High-precision current detection circuit
By designing a high-precision current detection circuit including a constant current module, a driving module and a current detection module, the problem of complex structure or low accuracy of conventional current detection circuits is solved, and the current detection effect with high precision and simple structure is achieved.
Patent Information
- Application Number
- CN202420716378.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-09
- Publication Date
- 2025-02-18
- Estimated Expiration
- 2034-04-09
AI Technical Summary
In high-power electronic products, conventional current detection circuits are complex in structure or have low accuracy, and cannot meet the needs of high precision and simple structure at the same time.
A high-precision current detection circuit is designed, including a constant current module, a driving module and a current detection module. The constant current module provides a constant current to the current detection module, and uses components such as operational amplifiers and NMOS tubes to achieve the first current. Test.
It realizes high accuracy and structural simplicity of current detection, can effectively detect overcurrent and undercurrent of loads, and meets the needs of multi-scenario applications.
Smart Images
Figure CN222506418U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of semiconductor integrated circuits, and in particular to a current detection circuit. Background Art
[0002] In some high-power electronic products, such as atomizers, if the device is loaded with too much current, it is easy to cause the electronic product device to burn out, or even cause the circuit to catch fire, causing a safety accident. Therefore, the chip often requires a current detection function in the design. However, conventional current detection or circuit structure is complex, or the accuracy is not high, and it cannot meet the requirements of high precision and simple structure at the same time.
[0003] In order to solve the above problems, people have been looking for an ideal technical solution that can simplify the circuit structure and still ensure the accuracy and sensitivity of current detection. Utility Model Content
[0004] In view of this, the utility model provides a high-precision current detection circuit, including a constant current module, a driving module and a current detection module;
[0005] The driving module is electrically connected to the load and the current detection module, and is used to provide a first current to the load and a second current to the current detection module, wherein the first current is n times the second current, and n is a positive number;
[0006] The constant current module is connected to the current detection module and is used to provide a constant current to the current detection module;
[0007] The current detection module is used to detect the first current.
[0008] In some possible implementations, the driving module includes a first port and a second port, the first port outputs a first current, the second port outputs a second current, and the current detection module includes a first operational amplifier, a first NMOS transistor, a second NMOS transistor, and an inverter;
[0009] The inverting input terminal of the first operational amplifier is electrically connected to the load, and is electrically connected to the first port of the driving module with the load, the non-inverting input terminal of the first operational amplifier is connected to the second port of the driving module, and the output terminal of the first operational amplifier is connected to the gate of the first NMOS tube and the gate of the second NMOS tube;
[0010] The source of the first NMOS tube is grounded, and the drain is electrically connected to the non-inverting input terminal of the first operational amplifier, and is electrically connected to the second port of the driving module with the non-inverting input terminal of the first operational amplifier;
[0011] The source of the second NMOS tube is grounded, the drain is electrically connected to the input end of the inverter, and the drain is electrically connected to the constant current module with the input end of the inverter.
[0012] In some possible implementations, the constant current module includes a second operational amplifier, a first PMOS transistor, a second PMOS transistor, and a resistor R;
[0013] The inverting input terminal of the second operational amplifier is connected to the reference voltage, the non-inverting input terminal of the second operational amplifier is grounded through a resistor R, and the output terminal of the operational amplifier is electrically connected to the gate of the first PMOS tube and the gate of the second PMOS tube;
[0014] The source of the first PMOS tube is connected to the operating voltage, and the drain is grounded through a resistor R;
[0015] The source of the second PMOS tube is connected to the working voltage, and the drain is connected to the current detection module.
[0016] In some possible implementations, the high-precision current detection circuit also includes a control module, which is electrically connected to the drive module and the current detection module and is used to control the drive module to stop providing the first current to the load when the current detection module detects that the first current is in an overcurrent state.
[0017] The present application provides a high-precision current detection circuit, including a constant current module, a driving module and a current detection module, wherein the driving module is electrically connected to a load and the current detection module, and is used to provide a first current to the load and a first current and a second current to the current detection module, wherein the constant current module is connected to the current detection module, and is used to provide a constant current to the current detection module, and the current detection module is used to detect the first current. The high-precision current detection circuit provided by the present application has a simple structure and high detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0019] in:
[0020] Figure 1 A schematic diagram of the structure of a high-precision current detection circuit provided in this application;
[0021] Figure 2 A schematic diagram of the structure of another high-precision current detection circuit provided by the present application;
[0022] Figure 3 A schematic diagram of the structure of another high-precision current detection circuit provided in this application.
[0023] Figure 4 A schematic diagram of another high-precision current detection circuit provided in this application DETAILED DESCRIPTION
[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0025] It should be understood that the references to "one embodiment" or "some embodiments" throughout the specification mean that specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present application. Therefore, the references to "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0026] The present application discloses a high-precision current detection circuit, such as Figure 1 As shown, it includes a constant current module 100, a driving module 300 and a current detection module 200, wherein the driving module 300 is electrically connected to the load 400 and the current detection module 200, and is used to provide a first current to the load 400 and a second current to the current detection module 200, the first current is n times the second current, the constant current module 100 is connected to the current detection module 200, and is used to provide a constant current to the current detection module 200, and the current detection module 200 is used to detect the first current.
[0027] In this embodiment, the first current is the current flowing through the load 400 (ie, the current to be detected), the first current is n times the second current, n is a positive number, the load 400 is a resistive load, and the current detection module 200 detects the first current.
[0028] In some embodiments, Figure 2As shown, the driving module 300 includes a first port 301 and a second port 302 , and the current detection module 200 includes a first operational amplifier OPA1 , a first NMOS transistor MN1 , a second NMOS transistor MN2 and an inverter INV. Among them, the inverting input terminal of the first operational amplifier OPA1 is electrically connected to the load 400, and is electrically connected to the first port 301 of the driving module 300 with the load 400, the non-inverting input terminal of the first operational amplifier OPA1 is connected to the second port 302 of the driving module 300, the output terminal of the first operational amplifier OPA1 is connected to the gate of the first NMOS tube MN1 and the gate of the second NMOS tube MN2, the source of the first NMOS tube MN1 is grounded, the drain is electrically connected to the non-inverting input terminal of the first operational amplifier OPA1, and is electrically connected to the second port 302 of the driving module 300 with the non-inverting input terminal of the first operational amplifier OPA1, the source of the second NMOS tube MN2 is grounded, the drain of the second NMOS tube MN2 is electrically connected to the inverter INV, and the drain and the input terminal of the inverter INV are electrically connected to the constant current module 100.
[0029] In this embodiment, when the resistance of the load 400 decreases, the first current increases, and there is a fixed multiple relationship between the first current and the second current. Therefore, the second current increases, the output voltage of the first operational amplifier OPA1 also increases, the gate voltage of the second NMOS tube MN2 increases, and the drain of the second NMOS tube MN2 is electrically connected to the constant current module 100, and the current of the second NMOS tube MN2 remains unchanged, so the drain-source voltage of the second NMOS tube MN2 decreases. When the drain-source voltage of the second NMOS tube MN2 decreases to be lower than the flip voltage of the inverter INV, the output of the inverter INV changes from low to high.
[0030] When the resistance of the load 400 increases, the first current will decrease, and the multiple relationship between the first current and the second current is fixed, so the second current decreases, the output voltage of the first operational amplifier OPA1 also decreases, the gate voltage of the second NMOS tube MN2 decreases, and the drain of the second NMOS tube MN2 is electrically connected to the constant current module 100, that is, the current of the second NMOS tube MN2 remains unchanged, so the drain-source voltage of the second NMOS tube MN2 increases. When the drain-source voltage of the second NMOS tube MN2 increases to a value higher than the flip voltage of the inverter INV, the output Y of the inverter INV changes from high to low.
[0031] In this embodiment, when the current flowing through the load 400 is too large (i.e., overcurrent), the output of the inverter INV in the current detection module 200 changes from low to high; when the current flowing through the load 400 is too small (i.e., undercurrent), the output of the inverter INV changes from high to low. It can detect the overcurrent condition of the load 400, and can also detect the undercurrent condition of the load 400, meeting the application requirements of multiple scenarios, and has a simple structure and high detection accuracy.
[0032] In some embodiments, the constant current module 100 includes a second operational amplifier OPA2, a first PMOS tube MP1, a first PMOS tube MP2, and a resistor R. The inverting input terminal of the second operational amplifier OPA2 is connected to the reference voltage VREF, the non-inverting input terminal of the second operational amplifier OPA2 is grounded through the resistor R, the output terminal of the second operational amplifier OPA2 is connected to the gate of the first PMOS tube MP1 and the gate of the second PMOS tube MP2, the source of the first PMOS tube MP1 is connected to the working voltage VDD, the drain of the first PMOS tube MP1 is grounded through the resistor R, the source of the second PMOS tube MP2 is connected to the working voltage VDD, and the drain of the second PMOS tube MP2 is connected to the current detection module 200, so as to provide a constant current for the current detection module 200.
[0033] In this embodiment, the magnitude of the first current corresponding to the flip voltage point of the inverter INV depends on the current provided by the constant current module 100 to the current detection module 200. Because the reference voltage VREF and the resistor R remain unchanged under different operating voltages VDD, the first current corresponding to the flip voltage point of the inverter INV also remains unchanged.
[0034] Table 1 shows the simulation results of the first current corresponding to the flip voltage point of the inverter INV under different working voltages VDD (2.6-4.2V) of the high-precision current detection circuit provided in the present application.
[0035] Working voltage VDD 2.6V 2.9V 3.2V 3.7V 4.2V The first current corresponding to the inverter INV flip voltage point 8.7A 8.7A 8.6A 8.6A 8.6A
[0036] Table 1
[0037] As shown in Table 1, for different operating voltages VDD (2.6-4.2V), the first current corresponding to the inverter INV flip voltage point is 8.6-8.7A, with a deviation of only 0.1A and high accuracy.
[0038] In some embodiments, Figure 4 As shown, the high-precision current detection circuit provided in the present application also includes a control module 500, which is electrically connected to the drive module 300 and the current detection module 200, and is used to control the drive module 300 to stop providing the first current to the load 400 when the current detection module 200 detects that the first current is in an overcurrent state (that is, the first current is too large).
[0039] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not intended to limit the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the utility model should be included in the protection scope of the claims of the utility model.
Claims
1. A high-precision current detection circuit, comprising a constant current module, a driving module and a current detection module, characterized in that: The driving module is electrically connected to the load and the current detection module, and is used to provide a first current to the load and a second current to the current detection module, wherein the first current is n times the second current, and n is a positive number; The constant current module is connected to the current detection module and is used to provide a constant current for the current detection module; The current detection module is used to detect the first current.
2. The high-precision current detection circuit according to claim 1, characterized in that: The driving module includes a first port and a second port, the first port outputs the first current, the second port outputs the second current, and the current detection module includes a first operational amplifier, a first NMOS tube, a second NMOS tube and an inverter; The inverting input terminal of the first operational amplifier is electrically connected to the load, and connected to the first port of the driving module with the load, the non-inverting input terminal of the first operational amplifier is connected to the second port of the driving module, and the output terminal of the first operational amplifier is connected to the gate of the first NMOS tube and the gate of the second NMOS tube; The source of the first NMOS tube is grounded, and the drain is electrically connected to the non-inverting input terminal of the first operational amplifier, and is electrically connected to the second port of the driving module with the non-inverting input terminal of the first operational amplifier; The source of the second NMOS tube is grounded, the drain is electrically connected to the input end of the inverter, and the drain is electrically connected to the constant current module with the input end of the inverter.
3. The high-precision current detection circuit according to claim 1 or 2, characterized in that: The constant current module includes a second operational amplifier, a first PMOS tube, a second PMOS tube and a resistor R; The inverting input terminal of the second operational amplifier is connected to a reference voltage, the non-inverting input terminal of the second operational amplifier is grounded through the resistor R, and the output terminal of the operational amplifier is electrically connected to the gate of the first PMOS tube and the gate of the second PMOS tube; The source of the first PMOS tube is connected to the operating voltage, and the drain is grounded through the resistor R; The source of the second PMOS tube is connected to the working voltage, and the drain is electrically connected to the current detection module.
4. The high-precision current detection circuit according to claim 1 or 2, characterized in that: Also includes: A control module is electrically connected to the driving module and the current detection module, and is used to control the driving module to stop providing the first current to the load when the current detection module detects that the first current is in an overcurrent state.