executed, it causes the one or more processors to, A process of obtaining a model of the parameter based on three measurement values of the parameter of the DUT obtained by the test measurement apparatus, A process of verifying the model based on the fourth and fifth measurement values of the parameter of the DUT obtained by the test measurement apparatus, A process of adjusting the operation of the test measurement apparatus regarding the parameter based on the verified model of the DUT A test measurement system that causes these processes to be performed.

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