Surge protection circuits, switching power supplies and electronic equipment

Abstract

This invention provides a surge protection circuit, a switching power supply, and an electronic device. The surge protection circuit includes a transient voltage suppressor (VT) transistor, an overvoltage protection circuit, and a resistor. The first terminal of the VT transistor is connected to the power supply line, and the second terminal is connected to the ground line. The VT transistor is adapted to form a first surge discharge path. The first terminal of the overvoltage protection circuit is connected to the first terminal of the VT transistor. The first terminal of the resistor is connected to the second terminal of the overvoltage protection circuit. Connecting the second terminal of the resistor to the VT transistor improves the reliability of surge protection and reduces costs.

Description

Technical Field

[0001] This utility model generally relates to the field of electronic circuit technology, and in particular to a surge protection circuit, a switching power supply and an electronic device. Background Technology

[0002] Surge protection circuits are widely used in various electronic devices to protect them from damage caused by surges. Improving the reliability of surge protection while reducing costs is the technical problem this invention aims to solve.

[0003] The content of the background section is merely the technology known to the inventor and does not necessarily represent the prior art in this field. Utility Model Content

[0004] In view of one or more of the problems existing in the prior art, the present invention provides a surge protection circuit that can improve the reliability of surge protection and reduce costs.

[0005] The surge protection circuit includes a transient voltage suppressor (VT) transistor, an overvoltage protection circuit, and a resistor. The first terminal of the VT transistor is connected to a power supply line, and the second terminal is connected to ground. The VT transistor is adapted to form a first surge discharge path. The first terminal of the overvoltage protection circuit is connected to the first terminal of the VT transistor. The first terminal of the resistor is connected to the second terminal of the overvoltage protection circuit, and the second terminal of the resistor is connected to the second terminal of the VT transistor. The resistor is adapted to form a second surge discharge path.

[0006] Optionally, the negative terminal of the transient voltage suppressor is connected to the power supply line, and the positive terminal of the transient voltage suppressor is connected to the ground line; the transient voltage suppressor is a unidirectional transient voltage suppressor.

[0007] Optionally, the on-resistance of the transient voltage suppressor is less than the resistance value of the resistor.

[0008] Optionally, the resistance value of the resistor is less than or equal to the impedance of the overvoltage protection circuit.

[0009] Optionally, the third terminal of the overvoltage protection circuit is adapted to be connected to a subsequent circuit or load.

[0010] Optionally, the overvoltage protection circuit includes: a first switching transistor, a first terminal of which is connected to a first terminal of the overvoltage protection circuit, a second terminal and a third terminal of which are connected to power ground, a first terminal of which is connected to power ground, and the resistor and the first switching transistor are adapted to form a first sub-path of the second surge discharge path.

[0011] Optionally, the overvoltage protection circuit includes: a second switching transistor, a first terminal of which is connected to a third terminal of the overvoltage protection circuit, a second terminal and a third terminal of which are connected to the power ground, and the second switching transistor and the resistor being adapted to form a second sub-path of the second surge discharge path.

[0012] Optionally, the overvoltage protection circuit further includes a third switching transistor, wherein the first and second terminals of the third switching transistor are respectively connected to the first terminals of the first switching transistor and the second switching transistor.

[0013] Optionally, the overvoltage protection circuit further includes a control circuit, wherein a first terminal of the control circuit is connected to the control terminal of the third switching transistor, and a second terminal of the control circuit is connected to the power ground.

[0014] Optionally, the first and second switching transistors include N-type metal-oxide-semiconductor field-effect transistors with their gates grounded; the third switching transistor includes a metal-oxide-semiconductor field-effect transistor.

[0015] This invention also provides a switching power supply. The switching power supply includes the surge protection circuit described above.

[0016] This invention also provides an electronic device. The electronic device includes the switching power supply described above.

[0017] The surge protection circuit of this invention can effectively discharge surges without blocking the path of external negative pressure into the overvoltage protection circuit or cutting off the path of static electricity discharge. This allows the overvoltage protection circuit to work continuously, improving the reliability of the surge protection circuit and reducing circuit complexity and cost. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 A structural block diagram of an exemplary surge protection circuit consistent with some embodiments of the present invention is shown.

[0020] Figure 2 A structural block diagram of an exemplary surge protection circuit consistent with some embodiments of the present invention is shown.

[0021] Figure 3 A structural block diagram of an exemplary switching power supply consistent with some embodiments of the present invention is shown.

[0022] Figure 4A structural block diagram of an exemplary electronic device consistent with some embodiments of the present invention is shown. Detailed Implementation

[0023] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0024] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "coupling" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The following provides many different embodiments or examples for implementing various structures of this invention. To simplify the invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0028] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0029] This invention provides a surge protection circuit. The surge protection circuit includes a transient voltage suppressor (TVS), an overvoltage protection circuit (OVP), and a resistor. The first terminal of the TVS is connected to a power supply line. The second terminal of the TVS is connected to ground. The TVS is adapted to form a first surge discharge path. The first terminal of the overvoltage protection circuit is connected to the first terminal of the TVS. The first terminal of the resistor is connected to the second terminal of the overvoltage protection circuit. The second terminal of the resistor is connected to the second terminal of the TVS. The resistor is adapted to form a second surge discharge path.

[0030] The surge protection circuit of this invention can effectively discharge surges without blocking the path of external negative pressure into the overvoltage protection circuit or cutting off the path of static electricity discharge. This allows the overvoltage protection circuit to work continuously, improving the reliability of the surge protection circuit and the customer experience, while reducing circuit complexity and cost.

[0031] Figure 1A structural block diagram of an exemplary surge protection circuit 10, consistent with some embodiments of the present invention, is shown. For example... Figure 1 As shown, the surge protection circuit 10 includes a transient voltage suppressor (TVS), an overvoltage protection circuit (OVP), and a resistor R. The first terminal of the TVS is connected to the power supply line L1. The second terminal of the TVS is connected to the ground line L2. The TVS is adapted to form a first surge discharge path r1. That is, ground line L2—TVS—power supply line L1 form the first surge discharge path r1. The first terminal of the OVP is connected to the first terminal of the TVS. The first terminal of the resistor R is connected to the second terminal of the OVP. The second terminal of the resistor R is connected to the second terminal of the TVS. The resistor R is adapted to form a second surge discharge path r2. That is, ground line L2—resistor R—OVP—power supply line L1 form the second surge discharge path r2. The third terminal of the OVP is adapted to connect to the subsequent circuit NC or the load LOAD. Figure 1 As shown, the subsequent circuit NC or load LOAD is connected to the third terminal of the overvoltage protection circuit OVP and the second terminal of the resistor R.

[0032] In some embodiments, such as Figure 1 As shown, the negative terminal (first terminal) of the transient voltage suppressor (TVS) is connected to the power supply line L1, and the positive terminal (second terminal) of the TVS is connected to the ground line L2. The first terminal (input terminal) of the overvoltage protection circuit OVP is connected to the negative terminal of the TVS. The TVS is a unidirectional transient voltage suppressor. That is, the ground line L2—TVS positive terminal—TVS negative terminal—power supply line L1 form the first surge discharge path r1. By discharging the surge through the first surge discharge path r1, the negative voltage impact of the surge on the overvoltage protection circuit OVP can be effectively reduced or even avoided, improving reliability and safety.

[0033] In some embodiments, such as Figure 1 As shown, the first terminal of resistor R is connected to the second terminal of the overvoltage protection circuit OVP. The second terminal of resistor R is connected to the positive terminal of the transient voltage suppressor (TVS). Ground line L2—resistor R—overvoltage protection circuit OVP—power line L1 form a second surge discharge path r2. This second surge discharge path r2, formed by resistor R, not only discharges surges but also does not block negative voltage from entering the overvoltage protection circuit OVP. It also increases the overall impedance of the negative voltage circuit of the overvoltage protection circuit OVP, reducing the current at the negative terminal of the overvoltage protection circuit OVP. This allows the overvoltage protection circuit OVP to operate continuously with low power consumption, improving the reliability and stability of the surge protection circuit and enhancing the customer experience.

[0034] In some embodiments, the resistor R can be selected from common materials, without the need for a special resistance value, ensuring that the resistor R has sufficient cost advantage. For example, the resistance value of the resistor R can be any value within the range of 5~100mΩ, 1~10Ω, or other resistance values. This invention is not limited to these; in practical applications, a suitable resistor can be selected according to requirements.

[0035] In some embodiments, the on-resistance of the transient voltage suppressor (TVS) is less than the resistance of the resistor R. In other words, the resistance of the resistor R is greater than the on-resistance of the TVS.

[0036] That is: R TVS <R R ... (Condition 1).

[0037] Among them, R TVS R is the on-resistance of the transient voltage suppressor (TVS). R Let R be the resistance value.

[0038] For example, R TVS If the resistance is 200mΩ, then R R Greater than 200mΩ.

[0039] It should be noted that this utility model does not limit R. TVS and R R The specific values ​​are as follows. In practical applications, appropriate transient voltage suppressor (TVS) and resistor R can be selected according to requirements.

[0040] It should be understood that (condition 1) specifies the lower limit of the resistance value of resistor R, so that the surge can be discharged preferentially through the first surge discharge path r1, thereby minimizing the negative voltage impact of the surge on the overvoltage protection circuit OVP.

[0041] In some embodiments, the resistance value of resistor R is R R The impedance R of the overvoltage protection circuit OVP is less than or equal to OVP .

[0042] That is: R R ≤R OVP ... (Condition 2).

[0043] Among them, R OVP R is the impedance of the overvoltage protection circuit OVP. R Let R be the resistance value.

[0044] For example, R OVP If the Ω is 10Ω, then R R Less than or equal to 10Ω.

[0045] It should be noted that this utility model does not limit R. OVP and RR The specific value can be set according to requirements in practical applications.

[0046] It should be understood that (Condition 2) specifies the upper limit of the resistance value of resistor R. Considering the normal operation of the overvoltage protection circuit OVP and its electrostatic discharge capability, the resistance value of resistor R should be sufficiently small. Under the condition of satisfying (Condition 2), the normal operation of the overvoltage protection circuit OVP and its electrostatic discharge capability can be well balanced.

[0047] In some embodiments, to provide good surge protection and allow the overvoltage protection circuit (OVP) to operate continuously, the resistance value of resistor R is R. R If both (condition 1) and (condition 2) are satisfied, then (condition 3) is satisfied.

[0048] That is: R TVS <R R ≤R OVP ... (Condition 3).

[0049] Although not shown in the figure, it is understood that the surge protection circuit 10 may also include other electronic components, and the upper and lower limits of the resistor R can be determined by the overall circuit, depending on the actual needs.

[0050] Figure 2 A structural block diagram of an exemplary surge protection circuit 10, consistent with some embodiments of the present invention, is shown. For example... Figure 2 As shown, the overvoltage protection circuit OVP includes a first terminal (i.e., input terminal IN), a second terminal (i.e., power ground PGND), and a third terminal (i.e., output terminal OUT). The overvoltage protection circuit OVP includes a first switching transistor K1. The first terminal of the first switching transistor K1 is connected to the first terminal (i.e., input terminal IN) of the overvoltage protection circuit OVP. The second and third terminals of the first switching transistor K1 are connected to power ground PGND. In some embodiments, the first switching transistor K1 can be a gate-grounded N-type metal-oxide-semiconductor field-effect transistor (GGNMOS). The first terminal of the resistor R is connected to power ground PGND. The second terminal of the resistor R is connected to ground line L2. The resistor R and the first switching transistor K1 are adapted to form a first sub-path r21 of the second surge discharge path r2. That is, ground line L2—resistor R—first switching transistor K1—power line L1 form the first sub-path r21. When a surge occurs, the first switching transistor K1 can automatically turn on to conduct the first sub-path r21 to discharge the surge.

[0051] In some embodiments, such as Figure 2As shown, the overvoltage protection circuit OVP includes a second switch K2. The first terminal of the second switch K2 is connected to the third terminal of the overvoltage protection circuit OVP (i.e., the output terminal OUT). The second and third terminals of the second switch K2 are connected to the power ground PGND. The second switch K2 can be a GGNMOS. The second switch K2 and the resistor R are adapted to form a second sub-path r22 of the second surge discharge path r2. That is, the ground line L2—resistor R—second switch K2—power line L1 form the second sub-path r22. When a surge occurs, the second switch K2 can automatically turn on to conduct the second sub-path r22 to discharge the surge.

[0052] In some embodiments, such as Figure 2 As shown, the overvoltage protection circuit OVP also includes a third switching transistor K3. The first and second terminals of the third switching transistor K3 are respectively connected to the first terminals of the first switching transistor K1 and the second switching transistor K2. That is, the first and second terminals of the third switching transistor K3 are respectively connected to the input terminal IN and the output terminal OUT of the overvoltage protection circuit OVP. In some embodiments, the third switching transistor K3 may include a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0053] It should be noted that the types of the first switch K1, the second switch K2, and the third switch K3 in the above embodiments are merely illustrative examples, and this utility model is not limited thereto. In practical applications, appropriate switch transistors can be selected according to requirements.

[0054] In some embodiments, such as Figure 2 As shown, the overvoltage protection circuit OVP also includes a control circuit LOGIC. The first terminal of the control circuit LOGIC is connected to the control terminal of the third switching transistor K3, for example, connected to the gate of a MOSFET. The second terminal of the control circuit LOGIC is connected to power ground PGND. The control circuit LOGIC can control the on / off state of the third switching transistor K3.

[0055] In some embodiments, such as Figure 2 As shown, the downstream circuit NC or load LOAD is connected to the output terminal OUT of the overvoltage protection circuit OVP and the second terminal of the resistor R. The control circuit LOGIC monitors the negative voltage of the overvoltage protection circuit OVP. When the negative voltage is determined to be greater than or equal to the threshold, the control circuit LOGIC can control the third switch K3 to turn off, thereby isolating the downstream circuit NC or load LOAD and preventing damage to the downstream circuit NC or load LOAD. When the negative voltage is determined to be less than the threshold, the control circuit LOGIC can control the third switch K3 to turn on, allowing the downstream circuit NC or load LOAD to continue operating.

[0056] In some embodiments, the control circuit LOGIC may include a central processing unit (CPU), and may also include other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and similar devices. The general-purpose processor may be a microcontroller unit (MCU) or any conventional processor.

[0057] In some embodiments, the surge protection circuit of this invention, including the transient voltage suppressor (TVS), overvoltage protection circuit (OVP), and resistor R, can be all or partly integrated together, or can be implemented independently. For example, all three or two can be integrated into one unit. Alternatively, each of the three can be separately located on a chip; for instance, the overvoltage protection circuit (OVP) can be located on one chip, the resistor R on another, and the TVS on yet another. In practical applications, the configuration can be adjusted according to requirements. All of these are within the scope of protection of this invention.

[0058] The surge protection circuit of this invention forms a first surge discharge path through a transient voltage suppression transistor and a second surge discharge path through a resistor. This can effectively reduce or even avoid the negative voltage impact of surges on the overvoltage protection circuit. It does not block the negative voltage from entering the overvoltage protection circuit and will not cause the overvoltage protection circuit to stop working. This allows the surge protection circuit to operate continuously with low power consumption, improving the surge negative voltage protection capability, integration, and user experience, while reducing costs.

[0059] The surge protection circuit of this invention meets the surge impact test (IEC61000-4-5 test) standard, and this test includes positive and negative voltage tests above 1000V. This surge protection circuit supports protection levels from 900V to 1600V, with a particularly improved protection level against surge negative voltage. It offers excellent surge protection, high reliability, and a cost-effectiveness, enhancing the customer experience.

[0060] This surge protection circuit can be widely used in industrial and consumer USB-powered products. When applied to switching power supplies, electronic devices, and other products, it can improve product reliability, stability, and safety, thus enhancing the customer experience.

[0061] This utility model also provides a switching power supply. Figure 3A structural block diagram of an exemplary switching power supply 20, consistent with some embodiments of the present invention, is shown. For example... Figure 3 As shown, the switching power supply 20 includes the surge protection circuit 10 as described above.

[0062] In some embodiments, the switching power supply 20 may be a DC switching power supply. In some embodiments, the switching power supply 20 may be an AC switching power supply. In some embodiments, the switching power supply 20 may be a switching power supply that simultaneously supports both DC and AC. In some embodiments, the switching power supply 20 may be a power adapter for an electronic device.

[0063] The switching power supply of this invention, by adopting the surge protection circuit described above, has good surge protection effect, high reliability, and cost-effectiveness. When a surge occurs, it supports low-power continuous and stable operation, which helps to improve the customer experience.

[0064] This utility model also provides an electronic device. Figure 4 A structural block diagram of an exemplary electronic device 30, consistent with some embodiments of the present invention, is shown. For example... Figure 4 As shown, the electronic device 30 includes the switching power supply 20 as described above.

[0065] It should be noted that this utility model does not limit the specific type and usage scenario of the electronic device 30. In some embodiments, the electronic device 30 may include mobile electronic devices, such as mobile phones, laptops, tablets, wearable devices, etc. In some embodiments, the electronic device 30 may include smart home devices, such as cameras, electric curtains, smart toilets, smart doors, smart locks, smart doorbells, smart lights, televisions, refrigerators, air conditioners, rice cookers, etc. In some embodiments, the electronic device 30 may include transportation equipment, such as new energy vehicles, airplanes, ships, agricultural vehicles, high-speed trains, trains, motorcycles, electric bicycles, drones, etc. In some embodiments, the electronic device 30 may include robots, such as household robots, industrial robots, medical robots, chatbots, public service robots, etc.

[0066] The electronic device of this invention, by adopting the switching power supply as described above, has good surge protection and supports low-power continuous operation when a surge occurs, which helps to improve the reliability, stability and service life of the electronic device and enhance the customer experience.

[0067] It should be noted that although several modules of surge protection circuits / switching power supplies / electronic devices have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules described above can be implemented in one module. Conversely, the features and functions of one module described above can be further divided and embodied by multiple modules.

[0068] It should be noted that this disclosure may include Figure 1-4 Any one or more features of any one or more embodiments. In other words, not all features shown in the figures need to be implemented simultaneously in the surge protection circuit / switching power supply / electronic equipment of this disclosure.

[0069] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A surge protection circuit, characterized by, include: A transient voltage suppressor, wherein a first end of the transient voltage suppressor is connected to a power supply line and a second end of the transient voltage suppressor is connected to a ground line, and the transient voltage suppressor is adapted to form a first surge discharge path; An overvoltage protection circuit, wherein the first terminal of the overvoltage protection circuit is connected to the first terminal of the transient voltage suppression transistor; and A resistor, the first end of which is connected to the second end of the overvoltage protection circuit, and the second end of which is connected to the second end of the transient voltage suppression tube, the resistor being adapted to form a second surge discharge path.

2. The surge protection circuit of claim 1, wherein, The negative terminal of the transient voltage suppressor is connected to the power supply line, and the positive terminal of the transient voltage suppressor is connected to the ground line; the transient voltage suppressor is a unidirectional transient voltage suppressor.

3. The surge protection circuit according to claim 1, characterized in that, The on-resistance of the transient voltage suppressor is less than the resistance value of the resistor.

4. The surge protection circuit according to any one of claims 1-3, characterized in that, The resistance value is less than or equal to the impedance of the overvoltage protection circuit.

5. The surge protection circuit according to any one of claims 1-3, characterized in that, The third terminal of the overvoltage protection circuit is suitable for connection to a subsequent circuit or load.

6. The surge protection circuit according to any one of claims 1-3, characterized in that, The overvoltage protection circuit includes: A first switching transistor, the first end of which is connected to the first end of the overvoltage protection circuit, the second and third ends of which are connected to power ground, the first end of which is connected to the power ground, and the resistor and the first switching transistor are adapted to form a first sub-path of the second surge discharge path.

7. The surge protection circuit according to claim 6, characterized in that, The overvoltage protection circuit includes: The second switch has its first terminal connected to the third terminal of the overvoltage protection circuit, and its second and third terminals connected to the power ground. The second switch and the resistor are adapted to form a second sub-path of the second surge discharge path.

8. The surge protection circuit according to claim 7, characterized in that, The overvoltage protection circuit also includes: A third switching transistor, wherein the first and second ends of the third switching transistor are respectively connected to the first ends of the first switching transistor and the second switching transistor; and A control circuit, wherein the first terminal of the control circuit is connected to the control terminal of the third switching transistor, and the second terminal of the control circuit is connected to the power ground.

9. The surge protection circuit according to claim 8, characterized in that, The first and second switching transistors are N-type metal-oxide-semiconductor field-effect transistors with their gates grounded; the third switching transistor is a metal-oxide-semiconductor field-effect transistor.

10. A switching power supply, characterized in that, Includes the surge protection circuit as described in any one of claims 1-9.

11. An electronic device, characterized in that, Including the switching power supply as described in claim 10.

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