Current measuring device with range switching function

Abstract

This application relates to a current measuring device with range switching function, including a current measuring module, a voltage comparison module, a switching module, and a main control module. The input terminal of the current measuring module is used to receive the current value to be measured. The current measuring module is connected to the input terminal of the voltage comparison module. The output terminal of the voltage comparison module is connected to the input terminal of the range switching unit. The output terminal of the range switching unit is connected to the control terminal of the switching module. The output terminal of the switching module is connected to the current measuring module. The current measuring module includes at least two current measuring units, and the voltage comparison module includes at least two voltage comparison units. Each of the at least two current measuring units corresponds to a different current measuring range. The technical solution provided by this application can achieve wide-range current measurement while also switching between different current ranges, thereby solving the technical problem of being unable to measure the current value when the current variation range is large.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a current measuring device with range switching function. Background Technology

[0002] In the application of microLED display chips, it is usually necessary to measure the magnitude of their driving current. However, due to the extreme fluctuation range of the driving current of microLED display chips under different display screens or different gray levels, for example, the maximum value corresponding to the fluctuation range of the driving current may reach thousands of milliamps, and the minimum value may reach a few microamps. However, conventional ammeters are limited by their range and it is difficult to accurately measure the current value with a large fluctuation range. Utility Model Content

[0003] To address the problems of existing technologies, this application provides a technical solution for a current measuring device with a range switching function. Specifically, this application sets up a range switching unit and at least two current measuring units, with each of the at least two current measuring units corresponding to a different current measurement range. This allows for the measurement of a wide range of currents using the at least two current measuring units. Furthermore, the range switching unit can be used to switch between the at least two current measuring units to accommodate different current ranges, thereby solving the technical problem of being unable to measure current values ​​when the current variation range is large.

[0004] This application provides a current measuring device with range switching function, including a current measuring module, a voltage comparison module, a switching module and a main control module, wherein the main control module includes a range switching unit;

[0005] The input terminal of the current measurement module is used to receive the current value to be measured. The current measurement module is connected to the input terminal of the voltage comparison module. The output terminal of the voltage comparison module is connected to the input terminal of the range switching unit. The output terminal of the range switching unit is connected to the control terminal of the switch module. The output terminal of the switch module is connected to the current measurement module.

[0006] The current measurement module includes at least two current measurement units, and the voltage comparison module includes at least two voltage comparison units. The current measurement units and the voltage comparison units are configured in a one-to-one correspondence, and each of the at least two current measurement units has a different current measurement range.

[0007] Furthermore, the voltage comparison unit includes a voltage amplification subunit and a voltage comparison subunit;

[0008] The first and second input terminals of the voltage amplification subunit are respectively connected to the two ends of the current measurement unit. The output terminal of the voltage amplification subunit is connected to the first input terminal of the voltage comparison subunit. The second input terminal of the voltage amplification subunit is used to receive a preset voltage threshold. The output terminal of the voltage amplification subunit is connected to the input terminal of the range switching unit.

[0009] Furthermore, the switching module includes at least one field-effect transistor;

[0010] The gate of the field-effect transistor is connected to the output terminal of the range switching unit, and the source and drain of the field-effect transistor are respectively connected to the two ends of the current measurement unit.

[0011] Furthermore, the current measuring device also includes a voltage acquisition module, and the main control module also includes an overcurrent detection unit;

[0012] The input terminal of the voltage acquisition module is connected to the output terminal of the voltage amplification subunit, and the output terminal of the voltage acquisition module is connected to the overcurrent detection unit.

[0013] Furthermore, the current measuring device also includes an on / off control module;

[0014] The control terminal of the on / off control module is connected to the output terminal of the overcurrent detection unit, the input terminal of the on / off control module is connected to the output terminal of the current measurement module, and the output terminal of the on / off control module is used to connect to the device to be driven.

[0015] Furthermore, the at least two current measuring units include a first current measuring unit, a second current measuring unit, and a third current measuring unit, wherein the first current measuring unit, the second current measuring unit, and the third current measuring unit are connected in series.

[0016] Further, the voltage amplification subunit includes a first operational amplifier, a second operational amplifier, and a third operational amplifier. The non-inverting and inverting input terminals of the first operational amplifier are respectively connected to the two ends of the first current measurement unit, and the output terminal of the first operational amplifier is connected to the input terminal of the voltage comparison subunit. The non-inverting and inverting input terminals of the second operational amplifier are respectively connected to the two ends of the second current measurement unit, and the output terminal of the second operational amplifier is connected to the input terminal of the voltage comparison subunit. The non-inverting and inverting input terminals of the third operational amplifier are respectively connected to the two ends of the third current measurement unit, and the output terminal of the third operational amplifier is connected to the input terminal of the voltage comparison subunit.

[0017] Furthermore, the voltage comparison subunit includes a first voltage comparator, a voltage comparison component, and a second voltage comparator;

[0018] The non-inverting input of the first voltage comparator is connected to the output of the first operational amplifier, the inverting input of the first voltage comparator is used to receive a first preset voltage value, the output of the first voltage comparator is connected to the input of the range switching unit, the input of the voltage comparator component is connected to the output of the second operational amplifier, the output of the voltage comparator component is connected to the input of the range switching unit, the non-inverting input of the second voltage comparator is connected to the output of the third operational amplifier, the inverting input of the second voltage comparator is used to receive a second preset voltage value, and the output of the second voltage comparator is connected to the input of the range switching unit.

[0019] Furthermore, the voltage comparison component includes a third voltage comparator and a fourth voltage comparator;

[0020] The non-inverting input of the third voltage comparator is connected to the output of the second operational amplifier, the inverting input of the third voltage comparator is used to receive a third preset voltage value, and the output of the third voltage comparator is connected to the input of the range switching unit. The non-inverting input of the fourth voltage comparator is connected to the output of the second operational amplifier, the inverting input of the fourth voltage comparator is used to receive a fourth preset voltage value, and the output of the fourth voltage comparator is connected to the input of the range switching unit.

[0021] Furthermore, the at least one field-effect transistor includes a first field-effect transistor and a second field-effect transistor;

[0022] The gate of the first field-effect transistor is connected to the output terminal of the range switching unit. The source and drain of the first field-effect transistor are respectively connected to one end of the second current measuring unit and the other end of the third current measuring unit. One end of the second current measuring unit is connected to the first current measuring unit, and the other end of the third current measuring unit is not connected to the second current measuring unit. The gate of the second field-effect transistor is connected to the output terminal of the range switching unit. The source and drain of the second field-effect transistor are respectively connected to the two ends of the third current measuring unit.

[0023] Implementing this application will have the following beneficial effects:

[0024] This application sets up a range switching unit and at least two current measurement units, with each of the at least two current measurement units having a different current measurement range. This allows for the measurement of a wide range of currents using the at least two current measurement units. Furthermore, the range switching unit can be used to switch between the at least two current measurement units to accommodate different current ranges, thereby solving the technical problem of being unable to measure current values ​​when the current variation range is large. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0026] Figure 1 A schematic diagram of a current measuring device with range switching function provided in an embodiment of this application;

[0027] Figure 2 A circuit diagram corresponding to a current measuring device with range switching function provided in the embodiments of this application;

[0028] In the figure, the corresponding reference numerals are as follows: 1-Current measurement module; 11-First current measurement unit; 12-Second current measurement unit; 13-Third current measurement unit; 2-Voltage comparison module; 21-Voltage amplification subunit; 211-First operational amplifier; 212-Second operational amplifier; 213-Third operational amplifier; 22-Voltage comparison subunit; 221-First voltage comparator; 222-Voltage comparison component; 2221-Third voltage comparator; 2222-Fourth voltage comparator; 223-Second voltage comparator; 3-Switching module; 31-First field-effect transistor; 32-Second field-effect transistor; 4-Main control module; 41-Range switching unit; 42-Overcurrent detection unit; 5-Voltage acquisition module; 6-On / off control module; 7-Device to be driven. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] It should be noted that, in this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] Hereinafter, embodiments will be described with reference to the accompanying drawings, which are not intended to limit the disclosure described in the claims.

[0032] Please see Figure 1 and Figure 2 The following is combined with Figure 1 and Figure 2 This application provides a detailed description of a current measuring device with range switching function provided in its embodiments.

[0033] This application provides a current measuring device with range switching function, such as... Figure 1 and Figure 2 As shown, specifically, the current measuring device with range switching function includes a current measuring module 1, a voltage comparison module 2, a switching module 3, and a main control module 4, the main control module 4 including a range switching unit 41.

[0034] The input terminal of the current measurement module 1 is used to receive the current value to be measured. The current measurement module 1 is connected to the input terminal of the voltage comparison module 2. The output terminal of the voltage comparison module 2 is connected to the input terminal of the range switching unit 41. The output terminal of the range switching unit 41 is connected to the control terminal of the switch module 3. The output terminal of the switch module 3 is connected to the current measurement module 1. The current measurement module 1 includes at least two current measurement units, and the voltage comparison module 2 includes at least two voltage comparison units. The current measurement units and voltage comparison units are set in a one-to-one correspondence. Each current measurement unit in the at least two current measurement units has a different current measurement range.

[0035] In this embodiment, the current measurement module 1 is used to measure the current value to be measured. The current measurement module 1 includes at least two current measurement units, each of which has a different current measurement range. Specifically, the current measurement range of the at least two current measurement units gradually decreases along the direction away from the input terminal of the current measurement module 1. The voltage comparison module 2 is used to determine the current range of the at least two current measurement units that is suitable for the current value to be measured, and sends a corresponding level signal to the range switching unit 41 so that the range switching unit 41 can switch the at least two current measurement units through the switch module 3. This enables wide-range current measurement while also allowing switching for different current ranges, thus solving the technical problem of being unable to measure the current value when the current variation range is large.

[0036] In practical applications, the number of units corresponding to at least two current measuring units can be 2, 3, 4, or 5, etc. The current measurement range corresponding to at least two current measuring units can be determined according to the specific values ​​of the current measuring units, and no specific limitation is made here.

[0037] In one alternative implementation, such as Figure 1 As shown, the voltage comparison unit includes a voltage amplification subunit 21 and a voltage comparison subunit 22; wherein, the first input terminal and the second input terminal of the voltage amplification subunit 21 are respectively connected to the two ends of the current measurement unit, the output terminal of the voltage amplification subunit 21 is connected to the first input terminal of the voltage comparison subunit 22, the second input terminal of the voltage amplification subunit is used to receive a preset voltage threshold, and the output terminal of the voltage amplification subunit is connected to the input terminal of the range switching unit 41.

[0038] In this embodiment, the voltage amplification subunit 21 is used to amplify the signals measured by at least two current measurement units, and the voltage comparison subunit 22 is used to compare the amplified voltage value with a preset voltage threshold, and send a corresponding level signal to the range switching unit 41 according to the comparison result. Then, the range switching unit 41 can switch at least two current measurement units by controlling the opening and closing of the switch module 3 based on the level signal.

[0039] In practical applications, the voltage amplification subunit 21 includes multiple operational amplifiers, each of which is configured in a one-to-one correspondence with a current measurement unit. In other words, the operational amplifier amplifies the signal measured by the current measurement unit connected to it, thereby enabling the amplification of the signal measured by any current measurement unit.

[0040] In an optional implementation, the switching module 3 includes at least one field-effect transistor; wherein the gate of the field-effect transistor is connected to the output terminal of the range switching unit 41, and the source and drain of the field-effect transistor are respectively connected to the two ends of the current measuring unit.

[0041] In this embodiment, at least one field-effect transistor is provided to switch between different current measurement ranges by means of the opening and closing of the switching module 3. In a specific embodiment, the number of at least one field-effect transistor can be 1, 2, 3 or 4, etc. The number of at least one field-effect transistor is closely related to the number of current measurement units. Specifically, when there are 2 current measurement units, 1 field-effect transistor is needed to switch them; when there are 3 current measurement units, 2 field-effect transistors are needed to switch them; and so on. When there are n current measurement units, n-1 field-effect transistors are needed to switch them, where n is greater than or equal to 2.

[0042] In one alternative implementation, such as Figure 1 As shown, the current measuring device also includes a voltage acquisition module 5, and the main control module 4 also includes an overcurrent detection unit 42. The input terminal of the voltage acquisition module 5 is connected to the output terminal of the voltage amplification subunit 21, and the output terminal of the voltage acquisition module 5 is connected to the overcurrent detection unit 42. In one specific embodiment, the current measuring device also includes a switching control module 6. The control terminal of the switching control module 6 is connected to the output terminal of the overcurrent detection unit 42, the input terminal of the switching control module 6 is connected to the output terminal of the current measuring module 1, and the output terminal of the switching control module 6 is used to connect to the device to be driven 7.

[0043] In this embodiment, a voltage acquisition module 5 is provided to acquire voltage. The voltage acquisition module 5 sends the acquired voltage value to the overcurrent detection unit 42, so that the overcurrent detection unit 42 converts the received voltage value into a corresponding current value. Then, based on the current value and the preset overcurrent threshold, it can determine whether there is an overcurrent state. When it is determined that there is an overcurrent state, a low-level overcurrent control signal is output to the on / off control module 6, so that the on / off control module 6 is in the off state, thereby realizing overcurrent protection.

[0044] In practical applications, when both the first field-effect transistor 31 and the second field-effect transistor 32 in at least one field-effect transistor are in the off state, the current to be measured will simultaneously flow through at least two current measuring units: the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13. If the resistance of the third current measuring unit 13 is the largest, the current value on the third current measuring unit 13 can be collected, and its relationship with the current measuring range corresponding to the third current measuring unit 13 can be determined. If it exceeds the maximum range value corresponding to the third current measuring unit 13, an interruption signal is sent to the on / off control module 6. A low-level signal is sent to keep the on / off control module 6 in the off state, thereby achieving overcurrent protection. Furthermore, when the first field-effect transistor 31 in at least one field-effect transistor is in the off state and the second field-effect transistor 32 is in the on state, the current value on the second current measurement unit 12 is collected, and the relationship between the current value and the current measurement range corresponding to the second current measurement unit 12 is determined. If the current value exceeds the maximum range value corresponding to the second current measurement unit 12, a low-level signal is sent to the on / off control module 6 to keep the on / off control module 6 in the off state, thereby achieving overcurrent protection.

[0045] It should be noted that the device to be driven, 7, can be a microLED display chip.

[0046] The following example demonstrates the range switching method of a current measuring device by using three current measuring units to measure a current with a range of 1uA to 1000mA.

[0047] In one specific implementation, such as Figure 2 As shown, at least two current measurement units include a first current measurement unit 11, a second current measurement unit 12, and a third current measurement unit 13, which are connected in series. The voltage amplification subunit 21 includes a first operational amplifier 211, a second operational amplifier 212, and a third operational amplifier 213. The non-inverting and inverting input terminals of the first operational amplifier 211 are respectively connected to the two ends of the first current measurement unit 11, and the output terminal of the first operational amplifier 211 is connected to the input terminal of the voltage comparison subunit 22. The non-inverting and inverting input terminals of the second operational amplifier 212 are respectively connected to the two ends of the second current measurement unit 12, and the output terminal of the second operational amplifier 212 is connected to the input terminal of the voltage comparison subunit 22. The non-inverting and inverting input terminals of the third operational amplifier 213 are respectively connected to the two ends of the third current measurement unit 13, and the output terminal of the third operational amplifier 213 is connected to the input terminal of the voltage comparison subunit 22.

[0048] In this embodiment, the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13 can all be sampling resistors with different resistance values. Therefore, current values ​​within different current measuring ranges can be measured using sampling resistors with different resistance values. In some embodiments, the resistance values ​​of the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13 can be 30mΩ, 3Ω, and 300Ω, respectively. Thus, the first current measuring unit 11 with a resistance of 30mΩ can measure current values ​​with a single range of 10mA to 1000mA, the second current measuring unit 12 with a resistance of 3Ω can measure current values ​​with a single range of 100uA to 10mA, and the second current measuring unit 12 with a resistance of 300Ω can measure current values ​​with a single range of 100uA to 10mA.

[0049] The following explains the determination of the resistance values ​​and corresponding single ranges for the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13. Specifically, the maximum voltage drop corresponding to the current measuring unit can be set to 30mV, and the minimum voltage drop corresponding to the current measuring unit can be set to 300uV. Therefore, the resistance value corresponding to the first current measuring unit 11 under the maximum current (1000mA) can be selected. Considering that the voltage / power loss on the first current measuring unit 11 should not be too large, the value of the first current measuring unit 11 should not be too large. Thus, the resistance value is determined when the maximum current is 1000mA and the maximum voltage drop is... At 30mV, according to Ohm's law, the resistance value of the first current measuring unit 11 can be selected as 30mΩ. Furthermore, considering the offset voltage parameter of the first operational amplifier 211, the voltage value across the first current measuring unit 11 should not be too small at the minimum current, otherwise it will lead to excessive loss of accuracy. Thus, with a minimum voltage drop of 300uV, according to Ohm's law, the minimum measuring current value of the first current measuring unit 11 can be determined to be 10mA. Therefore, the current measuring range of the first current measuring unit 11 is 10mA~1000mA, and its range span ratio is 100 times.

[0050] Similarly, when the maximum voltage drop corresponding to the current measuring unit is 30mV and the minimum voltage drop corresponding to the current measuring unit is 300uV, the resistance values ​​and single ranges of the second current measuring unit 12 and the third current measuring unit 13 can be determined. The resistance value of the second current measuring unit 12 is 100 times that of the first current measuring unit 11, and the resistance value of the third current measuring unit 13 is 100 times that of the second current measuring unit 12. That is, the resistance value of the second current measuring unit 12 is 3Ω, and its corresponding current measurement range is 100uA~10mA. The resistance value of the third current measuring unit 13 is 300Ω, and its corresponding current measurement range is 1uA~100uA. Furthermore, by superimposing the different measurement ranges of the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13, current measurement for a target current measurement range of 1uA~1000mA can be achieved.

[0051] It should be noted that the maximum voltage drop and the minimum voltage drop corresponding to the current measurement unit can also be other values, which can be selected according to the actual connection circuit, and no specific limitation is made here.

[0052] In some embodiments, the maximum gains of the first operational amplifier 211, the second operational amplifier 212, and the third operational amplifier 213 are all equal, with a maximum gain of 100. The maximum gain of the operational amplifier is determined based on the full-scale voltage of the voltage acquisition module 5 connected to the operational amplifier. Specifically, if the full-scale voltage of the voltage acquisition module 5 is 3.3V, and the maximum voltage drop of the current measurement unit is 30mV, then the maximum gain of the operational amplifier is G = 3300mV / 30mV = 110. Considering that the operational amplifier needs to reserve a certain parameter margin, the maximum gain of the operational amplifier can be selected as G = 100, and the maximum output voltage of the operational amplifier is 30mV * 100 = 3.0V.

[0053] In one specific implementation, such as Figure 2As shown, the voltage comparison subunit 22 includes a first voltage comparator 221, a voltage comparison component 222, and a second voltage comparator 223. The non-inverting input of the first voltage comparator 221 is connected to the output of the first operational amplifier 211, and the inverting input of the first voltage comparator 221 is used to receive a first preset voltage value. The output of the first voltage comparator 221 is connected to the input of the range switching unit 41. The input of the voltage comparison component 222 is connected to the output of the second operational amplifier 212, and the output of the voltage comparison component 222 is connected to the input of the range switching unit 41. The non-inverting input of the second voltage comparator 223 is connected to the output of the third operational amplifier 213, and the inverting input of the second voltage comparator 223 is used to receive a second preset voltage value. The output of the second voltage comparator 223 is connected to the input of the range switching unit 41.

[0054] Furthermore, the voltage comparison component 222 includes a third voltage comparator 2221 and a fourth voltage comparator 2222; wherein, the non-inverting input terminal of the third voltage comparator 2221 is connected to the output terminal of the second operational amplifier 212, the inverting input terminal of the third voltage comparator 2221 is used to receive a third preset voltage value, and the output terminal of the third voltage comparator 2221 is connected to the input terminal of the range switching unit 41; the non-inverting input terminal of the fourth voltage comparator 2222 is connected to the output terminal of the second operational amplifier 212, the inverting input terminal of the fourth voltage comparator 2222 is used to receive a fourth preset voltage value, and the output terminal of the fourth voltage comparator 2222 is connected to the input terminal of the range switching unit 41.

[0055] In one specific implementation, such as Figure 2 As shown, at least one field-effect transistor includes a first field-effect transistor 31 and a second field-effect transistor 32; wherein, the gate of the first field-effect transistor 31 is connected to the output terminal of the range switching unit 41, the source and drain of the first field-effect transistor 31 are respectively connected to one end of the second current measuring unit 12 and the other end of the third current measuring unit 13, one end of the second current measuring unit 12 is connected to the first current measuring unit 11, and the other end of the third current measuring unit 13 is not connected to the second current measuring unit 12, the gate of the second field-effect transistor 32 is connected to the output terminal of the range switching unit 41, and the source and drain of the second field-effect transistor 32 are respectively connected to the two ends of the third current measuring unit 13.

[0056] In this embodiment, the first preset voltage value and the fourth preset voltage value are equal, both being 30mV, and the third preset voltage value and the second preset voltage value are equal, both being 3V. Therefore, by determining the relationship between the voltage values ​​measured by the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13 and the corresponding preset voltage values, a corresponding level signal is sent to the range switching unit 41. Based on this level signal, the range switching unit 41 controls the opening and closing of the switch module 3 to switch between the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13. This solves the technical problem of being unable to measure current values ​​when the current variation range is large.

[0057] Specifically, the operating logic of the range switching unit 41 is as follows: Since the current measurement range corresponding to the first current measurement unit 11 is 10mA~1000mA, the current measurement range corresponding to the second current measurement unit 12 is 100uA~10mA, and the current measurement range corresponding to the third current measurement unit 13 is 1uA~100uA, when the current on the third current measurement unit 13 exceeds 100uA, it indicates that the current value to be measured is greater than the current measurement range corresponding to the third current measurement unit 13. Then, the voltage value output by the third operational amplifier 213 exceeds 3V, and the second voltage comparator 223 connected to the third operational amplifier 213 outputs a high-level signal. At this time, the range switching unit 41 can send a high-level control signal to the second field-effect transistor 32 based on the high-level signal. The second field-effect transistor 32 is in the conducting state, which can make the third current measurement unit 13 short-circuit, so as to eliminate the possibility of using the third current measurement unit 13 to measure the current value to be measured.

[0058] Secondly, when the current on the second current measuring unit 12 is less than 100uA, it indicates that the current value to be measured is less than the current measurement range corresponding to the second current measuring unit 12. Then, the voltage value output by the second operational amplifier 212 will be less than 30mV. As a result, the fourth voltage comparator 2222 connected to the second operational amplifier 212 outputs a high-level signal. At this time, the range switching unit 41 can send a low-level control signal to the second field-effect transistor 32 based on the high-level signal. The second field-effect transistor 32 is in the off state, so that the third current measuring unit 13 can be in the normal measurement state so that the current value to be measured can be measured using the third current measuring unit 13.

[0059] Furthermore, when the current on the second current measuring unit 12 exceeds 10mA, it indicates that the current value to be measured is greater than the current measurement range corresponding to the second current measuring unit 12. In this case, the voltage value output by the second current measuring unit 12 exceeds 3V, and the third voltage comparator 2221 connected to the second current measuring unit 12 outputs a high-level signal. At this time, the range switching unit 41 can send a high-level control signal to the first field-effect transistor 31 based on the high-level signal. The first field-effect transistor 31 is in the conducting state, which allows the second current measuring unit 12 and the third current measuring unit 13 to be in a short-circuit state so that the first current measuring unit 11 can be used to measure the current value to be measured.

[0060] Furthermore, when the current on the first current measuring unit 11 is less than 10mA, it indicates that the current value to be measured is less than the current measurement range corresponding to the first current measuring unit 11. Then, the voltage value output by the first operational amplifier 211 will be less than 3V, so the first voltage comparator 221 connected to the first operational amplifier 211 outputs a high-level signal. At this time, the range switching unit 41 can send a low-level control signal to the first field-effect transistor 31 based on the high-level signal. The first field-effect transistor 31 is in the off state, so that the second current measuring unit 12 can be in the normal measurement state, so that the current value to be measured can be measured by the second current measuring unit 12.

[0061] In summary, the first current measuring unit 11, the second current measuring unit 12, and the third current measuring unit 13 can be used to ensure that any current value in the current measurement range of 1uA to 1000mA can be accurately measured.

[0062] The above embodiments of this application have the following beneficial effects:

[0063] This application sets up a range switching unit and at least two current measurement units, with each of the at least two current measurement units having a different current measurement range. This allows for the measurement of a wide range of currents using the at least two current measurement units. Furthermore, the range switching unit can be used to switch between the at least two current measurement units to accommodate different current ranges, thereby solving the technical problem of being unable to measure current values ​​when the current variation range is large.

[0064] The structure shown in this embodiment is only a partial structure related to the solution of this application and does not constitute a limitation on the device to which the solution of this application is applied. Specific devices may include more or fewer components than shown, or combinations of certain components, or arrangements of different components. It should be understood that the methods, apparatuses, etc., disclosed in this embodiment can be implemented in other ways.

[0065] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A current measuring device with a range switching function, characterized by comprising: It includes a current measurement module (1), a voltage comparison module (2), a switching module (3) and a total control module (4), wherein the total control module (4) includes a range switching unit (41); The input terminal of the current measurement module (1) is used to receive the current value to be measured. The current measurement module (1) is connected to the input terminal of the voltage comparison module (2). The output terminal of the voltage comparison module (2) is connected to the input terminal of the range switching unit (41). The output terminal of the range switching unit (41) is connected to the control terminal of the switch module (3). The output terminal of the switch module (3) is connected to the current measurement module (1). The current measurement module (1) includes at least two current measurement units, and the voltage comparison module (2) includes at least two voltage comparison units. The current measurement units and the voltage comparison units are set in a one-to-one correspondence, and the current measurement range of each of the at least two current measurement units is different.

2. The current measuring device of claim 1, wherein, The voltage comparison unit includes a voltage amplification subunit (21) and a voltage comparison subunit (22); The first and second input terminals of the voltage amplification subunit (21) are respectively connected to the two ends of the current measurement unit. The output terminal of the voltage amplification subunit (21) is connected to the first input terminal of the voltage comparison subunit (22). The second input terminal of the voltage amplification subunit is used to receive a preset voltage threshold. The output terminal of the voltage amplification subunit is connected to the input terminal of the range switching unit (41).

3. The current measuring device of claim 1, wherein, The switching module (3) includes at least one field-effect transistor; The gate of the field-effect transistor is connected to the output terminal of the range switching unit (41), and the source and drain of the field-effect transistor are respectively connected to the two ends of the current measurement unit.

4. The current measuring device of claim 2, wherein, The current measuring device also includes a voltage acquisition module (5), and the main control module (4) also includes an overcurrent detection unit (42); The input terminal of the voltage acquisition module (5) is connected to the output terminal of the voltage amplification subunit (21), and the output terminal of the voltage acquisition module (5) is connected to the overcurrent detection unit (42).

5. The current measuring device of claim 4, wherein, The current measuring device also includes an on / off control module (6); The control terminal of the on / off control module (6) is connected to the output terminal of the overcurrent detection unit (42), the input terminal of the on / off control module (6) is connected to the output terminal of the current measurement module (1), and the output terminal of the on / off control module (6) is used to connect to the device to be driven (7).

6. The current measuring device of claim 2, wherein, The at least two current measuring units include a first current measuring unit (11), a second current measuring unit (12), and a third current measuring unit (13), wherein the first current measuring unit (11), the second current measuring unit (12), and the third current measuring unit (13) are connected in series.

7. The current measuring device of claim 6, wherein, The voltage amplification subunit (21) includes a first operational amplifier (211), a second operational amplifier (212), and a third operational amplifier (213). The non-inverting and inverting input terminals of the first operational amplifier (211) are respectively connected to the two ends of the first current measurement unit (11). The output terminal of the first operational amplifier (211) is connected to the input terminal of the voltage comparison subunit (22). The non-inverting and inverting input terminals of the second operational amplifier (212) are respectively connected to the two ends of the second current measurement unit (12). The output terminal of the second operational amplifier (212) is connected to the input terminal of the voltage comparison subunit (22). The non-inverting and inverting input terminals of the third operational amplifier (213) are respectively connected to the two ends of the third current measurement unit (13). The output terminal of the third operational amplifier (213) is connected to the input terminal of the voltage comparison subunit (22).

8. The current measuring device of claim 7, wherein, The voltage comparison subunit (22) includes a first voltage comparator (221), a voltage comparison component (222), and a second voltage comparator (223); The non-inverting input of the first voltage comparator (221) is connected to the output of the first operational amplifier (211). The inverting input of the first voltage comparator (221) is used to receive a first preset voltage value. The output of the first voltage comparator (221) is connected to the input of the range switching unit (41). The input of the voltage comparison component (222) is connected to the output of the second operational amplifier (212). The output of the voltage comparison component (222) is connected to the input of the range switching unit (41). The non-inverting input of the second voltage comparator (223) is connected to the output of the third operational amplifier (213). The inverting input of the second voltage comparator (223) is used to receive a second preset voltage value. The output of the second voltage comparator (223) is connected to the input of the range switching unit (41).

9. The current measuring device of claim 8, wherein, The voltage comparison component (222) includes a third voltage comparator (2221) and a fourth voltage comparator (2222); The non-inverting input of the third voltage comparator (2221) is connected to the output of the second operational amplifier (212). The inverting input of the third voltage comparator (2221) is used to receive a third preset voltage value. The output of the third voltage comparator (2221) is connected to the input of the range switching unit (41). The non-inverting input of the fourth voltage comparator (2222) is connected to the output of the second operational amplifier (212). The inverting input of the fourth voltage comparator (2222) is used to receive a fourth preset voltage value. The output of the fourth voltage comparator (2222) is connected to the input of the range switching unit (41).

10. The current measuring device of claim 6, wherein, The at least one field-effect transistor includes a first field-effect transistor (31) and a second field-effect transistor (32); The gate of the first field-effect transistor (31) is connected to the output terminal of the range switching unit (41). The source and drain of the first field-effect transistor (31) are respectively connected to one end of the second current measuring unit (12) and the other end of the third current measuring unit (13). One end of the second current measuring unit (12) is connected to the first current measuring unit (11), and the other end of the third current measuring unit (13) is not connected to the second current measuring unit (12). The gate of the second field-effect transistor (32) is connected to the output terminal of the range switching unit (41), and the source and drain of the second field-effect transistor (32) are respectively connected to the two ends of the third current measuring unit (13).

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