An overcurrent protection circuit and earphone charging bin

Abstract

This invention discloses an overcurrent protection circuit and an earphone charging case, relating to the field of electronic circuit technology. The overcurrent protection circuit includes: a power input interface; a voltage regulator; a power adapter, the output of which is connected to the input of the power input interface; a temperature detection module, the input of which is connected to the voltage regulator, and the output of which outputs a temperature-sensing voltage based on the operating temperature of the power input interface; and a temperature response branch, the input of which is connected to the output of the temperature detection module, and the output of which is connected to the power input interface. The temperature response branch is used to conduct when the temperature-sensing voltage exceeds a reference voltage, forming a low-resistance path in parallel with the power input interface, causing the output current of the power adapter to exceed a preset overcurrent protection value, thereby triggering the overcurrent protection function of the power adapter. This invention can improve the reliability of overcurrent protection while reducing its cost.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to an overcurrent protection circuit and an earphone charging case. Background Technology

[0002] In the field of earphone charging cases, the safety issue of the charging port overheating and causing the casing to melt has attracted much attention. Especially during the charging process, when the charging port is short-circuited due to foreign object intrusion or the formation of a local low-resistance path, if the overcurrent protection function of the power adapter is not triggered in time, the charging port will heat up rapidly due to the sudden increase in input current, leading to the risk of casing melting.

[0003] To prevent interface damage or fuse failure due to overheating, existing charging circuits typically utilize integrated control chips for overcurrent protection triggering. However, overcurrent triggering methods based on integrated control chips usually require high chip performance, rely on multiple analog-to-digital converter interfaces, and are complex to design and costly to implement. Furthermore, if the integrated control chip is damaged or fails, the overcurrent protection function cannot be triggered, leading to the risk of fuse failure. Utility Model Content

[0004] The purpose of this invention is to overcome at least one of the shortcomings of the prior art and provide an overcurrent protection circuit and an earphone charging case. By linking the temperature detection module with the temperature response branch, overcurrent protection can be triggered under abnormal temperature rise without relying on an integrated control chip. This can improve the reliability of overcurrent protection while reducing the cost of the overcurrent protection circuit.

[0005] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

[0006] According to one aspect of this utility model, an overcurrent protection circuit is provided, comprising: a power input interface; a voltage regulator; a power adapter, the output terminal of which is connected to the input terminal of the power input interface; a temperature detection module, the input terminal of which is connected to the voltage regulator, and the output terminal of which outputs a temperature sensing voltage according to the operating temperature of the power input interface; and a temperature response branch, the input terminal of which is connected to the output terminal of the temperature detection module, and the output terminal of which is connected to the power input interface. The temperature response branch is used to conduct when the temperature sensing voltage is greater than a reference voltage, and to form a low-resistance path in parallel with the power input interface, so that the output current of the power adapter is greater than a preset overcurrent protection value, thereby triggering the overcurrent protection function of the power adapter.

[0007] The overcurrent protection circuit provided by this invention does not rely on an integrated control chip. Overcurrent triggering can be achieved solely through hardware circuitry. The overall architecture consists of a power input interface, a voltage regulator, a power adapter, a temperature detection module, and a temperature response branch. Through the coordinated operation of these hardware units, under abnormal temperature rise conditions, the temperature response branch forms a low-resistance path in parallel with the power input interface. This ensures that the output current of the power adapter exceeds the overcurrent protection value, thereby triggering the overcurrent protection function of the power adapter. In contrast, related technologies typically rely on integrated control chips to monitor the output current of the power adapter and control overcurrent protection triggering through program logic. These technologies are highly dependent on chip performance and analog-to-digital conversion interface resources, leading to greater design complexity and higher overall cost. The overcurrent protection circuit in this invention effectively avoids these problems.

[0008] On the one hand, this utility model senses the operating temperature of the power input interface through a temperature detection module. The temperature detection module outputs a temperature sensing voltage based on the operating temperature to conduct the temperature response branch, thereby triggering the overcurrent protection function of the power adapter. The entire judgment and execution process does not require analog-to-digital conversion, digital logic judgment or software participation, thus significantly reducing circuit complexity.

[0009] On the other hand, since the overcurrent protection circuit in this utility model is entirely composed of hardware components, even if the external integrated control chip is damaged or fails, the circuit can still independently complete the triggering of overcurrent protection by relying on the linkage between hardware, thereby improving the stability of overcurrent protection under abnormal operating conditions.

[0010] On the other hand, the temperature response branch automatically turns on when the induced voltage exceeds the reference voltage, rapidly increasing the power adapter's output current to the overcurrent protection value through a low-resistance path connected in parallel with the power input interface, thereby triggering the power adapter's overcurrent protection function. This method eliminates the need for real-time detection of the power adapter's output current, enabling overcurrent protection even in scenarios where the output current has not significantly increased but there is already a risk of abnormal heating, effectively improving the response sensitivity and reliability of overcurrent triggering.

[0011] In some exemplary embodiments of this utility model, based on the foregoing solution, the overcurrent protection circuit may further include an overcurrent protection module. The input terminal of the overcurrent protection module is connected to the output terminal of the temperature response branch, and the output terminal of the overcurrent protection module is connected to the input terminal of the load circuit. When the input current of the overcurrent protection module is greater than a preset threshold value, the overcurrent protection module disconnects the current input to the load circuit.

[0012] In this embodiment, by incorporating an overcurrent protection module into the overcurrent protection circuit, the power supply path to the load circuit can be immediately cut off when the input current of the overcurrent protection module exceeds a preset threshold, forming an effective overvoltage isolation channel. On one hand, the overcurrent protection module can quickly block excessive current from entering the load circuit when the temperature response branch conducts, causing a sudden increase in the output current of the power adapter, effectively preventing component damage, circuit breakdown, and other faults caused by abnormal voltage. On the other hand, when the input current of the overcurrent protection module exceeds the threshold due to abnormal phenomena such as internal short circuits in the overcurrent protection circuit, it can effectively prevent overload current from entering the load circuit.

[0013] In some exemplary embodiments of this utility model, based on the foregoing scheme, the temperature detection module may include a thermistor voltage divider circuit, the input terminal of which is connected to the output terminal of the voltage regulator, the first output terminal of which is used to output the temperature sensing voltage to the temperature response branch, and the second output terminal of which is grounded.

[0014] In this embodiment, by incorporating a thermistor voltage divider circuit into the temperature detection module, a temperature-sensing voltage related to the current operating temperature of the power input interface can be output in real time, utilizing the characteristic that the resistance of the temperature-sensitive element changes with temperature, under the constant voltage provided by the voltage regulator. Firstly, this structure eliminates the need for current sampling and amplification circuits, simplifying circuit design. Secondly, this voltage divider circuit achieves continuous monitoring of the thermal state of the power input interface without the need for an analog-to-digital converter or complex logic units, thereby improving the real-time performance and stability of temperature detection. Furthermore, the temperature-sensing voltage output from the first output terminal of the thermistor voltage divider circuit can be directly used as the trigger for the temperature response branch, enabling the temperature response branch to conduct promptly when the operating temperature of the power input interface is too high, enhancing the timeliness and accuracy of the overcurrent protection triggering process.

[0015] In some exemplary embodiments of this utility model, based on the foregoing scheme, the above-mentioned thermistor voltage divider circuit includes a thermistor, the first end of which is connected to the output terminal of the voltage regulator, and the second end of which is connected to the input terminal of the temperature response branch; and a first voltage divider resistor, the first end of which is connected to the second end of the thermistor, and the second end of which is grounded.

[0016] In this embodiment, the thermistor voltage divider circuit connects a thermistor and a first voltage divider resistor in series between the output of the voltage regulator and ground, forming a voltage divider node that can dynamically adjust with temperature changes. This allows the operating temperature of the power input interface to be mapped to a temperature-sensing voltage. On one hand, as the ambient temperature rises, the resistance of the thermistor decreases, and the voltage across it drops, causing the voltage at the voltage divider node to rise, reflected as an increase in the temperature-sensing voltage. Conversely, when the temperature decreases, the resistance of the thermistor rises, and the voltage at the voltage divider node decreases, reflected as a decrease in the temperature-sensing voltage. This enables precise sensing of changes in the operating temperature of the power input interface. On the other hand, the thermistor voltage divider circuit operates based on the stable voltage provided by the voltage regulator. Combined with the temperature-sensitive characteristics of the thermistor itself, it can operate independently without the need for an integrated control chip.

[0017] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the temperature detection module includes a reference voltage output circuit. The input terminal of the reference voltage output circuit is connected to the output terminal of the voltage regulator. The first output terminal of the reference voltage output circuit is used to output the reference voltage to the temperature response branch, and the second output terminal of the reference voltage output circuit is grounded.

[0018] In this embodiment, the input terminal of the reference voltage output circuit is connected to the output terminal of the voltage regulator, and can generate a constant reference voltage signal based on the stable voltage provided by the voltage regulator; the first output terminal of the reference voltage output circuit is used to output a reference voltage to the temperature response branch, thereby providing a voltage reference for the judgment of the temperature sensing voltage; the second output terminal of the reference voltage output circuit is grounded, which can form a stable voltage divider circuit to ensure that the output reference voltage value is not affected by external noise or power fluctuations.

[0019] In some exemplary embodiments of this utility model, based on the foregoing scheme, the reference voltage output circuit may include a second voltage divider resistor and a third voltage divider resistor. The first end of the second voltage divider resistor is connected to the output terminal of the voltage regulator, and the second end of the second voltage divider resistor is connected to the input terminal of the temperature response branch. The first end of the third voltage divider resistor is connected to the second end of the second voltage divider resistor, and the second end of the third voltage divider resistor is grounded. The resistance value of the second voltage divider resistor is the same as that of the third voltage divider resistor.

[0020] In this embodiment, by setting a second and a third voltage-dividing resistor with the same resistance value in the reference voltage output circuit, the constant voltage output by the regulator can be proportionally divided to form a stable reference voltage signal. This reference voltage can serve as the judgment benchmark for the temperature response branch, ensuring that the temperature-sensing voltage can accurately trigger the conduction of the temperature response branch when it exceeds the reference voltage. This improves the accuracy and consistency of temperature anomaly detection and overcurrent protection triggering.

[0021] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the temperature response branch includes a voltage signal generation module and a switching device. The voltage signal generation module is connected to the output terminal of the temperature detection module. The voltage signal generation module is used to output a first level signal when the temperature sensing voltage is greater than a reference voltage, and to output a second level signal when the temperature sensing voltage is less than or equal to the reference voltage. The first terminal of the switching device is connected to the output terminal of the voltage signal generation module, the second terminal of the switching device is connected to the power input interface, the switching device is used to conduct when receiving the first level signal, and the third terminal of the switching device is grounded.

[0022] In this embodiment, when the operating temperature of the power input interface rises, causing the temperature-sensing voltage to exceed the reference voltage, the voltage signal generation module immediately outputs a first-level signal to drive the switching device to conduct, thereby establishing a low-impedance path in parallel with the power input interface. This causes a sudden surge in the output current of the power adapter, triggering subsequent overcurrent protection. The temperature response branch structure, composed of the voltage signal generation module and the switching device, is simple and can achieve accurate overcurrent protection triggering without relying on an integrated control chip. Furthermore, when the temperature-sensing voltage of the voltage signal generation module is less than or equal to the reference voltage, it outputs a second-level signal, which ensures that the switching device is in the off state when the operating temperature of the power input interface is normal. This avoids false triggering of the overcurrent protection mechanism, ensures that the normal power supply process is not disturbed, and improves the reliability of overcurrent protection triggering.

[0023] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the voltage signal generation module includes a voltage comparator. The positive input terminal of the voltage comparator receives the reference voltage, the negative input terminal of the voltage comparator receives the temperature sensing voltage, and the output terminal of the voltage comparator outputs a first level signal when the temperature sensing voltage is greater than the reference voltage.

[0024] In this embodiment, a voltage comparator is introduced into the voltage signal generation module, enabling it to output a corresponding level signal based on the potential difference between the reference voltage and the temperature sensing voltage. The output transition is triggered when the temperature sensing voltage is slightly higher than the reference voltage, ensuring clear boundaries and rapid response in the temperature judgment process and avoiding ambiguity in judgment caused by the temperature sensing voltage approaching the critical value. In addition, the voltage comparator can accurately convert the analog voltage that changes with the operating temperature of the power input interface into a stable level signal, providing a clear control basis for the conduction or cutoff of switching devices and improving the reliability and response speed of overcurrent protection.

[0025] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the temperature detection module includes a first filter capacitor and a second filter capacitor. The first end of the first filter capacitor is connected to the output end of the voltage regulator, and the second end of the first filter capacitor is grounded. The first end of the second filter capacitor is connected to the input end of the temperature response branch, and the second end of the second filter capacitor is grounded.

[0026] In this embodiment, the introduction of a first filter capacitor and a second filter capacitor in the temperature detection module creates a dual filtering path between the voltage regulator and the temperature response branch. Specifically, the first filter capacitor forms a low-pass filter branch to ground at the voltage regulator output, effectively suppressing high-frequency noise and ripple components in the voltage regulator output voltage, thereby providing a more stable input voltage for the thermistor voltage divider circuit and the reference voltage output circuit. The second filter capacitor receives the temperature-sensing voltage from the thermistor voltage divider circuit, performs transient suppression and high-frequency noise filtering on the temperature-sensing voltage signal, making the temperature-sensing voltage of the input temperature response branch more stable. This improves the accuracy of the temperature response branch in judging the temperature status of the power input interface and reduces the risk of false triggering of overcurrent protection due to voltage fluctuations.

[0027] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the voltage regulator is a low-dropout linear regulator. The input terminal of the low-dropout linear regulator is connected to the power supply, the output terminal of the low-dropout linear regulator is connected to the input terminal of the temperature detection module, the ground terminal of the low-dropout linear regulator is grounded, and the enable terminal of the low-dropout linear regulator is in a high-level state.

[0028] In this embodiment, because the low-dropout linear regulator has the ability to operate stably even when there is only a small difference between the input and output voltages, the above connection method can still provide a stable and low-noise input voltage to the temperature detection module under power supply voltage fluctuations, effectively improving the accuracy of the temperature sensing voltage and the reference voltage. Simultaneously, setting the enable pin to a high level ensures that the regulator remains active, preventing power interruption to the temperature detection module due to abnormal enable logic.

[0029] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the voltage regulator includes a pull-up resistor, the first end of which is connected to the power supply, and the second end of which is connected to the enable terminal.

[0030] In this embodiment, a pull-up resistor is used to raise the enable pin level, ensuring that the voltage regulator remains enabled even without an external signal. The pull-up resistor prevents the voltage regulator from accidentally shutting down or malfunctioning due to the enable pin being left floating, thus ensuring a stable output of a constant voltage signal and improving the power supply reliability to the temperature detection module.

[0031] In some exemplary embodiments of this utility model, based on the aforementioned scheme, the voltage regulator includes a third filter capacitor, the first end of which is connected to the input terminal of the voltage regulator, and the second end of which is grounded.

[0032] In this embodiment, the third filter capacitor can be used to filter the power signal at the input of the voltage regulator, which can effectively suppress high-frequency noise and transient interference in the input voltage, thereby improving the stability of the voltage at the input of the voltage regulator and ensuring that the voltage regulator outputs a constant voltage.

[0033] In some exemplary embodiments of this utility model, based on the foregoing scheme, the power input interface includes a transient voltage suppression diode, the first end of which is connected to the output end of the power input interface, and the second end of which is grounded.

[0034] In this embodiment, when electrostatic discharge or other transient voltage disturbances occur at the output terminal of the power input interface, the transient voltage suppression diode can quickly break down and conduct under high voltage to form a low-resistance discharge path, introducing the abnormal voltage to the ground wire, thereby limiting the voltage amplitude acting on the subsequent circuit, which helps to improve the protection capability of the entire circuit against transient high voltage impacts and enhance the circuit's operational stability and anti-interference capability.

[0035] In some exemplary embodiments of this utility model, based on the foregoing solution, the power input interface further includes an interface connector and a pull-down resistor. The interface connector is used to connect to a power adapter. The first end of the pull-down resistor is connected to the interface connector, and the second end of the pull-down resistor is grounded.

[0036] In this embodiment, by setting an interface connector and a pull-down resistor in the power input interface, the pull-down resistor can be used to pull the level of the configuration channel of the interface connector to a low potential while ensuring reliable power adapter connection. This enables rapid identification of the power connection status and avoids misjudgments caused by floating pins. Simultaneously, grounding the pull-down resistor reduces static current interference, improving the anti-interference capability and operational reliability of the entire overcurrent protection circuit.

[0037] According to another aspect of the present invention, an earphone charging case is provided, the earphone charging case including a load circuit and an overcurrent protection circuit as described in any of the above embodiments, wherein the overcurrent protection circuit triggers the overcurrent protection function of the power adapter to interrupt the power supply to the load circuit when the output current of the power adapter is greater than the overcurrent protection value.

[0038] In this embodiment, by incorporating an overcurrent protection circuit connected in series with the load circuit in the earphone charging case, the charging case is equipped with the ability to trigger the power adapter's overcurrent protection function. When the output current of the power adapter exceeds the set overcurrent protection value, the overcurrent protection circuit can interrupt the power supply path of the power adapter, thus forming an overcurrent protection mechanism that does not require intervention from the integrated control chip. This overcurrent protection mechanism can respond quickly to sudden current surges such as short circuits at the power input interface, preventing battery overheating or circuit damage, and further enhancing the operational safety of the earphone charging case. Attached Figure Description

[0039] The above and other features and advantages of this invention will become more apparent from a detailed description of exemplary embodiments with reference to the accompanying drawings.

[0040] Figure 1 This is a schematic diagram of the structural composition of one embodiment of the overcurrent protection circuit provided by this utility model.

[0041] Figure 2 This is a schematic diagram of the structural composition of another embodiment of the overcurrent protection circuit provided by this utility model.

[0042] Figure 3 This is a schematic diagram of the structural composition of another embodiment of the overcurrent protection circuit provided by this utility model.

[0043] Figure 4 This is a circuit diagram of one embodiment of the voltage regulator, temperature detection module and voltage comparator provided by this utility model.

[0044] Figure 5 This is a schematic diagram of the structural composition of another embodiment of the overcurrent protection circuit provided by this utility model.

[0045] Figure 6 This is a circuit diagram illustrating one embodiment of the power input interface and switching device provided by this utility model.

[0046] Figure 7 This is a schematic diagram illustrating the working process of one embodiment of the overcurrent protection circuit provided by this utility model.

[0047] Explanation of reference numerals in the attached figures

[0048] 1. Power input interface; 101. Transient voltage suppression diode; 102. Interface connector; 103. First pull-down resistor; 104. Second pull-down resistor;

[0049] 2. Voltage regulator; 201. Pull-up resistor; 202. Third filter capacitor;

[0050] 3. Temperature detection module; 31. Thermistor voltage divider circuit; 311. Thermistor; 312. First voltage divider resistor; 32. Reference voltage output circuit; 321. Second voltage divider resistor; 322. Third voltage divider resistor; 301. First filter capacitor; 302. Second filter capacitor;

[0051] 4. Temperature response branch; 41. Voltage comparator; 42. Switching device;

[0052] 5. Power adapter;

[0053] 6. Overcurrent protection module;

[0054] 7. Load circuit. Detailed Implementation

[0055] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0056] The features, structures, or characteristics described above can be combined in any suitable manner in one or more embodiments, and the features discussed in the various embodiments are interchangeable where possible. In the above description, numerous specific details are provided to give a full understanding of embodiments of the present invention. However, those skilled in the art will recognize that the technical solutions of the present invention can be practiced without one or more of the specific details described, or other methods, components, materials, etc., can be employed. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring various aspects of the present invention.

[0057] Although relative terms such as "up" and "down" are used in this invention to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the example shown in the accompanying drawings. It is understood that if the icon's arrangement is flipped so that it is upside down, the component described as "up" will become the component described as "down". Other relative terms such as "high", "low", "top", "bottom", "front", "back", "left", and "right" also have similar meanings. When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0058] In this utility model, the terms "a", "an", "the", "the", and "at least one" are used to indicate the existence of one or more elements / components / etc.; the terms "comprising", "including", and "having" are used to indicate an open-ended meaning of inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.

[0059] According to one aspect of this utility model, an overcurrent protection circuit is provided. (Reference) Figure 1 As shown, the overcurrent protection circuit may include a power input interface 1, a voltage regulator 2, a temperature detection module 3, a temperature response branch 4, and a power adapter 5. The output terminal of the power adapter 5 is connected to the input terminal of the power input interface 1. The input terminal of the temperature detection module 3 is connected to the voltage regulator 2, and its output terminal outputs a temperature-sensing voltage based on the operating temperature of the power input interface 1. The input terminal of the temperature response branch 4 is connected to the output terminal of the temperature detection module 3, and its output terminal is connected to the power input interface 1. The temperature response branch 4 is used to conduct when the temperature-sensing voltage exceeds a reference voltage, forming a low-resistance path in parallel with the power input interface 1, causing the output current of the power adapter 5 to exceed a preset overcurrent protection value, thereby triggering the overcurrent protection function of the power adapter 5.

[0060] Power input interface 1 represents an electrical connection unit for receiving power from an external power adapter. It introduces external power input into the overcurrent protection circuit and serves as the power supply input for subsequent modules. When the input current of power input interface 1, i.e., the output current of power adapter 5, exceeds the preset overcurrent protection value, the temperature of power input interface 1 is prone to continuous rise, leading to abnormal phenomena such as casing melting and circuit damage. Therefore, it is necessary to trigger overcurrent protection in a timely manner through linkage control of subsequent modules to avoid the risk of thermal damage. During charging, if power input interface 1 experiences a short circuit due to foreign object intrusion or the formation of a local low-resistance path, it is equivalent to forming a low-resistance loop between the power supply terminal and the ground terminal of power input interface 1, which is composed of foreign objects or a local low-resistance path. This causes a significant increase in the input current of power input interface 1, thereby causing its temperature to rise.

[0061] Voltage regulator 2 can represent a power management unit used to regulate the external input voltage and output a stable voltage, which can provide a constant voltage supply to the temperature detection module 3. By outputting a stable voltage, voltage regulator 2 can ensure that the temperature detection module 3 maintains accurate temperature sampling performance under different external input voltage fluctuations, thereby improving the response reliability and temperature control judgment accuracy of the entire overcurrent protection circuit.

[0062] The temperature detection module 3 represents a temperature sensing and signal conversion unit used to acquire the operating temperature of the power input interface 1 and convert it into a temperature sensing voltage for subsequent judgment. Its input terminal receives a stable voltage provided by the voltage regulator 2, and its output terminal can output a temperature sensing voltage reflecting the temperature change trend. The temperature sensing voltage can represent a voltage signal output by the temperature detection module 3, used to characterize the actual operating temperature change trend of the power input interface 1. For example, the magnitude of the temperature sensing voltage can increase as the operating temperature of the power input interface 1 increases. By converting the actual operating temperature of the power input interface 1 into a continuously changing temperature sensing voltage, the temperature detection module 3 can provide accurate thermal state information for the temperature response branch 4, thereby enabling timely identification of abnormal temperature rise and improving the overcurrent response sensitivity and safety assurance capability of the entire overcurrent protection circuit.

[0063] Temperature response branch 4 can represent a circuit unit that receives the temperature-sensing voltage output by temperature detection module 3 and controls its internal conduction state based on the comparison result between the temperature-sensing voltage and the reference voltage. Furthermore, temperature response branch 4 is in a conducting state when the temperature-sensing voltage is greater than the reference voltage. In the conducting state, the resistance of temperature response branch 4 is low, and one end of temperature response branch 4 is grounded, thus forming a low-impedance path in parallel with power input interface 1. The reference voltage can represent a voltage reference quantity used to compare with the temperature-sensing voltage to determine whether the current operating temperature of power input interface 1 exceeds a safe threshold. For example, the reference voltage can be provided by temperature detection module 3 or by an external reference voltage circuit, which can represent a voltage source for outputting the reference voltage to temperature response branch 4. The low-impedance path can represent a low-impedance current path established in parallel with power input interface 1 after the temperature response branch is turned on, used to increase the output current of power adapter 5. This can be achieved by setting a switching device in temperature response branch 4. When the temperature of power input interface 1 rises abnormally, it can be determined that a short circuit has occurred due to foreign object intrusion or the formation of a low-impedance path. However, because the impedance of this short circuit path is relatively high, the output current of power adapter 5 may not exceed the overcurrent protection value, thus failing to trigger the protection mechanism. At this time, by controlling the temperature response branch 4 to conduct, an auxiliary loop is formed in parallel with the internal short circuit path of power input interface 1. This loop, through switching devices and other structures, exhibits a low impedance characteristic far lower than the short-circuit impedance of power input interface 1 when in the conducting state, thereby significantly reducing the overall parallel equivalent impedance and ensuring that the output current of power adapter 5 exceeds the overcurrent protection value, thus successfully triggering the overcurrent protection function. The overcurrent protection value can be represented as the current boundary value used to determine whether the output current of power adapter 5 exceeds the safe threshold. When the output current of power adapter 5 exceeds the overcurrent protection value, it indicates a risk of thermal damage, and the overcurrent protection function of power adapter 5 needs to be triggered. Furthermore, the temperature response branch 4 can automatically turn on when the temperature sensing voltage exceeds the reference voltage, thereby forming a low-resistance path in parallel with the power input interface 1, causing the output current of the power adapter 5 to rise rapidly to the preset overcurrent protection value, thereby triggering the overcurrent protection function of the power adapter 5, realizing overcurrent triggering without the need for integrated control chip control, thus effectively preventing charging interface damage or fuse problems caused by abnormal temperature rise, and improving the safety and reliability of the charging process.

[0064] Power adapter 5 can represent a power supply device that provides a constant DC voltage output to a power input interface. Its input terminal can be connected to an AC power source or a previous DC power supply, and its output terminal is connected to the power input interface. The power adapter may be equipped with a current limiting module for overcurrent protection. When the output current of the power adapter exceeds the overcurrent protection value, the power adapter automatically triggers the overcurrent protection function, cutting off or limiting the current output to prevent damage to downstream circuits due to excessive current.

[0065] To provide multiple layers of protection for the load circuit, in some embodiments, reference is made to... Figure 2 As shown, the overcurrent protection circuit in this utility model may further include an overcurrent protection module 6. The input terminal of the overcurrent protection module 6 is connected to the output terminal of the temperature response branch 4, and the output terminal of the overcurrent protection module 6 is connected to the input terminal of the load circuit 7. When the input current of the overcurrent protection module 6 exceeds a preset threshold value, the overcurrent protection module 6 disconnects the current input to the load circuit 7.

[0066] The load circuit 7 can represent the downstream power circuit connected to the overcurrent protection circuit. Specifically, the overcurrent protection module 6 can monitor its input current in real time. When the input current exceeds a preset threshold, it immediately disconnects its output path, blocking the current flowing to the load circuit 7, thereby preventing damage to the load circuit 7 due to current surges. Using the overcurrent protection module 6, a second layer of protection is provided after the temperature response branch 4 is turned on, preventing overcurrent caused by internal circuit faults, electrical short circuits, or device failures from continuing to flow to the load circuit 7, effectively improving the safety of the overcurrent protection circuit. Preferably, the input current threshold of the overcurrent protection module 6 can be set to be less than the overcurrent protection value of the power adapter 5, so that when an abnormal current rise trend occurs, the overcurrent protection module 6 can preferentially disconnect the input current of the load circuit 7, preventing overcurrent damage to the load circuit 7.

[0067] In one embodiment, the overcurrent protection module 6 can be an overvoltage protection (OVP) device. Specifically, when the temperature response branch 4 is turned on, it forms a low-resistance parallel path with the power input interface 1, causing a sudden increase in the input current of the power input interface 1, which in turn causes its output voltage to rise rapidly. During this process, the input voltage received by the input terminal of the overvoltage protection module 6 also increases accordingly. When the input voltage exceeds the preset overvoltage threshold of the overvoltage protector, the overvoltage judgment circuit inside the overvoltage protector immediately triggers the overvoltage protection, controlling its internal switch to disconnect the conduction path between the input and output, thereby disconnecting the current input to the load circuit 7. In addition, when the input voltage received by the input terminal of the overvoltage protection module 6 is less than or equal to the preset overvoltage threshold, its internal switch remains closed, keeping the conduction path between the input and output unchanged, thereby ensuring that the load circuit 7 can normally obtain the current provided by the power input interface 1 and realize the normal power supply to the downstream electrical equipment.

[0068] In another embodiment, the overcurrent protection module 6 may include a metal-oxide-semiconductor (MOSFET) and a voltage control circuit. The source of the MOSFET is connected to the output of the power input interface 1, the drain is connected to the load circuit 7, and the gate is connected to the output of the temperature response branch 4 via the voltage control circuit. When the temperature response branch 4 is turned on, it forms a low-impedance parallel path with the power input interface 1, causing a sudden increase in the input current of the power input interface 1. This sudden current, flowing through the source-drain path of the overcurrent protection module 6, causes the source potential to rise rapidly. The voltage control circuit may include a current sampling resistor connected in series with the source and a voltage comparator for real-time monitoring of the source current. The current sampling resistor converts the current change through the source-drain path into a corresponding voltage signal and inputs this voltage signal to the voltage comparator. The voltage comparator compares the sampled voltage with a preset voltage reference value. When the sampled voltage exceeds the voltage reference value, it outputs a control signal to drive the gate voltage of the MOSFET to drop rapidly. Once the gate voltage falls below the threshold voltage, the metal-oxide-semiconductor field-effect transistor (MOSFET) transitions from the on state to the off state, disconnecting the main current path between its source and drain, thereby interrupting the power supply from the power input interface 1. Since the power supply path between the power input interface 1 and the overcurrent protection module 6 has been cut off by the overcurrent protection module 6, the power supply cannot continue to provide current to the load circuit 7, effectively avoiding the risk of the charging interface continuously overheating and causing a fuse.

[0069] In another embodiment, the overcurrent protection module 6 may include a mechanical relay and a control circuit connected to the drive end of the mechanical relay. The mechanical relay may represent an electromagnetically driven mechanical switching element, with its normally closed contacts connected in series between the output end of the power input interface 1 and the load circuit 7. One end of the electromagnetic coil of the mechanical relay is connected to the output end of the temperature response branch 4, and the other end is connected to the power supply end, which may be a voltage regulator 2. Under normal operating conditions, the temperature response branch 4 is not conducting, the mechanical relay maintains its normally closed contacts in a closed state, and the power input interface 1 can normally supply power to the load circuit 7. When the temperature detection module 3 detects an abnormal increase in the operating temperature of the power input interface 1 and outputs a corresponding temperature sensing voltage, the temperature response branch 4 is turned on, thus forming a low-resistance parallel path with the power input interface 1, causing a sudden increase in the input current of the power input interface 1. This sudden current flows into the electromagnetic coil of the relay, generating an enhanced magnetic field inside the coil. As the magnetic field strength rises rapidly, when it reaches the operating threshold of the mechanical relay, the internal armature structure is subjected to magnetic force to overcome the return force of the restoring spring, quickly attracting and driving the normally closed contacts to open. At this point, the main current path that originally connected the power input interface 1 and the load circuit 7 is physically cut off, and the power supply no longer supplies power to the load circuit 7, thereby achieving a rapid disconnection of the charging path.

[0070] In order to provide a temperature-sensing voltage to the temperature response branch 4, in some embodiments, reference is made to... Figure 3 As shown, the temperature detection module 3 may include a thermistor voltage divider circuit 31, wherein the input terminal of the thermistor voltage divider circuit 31 is connected to the output terminal of the voltage regulator 2, the first output terminal of the thermistor voltage divider circuit 31 is used to output a temperature sensing voltage to the temperature response branch 4, and the second output terminal of the thermistor voltage divider circuit 31 is grounded.

[0071] The thermistor voltage divider circuit 31 can represent a circuit unit composed of a temperature-sensitive element and a fixed-value voltage divider resistor connected in series. Under constant voltage input conditions, it can convert the operating temperature of the power input interface 1 into a corresponding temperature-sensing voltage based on the characteristic that the resistance of the temperature-sensitive element changes with temperature. For example, the connection point between the temperature-sensitive element and the voltage divider resistor can be used as the first output terminal of the thermistor voltage divider circuit 31 to output the temperature-sensing voltage, and the second output terminal of the thermistor voltage divider circuit 31 can be grounded. This ensures that the temperature-sensing voltage can change relative to a stable and definite zero potential, improving the accuracy of the sensing voltage output and the consistency of the voltage response, and avoiding misjudgments in the temperature response branch 4 caused by floating or uncertain potential.

[0072] refer to Figure 4The circuit diagram shown illustrates that, in some embodiments, the thermistor voltage divider circuit 31 may include a thermistor 311 and a first voltage divider resistor 312. The first terminal of the thermistor 311 is connected to the output terminal of the voltage regulator 2, and the second terminal of the thermistor 311 is connected to the input terminal of the temperature response branch 4. The resistance of the thermistor 311 is inversely proportional to the operating temperature. The first terminal of the first voltage divider resistor 312 is connected to the second terminal of the thermistor 311, and the second terminal of the first voltage divider resistor 312 is grounded.

[0073] The thermistor 311 can represent a temperature-sensitive element that responds to temperature changes, with its resistance decreasing as the operating temperature of the power input interface 1 increases. The first voltage divider resistor 312 can represent a resistor with a fixed resistance value, used to form a voltage divider structure with the thermistor 311.

[0074] Furthermore, the first terminal of the thermistor 311 is connected to the output terminal of the voltage regulator 2 to obtain a stable supply voltage; the second terminal of the thermistor 311 is connected to the input terminal of the temperature response branch 4 to transmit the temperature-sensing voltage to the subsequent circuit; the first terminal of the first voltage divider resistor 312 is electrically connected to the second terminal of the thermistor 311, and the second terminal is grounded to form a standard series voltage divider path. Through this connection method, when the external ambient temperature rises, the resistance of the thermistor 311 decreases, causing the voltage across it to drop. This causes the voltage value corresponding to the first terminal of the first voltage divider resistor 312, the intermediate node of the thermistor voltage divider circuit 31, to rise. This voltage is the temperature-sensing voltage related to temperature, used to drive the temperature response branch 4 to perform subsequent response operations.

[0075] For example, the resistance of the first voltage divider resistor 312 can be 10KΩ or other suitable values, and the thermistor 311 can be a negative temperature coefficient (NTC) thermistor. An NTC temperature sensor represents a thermistor with a negative temperature coefficient, whose resistance decreases as temperature increases, and is typically made of semiconductor ceramic material. The NTC temperature sensor can generate a temperature-dependent voltage signal by utilizing its temperature-dependent resistance characteristics in conjunction with the external voltage divider resistor, without requiring active power.

[0076] In order to provide a reference voltage to the temperature response branch 4, in some embodiments, the reference voltage is... Figure 3 As shown, the temperature detection module 3 may include a reference voltage output circuit 32. The input terminal of the reference voltage output circuit 32 is connected to the output terminal of the voltage regulator 2. The first output terminal of the reference voltage output circuit 32 is used to output a reference voltage to the temperature response branch 4, and the second output terminal of the reference voltage output circuit 32 is grounded.

[0077] The reference voltage output circuit 32 provides a stable reference voltage for comparison with the temperature-sensing voltage. Specifically, the input of the reference voltage output circuit 32 is connected to the output of the voltage regulator 2 to obtain a constant voltage, ensuring the stability and consistency of the reference voltage output. The first output of the reference voltage output circuit 32 provides a reference voltage to the temperature response branch 4 as a comparison benchmark for the temperature-sensing voltage. The second output is grounded, forming a closed loop in the voltage divider path of the reference voltage output circuit 32, thus ensuring stable circuit operation. By directly connecting the reference voltage output circuit 32 to the voltage regulator 2 and generating a stable reference voltage signal through a voltage divider structure, this structure can provide a reliable judgment reference voltage for the temperature response branch 4 without the need for an additional control chip.

[0078] refer to Figure 4 The circuit diagram shown illustrates that, in some embodiments, the reference voltage output circuit 32 may include a second voltage divider resistor 321 and a third voltage divider resistor 322. The first end of the second voltage divider resistor 321 is connected to the output terminal of the voltage regulator 2, and the second end of the second voltage divider resistor 321 is connected to the input terminal of the temperature response branch 4. The first end of the third voltage divider resistor 322 is connected to the second end of the second voltage divider resistor 321, and the second end of the third voltage divider resistor 322 is grounded. The resistance values ​​of the second voltage divider resistor 321 and the third voltage divider resistor 322 are the same.

[0079] The reference voltage output circuit 32 can output a stable reference voltage signal by proportionally dividing the constant voltage provided by the voltage regulator 2. Specifically, the reference voltage output circuit 32 may include a second voltage divider resistor 321 and a third voltage divider resistor 322. The first end of the second voltage divider resistor 321 is electrically connected to the output terminal of the voltage regulator 2, and the second end is connected to the input terminal of the temperature response branch 4, so as to introduce a portion of the voltage signal of the regulated voltage into the input terminal of the temperature response branch 4. The first end of the third voltage divider resistor 322 is connected to the second end of the second voltage divider resistor 321, and the second end is grounded, so as to form a complete voltage divider circuit. Furthermore, the resistance values ​​of the second voltage divider resistor 321 and the third voltage divider resistor 322 are set to be the same, so that the voltage divider structure can output a reference voltage of approximately half of the output voltage of the voltage regulator 2, which helps to improve the comparison accuracy between the temperature sensing voltage and the reference voltage, and ensures that the temperature response branch 4 can accurately trigger the conduction action when the temperature sensing voltage is greater than the reference voltage, thereby realizing an accurate response to the overcurrent trigger action. For example, the resistance values ​​of the second voltage divider resistor 321 and the third voltage divider resistor 322 are both 10KΩ. Of course, in other embodiments of this disclosure, the resistance values ​​of the second voltage divider resistor 321 and the third voltage divider resistor 322 can be set according to actual needs.

[0080] To ensure accurate conduction determination and response based on a reference voltage and a temperature-sensing voltage, in some embodiments, a reference voltage is used. Figure 5 As shown, the temperature response branch 4 includes a voltage signal generation module and a switching device 42. The voltage signal generation module is connected to the output terminal of the temperature detection module 3. The voltage signal generation module is used to output a first level signal when the temperature sensing voltage is greater than the reference voltage, and to output a second level signal when the temperature sensing voltage is less than or equal to the reference voltage. The first terminal of the switching device 42 is connected to the output terminal of the voltage signal generation module, the second terminal of the switching device 42 is connected to the power input interface 1, the switching device 42 is used to conduct when it receives the first level signal, and the third terminal of the switching device 42 is grounded.

[0081] The voltage signal generation module receives the temperature-sensing voltage and reference voltage from the temperature detection module 3, compares them, and generates a corresponding level signal. Specifically, the input terminals of the voltage signal generation module are connected to the output terminals of the thermistor voltage divider circuit 31 and the reference voltage output circuit 32, respectively. An internal voltage comparator determines the magnitude relationship between the temperature-sensing voltage and the reference voltage. When the temperature-sensing voltage is greater than the reference voltage, the voltage signal generation module outputs a first level signal; when the temperature-sensing voltage is less than or equal to the reference voltage, it outputs a second level signal. The first terminal of the switching device 42 is connected to the output terminal of the voltage signal generation module, the second terminal is connected to the power input interface 1, and the third terminal is grounded. When the first level signal is received, the switching device 42 enters the conducting state, forming a low-impedance path in parallel with the power input interface 1, thereby causing a rapid increase in the input current of the power input interface 1, providing a trigger condition for subsequent overcurrent protection action. Specifically, after the switching device 42 is turned on, a low-impedance loop is formed between the power supply terminal of the power input interface 1 connected to the second terminal and the third terminal. This loop forms a parallel structure with the short-circuit path caused by foreign objects or impurities. Since the switching device 42 has a conduction impedance much smaller than the original short-circuit path when it is on, the overall parallel equivalent impedance is significantly reduced, thereby causing the output current of the power adapter 5 to rise rapidly above its built-in overcurrent protection threshold. When the second level signal is received, the switching device 42 remains in the off state, and the circuit maintains normal operation.

[0082] To accurately compare the temperature-sensing voltage and the reference voltage, in some embodiments, the reference voltage is... Figure 4 As shown, the voltage signal generation module includes a voltage comparator 41. The positive input terminal of the voltage comparator 41 receives a reference voltage, the inverting input terminal of the voltage comparator 41 receives a temperature sensing voltage, and the output terminal of the voltage comparator 41 outputs a first level signal when the temperature sensing voltage is greater than the reference voltage.

[0083] Specifically, the voltage comparator 41 includes at least a positive input terminal (IN+), an inverting input terminal (IN-), and an output terminal (OUT). The positive input terminal receives the reference voltage output from the reference voltage output circuit 32 in the temperature detection module 3, and the inverting input terminal receives the temperature-sensing voltage generated by the thermistor voltage divider circuit 31. When the temperature-sensing voltage is higher than the reference voltage, the voltage comparator 41 drives its output terminal to output a first-level signal to control the switching device 42 to be in the on state. When the temperature-sensing voltage is not higher than the reference voltage, the voltage comparator 41 drives its output terminal to output a second-level signal to control the switching device 42 to be in the off state. Furthermore, the power supply terminal of the voltage comparator 41 is connected to an external power supply voltage VBAT, and the ground terminal of the voltage comparator 41 is grounded to establish a unified potential reference, enabling the voltage comparator 41 to accurately determine the magnitude relationship between the reference voltage and the temperature-sensing voltage.

[0084] To accurately achieve the on / off state of temperature response branch 4, in some embodiments, reference is made to... Figure 6 As shown, the switching device 42 can be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), which includes a gate (G), a drain (D), and a source (S). The gate is connected to the output of the voltage signal generation module; the drain is connected to the power input interface 1; and the source is grounded. Specifically, the gate of the MOSFET is connected to the output of the voltage comparator 41. Specifically, when the temperature-sensing voltage is greater than the reference voltage, the MOSFET turns on, forming a low-impedance path between the drain and source. This allows the power supply terminal of the power input interface 1 to be grounded via the MOSFET's conduction path, thus establishing a low-impedance loop between the power supply terminal of the power input interface 1 and ground. This low-impedance loop is connected in parallel with the original high-impedance short-circuit path formed by foreign objects or local low resistance, significantly reducing the equivalent impedance of the overall loop and causing the output current of the power adapter 5 to rise rapidly beyond its overcurrent protection value.

[0085] Of course, in other embodiments of this disclosure, the switching device 42 can also be a bipolar transistor (BJT), an insulated-gate bipolar transistor (IGBT), or other suitable electrical components with conduction and cutoff control capabilities. For example, when the switching device 42 is a bipolar transistor, it may include a base, a collector, and an emitter. The base is used to receive the output signal from the voltage comparator 41 to control the conduction state of the bipolar transistor; the collector is connected to the power input interface 1 to receive the input current; and the emitter is grounded to form a path to release current when the device is turned on, thereby realizing the conduction or disconnection control of the input power supply path. When the switching device 42 is an insulated-gate bipolar transistor, it may include a gate, a collector, and an emitter. The gate is connected to the output terminal of the voltage signal generation module to receive the control signal; the collector is connected to the power input interface 1 to form an input current path; and the emitter is grounded.

[0086] In order to filter out high-frequency noise in the output voltage of voltage regulator 2, in some embodiments, reference is made to... Figure 4 As shown, the temperature detection module 3 includes a first filter capacitor 301. The first end of the first filter capacitor 301 is connected to the output end of the voltage regulator 2, and the second end of the first filter capacitor 301 is grounded.

[0087] Specifically, the first terminal of the first filter capacitor 301 is connected to the output terminal of the voltage regulator 2 to receive the regulated voltage signal output by the voltage regulator 2; the second terminal of the first filter capacitor 301 is grounded to form a capacitor-to-ground filter path, thereby constructing a low-pass filter branch in the output circuit of the voltage regulator 2. Through the above configuration, high-frequency noise and ripple components in the output voltage of the voltage regulator 2 can be effectively suppressed, thereby improving the input voltage stability of the thermal voltage divider circuit 31 and the reference voltage output circuit 32.

[0088] To smooth voltage fluctuations at the input of temperature response branch 4, in some embodiments, reference is made to... Figure 4 As shown, the temperature detection module 3 includes a second filter capacitor 302. The first end of the second filter capacitor 302 is connected to the input end of the temperature response branch 4, and the second end of the second filter capacitor 302 is grounded.

[0089] Specifically, the first terminal of the second filter capacitor 302 is connected to the input terminal of the temperature response branch 4, and can be used to receive the temperature-sensing voltage from the thermistor voltage divider circuit 31; the second terminal of the second filter capacitor 302 is grounded, used to construct a capacitor-to-ground filter branch. Through the above configuration, transient suppression and high-frequency noise filtering of the temperature-sensing voltage signal can be performed, making the temperature-sensing voltage of the input temperature response branch 4 more stable, thereby improving the accuracy of the temperature response branch 4 in judging the temperature state of the power input interface 1 and enhancing the reliability of overcurrent trigger response.

[0090] To ensure the stability and reliability of the output voltage of regulator 2, in some embodiments, reference is made to... Figure 4 As shown, regulator 2 is a low-dropout linear regulator. The input terminal of the low-dropout linear regulator is connected to the power supply, the output terminal of the low-dropout linear regulator is connected to the input terminal of the temperature detection module 3, the ground terminal of the low-dropout linear regulator is grounded, and the enable terminal of the low-dropout linear regulator is in a high-level state.

[0091] The low dropout regulator (LDO) is a linear voltage regulator with low input-output voltage drop characteristics. Its operating principle involves adjusting the conduction state of its internal power transistors to maintain the output voltage at a constant preset value, and it has the ability to maintain a stable output even when the input voltage is only slightly higher than the output voltage. Specifically, the input terminal (IN) of the LDO receives the DC supply voltage VBAT from an external power source. The output terminal (OUT) of the LDO is connected to the input terminal of the temperature detection module 3 to output a stable low dropout DC voltage as the operating power supply for the temperature detection module 3. The ground terminal of the LDO is grounded to form a stable power supply loop; this ground terminal may include a first ground terminal (GND1) and a second ground terminal (GND2). Simultaneously, the enable terminal (EN) of the LDO is set to a high level to activate the output capability of the regulator 2, ensuring that a constant voltage is immediately provided to the temperature detection module 3 after power-on.

[0092] To ensure that the enable pin of voltage regulator 2 is at a high level, in some embodiments, reference is made to... Figure 4 As shown, the voltage regulator 2 includes a pull-up resistor 201. The first end of the pull-up resistor 201 is connected to the power supply, and the second end of the pull-up resistor 201 is connected to the enable terminal.

[0093] The pull-up resistor 201 can represent a resistor element used to maintain the control pin at a high level. For example, the resistance value of the pull-up resistor 201 can be 10KΩ or other suitable values. The pull-up resistor 201 ensures that the enable pin of the voltage regulator 2 is at an effective level, thereby maintaining the normal output function of the voltage regulator 2. Specifically, the first end of the pull-up resistor 201 is connected to the power supply VBAT to provide a high-level voltage. The second end of the pull-up resistor 201 is connected to the enable pin of the voltage regulator 2 to pull the enable pin level high, so that the voltage regulator 2 remains enabled even without external signal drive. The pull-up resistor 201 prevents the voltage regulator 2 from being accidentally turned off or malfunctioning due to the enable pin being floating, thereby ensuring that the voltage regulator 2 stably outputs a constant voltage signal, and thus improving the power supply reliability to the temperature detection module 3.

[0094] To ensure the stability of the input voltage of regulator 2, in some embodiments, reference is made to... Figure 4 As shown, the voltage regulator 2 may also include a third filter capacitor 202, the first end of which is connected to the input terminal of the voltage regulator 2, and the second end of which is grounded.

[0095] The third filter capacitor 202 is used to filter the input voltage signal of the voltage regulator 2, thereby improving the input stability of the voltage regulator 2. Specifically, the first terminal of the third filter capacitor 202 is connected to the input terminal of the voltage regulator 2, that is, between the power supply VBAT and the input terminal of the voltage regulator 2, and the second terminal is grounded. The third filter capacitor 202 can effectively suppress high-frequency noise and transient voltage spikes in the output voltage of the power supply VBAT, reducing the impact of input disturbances on the regulated output of the voltage regulator 2.

[0096] To enhance the overcurrent protection circuit's ability to withstand sudden high voltage surges and prevent circuit damage due to voltage spikes, in some embodiments, reference is made to... Figure 6 As shown, the power input interface 1 includes a transient voltage suppression diode 101. The first end of the transient voltage suppression diode 101 is connected to the output end of the power input interface 1, and the second end of the transient voltage suppression diode 101 is grounded.

[0097] The transient voltage suppression diode (TVS diode) can be described as a protective element used to protect a circuit from transient high voltage surges. Specifically, the first terminal of the TVS diode 101 is connected to the output terminal of the power input interface 1 to receive the voltage signal input from an external power source. The second terminal of the TVS diode 101 is grounded to discharge voltage energy to ground in the event of a surge voltage or transient high voltage interference.

[0098] To pull the interface pin potential low, avoid instability caused by floating, and improve the reliability of interface identification, in some embodiments, reference is made to... Figure 6 As shown, the power input interface 1 also includes an interface connector 102 and a pull-down resistor. The interface connector 102 is used to connect to the power adapter 5; the first end of the pull-down resistor is connected to the interface connector 102, and the second end of the pull-down resistor is grounded.

[0099] The interface connector 102 can represent a structural element used to achieve an electrical connection between the power adapter 5 and the power input interface 1, and may include, but is not limited to, other plug-in devices conforming to electrical connection standards such as USB interfaces and Type-C interfaces. (See reference) Figure 6 As shown, interface connector 102 is a 16-pin Type-C interface, with pull-down resistors including a first pull-down resistor 103 and a second pull-down resistor 104. Interface connector 102 includes multiple sets of functional pins, specifically: multiple GND pins for providing ground potential reference, a first VBUS pin for inputting the main power supply voltage, configuration channel pins CC1 and CC2 for power supply direction identification and current negotiation, SBU1 and SBU2 pins for transmitting auxiliary data signals, two sets of D+ and D- pins for supporting differential signal communication, and a second VBUS pin for auxiliary power supply. The first pull-down resistor 103 and the second pull-down resistor 104 are respectively configured on interface connector 102. The first ends of the first pull-down resistor 103 and the second pull-down resistor 104 are connected to the configuration channel pins CC2 and CC1 in interface connector 102, respectively, and the second ends are both grounded. This ensures the accuracy of power supply direction determination and load connection status identification, thereby improving the connection reliability of interface connector 102.

[0100] Furthermore, this disclosure also provides an overcurrent protection method, which can be applied to the overcurrent protection circuit in the above embodiments. (See reference...) Figure 7 As shown, the overcurrent protection method includes the following technical steps:

[0101] Step 701, Start. The charging process begins, preparing for temperature detection and overcurrent protection logic checks.

[0102] Step 702: Normal charging, temperature detection module detects temperature. During charging, the temperature detection module continuously monitors the operating temperature of the power input interface in real time and converts the temperature signal into a temperature-sensitive voltage.

[0103] Step 703: Determine whether the temperature sensing voltage is greater than or equal to the reference voltage. If yes, proceed to step 704; otherwise, proceed to step 702 to maintain the normal charging process.

[0104] Step 704: The voltage comparator outputs a high level. When the temperature sensing voltage exceeds the reference voltage, the voltage comparator outputs a high-level signal.

[0105] Step 705: The switching device is turned on. In response to the high-level signal output by the voltage comparator, the switching device is turned on, thereby forming a low-impedance parallel path between the temperature response branch and the power input interface.

[0106] Step 706: Overcurrent protection is triggered. The temperature response branch conducts, causing the power adapter's output current to exceed the overcurrent protection value, thus triggering the power adapter's overcurrent protection function.

[0107] Step 707, Stop charging. After triggering the overcurrent protection function, the power adapter automatically cuts off the power supply to the power input interface and load circuit, thereby forcibly stopping the charging process and avoiding the risk of thermal damage caused by continuous power supply at high temperatures.

[0108] Next, this disclosure also provides an earphone charging case, which may include a load circuit and an overcurrent protection circuit as described in any of the above embodiments. When the output current of the power adapter exceeds the overcurrent protection value, the overcurrent protection circuit triggers the overcurrent protection function of the power adapter to interrupt the power supply to the load circuit.

[0109] The load circuit can represent a power consumption module connected to the output of the overcurrent protection circuit. It receives power from the power adapter and performs normal operation of the headphone charging case. Specifically, the load circuit can be connected to the output of the power input interface and the output of the temperature response branch. The load circuit may include components such as the headphone's charging control module, battery, battery management unit, and status indicator circuit, and continuously consumes power under normal power supply conditions. When the overcurrent protection circuit detects that the power adapter's output current exceeds the overcurrent protection value, it cuts off the current input to the load circuit to prevent overheating or damage to the components due to continuous power supply under abnormal conditions.

[0110] It should be understood that this invention is not limited to the detailed structure and arrangement of the components proposed in this invention. This invention can have other embodiments and can be implemented and performed in various ways. The foregoing variations and modifications fall within the scope of this invention. It should be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more individual features mentioned or apparent in the text and / or drawings. All these different combinations constitute multiple alternative aspects of this invention. The embodiments described herein illustrate the best known mode for implementing this invention and will enable those skilled in the art to utilize this invention.

Claims

1. An overcurrent protection circuit, characterized by comprising: include: Power input interface; Voltage regulator; A power adapter, the output of which is connected to the input of the power input interface; A temperature detection module, the input terminal of which is connected to the voltage regulator, and the output terminal of which outputs a temperature sensing voltage according to the operating temperature of the power input interface; A temperature response branch is provided, the input of which is connected to the output of the temperature detection module, and the output of which is connected to the power adapter through the power input interface. The temperature response branch is used to conduct when the temperature sensing voltage is greater than the reference voltage, and to form a low-resistance path in parallel with the power input interface, so that the output current of the power adapter is greater than a preset overcurrent protection value, thereby triggering the overcurrent protection function of the power adapter.

2. The overcurrent protection circuit of claim 1, wherein, Also includes: An overcurrent protection module is provided, wherein the input terminal of the overcurrent protection module is connected to the output terminal of the temperature response branch, and the output terminal of the overcurrent protection module is connected to the input terminal of the load circuit. When the input current of the overcurrent protection module exceeds a preset threshold value, the overcurrent protection module disconnects the current input to the load circuit.

3. The overcurrent protection circuit of claim 1, wherein, The temperature detection module includes: A thermistor voltage divider circuit is provided, wherein the input terminal of the thermistor voltage divider circuit is connected to the output terminal of the voltage regulator, the first output terminal of the thermistor voltage divider circuit is used to output the temperature sensing voltage to the temperature response branch, and the second output terminal of the thermistor voltage divider circuit is grounded.

4. The overcurrent protection circuit of claim 3, wherein, The thermistor voltage divider circuit includes: A thermistor, wherein the first end of the thermistor is connected to the output terminal of the voltage regulator, the second end of the thermistor is connected to the input terminal of the temperature response branch, and the resistance of the thermistor is inversely proportional to the operating temperature; A first voltage divider resistor, the first end of which is connected to the second end of the thermistor, and the second end of which is grounded.

5. The overcurrent protection circuit of claim 1, wherein, The temperature detection module includes: A reference voltage output circuit is provided, wherein the input terminal of the reference voltage output circuit is connected to the output terminal of the voltage regulator, the first output terminal of the reference voltage output circuit is used to output the reference voltage to the temperature response branch, and the second output terminal of the reference voltage output circuit is grounded.

6. The overcurrent protection circuit of claim 5, wherein, The reference voltage output circuit includes: The second voltage divider resistor has its first end connected to the output terminal of the voltage regulator and its second end connected to the input terminal of the temperature response branch. The third voltage divider resistor has its first end connected to the second end of the second voltage divider resistor, and its second end is grounded. The resistance value of the second voltage divider resistor is the same as that of the third voltage divider resistor.

7. The overcurrent protection circuit of claim 1, wherein, The temperature response branch includes: A voltage signal generation module is connected to the output terminal of the temperature detection module. The voltage signal generation module is used to output a first level signal when the temperature sensing voltage is greater than the reference voltage, and to output a second level signal when the temperature sensing voltage is less than or equal to the reference voltage. A switching device, wherein the first end of the switching device is connected to the output end of the voltage signal generation module, the second end of the switching device is connected to the power input interface, the switching device is used to conduct when receiving the first level signal, and the third end of the switching device is grounded.

8. The overcurrent protection circuit of claim 7, wherein, The voltage signal generation module includes: A voltage comparator, wherein the positive input terminal of the voltage comparator receives the reference voltage, the inverting input terminal of the voltage comparator receives the temperature-sensing voltage, and the output terminal of the voltage comparator outputs a first level signal when the temperature-sensing voltage is greater than the reference voltage.

9. The overcurrent protection circuit of claim 1, wherein, The temperature detection module includes: A first filter capacitor, the first end of which is connected to the output terminal of the voltage regulator, and the second end of which is grounded; The second filter capacitor has its first terminal connected to the input terminal of the temperature response branch, and its second terminal grounded.

10. The overcurrent protection circuit of claim 1, wherein, The voltage regulator is a low-dropout linear voltage regulator; The input terminal of the low-dropout linear regulator is connected to the power supply, the output terminal of the low-dropout linear regulator is connected to the input terminal of the temperature detection module, the ground terminal of the low-dropout linear regulator is grounded, and the enable terminal of the low-dropout linear regulator is in a high-level state.

11. The overcurrent protection circuit of claim 10, wherein, The voltage regulator includes: A pull-up resistor, the first end of which is connected to the power supply, and the second end of which is connected to the enable terminal.

12. The overcurrent protection circuit of claim 10, wherein, The voltage regulator includes: The third filter capacitor has its first end connected to the input terminal of the voltage regulator and its second end grounded.

13. The overcurrent protection circuit of claim 2, wherein, The power input interface includes a transient voltage suppression diode, the first end of which is connected to the output terminal of the power input interface, and the second end of which is grounded.

14. The overcurrent protection circuit of claim 1, wherein, The power input interface also includes: An interface connector for connecting to the power adapter; A pull-down resistor, the first end of which is connected to the interface connector, and the second end of which is grounded.

15. An earphone charging pod, comprising: include: The load circuit and the overcurrent protection circuit as described in any one of claims 1 to 14, wherein the overcurrent protection circuit triggers the overcurrent protection function of the power adapter to interrupt the power supply to the load circuit when the output current of the power adapter is greater than the overcurrent protection value.

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