A device for detecting a target current

Abstract

The application provides a device for detecting target current, which comprises an interface circuit, a load control circuit, a signal amplification circuit and a microcontroller, the interface circuit is electrically connected between a circuit to be detected and the load control circuit, and is used for transferring the target current in the circuit to be detected to the load control circuit, the signal amplification circuit is electrically connected between the load control circuit and the microcontroller, wherein the load control circuit comprises a plurality of load control sub-circuits, and the microcontroller comprises a plurality of gate ports which are electrically connected with the plurality of load control sub-circuits respectively, and are used for sending the gate control signals to the plurality of load control sub-circuits, so as to trigger one load control sub-circuit in the load control circuit to be turned on. The technical scheme provided by the embodiment of the application greatly improves the accuracy of current detection.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a device for detecting target current. Background Technology

[0002] In standard product design, it is often necessary to detect the actual operating current of a product. Currently, most existing detection circuits use a single load resistor and an operational amplifier to detect the current in the target circuit. However, in practical applications, it is difficult to ensure that the resistance value of the load resistor covers both the minimum and maximum values ​​of a wide measurement range. This makes it difficult for the measured current to exceed two orders of magnitude, thus limiting the range of the detected current. Summary of the Invention

[0003] In view of this, in order to overcome the shortcomings of the prior art, the present invention provides a device for detecting target current.

[0004] The present invention provides a device for detecting target current, the device comprising: an interface circuit, a load control circuit, a signal amplification circuit, and a microcontroller;

[0005] The interface circuit is electrically connected between the circuit under test and the load control circuit, and is used to transfer the target current in the circuit under test to the load control circuit.

[0006] The signal amplification circuit is electrically connected to the load control circuit and the microcontroller, respectively, and is used to amplify the voltage signal output by the load control circuit and transmit the amplified voltage signal to the microcontroller to complete the detection of the target current.

[0007] The load control circuit includes multiple load control sub-circuits;

[0008] The microcontroller includes a plurality of gating ports that are electrically connected to the plurality of load control sub-circuits, respectively, for sending gating control signals to the plurality of load control sub-circuits to trigger one of the load control sub-circuits to be turned on.

[0009] Furthermore, each of the load control sub-circuits includes a current input port, a signal output port, and a control port. The current input port is used to receive the target current. The control port is electrically connected to the corresponding gating port on the microcontroller to receive the gating control signal sent by the microcontroller. The signal output port is used to output the voltage signal to the signal amplification circuit.

[0010] Furthermore, each of the load control sub-circuits includes a sampling resistor, and the sampling resistors in the plurality of load control sub-circuits have different resistance ranges to detect target currents of different ranges.

[0011] Furthermore, each of the load control sub-circuits includes a first circuit unit and a second circuit unit;

[0012] The first circuit unit includes a first resistor, a second resistor, and a transistor. The gate of the transistor is electrically connected to the control port of the load control sub-circuit through the first resistor. One end of the second resistor is electrically connected between the first resistor and the gate of the transistor, and the other end of the second resistor is electrically connected between the source of the transistor and ground.

[0013] The second circuit unit includes the sampling resistor switch control module. One end of the sampling resistor is electrically connected to the current input port, and the other end of the sampling resistor is grounded through the switch control module. The control terminal of the switch control module is electrically connected to the drain of the transistor to receive a control signal from the drain of the transistor and trigger the switch control module to ground the other end of the sampling resistor based on the control signal.

[0014] Furthermore, the switch control module includes any one of electronic switches, analog switches, and relays.

[0015] Further, the relay includes a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, a sixth terminal, and an electromagnetic switch. The first terminal is electrically connected to the current input port of the load control sub-circuit via the sampling resistor. The second terminal is electrically connected between the excitation winding of the relay and the drain of the transistor to receive a control signal from the drain of the transistor and trigger the excitation winding of the relay to conduct based on the control signal. The third and fourth terminals are grounded. The fifth terminal is electrically connected between the control power supply and the excitation winding. The electromagnetic switch is electrically connected between the third and fourth terminals. The sixth terminal is an unconnected terminal of the electromagnetic switch. When the excitation winding is not conducting, the moving contact of the electromagnetic switch is attracted and electrically connected to the sixth terminal, so that the sampling resistor is not working. When the excitation winding is conducting, the moving contact of the electromagnetic switch is attracted and electrically connected to the first terminal, so that the sampling resistor is working.

[0016] Furthermore, the second circuit unit also includes a capacitor, one end of which is electrically connected to the control power supply, and the other end of which is electrically connected between the second terminal and the drain of the transistor.

[0017] Furthermore, the second circuit unit also includes a freewheeling diode, which is connected in parallel with the capacitor.

[0018] Furthermore, the transistor is a bipolar junction transistor (BJT) or a field-effect transistor (FET).

[0019] Furthermore, the interface circuit has a first input port, a first output port, a second input port, and a second output port. The first input port is used to be electrically connected to a power supply, the first output port is used to be electrically connected to the power input terminal of the circuit under test to supply power to the circuit under test, the second input port is used to receive the target current in the circuit under test, and the second output port is electrically connected to the load control circuit.

[0020] Furthermore, the signal amplification circuit includes a low-noise operational amplifier.

[0021] Furthermore, the microcontroller includes an analog-to-digital converter (ADC) for converting the voltage signal in analog form into a digital signal.

[0022] Optionally, the load control circuit includes four load control sub-circuits, and the resistance ranges of the sampling resistors of the four load control sub-circuits differ by a factor of 10 or 100, respectively.

[0023] The device for detecting target current provided in this embodiment of the invention includes an interface circuit, a load control circuit, a signal amplification circuit, and a microcontroller. The interface circuit is electrically connected between the circuit under test and the load control circuit, and is used to transfer the target current in the circuit under test to the load control circuit. The signal amplification circuit is electrically connected between the load control circuit and the microcontroller. The load control circuit includes multiple load control sub-circuits, and the microcontroller includes multiple gating ports respectively electrically connected to the multiple load control sub-circuits, used to send gating control signals to the multiple load control sub-circuits to trigger the conduction of one of the load control sub-circuits. The technical solution provided in this embodiment of the invention greatly improves the accuracy of current detection.

[0024] Furthermore, the signal output port of the load control circuit is used to output the voltage signal to the signal amplification circuit. The voltage value generated by the current flowing through the selected sampling resistor in each load control sub-circuit is then sent to the signal amplification circuit for amplification, and then sent to the microcontroller for signal conversion, so as to accurately measure the actual current of the circuit under test.

[0025] Furthermore, since the sampling resistors in the multiple load control sub-circuits have different resistance ranges, the device for detecting the target current can be applied to current detection on target boards (e.g., PCB boards) of circuits under test with different current values, thereby broadening the application range of the device for detecting the target current. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention. For those skilled in the art, other implementation methods can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a structural block diagram of the device for detecting target current provided in an embodiment of the present invention.

[0028] Figure 2 It is based on Figure 1 The diagram shows the electrical connection between the load control circuit and the microcontroller of the device for detecting the target current.

[0029] Figure 3 It is based on Figure 2 The diagram shows the structure of the load control sub-circuit of the load control circuit provided in the diagram.

[0030] Figure 4 It is based on Figure 1 The diagram shows the structure of the signal amplification circuit in the device for detecting the target current provided in the document. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0033] Figure 1 This is a structural block diagram of the device for detecting target current provided in an embodiment of the present invention. Figure 2It is based on Figure 1 The diagram shows the electrical connection between the load control circuit and the microcontroller of the device for detecting the target current.

[0034] like Figure 1 and Figure 2 As shown, the device for detecting target current provided in this embodiment of the invention includes: an interface circuit 100, a load control circuit 200, a signal amplification circuit 300, and a microcontroller 400; the interface circuit 100 is electrically connected between the circuit under test and the load control circuit 200, and is used to transfer the target current in the circuit under test to the load control circuit 200; the signal amplification circuit 300 is electrically connected to the load control circuit 200 and the microcontroller 400 respectively, and is used to amplify the voltage signal output by the load control circuit 200 and transmit the amplified voltage signal to the microcontroller 400 to complete the detection of the target current; the load control circuit 200 includes a plurality of load control sub-circuits 210; the microcontroller 400 includes a plurality of gating ports respectively electrically connected to the plurality of load control sub-circuits, and is used to send gating control signals to the plurality of load control sub-circuits to trigger one of the load control sub-circuits in the load control circuit 200 to conduct.

[0035] For example, the interface circuit 100 has a first input port 11, a first output port 12, a second input port 13, and a second output port 14. The first input port 11 is used to be electrically connected to a power supply, the first output port 12 is used to be electrically connected to the power input terminal of the circuit under test to supply power to the circuit under test, the second input port 13 is used to receive the target current in the circuit under test, and the second output port 14 is electrically connected to the load control circuit 200 to transfer the target current to the load control circuit 200.

[0036] For example, the load control circuit includes multiple independent load control sub-circuits. Each load control sub-circuit 210 includes a current input port, a signal output port 201, and a control port. The current input port is used to receive the target current. The control port is electrically connected to a corresponding gating port on the microcontroller 400 to receive a gating control signal sent by the microcontroller 400. The signal output port 201 is used to output the voltage signal to the signal amplification circuit 300.

[0037] Each of the load control sub-circuits 210 includes a sampling resistor, and the sampling resistors in the plurality of load control sub-circuits 210 have different resistance ranges to detect target currents of different ranges.

[0038] Specifically, in this embodiment of the invention, the sampling resistors in the plurality of load control sub-circuits 210 have different resistance ranges. The plurality of selection ports of the microcontroller 400 are electrically connected to the control ports in the plurality of load control sub-circuits 210 respectively to select the sampling resistors corresponding to different resistance ranges. Then, by detecting the voltage drop across the sampling resistors with different resistance ranges, the target current of the circuit under test with different ranges can be detected.

[0039] Furthermore, the voltage drop signal generated by the current flowing through the selected sampling resistor in each load control sub-circuit 210 is then sent to the signal amplification circuit 300 for amplification, and then sent to the microcontroller 400 for signal conversion, thereby enabling accurate measurement of the actual current of the circuit under test.

[0040] The technical solution provided by the embodiments of the present invention greatly improves the accuracy of current detection. Furthermore, since the sampling resistors in the plurality of load control sub-circuits 210 have different resistance ranges, the device for detecting target current can be applied to current detection on target boards (e.g., PCB boards) of circuits under test with different current values, thereby broadening the application range of the device for detecting target current.

[0041] Figure 3 It is based on Figure 2 The diagram shows the structure of the load control sub-circuit of the load control circuit provided in the diagram.

[0042] For example, such as Figure 3 As shown, each of the load control sub-circuits includes a first circuit unit 211 and a second circuit unit 212; the first circuit unit 211 includes a first resistor R35, a second resistor R39 and a transistor Q5, the gate of the transistor Q5 is electrically connected to the control port of the load control sub-circuit 210 through the first resistor R35, one end of the second resistor R39 is electrically connected between the first resistor R35 and the gate of the transistor Q5, and the other end of the second resistor R39 is electrically connected between the source of the transistor Q5 and ground.

[0043] The second circuit unit includes the sampling resistor R31 and a switch control module. One end of the sampling resistor R31 is electrically connected to the current input port, and the other end of the sampling resistor R31 is grounded through the switch control module. The control terminal of the switch control module is electrically connected to the drain of the transistor Q5 to receive a control signal from the drain of the transistor Q5 and trigger the switch control module to ground the other end of the sampling resistor R31 based on the control signal.

[0044] For example, the switch control module is a relay 60, which includes a first terminal 1, a second terminal 2, a third terminal 3, a fourth terminal 4, a fifth terminal 5, a sixth terminal 6, and an electromagnetic switch. The first terminal 1 is electrically connected to the current input port of the load control sub-circuit 210 via the sampling resistor R31. The second terminal 2 is electrically connected between the excitation winding of the relay 60 and the drain of the transistor Q5 to receive a control signal from the drain of the transistor Q5 and trigger the conduction of the excitation winding in the relay 60 based on the control signal. The third terminal 3 and the fourth terminal 4 are grounded. The fifth terminal 5 is electrically connected between the control power supply (e.g., 5V) and the excitation winding. The electromagnetic switch is electrically connected between the third terminal 3 and the fourth terminal 4. The sixth terminal 6 is the unconnected terminal of the electromagnetic switch.

[0045] When the excitation winding is not conducting, the moving contact of the electromagnetic switch is attracted and electrically connected to the sixth terminal 6, so that the sampling resistor R31 is not working; when the excitation winding is conducting, the moving contact of the electromagnetic switch is attracted and electrically connected to the first terminal 1, so that the sampling resistor R31 is working.

[0046] It should be understood that, in the embodiments of the present invention, the relay in the switch control module described above can also be replaced by any one of electronic switches or analog switches.

[0047] For example, in an embodiment of the present invention, each load control sub-circuit 210 in the load control circuit 200 may receive a strobe control signal from the microcontroller 400 in a timing sequence, and select one of the load control sub-circuits 210 to be turned on. For a load control sub-circuit 210 that is turned on, its second circuit unit 212 receives a control signal from its first circuit unit 211 and triggers the excitation winding in the relay 60 to turn on based on the current signal generated by the drain of transistor Q5 in the first circuit unit 211. After the excitation winding is turned on, it will generate a pull-in current, which will pull the excitation winding to the cavity wall of the relay 60, thereby causing the moving contact of the electromagnetic switch to be pulled in and electrically connected to the first terminal 1. At this time, one end of the sampling resistor R31 is electrically connected to the current input port that receives the target current, and the other end of the sampling resistor R31 is grounded, thus forming a load loop. Then, by detecting or outputting the voltage drop across the sampling resistor R31 in the load control sub-circuit 210, the target current of the circuit under test can be accurately measured.

[0048] For example, in one embodiment of the present invention, the microcontroller 400 includes a single-chip microcomputer, on which software is burned to control multiple selection ports on the microcontroller 400 to select between the multiple load control sub-circuits 210 according to a set program.

[0049] For example, such as Figure 2 As shown, the load control circuit 200 includes four load control sub-circuits 210, and the resistance ranges of the sampling resistors of the four load control sub-circuits 210 differ by a factor of 10 or 100, respectively.

[0050] For example, the sampling resistor of the first load control subcircuit in the four load control subcircuits 210 has a resistance range of 2 ohms to 2.6 ohms, the sampling resistor of the second load control subcircuit in the four load control subcircuits 210 has a resistance range of 20 ohms to 26 ohms, the sampling resistor of the third load control subcircuit in the four load control subcircuits 210 has a resistance range of 2K ohms to 2.6K ohms, and the sampling resistor of the fourth load control subcircuit in the four load control subcircuits 210 has a resistance range of 200K ohms to 260K ohms.

[0051] Furthermore, the second circuit unit 212 also includes a capacitor C31, one end of which is electrically connected to the control power supply, and the other end of which is electrically connected between the second terminal 2 and the drain of the transistor Q5.

[0052] In this embodiment of the invention, when the second circuit unit 212 is powered on, one end of capacitor C31 is electrically connected to the control power supply, and one end of capacitor C31 begins to charge, causing the node voltage between the other end of capacitor C31 and the drain of transistor Q5 to continuously increase. Even when the second circuit unit 212 is powered off, one end of capacitor C31 can reverse the power supply to relay 60, thus maintaining the normal operation of relay 60 for a period of time.

[0053] Furthermore, the second circuit unit 212 also includes a freewheeling diode D10, which is connected in parallel with the capacitor C31 to protect the components from being broken down and burned by the induced voltage generated by the internal coil of the relay.

[0054] Specifically, the freewheeling diode D10 is connected in parallel to the two ends of the element that generates the induced electromotive force. That is, one end of the freewheeling diode D10 is electrically connected to the control power supply, and the other end of the freewheeling diode D10 is electrically connected between the second terminal 2 and the drain of the transistor Q5 to form a circuit with it, so that the high electromotive force generated by it is consumed in the circuit in the form of freewheeling current, thereby protecting the circuit components from damage.

[0055] For example, in one embodiment of the present invention, the transistor Q5 is a bipolar transistor. Since a bipolar transistor amplifies current, a small change in the current at the base (gate) of the transistor will result in a significant change in the current IC between the collector and emitter (source and drain) of the transistor. This generates a large current to trigger the excitation winding in the relay 60 to conduct and produce a pull-in current. Optionally, in other embodiments of the present invention, the transistor Q5 can also be a field-effect transistor (FET), and the voltage difference between the gate and source of the FET is used to control the switching on and off of the FET.

[0056] Furthermore, the microcontroller 400 includes an analog-to-digital converter (ADC) unit, which converts the voltage signal in analog form into a digital signal. The digital signal can then be processed by a digital signal processing module. In some embodiments, various types of integrated ADCs are used, including 8-bit, 10-bit, and 16-bit ADCs. An n-bit ADC means that it has 2^n scales. For example, an 8-bit ADC outputs 256 numbers from 0 to 255, which is one data scale of 2^8.

[0057] Figure 4 It is based on Figure 1 The diagram shows the structure of the signal amplification circuit in the device for detecting the target current provided in the document.

[0058] Combination Figures 1-4 As shown, the target current to be detected is converted into a voltage signal by the load control circuit 200. The signal amplification circuit 300 is electrically connected to the load control circuit 200 and the microcontroller 400 respectively. It is used to amplify the voltage signal output by the load control circuit 200 and transmit the amplified voltage signal to the microcontroller 400 to complete the detection of the target current.

[0059] Specifically, the voltage signal output from the third terminal 3 of the relay 60 of the load control circuit 200 is sent to the positive input terminal R30 of the operational amplifier U8 of the signal amplification circuit 300. The operational amplifier U8 amplifies the small voltage signal by an integer multiple so that the voltage value can be sensitively detected at the input terminal of the analog-to-digital conversion unit of the microcontroller 400, thereby accurately detecting the target current of the circuit under test.

[0060] Optionally, the signal amplification circuit 300 includes a low-noise operational amplifier, for example, operating at 3.3V and capable of amplifying voltage by a factor of 24. These high-speed, low-distortion operational amplifiers can achieve high signal fidelity under the most demanding conditions, thereby achieving low overall system noise performance for the device for detecting the target current.

[0061] As can be seen from the above, the device for detecting target current provided in this embodiment of the invention includes an interface circuit, a load control circuit, a signal amplification circuit, and a microcontroller. The interface circuit is electrically connected between the circuit under test and the load control circuit, and is used to transfer the target current in the circuit under test to the load control circuit. The signal amplification circuit is electrically connected between the load control circuit and the microcontroller. The load control circuit includes multiple load control sub-circuits, and the microcontroller includes multiple gating ports respectively electrically connected to the multiple load control sub-circuits, used to send gating control signals to the multiple load control sub-circuits to trigger the conduction of one of the load control sub-circuits. The technical solution provided in this embodiment of the invention greatly improves the accuracy of current detection.

[0062] Furthermore, the signal output port of the load control circuit is used to output the voltage signal to the signal amplification circuit. The voltage value generated by the current flowing through the selected sampling resistor in each load control sub-circuit is then sent to the signal amplification circuit for amplification, and then sent to the microcontroller for signal conversion, so as to accurately measure the actual current of the circuit under test.

[0063] Furthermore, since the sampling resistors in the multiple load control sub-circuits have different resistance ranges, the device for detecting the target current can be applied to current detection on target boards (e.g., PCB boards) of circuits under test with different current values, thereby broadening the application range of the device for detecting the target current.

[0064] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0065] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for detecting target current, characterized in that, The device includes: an interface circuit, a load control circuit, a signal amplification circuit, and a microcontroller; The interface circuit is electrically connected between the circuit under test and the load control circuit, and is used to transfer the target current in the circuit under test to the load control circuit. The signal amplification circuit is electrically connected to the load control circuit and the microcontroller, respectively, and is used to amplify the voltage signal output by the load control circuit and transmit the amplified voltage signal to the microcontroller to complete the detection of the target current. The load control circuit includes multiple load control sub-circuits; each load control sub-circuit includes a current input port, a signal output port, a control port, a first circuit unit, and a second circuit unit; the current input port is used to receive the target current, the control port is electrically connected to a corresponding gating port on the microcontroller to receive a gating control signal sent by the microcontroller, and the signal output port is used to output the voltage signal to the signal amplification circuit; the first circuit unit includes a first resistor, a second resistor, and a transistor, the gate of the transistor is electrically connected to the control port of the load control sub-circuit through the first resistor, one end of the second resistor is electrically connected between the first resistor and the gate of the transistor, and the other end of the second resistor is electrically connected between the source of the transistor and ground; the second circuit unit includes a sampling resistor and a switch control module, one end of the sampling resistor is electrically connected to the current input port, the other end of the sampling resistor is grounded through the switch control module, and the control terminal of the switch control module is electrically connected to the drain of the transistor to receive a control signal from the drain of the transistor and trigger the switch control module to ground the other end of the sampling resistor based on the control signal; The microcontroller includes a plurality of gating ports that are electrically connected to the plurality of load control sub-circuits, respectively, for sending gating control signals to the plurality of load control sub-circuits to trigger one of the load control sub-circuits to be turned on.

2. The device for detecting target current according to claim 1, characterized in that, The sampling resistors in the multiple load control sub-circuits have different resistance ranges to detect target currents of different ranges.

3. The device for detecting target current according to claim 1, characterized in that, The switch control module includes any one of electronic switches, analog switches, and relays.

4. The device for detecting target current according to claim 3, characterized in that, The relay includes a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, a sixth terminal, and an electromagnetic switch. The first terminal is electrically connected to the current input port of the load control sub-circuit via the sampling resistor. The second terminal is electrically connected between the excitation winding of the relay and the drain of the transistor to receive a control signal from the drain of the transistor and trigger the excitation winding of the relay to conduct based on the control signal. The third and fourth terminals are grounded. The fifth terminal is electrically connected between the control power supply and the excitation winding. The electromagnetic switch is electrically connected between the third and fourth terminals. The sixth terminal is an unconnected terminal of the electromagnetic switch. In the case that the excitation winding is not conducting, the moving contact of the electromagnetic switch is attracted and electrically connected to the sixth terminal, so that the sampling resistor is not working; When the excitation winding is turned on, the moving contact of the electromagnetic switch is attracted and electrically connected to the first terminal, so that the sampling resistor is working.

5. The device for detecting target current according to claim 4, characterized in that, The second circuit unit further includes a capacitor, one end of which is electrically connected to the control power supply, and the other end of which is electrically connected between the second terminal and the drain of the transistor.

6. The device for detecting target current according to claim 5, characterized in that, The second circuit unit further includes a freewheeling diode, which is connected in parallel with the capacitor.

7. The device for detecting target current according to claim 1, characterized in that, The transistor is a bipolar junction transistor (BJT) or a field-effect transistor (FET).

8. The device for detecting target current according to claim 1, characterized in that, The interface circuit has a first input port, a first output port, a second input port, and a second output port. The first input port is used to be electrically connected to the power supply, the first output port is used to be electrically connected to the power input terminal of the circuit under test to supply power to the circuit under test, the second input port is used to receive the target current in the circuit under test, and the second output port is electrically connected to the load control circuit.

9. The device for detecting target current according to claim 1, characterized in that, The microcontroller includes an analog-to-digital converter (ADC) for converting the voltage signal in analog form into a digital signal.

10. The device for detecting target current according to claim 2, characterized in that, The load control circuit includes four load control sub-circuits, and the resistance ranges of the sampling resistors of the four load control sub-circuits differ by a factor of 10 or 100, respectively.

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