Overvoltage protection circuit and vehicle-mounted aromatherapy device

Abstract

The utility model discloses an overvoltage protection circuit and a vehicle-mounted aromatherapy device thereof, and the overvoltage protection circuit comprises a power input end which is used for being connected with a power supply; the first pole of the first switch assembly is electrically connected with one end of the voltage stabilizing unit, the second pole of the first switch assembly is electrically connected with the power input end, and the third pole of the first switch assembly and the other end of the voltage stabilizing unit are grounded; a first pole of the second switch assembly is electrically connected with a third pole of the first switch assembly and one end of the first load unit, the other end of the first load unit is grounded, and a second pole of the second switch assembly is electrically connected with the power supply input end; and the power output end is electrically connected with the third pole of the second switch assembly. According to the invention, the charging safety and stability can be improved.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of overvoltage protection circuit technology, and in particular to an overvoltage protection circuit and its in-vehicle air freshener. Background Technology

[0002] With the rapid development of electronic technology, electronic devices, especially portable electronic devices, have become widely used in people's daily lives. It is very important to implement overvoltage protection during the charging process of electronic devices in order to avoid damage to electronic devices due to overvoltage.

[0003] In related technologies, overvoltage protection for electronic devices is often achieved by designing complex circuits. However, complex overvoltage protection circuits contain a large number of components, which greatly increases the probability of electromagnetic interference and noise generated between a large number of components. This can easily lead to component aging and failure. Moreover, it is difficult to provide enough space in a limited electronic device to accommodate too many components, thus reducing the safety and stability of charging. Utility Model Content

[0004] This application provides an overvoltage protection circuit and its in-vehicle air freshener, aiming to improve charging safety and stability.

[0005] In a first aspect, embodiments of this application provide an overvoltage protection circuit, including:

[0006] Power input terminal, used to connect to the power supply;

[0007] The first switching assembly and the voltage regulator unit are connected, the first pole of the first switching assembly and one end of the voltage regulator unit are electrically connected, the second pole of the first switching assembly is electrically connected to the power input terminal, and the third pole of the first switching assembly and the other end of the voltage regulator unit are grounded.

[0008] The second switching assembly and the first load unit are respectively connected to the third pole of the first switching assembly and one end of the first load unit, the other end of the first load unit is grounded, and the second pole of the second switching assembly is connected to the power input terminal.

[0009] The power output terminal is electrically connected to the third pole of the second switching assembly.

[0010] Specifically, when the supply voltage provided by the power supply is less than the preset voltage threshold of the voltage regulator unit, the first switching component is turned off. When the first switching component is turned off, the potential difference between the first and second poles of the second switching component satisfies the preset first switching closing condition, and the second switching component is turned on.

[0011] According to some embodiments of this application, the first switching component is a PNP transistor, the base of the first switching component is electrically connected to one end of the voltage regulator unit, the emitter of the first switching component is electrically connected to the power input terminal, and the collector of the first switching component is grounded.

[0012] According to some embodiments of this application, the second switching component is a P-channel field-effect transistor. The gate of the second switching component is electrically connected to the third terminal of the first switching component and one end of the first load unit, respectively. The source of the second switching component is electrically connected to the power input terminal, and the drain of the second switching component is electrically connected to the power output terminal.

[0013] According to some embodiments of this application, it also includes a protocol detection component and a control component. The voltage regulation unit includes a third switching component and a plurality of Zener diodes with different voltage regulation values. One end of the protocol detection component is electrically connected to the power input terminal, the other end of the protocol detection component is electrically connected to one end of the control component, the other end of the control component is electrically connected to the first end of the third switching component, and the second end of the third switching component is electrically connected to the plurality of Zener diodes respectively.

[0014] The control component determines the current protocol type based on the protocol detection component and controls the second terminal of the third switch component to transmit an electrical signal to the selected Zener diode so that the selected Zener diode is turned on.

[0015] According to some embodiments of this application, a second load unit is also included, one end of which is electrically connected to the first pole of the first switching assembly, and the other end of which is electrically connected to one end of the voltage regulator unit.

[0016] According to some embodiments of this application, the overvoltage protection circuit further includes a first ground terminal, a second ground terminal, and a fourth switching component. The first pole of the fourth switching component is electrically connected to the power input terminal, the second pole of the fourth switching component is electrically connected to the first ground terminal, and the third pole of the fourth switching component is electrically connected to the second ground terminal.

[0017] When no power supply current is connected to the power input terminal and the first electrode of the fourth switching component is at the first potential, the second electrode of the fourth switching component is at the second potential. The potential difference between the first potential and the second potential does not meet the preset second switch closing condition, and the second and third electrodes of the fourth switching component are not connected.

[0018] According to some embodiments of this application, the fourth switching component is an N-channel field-effect transistor, the gate of the fourth switching component is electrically connected to the power input terminal, the drain of the fourth switching component is electrically connected to the first ground terminal, and the source of the fourth switching component is electrically connected to the second ground terminal.

[0019] According to some embodiments of this application, a third load unit is also included, one end of which is electrically connected to the power input terminal, and the other end of which is electrically connected to the first pole of the fourth switching assembly.

[0020] According to some embodiments of this application, a fourth load unit is also included, one end of which is electrically connected to the power input terminal, and the other end of which is electrically connected to one end of the voltage regulator unit.

[0021] Secondly, embodiments of this application also provide a car air freshener, including any of the overvoltage protection circuits described in the first aspect.

[0022] The embodiments of this application include at least the following beneficial effects: The overvoltage protection circuit proposed in this application includes a power input terminal for connection to a power supply; a first switching assembly and a voltage regulator unit, wherein the first electrode of the first switching assembly is electrically connected to one end of the voltage regulator unit, the second electrode of the first switching assembly is electrically connected to the power input terminal, and the third electrode of the first switching assembly and the other end of the voltage regulator unit are grounded; a second switching assembly and a first load unit, wherein the first electrode of the second switching assembly is electrically connected to the third electrode of the first switching assembly and one end of the first load unit, the other end of the first load unit is grounded, and the second electrode of the second switching assembly is electrically connected to the power input terminal; and a power output terminal electrically connected to the third electrode of the second switching assembly; wherein, when the supply voltage provided by the power supply is less than a preset voltage threshold of the voltage regulator unit, the first switching assembly is turned off; when the first switching assembly is turned off, the potential difference between the first and second electrodes of the second switching assembly satisfies a preset first switch closing condition, and the second switching assembly is turned on. This application can improve charging safety and stability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the circuit structure of an overvoltage protection circuit provided in one embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the PMOS transistor conduction conditions provided in one embodiment of this application;

[0025] Figure 3 This is a schematic diagram of the circuit structure of an overvoltage protection circuit provided in another embodiment of this application;

[0026] Figure 4 This is a schematic diagram of the conduction conditions of the fourth switch assembly provided in one embodiment of this application;

[0027] Figure label:

[0028] First switching assembly 110, voltage stabilizing unit 120, second switching assembly 130, first load unit 140, protocol detection assembly 210, control assembly 220, third switching assembly 230, second load unit 240, fourth switching assembly 250, third load unit 260, and fourth load unit 270. Detailed Implementation

[0029] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and 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. Therefore, they should not be construed as limitations on the embodiments of this application.

[0030] It should be understood that in the description of the embodiments of this application, "a few" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of terms such as "first" and "second" is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0031] In the description of the embodiments of this application, unless otherwise expressly limited, terms such as setting, installing, and connecting should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in the embodiments of this application in combination with the specific content of the technical solution.

[0032] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] The following is combined Figures 1 to 4 The embodiments of this application will be further described below, wherein each structure Figures 1 to 4 Both are mentioned in the text.

[0034] With the rapid development of electronic technology, electronic devices, especially portable electronic devices, have become widely used in people's daily lives. It is very important to implement overvoltage protection during the charging process of electronic devices in order to avoid damage to electronic devices due to overvoltage.

[0035] In related technologies, overvoltage protection for electronic devices is often achieved by designing complex circuits. However, complex overvoltage protection circuits contain a large number of components, which greatly increases the probability of electromagnetic interference and noise generated between a large number of components. This can easily lead to component aging and failure. Moreover, it is difficult to provide enough space in a limited electronic device to accommodate too many components, thus reducing the safety and stability of charging.

[0036] Based on this, this application proposes an overvoltage protection circuit and its in-vehicle air freshener, which will be described in detail below, and the beneficial effects of this application will gradually become apparent.

[0037] like Figure 1 As shown, Figure 1 This is a schematic diagram of the circuit structure of an overvoltage protection circuit provided in one embodiment of this application, wherein the overvoltage protection circuit includes:

[0038] Power input terminal, used to connect to the power supply;

[0039] The first switching assembly 110 and the voltage regulator unit 120 are connected. The first pole of the first switching assembly 110 is electrically connected to one end of the voltage regulator unit 120, the second pole of the first switching assembly 110 is electrically connected to the power input terminal, and the third pole of the first switching assembly 110 and the other end of the voltage regulator unit 120 are grounded.

[0040] The second switch assembly 130 and the first load unit 140 are respectively connected to the third pole of the first switch assembly 110 and one end of the first load unit 140. The other end of the first load unit 140 is grounded. The second pole of the second switch assembly 130 is electrically connected to the power input terminal.

[0041] The power output terminal is electrically connected to the third pole of the second switching assembly 130;

[0042] When the supply voltage provided by the power supply is less than the preset voltage threshold of the voltage regulator unit 120, the first switch assembly 110 is turned off. When the first switch assembly 110 is turned off, the potential difference between the first and second poles of the second switch assembly 130 satisfies the preset first switch closing condition, and the second switch assembly 130 is turned on.

[0043] In this embodiment, the power input terminal is the connection point between the overvoltage protection circuit (hereinafter referred to as "circuit" for ease of description) provided in this embodiment and the external power supply, such as... Figure 1As shown, in the circuit of this application embodiment, the VCC terminal is the power input terminal, and the VCC_V1 terminal is the power output terminal. The power input terminal allows current to flow into the circuit, providing the required electrical energy to the various components of the circuit, and flows out from the power output terminal. In practical applications, various uncertainties exist in the process of power supply to electrical equipment, such as voltage fluctuations and harmonic interference. These factors may lead to a decrease in circuit performance or malfunctions. Therefore, it is necessary to promptly avoid these adverse factors using the overvoltage protection circuit proposed in this application embodiment, preventing the components in the circuit from being subjected to overvoltage surges that could damage their performance or even cause safety problems due to the components, thereby improving the stability and safety of the electrical equipment (electronic equipment) during the charging process.

[0044] Furthermore, the power supply can be a 220-volt (V) AC power supply, a storage battery, etc. The embodiments of this application do not limit the specific type of power supply. Regardless of the type, the overvoltage protection circuit provided in the embodiments of this application can be electrically connected to the power supply through the power input terminal. When the power supply voltage provided by the power supply is greater than the limit that the circuit can withstand, the current cannot flow from the power input terminal to the power output terminal, thereby achieving overvoltage protection.

[0045] For example, the power supply can be located inside the vehicle. It is understood that with the widespread adoption and rapid development of electronic devices, the vehicle power supply not only needs to provide driving support for the vehicle but also needs to meet the additional charging needs of users for electronic devices. The charging current required by electronic devices is usually lower than the rated current of the power supply. Electronic devices include, but are not limited to, laptops, mobile phones, tablets, and car air fresheners. This application embodiment does not limit the specific type of electronic device. Regardless of the type, the overvoltage protection circuit provided in this application embodiment can be electrically connected to the electronic device through the power output terminal. When the supply voltage provided by the vehicle power supply exceeds the limit that the overvoltage protection circuit can withstand, the current in this application embodiment cannot flow from the power input terminal to the power output terminal, thereby protecting the electronic device and improving charging safety and stability.

[0046] It should be noted that the term "electrical connection" in the embodiments of this application, also known as "electrical property connection," is a description of the connection relationship used to illustrate this characteristic of the circuit when describing the circuit structure of a product. It can be understood as a form of connection between different components in the circuit structure via physical lines capable of transmitting electrical signals, such as copper foil or wires on a printed circuit board (PCB). It is understood that the two electronic components in an "electrical connection" can be directly connected, or indirectly connected by other electronic components in between.

[0047] In other words, in the overvoltage protection circuit proposed in this application embodiment, other components can be set between electronic components that are electrically connected, depending on the actual situation. For example, a load unit such as a resistor can be set between the power input terminal and the first switching assembly 110. When the power input terminal is suddenly connected to the power supply voltage provided by the power supply, it can protect the first switching assembly 110 from damage caused by the sudden voltage change. This application embodiment does not limit the components that can be set between two electronic components that are electrically connected; the specific settings can be made according to the actual situation.

[0048] In this embodiment, the first switching component 110 is used to control the current flow in the circuit. The first terminal of the first switching component 110 is electrically connected to the voltage regulator unit 120, the second terminal is electrically connected to the power input terminal, and the third terminal is grounded. The first switching component 110 is only turned on when the three terminals of the first switching component 110 meet the corresponding voltage difference conditions. Thus, depending on the voltage provided by the power supply, the first switching component 110 will exhibit different conduction states, thereby enabling the first switching component 110 to cooperate with the second switching component 130 to control the current conduction at the power input terminal and the power output terminal.

[0049] In this embodiment, the second switching component 130 is also used to control the current flow in the circuit. The first terminal of the second switching component 130 is electrically connected to the third terminal of the first switching component 110 and one end of the first load unit 140, respectively. The second terminal of the second switching component 130 is electrically connected to the power input terminal, and the power output terminal is electrically connected to the third terminal of the second switching component 130. Thus, considering the current supply voltage at the power input terminal, the different conduction states of the first switching component 110, and the presence of the first load unit 140, the potentials of the first and second terminals of the second switching component 130 will change accordingly, thereby causing different changes in the conduction state of the second switching component 130. The first switch closing condition refers to the closing condition of the second switching component 130.

[0050] The following will provide a detailed explanation of the above content to help readers better understand the overvoltage protection circuit proposed in the embodiments of this application and its beneficial effects. First, the electronic components will be described in detail:

[0051] In the embodiments of this application, such as Figure 1 As shown, the first switching component 110 (Q1) is a PNP transistor. The base of the first switching component 110 is electrically connected to one end of the voltage regulator unit 120. The emitter of the first switching component 110 is electrically connected to the power input terminal. The collector of the first switching component 110 is grounded.

[0052] A PNP transistor is a bipolar junction transistor composed of two layers of P-type semiconductors sandwiching one layer of N-type semiconductors. This structure allows the PNP transistor to be used as a switch in the circuit proposed in this application. A PNP transistor has three terminals: the base (B), the emitter (E), and the collector (C). When the PNP transistor is turned on, current flows from the emitter to the collector.

[0053] It should be noted that the PNP transistor is chosen as the first switching component 110 in this embodiment because the PNP transistor has a low on-resistance when conducting. Therefore, during power supply, the current transfer efficiency from the power input terminal to the power output terminal is high, reducing energy loss and improving power supply efficiency. Besides, the first switching component 110 can also be other types of components, such as an NPN transistor, an N-channel MOSFET, or a P-channel MOSFET. This embodiment does not limit the specific component type used in the first switching component 110 and can be adapted according to actual conditions.

[0054] A PNP transistor conducts when the following conditions are met: the emitter (E) voltage must be higher than the base (B) voltage, and simultaneously, the base (B) voltage must be higher than the collector (C) voltage. Specifically, the transistor begins to conduct when the emitter voltage is higher than the base voltage; and it is fully conducted when the base voltage is higher than the collector voltage. The conduction condition for the PNP transistor used in this embodiment is U... BE ≤-0.7V, that is, when Figure 1 The first switching component 110 (Q1) in the middle satisfies U BE Q1 conducts when the voltage is ≤-0.7V.

[0055] It should be noted that when the PNP transistor is a silicon transistor, U EB The transistor typically conducts between 0.6V and 0.7V; when the PNP transistor is a germanium transistor, U EB The transistor typically conducts between 0.2V and 0.3V; that is, the conduction voltage of a PNP transistor depends on the type of transistor selected. This application is only for illustrative purposes and does not imply any limitation on the embodiments of this application.

[0056] In the embodiments of this application, such as Figure 1As shown, the second switching component 130 (Q2) is a P-channel field-effect transistor (PMOS transistor). The gate of the second switching component 130 is electrically connected to the third terminal of the first switching component 110 and one end of the first load unit 140, respectively. The source of the second switching component 130 is electrically connected to the power input terminal, and the drain of the second switching component 130 is electrically connected to the power output terminal.

[0057] Among them, the PMOS transistor is a common field-effect transistor, belonging to the metal-oxide-semiconductor field-effect transistor (MOSFET). A PMOS transistor has three terminals: gate (G), source (S), and drain (D); its conductive channel is composed of P-type semiconductor, and the electron concentration of the P-type semiconductor material is controlled by an electric field to regulate the changes in on-resistance and current. When a negative voltage is applied to the gate, an inversion region is formed between the gate and the channel, restricting the current flow from the source to the drain; when a positive voltage is applied to the gate, the inversion region disappears, and the current can flow freely. This ability to control current makes the PMOS transistor in the circuit of this application an excellent switching control component.

[0058] It should be noted that, similar to the first switching component 110, the second switching component 130 can also be specifically selected according to the actual situation. That is to say, the second switching component 130 is not limited to the PMOS transistor in the example of the embodiment of this application, but can also be an NPN transistor, a PNP transistor or an N-channel field-effect transistor.

[0059] In the embodiments of this application, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the PMOS transistor conduction condition provided in one embodiment of this application. The conduction condition of the PMOS transistor used in this embodiment is U. GS <-UGS(th), where UGS(th) is the threshold voltage of the PMOS transistor, UGS(th) = 1.3V. That is, when Figure 1 The second switching component 130(Q2) in the middle satisfies U GS Q2 is turned on when the voltage is less than -1.3V.

[0060] In this embodiment, the voltage regulator unit 120 is a circuit or device with a function of stabilizing the output voltage. For example... Figure 1As shown, the voltage regulator unit 120 in the circuit of this embodiment is a Zener diode (Z1). Of course, the voltage regulator unit 120 can also be a linear regulator or other types of voltage regulator. Furthermore, the voltage regulator unit 120 can include multiple voltage regulator devices; for example, the voltage regulator unit 120 can include multiple Zener diodes with different voltage regulation values. The voltage regulator unit 120 can ensure that the first terminal of the first switching component 110 in the circuit remains at a preset, relatively stable voltage level: when the voltage supplied by the power supply fluctuates, the voltage regulator unit 120 will adjust its internal resistance or other parameters to maintain the stability of the output voltage, thereby helping to protect the circuit from the influence of power supply voltage fluctuations, thus improving the stability and reliability of the entire charging process.

[0061] It should be noted that the number of voltage regulators included in the voltage regulator unit 120, the specifications of each voltage regulator, and the specific connection method between each voltage regulator are all set according to the actual situation, and the comparison of the embodiments in this application is not limited.

[0062] In this embodiment, the first load unit 140 is an energy-consuming element in the circuit. It can be a resistor, a light bulb, a motor, or any other device that consumes electrical energy. Furthermore, the presence of the first load unit 140 can affect the current distribution and voltage drop in the circuit, thereby impacting the circuit's performance and stability. Figure 1 As shown, the first load unit 140 in this embodiment is a resistor R3 with a resistance of 4.7 kΩ. One end of the resistor R3 is electrically connected to the third terminal of the first switching assembly 110, and the other end of the resistor R3 is grounded.

[0063] It should be noted that the first load unit 140 can also be composed of multiple energy-consuming devices connected in series or in parallel. The energy-consuming devices can be resistors, light bulbs, motors, etc., and the specifications of each energy-consuming device can be set according to the actual situation. This application embodiment does not limit this.

[0064] After understanding the specific connection relationship of each electronic component in the circuit of the embodiment of this application and the example specification parameters, the following will explain how the first switching assembly 110, the voltage regulator unit 120, the second switching assembly 130 and the first load unit 140 cooperate with each other to realize the overvoltage protection of the circuit.

[0065] Assuming the embodiments of this application Figure 1 The Zener diode (Z1) in the circuit has a Zener voltage of 5.6V; the first switching assembly 110 (Q1) is turned on under the condition of U. BE ≤-0.7V; the conduction condition of the second switching assembly 130 (Q2) is U GS <-1.3V. In this example, there are two possible cases:

[0066] Case 1 (Input Voltage < Regulated Voltage): When the input voltage at the power input terminal is 5V, since the input voltage 5V < the regulated voltage of 5.6V, the breakdown value of the Zener diode is not reached, and Z1 is not conducting; at this time, the base voltage of Q1 is 5V, the emitter voltage is 5V, and U... BE =5-5=0V, which does not meet the conduction condition of the PNP transistor, so Q1 is not conducting; since the gate of Q2 is grounded, U at this time GS =0-5V < -1.3V, which meets the conduction condition of the PMOS transistor, so Q2 conducts. That is, in practical applications, when the supply voltage provided by the power supply does not exceed the threshold voltage of the circuit, the current from the power input terminal can flow smoothly to the power output terminal to charge the electronic devices connected to the power output terminal.

[0067] The second scenario (input voltage > regulated voltage): When the input voltage at the power input terminal is 6.3V, since the input voltage of 6.3V > the regulated voltage of 5.6V, the Zener diode breaks down, and Z1 conducts; at this time, the base voltage of Q1 is 5.6V, the emitter voltage is 6.3V, and U... BE =5-6.3=-0.7V, which meets the conduction condition of the PNP transistor, so Q1 conducts; due to the grounding of Q2's gate and the effect of resistor R3, U at this time GS =6.3 - 6.3 > -1.3V, which does not meet the conduction condition of the PMOS transistor, therefore Q does not conduct. In practical applications, when the supply voltage provided by the power supply exceeds the circuit's threshold voltage, the current from the power input cannot flow smoothly to the power output, disconnecting the charging connection between the power supply and the electronic device. This protects the electronic device from overvoltage damage and improves the charging safety and stability of the electronic device.

[0068] In another embodiment, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the circuit structure of an overvoltage protection circuit provided in another embodiment of this application. Specifically, Figure 1 The VCC-R1-Z1-GND branch is replaced with Figure 3 The path shown, the rest of the circuit in another embodiment and Figure 1 The other parts are the same. Figure 3 It will not be shown again in the text.

[0069] Specifically, the overvoltage protection circuit may further include a protocol detection component 210 and a control component 220. The voltage regulation unit 120 includes a third switching component 230 and multiple Zener diodes with different voltage regulation values. One end of the protocol detection component 210 is electrically connected to the power input terminal, the other end of the protocol detection component 210 is electrically connected to one end of the control component 220, the other end of the control component 220 is electrically connected to the first end of the third switching component 230, and the second end of the third switching component 230 is electrically connected to multiple Zener diodes respectively.

[0070] The control component 220 controls the second terminal of the third switch component 230 to transmit an electrical signal to the selected Zener diode according to the current protocol type determined by the protocol detection component 210, so that the selected Zener diode is turned on.

[0071] In another embodiment, since different electronic devices have different charging requirements, their overvoltage protection thresholds also differ. To improve the flexibility of the overvoltage protection circuit, the voltage regulator unit 120 of the overvoltage protection circuit can include not only a single voltage regulator but also multiple voltage regulators connected in parallel, and the third switching component 230 determines which voltage regulator can be connected to the overvoltage protection circuit. In this way, the overvoltage protection circuit can adaptively select voltage regulators with different voltage values ​​to provide targeted protection for different electronic devices, improving the accuracy of overvoltage protection.

[0072] Furthermore, to achieve this objective, the overvoltage protection circuit also includes a protocol detection component 210 and a control component 220. The protocol detection component 210 is a circuit component representing the communication protocol type. It identifies the current protocol type by monitoring signal characteristics at the power input terminal, such as voltage, current, and frequency. Different protocol types typically correspond to different rated voltages; for example, mobile phones and tablets have different rated voltages, thus requiring different Zener diodes with varying voltage regulation values ​​to set different protection threshold voltages. The control component 220 receives the level signal from the protocol detection component 210 and controls the opening and closing state of the third switch component 230 based on this signal, thereby selecting the Zener diode connected to the circuit and improving the flexibility of the overvoltage protection circuit in protecting the charging of electronic devices.

[0073] Furthermore, the protocol detection component 210 can be a dedicated protocol detection chip, microprocessor, microcontroller, programmable logic device, etc. The protocol detection component 210 can be adapted to the actual situation, and the embodiments of this application do not limit it in this regard.

[0074] The third switch assembly 230 is an electronic component capable of controlling the on / off state of the circuit. It can connect or disconnect any one of the Zener diodes in the voltage regulator unit 120. Different electronic components are selected as the third switch assembly 230 depending on the number of Zener diodes in the voltage regulator unit 120. Furthermore, depending on the specific third switch assembly 230 selected, the method by which the third switch assembly 230 determines which Zener diode is connected to the circuit also varies. For example, the third switch assembly 230 can determine which Zener diode is turned on by sending different level signals to each Zener diode, or it can determine the turned-on Zener diode by toggling the third switch assembly 230.

[0075] For example, such asFigure 3 As shown, in another embodiment, the voltage regulating unit 120 includes two Zener diodes, in which case the third switching component 230 can be a single-pole double-throw switch. Of course, this application embodiment does not limit the specific number of Zener diodes included in the voltage regulating unit 120; it can be set according to actual conditions. When there are multiple Zener diodes in the voltage regulating unit 120, the third switching component 230 can be a multiplexer. Further, the multiplexer can be a data selector, an analog signal multiplexer, a toggle multiplexer, a rotary multiplexer, etc. The third switching component 230 can be adaptively adjusted according to actual conditions, and this application embodiment does not limit this.

[0076] The electrical signal emitted by the protocol detection component 210 can be at least one of the following: a high-level signal, a low-level signal, a signal with and without a level, a first-level signal, and a second-level signal. In this embodiment, the voltage regulator unit 120, comprising two Zener diodes, is used as an example. The high-level signal emitted by the protocol detection component 210 is typically defined as a voltage greater than 2.4V, the specific value of which can be set according to actual conditions. Furthermore, the high-level signal is used to represent the physical implementation of logic "1". In this embodiment, the high-level signal controls the third switching component 230 to connect with one of the Zener diodes, and the low-level signal controls the third switching component 230 to connect with the other Zener diode. This allows for the connection of different Zener diodes according to different current protocol types, thereby achieving flexible overvoltage protection.

[0077] In this embodiment of the application, the overvoltage protection circuit further includes a second load unit 240, one end of which is electrically connected to the first pole of the first switching assembly 110, and the other end of which is electrically connected to one end of the voltage regulator unit 120.

[0078] In this embodiment of the application, the overvoltage protection circuit further includes a third load unit 260, one end of which is electrically connected to the power input terminal, and the other end of which is electrically connected to the first pole of the fourth switching assembly 250.

[0079] In this embodiment of the application, the overvoltage protection circuit further includes a fourth load unit 270, one end of which is electrically connected to the power input terminal, and the other end of which is electrically connected to one end of the voltage regulator unit 120.

[0080] In the embodiments of this application, such as Figure 1As shown, the second load unit 240 is a resistor R2 with a resistance of 4.7KΩ, the third load unit 260 is a resistor R4 with a resistance of 1KΩ, and the fourth load unit 270 is a resistor R1 with a resistance of 2KΩ. The second, third, and fourth load units 270 are all energy-consuming components in the circuit, and can be resistors, light bulbs, motors, or any other devices that can consume electrical energy.

[0081] Furthermore, since there is a diode structure between the base and emitter of the transistor, excessive base current may cause the transistor to overheat or be damaged. Therefore, resistor R2 is used to limit the current flowing into the base of the PNP transistor to prevent excessive current from damaging the transistor. Resistor R4 acts as a current limiter, preventing the power supply from directly impacting the gate of the PMOS transistor with excessive current, thus protecting the PMOS gate from being burned out or its performance impaired. In addition, resistor R4 can make the gate voltage of the PMOS transistor relatively stable, less susceptible to the influence of power supply voltage fluctuations, and improve the operating stability of the PMOS transistor. Resistor R1 can limit the current through the Zener diode, preventing excessive current from damaging the Zener diode.

[0082] It should be noted that the second, third, and fourth load units 270 may each include more than one load electronic element, and the connection method between the load electronic elements is not limited in this embodiment; it can be set according to the actual situation. For example, as shown... Figure 1 As shown, in addition to resistor R4, the third load unit 260 of this application embodiment may also include resistor R5 with a resistance of 10KΩ. One end of resistor R5 is electrically connected to resistor R4, and the other end of resistor R5 is electrically connected to the second pole of the fourth switch assembly 250.

[0083] In this embodiment of the application, the overvoltage protection circuit further includes a first ground terminal, a second ground terminal, and a fourth switch assembly 250. The first pole of the fourth switch assembly 250 is electrically connected to the power input terminal, the second pole of the fourth switch assembly 250 is electrically connected to the first ground terminal, and the third pole of the fourth switch assembly 250 is electrically connected to the second ground terminal.

[0084] When no power supply current is connected to the power input terminal and the first electrode of the fourth switch assembly 250 is at the first potential, the second electrode of the fourth switch assembly 250 is at the second potential. The potential difference between the first potential and the second potential does not meet the preset second switch closing condition, and the second and third electrodes of the fourth switch assembly 250 are not connected.

[0085] like Figure 1As shown, the first grounding terminal is GND, the second grounding terminal is PGND, and the fourth switch assembly 250 is Q3. In this embodiment, the first grounding terminal and the second grounding terminal are connected via the fourth switch assembly 250, and the fourth switch assembly 250 is also electrically connected to the power input terminal. The grounding terminal provides a common reference potential for all components in the circuit. Typically, the first grounding terminal is connected to the charging port ground, and the second grounding terminal is connected to the PCB ground. Depending on the location of the overvoltage protection circuit, the charging port and PCB can refer to either the power supply side or the charging device side.

[0086] For example, when a human body or other object comes into contact with the charging port of a device providing power, electrostatic discharge may occur. This electrostatic energy may damage electronic components in the circuit. Therefore, in this embodiment, a first grounding terminal and a second grounding terminal are connected to the charging port ground terminal and the PCB ground terminal to form an isolation circuit between the charging port ground terminal and the PCB ground terminal. This ensures that electrostatic energy is safely released through the grounding wire, protecting the circuit from damage and improving circuit stability. Furthermore, if the charging port ground terminal and the PCB ground terminal are not connected, a short circuit may occur due to some reason (such as external interference, electronic failure, etc.). Connecting these two grounding terminals provides an additional current path, allowing the short-circuit current to be diverted, thereby reducing the risk of a short circuit.

[0087] In this embodiment, the fourth switching component 250 (Q3) is an N-channel field-effect transistor (NMOS transistor). The gate of the fourth switching component 250 is electrically connected to the power input terminal, the drain of the fourth switching component 250 is electrically connected to the first ground terminal, and the source of the fourth switching component 250 is electrically connected to the second ground terminal. The second switch closing condition refers to the closing condition of the fourth switching component 250.

[0088] Among them, the NMOS transistor is a common field-effect transistor, which belongs to the metal-oxide-semiconductor field-effect transistor (MOSFET). The NMOS transistor has three terminals: gate (G), source (S), and drain (D). When the source voltage and drain voltage meet a preset voltage difference, the NMOS transistor allows current to flow from the drain to the source. This ability to control current makes the NMOS transistor in the circuit of this application a good switching control component 220.

[0089] It should be noted that, similar to the first switching component 110, the fourth switching component 250 can also be specifically selected according to the actual situation. That is to say, the fourth switching component 250 is not limited to the NMOS transistor in the example of the embodiment of this application, but can also be an NPN transistor, a PNP transistor or a P-channel field-effect transistor. The embodiment of this application does not limit this.

[0090] Furthermore, such as Figure 4 As shown, Figure 4 This is a schematic diagram illustrating the conduction conditions of a fourth switch assembly according to an embodiment of this application. Specifically, the conduction condition of the fourth switch assembly 250 provided in this embodiment at 125 degrees Celsius (°C) is U. GS ≥1.25V, conduction condition at 25℃ is U GS ≥1.4V; assuming the current temperature is 25℃ and the threshold voltage of the voltage regulator unit 120 is 5.6V. In this example, the following two cases exist:

[0091] Case 1 (no input voltage connected, VCC = 0V): First potential is 0V, second potential is 0V, U GS =0V, by Figure 4 It is known that the conduction condition of the NMOS transistor is not met at this time, so the NMOS transistor does not conduct, and the first ground terminal and the second ground terminal are not connected, effectively blocking static electricity and preventing the circuit from being damaged.

[0092] The second scenario (no input voltage connected, VCC = 5V): The first potential is 5V, the second potential is 0V, U GS =5V, from Figure 4 At this time, the conduction condition of the NMOS transistor is met, the NMOS transistor is turned on, the first ground terminal and the second ground terminal are connected, and the electrostatic energy is released safely through the grounding wire, protecting the circuit from damage.

[0093] The overvoltage protection circuit proposed in this application embodiment can be installed in a car air freshener. When the voltage provided by the car battery or other power source is too high, the overvoltage protection circuit installed in the car air freshener can monitor the input voltage and automatically cut off or limit the voltage transmission when the voltage exceeds the safe range, thereby effectively protecting the air freshener circuit from damage.

[0094] Alternatively, the overvoltage protection circuit proposed in this application embodiment can be set on the power supply output port side of the power supply to achieve overvoltage protection for the electronic device being charged. Taking a practical application scenario as an example, during the production process, the overvoltage protection circuit proposed in this application embodiment is set on the power supply output port of the vehicle's internal power supply. In the in-vehicle usage scenario, overvoltage protection is performed on different electronic devices, thereby achieving efficient charging of each electronic device, improving charging flexibility, and enhancing the user experience.

[0095] Alternatively, the overvoltage protection circuit proposed in this application embodiment can also be set in an independent overvoltage protection device, so that the overvoltage protection device can be installed on the power supply side or the charging side according to the user's needs.

[0096] It should also be understood that the various implementation methods provided in this application can be combined arbitrarily to achieve different technical effects.

[0097] The above provides a detailed description of the preferred embodiments of this application. However, this application is not limited to the above-described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. An overvoltage protection circuit, characterized in that, include: A power input terminal, which is used to connect to a power supply; A first switching assembly and a voltage regulator unit, wherein a first terminal of the first switching assembly is electrically connected to one end of the voltage regulator unit, a second terminal of the first switching assembly is electrically connected to the power input terminal, and a third terminal of the first switching assembly and the other end of the voltage regulator unit are grounded; The second switch assembly and the first load unit are respectively connected to the third pole of the first switch assembly and one end of the first load unit, and the other end of the first load unit is grounded. The second pole of the second switch assembly is electrically connected to the power input terminal. The power output terminal is electrically connected to the third pole of the second switching assembly; When the supply voltage provided by the power supply is less than the preset voltage threshold of the voltage regulator unit, the first switching component is turned off. When the first switching component is turned off, the potential difference between the first and second poles of the second switching component satisfies the preset first switching closing condition, and the second switching component is turned on.

2. The overvoltage protection circuit according to claim 1, characterized in that, The first switching component is a PNP transistor. The base of the first switching component is electrically connected to one end of the voltage regulator unit, the emitter of the first switching component is electrically connected to the power input terminal, and the collector of the first switching component is grounded.

3. The overvoltage protection circuit according to claim 1, characterized in that, The second switching component is a P-channel field-effect transistor. The gate of the second switching component is electrically connected to the third terminal of the first switching component and one end of the first load unit, respectively. The source of the second switching component is electrically connected to the power input terminal, and the drain of the second switching component is electrically connected to the power output terminal.

4. The overvoltage protection circuit according to claim 1, characterized in that, It also includes a protocol detection component and a control component. The voltage regulation unit includes a third switching component and multiple Zener diodes with different voltage regulation values. One end of the protocol detection component is electrically connected to the power input terminal, the other end of the protocol detection component is electrically connected to one end of the control component, the other end of the control component is electrically connected to the first end of the third switching component, and the second end of the third switching component is electrically connected to the multiple Zener diodes respectively. The control component determines the current protocol type based on the protocol detection component and controls the second terminal of the third switch component to transmit an electrical signal to the selected Zener diode, so that the selected Zener diode is turned on.

5. The overvoltage protection circuit according to claim 1, characterized in that, It also includes a second load unit, one end of which is electrically connected to the first pole of the first switching assembly, and the other end of which is electrically connected to one end of the voltage regulator unit.

6. The overvoltage protection circuit according to claim 1, characterized in that, The overvoltage protection circuit further includes a first grounding terminal, a second grounding terminal, and a fourth switching assembly. The first pole of the fourth switching assembly is electrically connected to the power input terminal, the second pole of the fourth switching assembly is electrically connected to the first grounding terminal, and the third pole of the fourth switching assembly is electrically connected to the second grounding terminal. Specifically, when no power supply current is connected to the power input terminal and the first electrode of the fourth switch assembly is at a first potential, the second electrode of the fourth switch assembly is at a second potential, and the potential difference between the first potential and the second potential does not meet the preset second switch closing condition, the second electrode and the third electrode of the fourth switch assembly are not connected.

7. The overvoltage protection circuit according to claim 6, characterized in that, The fourth switching component is an N-channel field-effect transistor. The gate of the fourth switching component is electrically connected to the power input terminal, the drain of the fourth switching component is electrically connected to the first ground terminal, and the source of the fourth switching component is electrically connected to the second ground terminal.

8. The overvoltage protection circuit according to claim 6, characterized in that, It also includes a third load unit, one end of which is electrically connected to the power input terminal, and the other end of which is electrically connected to the first pole of the fourth switching assembly.

9. The overvoltage protection circuit according to claim 1, characterized in that, It also includes a fourth load unit, one end of which is electrically connected to the power input terminal, and the other end of which is electrically connected to one end of the voltage regulator unit.

10. A car air freshener, characterized in that, Includes the overvoltage protection circuit as described in any one of claims 1 to 9.

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