Current Measuring Device and Method

Abstract

The present invention discloses a current measurement device and method. The device includes a selection unit and N measurement units, and each of the N measurement units includes a sampling resistor. The N measurement units respectively obtain the actual resistance values of the sampling resistors in each measurement unit according to a reference current, and measure the current value of a current to be measured according to the actual resistance values of the corresponding sampling resistors. Wherein, the actual current value of the current to be measured is equal to the sum of the current values obtained by the N measurement units, and N is a positive integer. The current measurement device and method can realize the accurate superimposed measurement of a large current jointly by multiple high-precision small-range measurement devices, and solve the problem that the measurement structure of the existing tester cannot simultaneously realize the accurate measurement of a large current with high-precision requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of current measurement, and particularly to a current measurement device and method. Background Art

[0002] In integrated circuit testing, a voltage-current source (hereinafter referred to as a VI source) is required to perform signal excitation and voltage and current measurement on a device under test (hereinafter referred to as a DUT, Device Under Test).

[0003] In a prior art testing machine (such as an STS8200 testing machine), the current measurement of a chip under test is usually performed by using the FOVI measurement terminal and the FPVI measurement terminal of a measurement board. However, among the measurement terminals of these two measurement boards, the maximum current range of the FOVI measurement terminal is ±1A, and the accuracy of the current range is ±5mA. Therefore, the FOVI measurement terminal alone cannot measure a current under test greater than 1A. The accuracy of the ±1A current range corresponding to the FPVI measurement terminal is ±1mA, but the number of output ports corresponding to this measurement terminal is too small to meet the superimposed measurement of large currents. The maximum current range of the FPVI measurement terminal is ±10A, but the accuracy of this current range is only ±50mA. Therefore, the FOVI measurement terminal alone cannot meet the measurement conditions for large currents with high accuracy requirements.

[0004] The existing solution is to convert large currents during actual chip measurement, but there is a deviation between the converted value and the true value. Therefore, even if the converted value is accurately measured, the final measurement result obtained is still not accurate enough relative to the true value of this large current.

[0005] Therefore, it is necessary to provide an improved technical solution to overcome the above technical problems existing in the prior art. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a current measurement device and method, which can jointly achieve accurate superimposed measurement of large currents by multiple high-precision small-range measurement devices, and solves the problem that the measurement structure of the existing testing machine cannot simultaneously achieve accurate measurement of large currents with high accuracy requirements.

[0007] On the one hand, a current measurement device according to the present invention includes: a selection unit, a first input terminal receives a reference current, a second input terminal receives a current under test, and an output terminal selectively outputs one of the reference current and the current under test;

[0008] N measurement units, the first end of each of the N measurement units is connected to the output end of the selection unit, the second end of each measurement unit is connected to the current pulling device, and the third end of each measurement unit is connected to the voltage measuring device,

[0009] wherein, each measurement unit includes a sampling resistor;

[0010] When the reference current is selectively output at the output end of the selection unit, the N measurement units are used to respectively obtain the actual resistance value of the sampling resistor in each measurement unit according to the reference current; and

[0011] When the current to be measured is selectively output at the output end of the selection unit, each of the N measurement units is used to measure the current value of the current to be measured according to the actual resistance value of the corresponding sampling resistor, wherein the actual current value of the current to be measured is equal to the sum of the current values measured by each of the N measurement units,

[0012] wherein, N is a positive integer.

[0013] Optionally, the current pulled by the current pulling device at the second end of each of the N measurement units is equal to the reference current.

[0014] Optionally, each measurement unit further includes: a first switch, a second switch and a third switch;

[0015] A differential amplifier, the first input end of the differential amplifier is connected to the first end through the first switch, the second input end of the differential amplifier is connected to the reference ground through the second switch, and the second input end of the differential amplifier is further connected to the second end through the third switch, and the output end of the differential amplifier is connected to the third end,

[0016] wherein, the sampling resistor is connected between the first input end and the second input end of the differential amplifier.

[0017] Optionally, the selection unit includes:

[0018] A fourth switch, connected between the first input end and the output end of the selection unit;

[0019] A fifth switch, connected between the second input end and the output end of the selection unit.

[0020] Optionally, the selection unit is a multiple-choice selection switch.

[0021] Optionally, each of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch is any one of a push-button switch, a toggle switch, and a rotary switch.

[0022] Optionally, each of the first switch, the second switch, the third switch, the fourth switch, and the fifth switch is any one of a bipolar transistor, a field-effect transistor, and a relay.

[0023] Optionally, both the current pulling device and the voltage measuring device are measurement boards in a tester.

[0024] Optionally, the sum of the currents pulled by the current pulling device from the second ends of each of the N measurement units is equal to the target value of the current to be measured.

[0025] On the other hand, according to a current measurement method provided by the present invention, the current measurement method can be applied to the current measurement device as described above. The method includes:

[0026] Input a reference current to the N current measurement units in the current measurement device, and respectively obtain the actual resistance values of the sampling resistors in each measurement unit based on the reference current;

[0027] Disconnect the input of the reference current, input the current to be measured to the N current measurement units in the current measurement device, use the current pulling device to simultaneously pull currents from the sampling resistors in each current measurement unit, and measure the current value of the current to be measured based on the actual resistance values of the sampling resistors corresponding to each measurement unit obtained,

[0028] wherein, the actual current value of the current to be measured is equal to the sum of the current values measured by each of the N measurement units,

[0029] wherein, N is a positive integer.

[0030] Optionally, the currents pulled by the current pulling device from the second ends of each of the N measurement units are all equal to the reference current.

[0031] The beneficial effects of the present invention are as follows: The disclosed current measurement device and method can perform superimposed measurement on a to-be-measured current with a large current value by N measurement units connected in parallel, enabling an accurate measurement of a large current value with high precision requirements by a measurement device with a small range and high precision. During measurement, the current pulling device connected to each measurement unit simultaneously pulls the to-be-measured current corresponding to the N measurement units, so that a component of the to-be-measured current can flow through the sampling resistor in each measurement unit. Then, after sampling the components of the to-be-measured current corresponding to each measurement unit, the current measurement can be indirectly achieved by measuring the voltage value across the sampling resistor. Since the measurement accuracy of the voltage measurement device of the existing testing machine (such as STS8200) is higher than that of the current measurement device, the measurement unit in the present disclosure can well ensure the high accuracy of the to-be-measured current. At the same time, before measuring the to-be-measured current, the actual resistance value of the sampling resistor in each measurement unit is accurately measured by a reference current with higher precision, which can greatly reduce the influence of the error between the rated resistance value and the actual resistance value of the sampling resistor in each measurement unit on the measurement result, and further improve the accuracy of the to-be-measured current measurement.

[0032] On the other hand, when the current pulling device is set to simultaneously pull the to-be-measured current corresponding to the N measurement units, the current pulled at the second end of each measurement unit (i.e., the current flowing through the sampling resistor in each measurement unit) is equal to the preset reference current. In this way, the influence of the temperature change caused by the reference current on the actual resistance value of the sampling resistor during the measurement of the actual resistance value of the sampling resistor can be made the same as the influence of the temperature change caused by the component of the to-be-measured current on the actual resistance value of the sampling resistor when measuring the to-be-measured current of the chip under test, that is, the change in the resistance value caused by the thermal effect is eliminated, and the accuracy of the measurement result of the to-be-measured current is further improved.

[0033] It should be noted that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Through the following description of the embodiments of the present invention with reference to the drawings, the above and other objects, features, and advantages of the present invention will become clearer.

[0035] Figure 1 The structural block diagram of the current measurement device provided according to an embodiment of the present disclosure is shown;

[0036] Figure 2 The circuit structure schematic diagram of the current measurement device provided according to an embodiment of the present disclosure is shown;

[0037] Figure 3 The flow block diagram of the current measurement method provided according to an embodiment of the present disclosure is shown. Detailed implementation manners

[0038] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] Below, the present invention will be described in detail with reference to the drawings.

[0041] Figure 1 A structural block diagram showing a current measurement device provided according to an embodiment of the present disclosure Figure 2 A schematic circuit diagram showing a current measurement device provided according to an embodiment of the present disclosure.

[0042] As Figure 1 shown, in this embodiment, the current measurement device includes: a selection unit 200 and N measurement units 300 (including a first measurement unit 310, a second measurement unit 320,..., an Nth measurement unit 310). Wherein, N is a positive integer.

[0043] Among them, a first input terminal of the selection unit 200 receives a reference current, a second input terminal of the selection unit 200 is connected to the chip under test 500 to receive a current to be measured, and an output terminal of the selection unit 200 selectively outputs one of the reference current and the current to be measured.

[0044] In an embodiment of the present disclosure, the selection unit 200 is a multiple-choice switch. The first input terminal of the multiple-choice switch receives a reference current, the second input terminal receives a current to be measured, and the output terminal selectively outputs one of the reference current and the current to be measured. Optionally, the multiple-choice switch can be a switch with an automatic switching function according to a control signal, or a switch with a manual switching function, or a switch with both of the above two functions, which can be specifically selected according to the actual application scenario.

[0045] In another embodiment of the present disclosure, refer to Figure 2, the selection switch 200 includes a fourth switch KS1 and a fifth switch KS2. Among them, the fourth switch KS1 is connected between the first input terminal and the output terminal of the selection unit 200; the fifth switch KS2 is connected between the second input terminal and the output terminal of the selection unit 200. Optionally, the fourth switch KS1 and the fifth switch KS2 can be any one of a push-button switch, a toggle switch, and a rotary switch that can be manually controlled to switch; or any one of a bipolar transistor, a field-effect transistor, and a relay that are automatically switched by a control signal. Specifically, it can be selected according to the actual application scenario.

[0046] It should be understood that when one of the input terminals of the selection unit 200 is connected to its output terminal, the current signal received corresponding to this input terminal will be transmitted to the subsequent circuit connected to the output terminal of the selection unit 200.

[0047] The first end of each measurement unit 310 in the N measurement units 300 is connected to the output terminal of the selection unit 100, the second end of each measurement unit 310 is connected to the current pulling device, and the third end of each measurement unit 310 is connected to the voltage measurement device.

[0048] Furthermore, each measurement unit 310 includes a sampling resistor. Refer to Figure 2 , taking N equal to 3 as an example, where the resistor R1, the resistor R2, and the resistor R3 are the sampling resistors in the first measurement unit 310, the second measurement unit 310, and the third measurement unit 310 among the N measurement units 300 respectively.

[0049] Specifically, when the reference current is selected and output at the output terminal of the selection unit 200, the N measurement units 300 are used to respectively obtain the actual resistance value of the sampling resistor in each measurement unit 310 according to the reference current. And when the current to be measured is selected and output at the output terminal of the selection unit 200, each measurement unit 3130 in the N measurement units 300 is used to measure the current value of the current to be measured according to the actual resistance value of the corresponding sampling resistor. Among them, the actual current value of the current to be measured is equal to the sum of the current values measured by each measurement unit 310 in the N measurement units 300.

[0050] Exemplarily, when the reference current is selected and output at the output end of the selection unit 200, the reference current is sequentially provided to each measurement unit 310, and then the actual resistance values of the sampling resistors R1, R2, R3, ..., Rn in each measurement unit 310 are respectively measured. In this way, the influence of the error between the rated resistance value and the actual resistance value of the sampling resistor in each measurement unit on the measurement result can be greatly reduced. After that, the output of the reference current is disconnected, and instead, the current to be measured is simultaneously output to the N measurement units 300, and the current pulling device simultaneously pulls the current of each measurement unit 310, so that a component of the current to be measured can flow through the sampling resistor in each measurement unit, facilitating the N measurement units 300 to perform superposition measurement on the current to be measured. Therefore, by measuring the voltage across the sampling resistor in each measurement unit at this time and based on the actual resistance value of each obtained sampling resistor, the measurement of the current can be indirectly realized. Among them, the current values respectively measured by each measurement unit 310 can be respectively denoted as I1, I2, I3, ..., In. Finally, the actual current value of the current to be measured is equal to the sum of the multiple measured values I1, I2, I3, ..., In. Therefore, by reasonably setting the number of measurement units, a large current with high-precision requirements can be measured by using a high-precision small-range measurement device, making up for the defects of the existing test machine. And, since the measurement accuracy of the voltage measurement device in the existing test machine (such as STS8200) is higher than that of the current measurement device, the measurement unit in the present disclosure can well ensure the high accuracy of the current to be measured.

[0051] In the present disclosure, the reference current can be output from the FPVI measurement terminal of the first measurement board 100 (such as a test machine of model STS8200) provided with a high-precision current source in the test machine, and this FPVI measurement terminal is, for example, a high-precision current output terminal with an accuracy of 1 mA in the STS8200 test machine. At the same time, the aforementioned current pulling device and voltage measurement device are also measurement boards in the test machine, and preferably, the current pulling device and voltage measurement device are the same measurement board in the test machine, namely the second measurement board 400. Or rather, the second measurement board 400 in this test set can simultaneously achieve the same functions as the current pulling device and voltage measurement device through different ports. The second measurement board 400 includes a plurality of FOVI measurement terminals, and each measurement unit 310 in the N measurement units 300 is connected to two of the measurement terminals of the second measurement board 400 (for example, the first measurement unit 310 in the N measurement units 300 is respectively connected to the FOVI1 measurement terminal and the FOVI2 measurement terminal of the second measurement board 400, the second measurement unit 310 is respectively connected to the FOVI3 measurement terminal and the FOVI4 measurement terminal of the second measurement board 400, and the Nth measurement unit 310 is respectively connected to the FOVI(n - 1) measurement terminal and the FOVIn measurement terminal of the second measurement board 400) to respectively achieve the functions of current pulling and voltage measurement across the sampling resistor. It should be understood that when the number of FOVI measurement terminals of a second measurement board 400 in the test machine cannot meet the requirements of the N measurement units, multiple second measurement boards 400 can be set in the test set.

[0052] Furthermore, the sum of the currents pulled by the current pulling device at the second end of each of the N measurement units is equal to the target value of the current to be measured. That is to say, when setting the value of the reference current required for the actual resistance value of the measurement sampling resistor and the pulling value of the current pulling device for each measurement unit 310, it is calculated according to the target value of the current to be measured and the number of measurement units to be used, that is, the reference current is equal to the target value of the current to be measured divided by the number of measurement units to be used. Among them, the target value of the current to be measured is, for example, the rated current value of the chip to be measured or the theoretical calculated value under a certain working state, etc. And since the actual value of the current to be measured generally does not differ much from the target value, and by way of example, the current pulling device for realizing the current pulling function can specifically be a current source or a load set on the second measurement board 400, and its current pulling for the N measurement units 300 can achieve the proportional distribution of the current to be measured on the N measurement units 300. Therefore, adopting this solution will not affect the accuracy of the final measurement result.

[0053] Furthermore, the current pulled by the current pulling device at the second end of each measurement unit 310 among the N measurement units 300 is equal to the reference current. In this way, when measuring the actual resistance value of the sampling resistor, the influence of the temperature change caused by the reference current on the actual resistance value of the sampling resistor can be made the same as the influence of the temperature change caused by the component of the current to be measured on the actual resistance value of the sampling resistor when measuring the current to be measured of the chip 500 to be measured, that is, the change in the resistance value caused by the thermal effect is eliminated, and the accuracy of the measurement result of the current to be measured is further improved.

[0054] Reference Figure 2 , in the present disclosure, each measurement unit further includes: a first switch, a second switch, a third switch, and a differential amplifier. Among them, the first input terminal of the differential amplifier is connected to the first end of the corresponding measurement unit through the first switch, the second input terminal of the differential amplifier is connected to the reference ground through the second switch, and at the same time, the second input terminal of the differential amplifier is also connected to the second end of the corresponding measurement unit through the third switch, and the output terminal of the differential amplifier is connected to the third end of the corresponding measurement unit. Among them, the sampling resistor corresponding to each measurement unit is connected between the first input terminal and the second input terminal of the differential amplifier in the measurement unit.

[0055] Optionally, the first switch, the second switch, and the third switch can be any one of a push-button switch, a toggle switch, and a rotary switch that can be manually controlled to switch; or any one of a bipolar transistor, a field effect transistor, and a relay that is automatically switched by a control signal. Specifically, it can be selected according to the actual application scenario.

[0056] It should be noted that in actual application, the current measurement device involved in the present disclosure can be set to integrate a corresponding number of measurement units in the current measurement device according to specific actual needs to form multiple models of current measurement devices with different numbers of measurement units; or directly integrate a certain number of measurement units in the current measurement device, and then control the opening and closing of the first switch in each measurement unit according to different actual needs to change the number of measurement units that can effectively achieve effective measurement, etc., all of which are acceptable.

[0057] Exemplarily, taking N equal to 3 as an example, that is, in this current measurement device, it includes a first measurement unit, a second measurement unit, and a third measurement unit. Then the first switch, the second switch, and the third switch corresponding to the first measurement unit are switch S1, switch S3, and switch S2 respectively. The sampling resistor corresponding to it is sampling resistor R1, the differential amplifier corresponding to it is differential amplifier U1, and the second end and the third end corresponding to the first measurement unit are respectively connected to the FOVI1 measurement terminal and the FOVI2 measurement terminal. Similarly, the first switch, the second switch, and the third switch corresponding to the second measurement unit are switch S4, switch S6, and switch S5 respectively. The sampling resistor corresponding to it is sampling resistor R2, the differential amplifier corresponding to it is differential amplifier U2, and the second end and the third end corresponding to the second measurement unit are respectively connected to the FOVI3 measurement terminal and the FOVI4 measurement terminal. The first switch, the second switch, and the third switch corresponding to the third measurement unit are switch S7, switch S9, and switch S8 respectively. The sampling resistor corresponding to it is sampling resistor R3, the differential amplifier corresponding to it is differential amplifier U3, and the second end and the third end corresponding to the third measurement unit are respectively connected to the FOVI5 measurement terminal and the FOVI6 measurement terminal.

[0058] At the same time, taking the target value of the current to be measured of the chip under test as 3A as an example, when measuring the actual resistance value of the sampling resistor, first close switch KS1, switch S1, and switch S3, input a 1A current with higher precision through the FPVI measurement terminal of the first measurement board, and measure the voltage value at this time using the FOVI2 measurement terminal to obtain the accurate resistance value of sampling resistor R1 under 1A current. Then use the same method to simultaneously close the combinations of switch KS1, switch S4, switch S6 and switch KS1, switch S7, switch S9 respectively to actually measure the accurate resistance values of sampling resistor R2 and sampling resistor R3.

[0059] After that, open switch KS1, switch S3, switch S6, and switch S9. While closing switch KS2, switch S1, switch S2, switch S4, switch S5, switch S7, and switch S8 at the same time, the current pulling device pulls 1A current from the FOVI1 measurement terminal, the FOVI3 measurement terminal, and the FOVI5 measurement terminal respectively, and the voltage measurement device measures the voltage values at both ends of sampling resistors R1, R2, and R3 from the FOVI2 measurement terminal, the FOVI4 measurement terminal, and the FOVI6 measurement terminal respectively. Then substitute the actual resistance values of sampling resistors R1, R2, and R3 measured above under 1A current to inversely deduce the actual current values I1, I2, and I3 flowing through each sampling resistor. Among them, I1 + I2 + I3 is the actual current value of the current to be measured.

[0060] It is understandable that the current measurement device in the present disclosure can also be applied to other measurement devices besides the test machine, as long as the measurement device has the same or similar defects as the test machine. The present switch does not limit this.

[0061] Figure 3 The flowchart showing the current measurement method provided according to an embodiment of the present disclosure.

[0062] The current measurement method in the present disclosure can be applied to a current measurement device as described in Figure 1 and Figure 2 . Referring to Figure 3 , the current measurement method includes performing step S01 and step S02.

[0063] Specifically, in step S01, a reference current is input to N current measurement units in the current measurement device, and the actual resistance values of the sampling resistors in each measurement unit are obtained based on the reference current. Here, N is a positive integer.

[0064] Referring to Figure 1 and Figure 2 , in this embodiment, when measuring the actual resistance value of the sampling resistor, first close the fourth switch KS1, and then close the first switch and the second switch in each measurement unit 310 in groups, and input a reference current with higher precision through the FPVI measurement terminal of the first measurement board 100. Then measure the voltage value across the sampling resistor in the corresponding measurement unit at this time through the third terminal of each measurement unit 310, and obtain the accurate resistance values of the sampling resistors respectively based on the measured voltage value and the reference current value. Among them, the first switch and the second switch in the same measurement unit 310 are closed simultaneously, and the first switches and the second switches in different measurement units 310 are closed at different times to ensure that each reference current can flow through all the sampling resistors to be measured.

[0065] In step S02, the input of the reference current is disconnected, a current to be measured is input to N current measurement units in the current measurement device, a current pulling device is used to pull the current from the sampling resistor in each current measurement unit simultaneously, and the current value of the current to be measured is measured based on the actual resistance value of the sampling resistor corresponding to each measurement unit obtained.

[0066] After obtaining the accurate resistance values of each sampling resistor, disconnect the fourth switch KS1 and the first and second switches in each measurement unit 310, and then simultaneously close the fifth switch KS2 and the first and third switches in each measurement unit 310. The current pulling device pulls currents from the second ends of each measurement unit 310 respectively, and at the same time, the voltage measuring device measures the voltage values across the sampling resistors in the corresponding measurement units at the third ends of each measurement unit 310 respectively. Then, substitute the actual resistance values of the foregoing measured sampling resistors under the reference current to inversely deduce the actual current values flowing through each sampling resistor. Among them, the actual current value of the current to be measured is equal to the sum of the current values obtained by measuring each of the N measurement units 300 in the measurement unit 310.

[0067] Furthermore, the sum of the currents pulled by the current pulling device from the second ends of each of the N measurement units is equal to the target value of the current to be measured.

[0068] Furthermore, the currents pulled by the current pulling device from the second ends of each of the N measurement units 310 in the N measurement units 300 are all equal to the reference current.

[0069] Furthermore, the present disclosure also relates to a testing machine, which includes a first measurement board 100 as shown in Figure 1 and a second measurement board 400, and a current measuring device as described in Figure 1 and Figure 2 Among them, the first measurement board 100 is connected to the current measuring device to provide a reference current for the current measuring device, and the second measurement board 400 is connected to the current measuring device to provide current pulling and voltage measuring functions for each measurement unit in the current measuring device. Furthermore, the testing machine can effectively measure the large current value with high precision based on the first measurement board 100, the second measurement board 400 and the current measuring device, making up for the defects of the existing testing machine. Among them, the model of the testing machine involved in the present disclosure is, for example, STS8200.

[0070] In summary, for the current measurement device and method disclosed in the present invention, N measurement units are connected in parallel to jointly measure a to-be-measured current with a large current value, enabling an accurate measurement of a large current value with high precision requirements by a measurement device with a small range and high precision. During measurement, a current pulling device connected to each measurement unit simultaneously pulls the to-be-measured current corresponding to the N measurement units, so that a component of the to-be-measured current can flow through the sampling resistor in each measurement unit. Then, after sampling the to-be-measured current components corresponding to each measurement unit, the current measurement can be indirectly achieved by measuring the voltage value across the sampling resistor. Since the measurement accuracy of the voltage measurement device of the existing test machine (such as STS8200) is higher than that of the current measurement device, the measurement units in the present disclosure can well ensure the high accuracy of the to-be-measured current. At the same time, before measuring the to-be-measured current, the actual resistance value of the sampling resistor in each measurement unit is accurately measured by a reference current with higher precision, which can greatly reduce the influence of the error between the rated resistance value and the actual resistance value of the sampling resistor in each measurement unit on the measurement result, and further improve the accuracy of the to-be-measured current measurement.

[0071] On the other hand, when setting the current pulling device to simultaneously pull the to-be-measured current corresponding to the N measurement units, the current pulled at the second end of each measurement unit (i.e., the current flowing through the sampling resistor in each measurement unit) is equal to the preset reference current. In this way, the influence of the temperature change caused by the reference current on the actual resistance value of the sampling resistor during the measurement of the actual resistance value of the sampling resistor can be the same as the influence of the temperature change caused by the component of the to-be-measured current on the actual resistance value of the sampling resistor when measuring the to-be-measured current of the device under test, that is, the change in the resistance value caused by the thermal effect is eliminated, and the accuracy of the measurement result of the to-be-measured current is further improved.

[0072] It should be noted that in this article, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without more limitations, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the said element.

[0073] Finally, it should be noted that: Obviously, the above embodiments are merely examples given to clearly illustrate the present invention, rather than limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A current measurement device, wherein, comprising: a selection unit, with a first input terminal receiving a reference current, a second input terminal receiving a current to be measured, and an output terminal selectively outputting one of the reference current and the current to be measured; N measurement units, with the first end of each of the N measurement units connected to the output terminal of the selection unit, the second end of each measurement unit connected to a current pulling device, and the third end of each measurement unit connected to a voltage measurement device, wherein each measurement unit includes: a sampling resistor, a first switch, a second switch, a third switch, and a differential amplifier; a first input terminal of the differential amplifier is connected to the first end through the first switch, a second input terminal of the differential amplifier is connected to a reference ground through the second switch, and the second input terminal of the differential amplifier is further connected to the second end through the third switch, and an output terminal of the differential amplifier is connected to the third end; the sampling resistor is connected between the first input terminal and the second input terminal of the differential amplifier; when the output terminal of the selection unit selectively outputs the reference current, the N measurement units are used to respectively obtain the actual resistance value of the sampling resistor in each measurement unit according to the reference current; and when the output terminal of the selection unit selectively outputs the current to be measured, each of the N measurement units is used to measure the current value of the current to be measured according to the actual resistance value of the corresponding sampling resistor, wherein the actual current value of the current to be measured is equal to the sum of the current values measured by each of the N measurement units, wherein N is a positive integer.

2. The current measurement device according to claim 1, wherein, the current pulled by the current pulling device at the second end of each of the N measurement units is equal to the reference current.

3. The current measurement device according to claim 1, wherein, the selection unit includes: a fourth switch, connected between the first input terminal and the output terminal of the selection unit; a fifth switch, connected between the second input terminal and the output terminal of the selection unit.

4. The current measurement device according to claim 1, wherein, the selection unit is a multiple-choice selection switch.

5. The current measurement device according to claim 3, wherein, the first switch, the second switch, the third switch, the fourth switch, and the fifth switch are each any one of a push-button switch, a toggle switch, and a rotary switch.

6. The current measurement device according to claim 3, wherein, the first switch, the second switch, the third switch, the fourth switch, and the fifth switch are each any one of a bipolar transistor, a field-effect transistor, and a relay.

7. The current measurement device according to claim 1, wherein, the current pulling device and the voltage measurement device are each a measurement board card in a tester.

8. The current measurement device according to any one of claims 1-7, wherein, The sum of the currents pulled by the current pulling device at the second end of each of the N measurement units is equal to the target value of the current to be measured.

9. A current measurement method, wherein, the current measurement method can be applied to the current measurement device according to any one of claims 1-8, and the method includes: inputting a reference current to N current measurement units in the current measurement device, and respectively obtaining the actual resistance values of the sampling resistors in each measurement unit based on the reference current; disconnecting the input of the reference current, inputting the current to be measured to the N current measurement units in the current measurement device, using the current pulling device to simultaneously pull the current from the sampling resistors in each current measurement unit, and measuring the current value of the current to be measured based on the actual resistance values of the sampling resistors corresponding to each measurement unit obtained, wherein, the actual current value of the current to be measured is equal to the sum of the current values measured by each of the N measurement units, wherein, N is a positive integer.

10. The current measurement method according to claim 9, wherein, the currents pulled by the current pulling device at the second end of each of the N measurement units are all equal to the reference current.

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