Current detection circuit and switch
By using a Zener diode to extend the common-mode input voltage range of the operational amplifier in the current detection circuit, and combining it with a high-precision chip and precision resistors, the problem of limited measurement range and insufficient accuracy of traditional current detection circuits in high-voltage and high-current application scenarios is solved, achieving efficient and reliable current detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- UNIPOE IOT TECH CO LTD
- Filing Date
- 2025-03-28
- Publication Date
- 2026-07-03
AI Technical Summary
Traditional current detection circuits suffer from limited measurement range and insufficient accuracy in high-voltage and high-current applications, and are difficult to adapt to different voltage and current range requirements, lacking flexibility and scalability.
The power supply voltage of the operational amplifier is clamped by a Zener diode, which expands its common-mode input voltage range. Combined with a high-precision current, voltage and power monitoring chip and precision resistors, the accuracy and stability of current detection are improved.
It achieves efficient and reliable current detection in high-voltage environments ranging from 40V to 400V, expands the common-mode input voltage range of the operational amplifier, and improves measurement accuracy and circuit reliability.
Smart Images
Figure CN224456874U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of switches, and more particularly to a current detection circuit and a switch. Background Technology
[0002] In modern electronic systems, current sensing circuits are commonly used to monitor load current to achieve functions such as overcurrent protection, power measurement, and system monitoring. Traditional current sensing circuits typically use shunt resistors to detect current, indirectly obtaining current information by measuring the voltage drop across the shunt resistor. However, traditional current sensing circuits have some limitations in high-voltage, high-current applications.
[0003] For example, traditional current sensing circuits are typically based on low-voltage operational amplifiers with a narrow common-mode input voltage range, making them unsuitable for high-voltage environments. In some industrial applications, power supply voltages can reach hundreds of volts, and the input voltage range of traditional operational amplifiers often cannot meet the demands of such high-voltage sensing. Under high-voltage, high-current conditions, traditional current sensing circuits may be affected by electromagnetic interference and noise, leading to decreased measurement accuracy. Furthermore, the accuracy and stability of the resistors and operational amplifiers used in traditional circuits may also limit measurement precision. To achieve high-voltage current sensing, traditional methods may require complex circuit designs, such as using isolation transformers and optocouplers for signal isolation, increasing circuit complexity and cost. In high-voltage applications, circuits are susceptible to overvoltage, overcurrent, and other abnormal conditions, and traditional current sensing circuits may lack sufficient protection, leading to circuit damage or system failure. Traditional current sensing circuit designs are typically tailored to specific voltage ranges and application scenarios, making it difficult to adapt to different voltage and current range requirements, lacking flexibility and scalability.
[0004] No effective solution has yet been proposed to address the above problems. Utility Model Content
[0005] This application provides a current detection circuit and switch to at least solve the technical problems of limited measurement range and insufficient accuracy of existing current detection circuits in high-voltage and high-current application scenarios.
[0006] According to one aspect of the embodiments of this application, a current detection circuit is provided, comprising: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first Zener diode, a second Zener diode, a MOSFET, an operational amplifier, and a chip; wherein: the first resistor is disposed on a line between a power supply and a load; the first end of the second resistor is connected to the line between the power supply and the first resistor, and the second end of the second resistor is connected to the negative input terminal of the operational amplifier and the source terminal of the MOSFET; the first end of the third resistor is connected to the line between the load and the first resistor, and the second end of the third resistor is connected to the positive input terminal of the operational amplifier; the first end of the fourth resistor is connected to the negative input terminal of the operational amplifier and the positive terminal of the first Zener diode. The connection is as follows: the first end of the fourth resistor is grounded; the common terminal of the first Zener diode connected to the positive input terminal of the operational amplifier is connected to the line between the power supply and the first resistor; the first end of the fifth resistor is connected to the drain of the MOSFET, the second end of the fifth resistor is grounded, and the gate of the MOSFET is connected to the output terminal of the operational amplifier; the first input terminal of the chip is connected to the first end of the fifth resistor, and the second input terminal of the chip is connected to the second end of the fifth resistor; one end of the sixth and seventh resistors connected in series is connected to the line between the power supply and the first resistor, and the other end of the series connection is grounded; the first end of the second Zener diode is connected to the line between the sixth and seventh resistors, and the second end of the second Zener diode is grounded.
[0007] Optionally, the first resistor is a shunt resistor.
[0008] Optionally, both the second resistor and the third resistor are sampling resistors, which are used to detect current.
[0009] Optionally, the fourth resistor is a current-limiting resistor, which is used to limit the current flowing through the first Zener diode.
[0010] Optionally, the fifth resistor is a feedback resistor, which is used for signal amplification.
[0011] Optionally, both the sixth resistor and the seventh resistor are voltage divider resistors, which are used for voltage division and current limiting.
[0012] Optionally, the first Zener diode is used to clamp the supply voltage of the operational amplifier and extend the common-mode input voltage range; the second Zener diode is used to clamp the input voltage and protect the circuit.
[0013] Optionally, the MOS transistor is a PMOS transistor, which is used for isolation and signal transmission.
[0014] Optionally, the common-mode input voltage range of the operational amplifier is 40V to 400V.
[0015] According to another aspect of the embodiments of this application, a switch is also provided, the switch including the current detection circuit described above.
[0016] In this embodiment, by using a Zener diode to clamp the operational amplifier's supply voltage, the common-mode input voltage range of the operational amplifier is extended, enabling it to adapt to high-voltage environments from 40V to 400V. By employing a high-precision current, voltage, and power monitoring chip, combined with precision resistors, the accuracy and stability of current detection are improved. This solves the technical problems of limited measurement range and insufficient accuracy in existing current detection circuits in high-voltage, high-current applications, achieving the technical effects of extending the common-mode input voltage range of the operational amplifier, improving measurement accuracy, and thus realizing efficient and reliable current detection functionality. Attached Figure Description
[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0018] Figure 1 A schematic diagram of a current detection circuit provided in an embodiment of this application;
[0019] Figure 2 This is a schematic diagram of another current detection circuit provided in an embodiment of this application.
[0020] The above figures include the following reference numerals:
[0021] AC, power supply; Load, load; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; D1, first Zener diode; D2, second Zener diode; Q1, MOSFET; U1, operational amplifier; U2, chip. Detailed Implementation
[0022] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that embodiments of this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the embodiments of this application. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this application.
[0023] According to one aspect of the embodiments of this application, a current detection circuit is provided that is suitable for high-voltage, high-current industrial applications. The circuit extends the common-mode input voltage range of the operational amplifier through a Zener diode, enabling the measurement of voltages up to 400V.
[0024] Figure 1 This is a schematic diagram of a current detection circuit provided in an embodiment of this application, as shown below. Figure 1 As shown, the current detection circuit includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a first Zener diode D1, a second Zener diode D2, a MOSFET Q1, an operational amplifier U1, and a chip U2; wherein:
[0025] The first resistor R1 is placed on the line between the power supply AC and the load Load; wherein, the voltage provided by the power supply AC includes, but is not limited to, 400V; the load Load is a component or device in the circuit that consumes electrical energy. In this current detection circuit, one end of the load is used to connect to the power supply, and the other end is used to ground.
[0026] The first end of the second resistor R2 is connected to the line between the power supply AC and the first resistor R1, and the second end of the second resistor R2 is connected to the negative input terminal of the operational amplifier U1 and the source of the MOSFET Q1, respectively.
[0027] The first end of the third resistor R3 is connected to the line between the load Load and the first resistor R1, and the second end of the third resistor R3 is connected to the positive input terminal of the operational amplifier U1.
[0028] The first end of the fourth resistor R4 is connected to the negative input terminal of the power supply of the operational amplifier U1 and the positive terminal of the first Zener diode D1. The first end of the fourth resistor R4 is used for grounding. The common terminal after the negative terminal of the first Zener diode D1 is connected to the positive input terminal of the power supply of the operational amplifier U1 is connected to the line between the power supply AC and the first resistor R1.
[0029] The first end of the fifth resistor R5 is connected to the drain of the MOSFET Q1, the second end of the fifth resistor R5 is grounded, and the gate of the MOSFET Q1 is connected to the output of the operational amplifier U1.
[0030] The first input terminal of chip U2 is connected to the first terminal of the fifth resistor R5, and the second input terminal of chip U2 is connected to the second terminal of the fifth resistor R5; chip U2 is a high-precision current, voltage and power monitoring chip.
[0031] One end of the series connection between the sixth resistor R6 and the seventh resistor R7 is connected to the line between the power supply AC and the first resistor R1, while the other end is grounded. The first end of the second Zener diode D2 is connected to the line between the sixth resistor R6 and the seventh resistor R7, and the second end of the second Zener diode D2 is grounded. By incorporating voltage divider resistors and Zener diodes, the circuit's overvoltage and overcurrent protection capabilities are enhanced, improving its reliability.
[0032] In this embodiment, by using a Zener diode to clamp the operational amplifier's supply voltage, the common-mode input voltage range of the operational amplifier is extended, enabling it to adapt to high-voltage environments from 40V to 400V. By employing a high-precision current, voltage, and power monitoring chip, combined with precision resistors, the accuracy and stability of current detection are improved. This solves the technical problems of limited measurement range and insufficient accuracy in existing current detection circuits in high-voltage, high-current applications, achieving the technical effects of extending the common-mode input voltage range of the operational amplifier, improving measurement accuracy, and thus realizing efficient and reliable current detection functionality.
[0033] As an optional embodiment, the first resistor R1 is a shunt resistor; wherein, the resistance value of the shunt resistor can be selected according to the needs of the application scenario; the shunt resistor is used to measure current, and by converting the current signal into a voltage signal, it is convenient for detection, control and protection circuits.
[0034] As an optional embodiment, both the second resistor R2 and the third resistor R3 are sampling resistors used to detect current. The resistance values of the second resistor R2 and the third resistor R3 are different, but their resistance values can be selected according to the needs of the application scenario. For example, the resistance value of the second resistor R2 can be 10Ω, and the resistance value of the third resistor R3 can be 10kΩ.
[0035] As an optional embodiment, the fourth resistor R4 is a current-limiting resistor, which is used to limit the current flowing through the first Zener diode D1; wherein, the resistance value of the current-limiting resistor can be selected according to the needs of the application scenario.
[0036] As an optional embodiment, the fifth resistor R5 is a feedback resistor used for signal amplification; the resistance value of the feedback resistor can be selected according to the needs of the application scenario, for example, the resistance value of the feedback resistor can be 10Ω.
[0037] As an optional embodiment, both the sixth resistor R6 and the seventh resistor R7 are voltage divider resistors, which are used for voltage division and current limiting. The resistance values of the sixth resistor R6 and the seventh resistor R7 are different, but their resistance values can be selected according to the needs of the application scenario. For example, the resistance value of the sixth resistor R6 can be 300kΩ, and the resistance value of the third resistor R3 can be 4.75kΩ.
[0038] As an optional embodiment, the first Zener diode D1 is used to clamp the supply voltage of the operational amplifier U1, expanding the common-mode input voltage range; the second Zener diode D2 is used to clamp the input voltage and protect the circuit. The first Zener diode D1 and the second Zener diode D2 can be selected according to the application requirements; for example, the Zener diode D1 can have a Zener voltage of 5.1V, and the Zener diode D2 can have a Zener voltage of 36V.
[0039] As an optional embodiment, MOSFET Q1 is a PMOS transistor, which is used for isolation and signal transmission; wherein, the PMOS transistor can be selected according to the needs of the application scenario, for example, the PMOS transistor can be a P-channel field-effect transistor with a rated voltage of 600V.
[0040] As an optional embodiment, the common-mode input voltage range of operational amplifier U1 is 40V to 400V.
[0041] Figure 2 A schematic diagram of another current detection circuit provided in an embodiment of this application is shown below. Figure 2 As shown, in this current detection circuit, a voltage drop (Vsense) is generated when current flows through R2, and this voltage drop is proportional to the current flowing through it. Due to the presence of negative feedback, the virtual short and virtual open conditions of operational amplifier U1 are met. Because of the "virtual short," Vp = Vn. And because of the "virtual open," almost no current flows into the non-inverting and inverting input terminals, so Vp = V2. Also because of the "virtual short," Vn = Vp = V2, the voltage across R2 is equal to V1 - V2 (Vsense in the diagram), which is equal to the voltage across the current sampling resistor Rsense. Since MOSFET Q1 is a voltage-controlled device, almost no current flows from its gate into R5, so the voltage across R5 is equal to R5 * (Vsense / R2). Since R5 and R2 have the same value, VR2 = Vsense.
[0042] It should be noted that, in Figure 2In the operational amplifier U1 shown, 1 represents the output terminal of operational amplifier U1; 2 represents the negative input terminal of operational amplifier U1; 3 represents the positive input terminal of operational amplifier U1, also known as the non-inverting input terminal; 4 represents the negative input terminal of operational amplifier U1, also known as the inverting input terminal; and 5 represents the positive input terminal of operational amplifier U1.
[0043] This application's embodiments extend the common-mode input range of the operational amplifier by changing its supply voltage. This design approach offers strong flexibility and scalability. The selection of the Zener diode and circuit parameters can be adjusted according to different application scenarios and voltage range requirements, thereby adapting to a wider range of current sensing needs. This design overcomes the voltage limitations of traditional operational amplifiers, making them suitable for high-voltage environments.
[0044] According to another aspect of the embodiments of this application, a switch is also provided, which includes the current detection circuit provided in the embodiments of this application. Therefore, the switch includes all the technical effects of the aforementioned current detection circuit. Since the technical effects of the current detection circuit have been described in detail above, they will not be repeated here.
[0045] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.
[0046] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.
[0047] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A current detection circuit, characterized by, include: The system comprises: a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7), a first Zener diode (D1), a second Zener diode (D2), a MOSFET (Q1), an operational amplifier (U1), and a chip (U2); where: The first resistor (R1) is placed on the line between the power supply (AC) and the load (Load); The first end of the second resistor (R2) is connected to the line between the power supply (AC) and the first resistor (R1), and the second end of the second resistor (R2) is connected to the negative input terminal of the operational amplifier (U1) and the source of the MOS transistor (Q1). The first end of the third resistor (R3) is connected to the line between the load and the first resistor (R1), and the second end of the third resistor (R3) is connected to the positive input terminal of the operational amplifier (U1). The first end of the fourth resistor (R4) is connected to the negative input terminal of the power supply of the operational amplifier (U1) and the positive terminal of the first Zener diode (D1). The first end of the fourth resistor (R4) is used for grounding. The common terminal of the first Zener diode (D1) after being connected to the positive input terminal of the power supply of the operational amplifier (U1) is connected to the line between the power supply (AC) and the first resistor (R1). The first end of the fifth resistor (R5) is connected to the drain of the MOS transistor (Q1), the second end of the fifth resistor (R5) is grounded, and the gate of the MOS transistor (Q1) is connected to the output of the operational amplifier (U1). The first input terminal of the chip (U2) is connected to the first terminal of the fifth resistor (R5), and the second input terminal of the chip (U2) is connected to the second terminal of the fifth resistor (R5). One end of the sixth resistor (R6) and the seventh resistor (R7) connected in series is connected to the line between the power supply (AC) and the first resistor (R1), and the other end of the series connection is grounded. The first end of the second Zener diode (D2) is connected to the line between the sixth resistor (R6) and the seventh resistor (R7), and the second end of the second Zener diode (D2) is grounded.
2. The current sense circuit of claim 1, wherein, The first resistor (R1) is a shunt resistor.
3. The current detection circuit according to claim 1, characterized in that, The second resistor (R2) and the third resistor (R3) are both sampling resistors, which are used to detect current.
4. The current sense circuit of claim 1, wherein, The fourth resistor (R4) is a current-limiting resistor, which is used to limit the current flowing through the first Zener diode (D1).
5. The current sense circuit of claim 1, wherein, The fifth resistor (R5) is a feedback resistor, which is used for signal amplification.
6. The current sense circuit of claim 1, wherein, The sixth resistor (R6) and the seventh resistor (R7) are both voltage divider resistors, which are used for voltage division and current limiting.
7. The current sense circuit of claim 1, wherein, The first Zener diode (D1) is used to clamp the supply voltage of the operational amplifier (U1) and extend the common-mode input voltage range; the second Zener diode (D2) is used to clamp the input voltage and protect the circuit.
8. The current sense circuit of claim 1, wherein, The MOS transistor (Q1) is a PMOS transistor, which is used for isolation and signal transmission.
9. The current sense circuit of any one of claims 1 to 8, wherein, The common-mode input voltage range of the operational amplifier (U1) is 40V to 400V.
10. A switch, characterized by The switch includes the current detection circuit according to any one of claims 1 to 9.