Protection circuit and electrical apparatus

Abstract

The application provides a protection circuit and an electrical equipment, which comprises a first unidirectional conduction module, a voltage stabilizing energy storage module, a breakdown conduction module, a switching module and a second unidirectional conduction module. After AC power is connected, the first unidirectional conduction module performs unidirectional rectification on the AC power, and outputs a forward voltage signal to charge the voltage stabilizing energy storage module; within a preset charging duration of the voltage stabilizing energy storage module, the second unidirectional conduction module conducts a half-wave signal of the AC power in a unidirectional manner, maintains a half-wave working loop of the load and the AC power, and makes the load work in a half-power slow start state to slow down the power-on impact; when the charging voltage reaches the preset charging duration, the breakdown conduction module breaks down and conducts to output a conduction voltage, drives the switching module to close an output switch end, a full-wave working loop is conducted, and the half-wave working loop is cut off at the same time, and the load is switched to a full-wave working mode to normally operate at full power. Through the above scheme, the protection circuit realizes slow start of the load.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and in particular to a protection circuit and electrical equipment. Background Technology

[0002] In an AC power supply system, the power grid provides operating power to various electrical devices. For some AC loads, when they are connected to the power grid and power-on, the load will immediately start operating at full power because the internal impedance of the load has not yet established a steady-state operating point. This rapid start-up process will cause serious impact on the load itself or the power supply system, which may shorten the equipment's lifespan or even damage the equipment. Summary of the Invention

[0003] This application provides a protection circuit and electrical equipment. By setting up the protection circuit, the load can be started slowly, thereby effectively reducing the damage to the load caused by power-on shock.

[0004] In a first aspect, embodiments of this application provide a protection circuit, including: a first unidirectional conduction module, a voltage regulator and energy storage module, a breakdown conduction module, a switch module, and a second unidirectional conduction module. A first unidirectional conduction module is connected to the first terminal of the AC power supply and is used to unidirectionally conduct the AC power supply to obtain a positive voltage signal. A voltage-stabilized energy storage module is connected to the first unidirectional conduction module and is used to charge based on the positive voltage signal. A breakdown conduction module is connected to the voltage-stabilized energy storage module. The control terminal of the switching module is connected to the breakdown conduction module, and the output switch terminal of the switching module is used to conduct the connection between the first terminal of the load and the second terminal of the AC power supply, and the second terminal of the load is connected to the first terminal of the AC power supply. A second unidirectional conduction module is connected in parallel to the output switch terminal of the switching module. The second unidirectional conduction module is used to unidirectionally conduct the half-wave signal of the AC power supply within a preset charging time of the voltage-stabilized energy storage module to conduct the half-wave working circuit of the load and the AC power supply. The breakdown conduction module is used to break down and conduct after the voltage-stabilized energy storage module has been charged for the preset charging time to output a conduction voltage. The switching module is used to close the output switch terminal based on the conduction voltage to conduct the full-wave working circuit of the AC power supply and the load and cut off the half-wave working circuit, so that the load operates in the full-wave band of the AC power supply.

[0005] In one or more embodiments, the voltage-stabilized energy storage module includes: a voltage divider unit, a voltage-stabilized output unit, and an energy storage unit; the voltage divider unit is connected to the first unidirectional conduction module and is used to obtain a first voltage divider signal based on the positive voltage signal; the voltage-stabilized output unit is connected to the voltage divider unit and is used to output a constant voltage signal based on the first voltage divider signal; the energy storage unit is connected to the voltage-stabilized output unit and the breakdown conduction module, the energy storage unit is used to charge and store energy based on the constant voltage signal, and is used to conduct the breakdown conduction module after charging for the preset charging time, so that the breakdown conduction module outputs the conduction voltage to the control terminal of the switching module.

[0006] In one or more embodiments, the energy storage unit includes a resistor R3 and a capacitor CE2; the first end of the resistor R3 is connected to the voltage regulator output unit, the second end of the resistor R3 is connected to the first end of the capacitor CE2, and the second end of the capacitor CE2 is grounded; the breakdown conduction module is connected to the first end of the resistor R3; the capacitor CE2 is used for charging and energy storage based on the constant voltage signal, and is used to conduct the breakdown conduction module after charging for the preset charging time.

[0007] In one or more embodiments, the regulated output unit includes a switching device and a voltage regulator; a first terminal of the switching device is connected to the voltage divider unit, a second terminal of the switching device is connected to the first terminal of the voltage regulator and the energy storage unit, and a third terminal of the switching device is connected to the second terminal of the voltage regulator; the switching device is configured to connect the voltage divider unit and the energy storage unit based on the first voltage divider signal, and output the constant voltage signal to the voltage regulator; the voltage regulator is configured to control the connection between the voltage divider unit and the energy storage unit of the switching device when the constant voltage signal is greater than or equal to a preset voltage threshold.

[0008] In one or more embodiments, the protection circuit further includes an overvoltage protection module; the control terminal of the overvoltage protection module is connected to the voltage divider unit, and the output terminal of the overvoltage protection module is connected to the energy storage unit; the voltage divider unit is further configured to output a second voltage divider signal to the control terminal of the overvoltage protection module based on the positive voltage signal, and the overvoltage protection module is configured to conduct when the second voltage divider signal exceeds a preset voltage value; the conducting overvoltage protection module and the voltage divider unit are configured to cooperate to form a discharge channel for the energy storage unit, so that the breakdown conduction module is turned off; the switching module is further configured to disconnect the full-wave operating circuit when the breakdown conduction module is turned off.

[0009] In one or more embodiments, the first unidirectional conduction module includes a diode D1; the anode of the diode D1 is connected to the first terminal of the alternating current, and the cathode of the diode D1 is connected to the voltage-stabilized energy storage module; the diode D1 is used to rectify the alternating current to output the positive voltage signal to the voltage-stabilized energy storage module.

[0010] In one or more embodiments, the second unidirectional conduction module includes a diode D3; the anode of the diode D3 is connected to the first terminal of the output switch, the cathode of the diode D3 is connected to the second terminal of the output switch, the first terminal of the output switch is connected to the first terminal of the load, and the second terminal of the output switch is connected to the second terminal of the AC power supply; the first terminal of the AC power supply, the second terminal of the load, the anode of the diode D3, and the cathode of the diode D3 are sequentially connected to form the half-wave operating circuit; the diode D3 is used to unidirectionally conduct the half-wave band signal of the AC power supply during a preset charging time of the voltage-stabilized energy storage module to maintain the half-wave operating circuit of the load and the AC power supply.

[0011] In one or more embodiments, the switching module includes a relay; a first coil pin of the relay is connected to the breakdown conduction module, a second coil pin of the relay is grounded, a common contact terminal of the relay is connected to a second terminal of the AC power supply, a normally open terminal of the relay is connected to the load, and a second terminal of the relay's output switch terminal is connected to the second terminal of the AC power supply; a second unidirectional conduction module is connected in parallel to the common contact terminal and the normally open terminal; the first terminal of the AC power supply, the second terminal of the load, the first terminal of the load, the normally open terminal of the relay, the common contact terminal of the relay, and the second terminal of the AC power supply are sequentially connected to form the full-wave operating circuit; the relay is used to close the common contact terminal and the normally open terminal when the conduction voltage output by the breakdown conduction module is reached, so as to conduct the full-wave operating circuit and cut off the half-wave operating circuit.

[0012] In one or more embodiments, the breakdown conduction module includes a reverse breakdown Zener diode DZ1, the cathode of which is connected to the voltage-stabilized energy storage module, and the anode of which is connected to the control terminal of the switching module.

[0013] Secondly, embodiments of this application provide an electrical device that includes a protection circuit as described in any of the first aspects.

[0014] The beneficial effects of this application are as follows: This application provides a protection circuit and electrical equipment. The protection circuit includes a first unidirectional conduction module, a voltage-stabilized energy storage module, a breakdown conduction module, a switching module, and a second unidirectional conduction module. After AC power is connected, the first unidirectional conduction module unidirectionally rectifies the AC power and outputs a positive voltage signal to charge the voltage-stabilized energy storage module. During the preset charging time of the voltage-stabilized energy storage module, the second unidirectional conduction module unidirectionally conducts the half-wave signal of the AC power, maintaining the half-wave working circuit between the load and the AC power, so that the load operates in a half-power slow-start state, mitigating the power-on surge. When the charging voltage reaches the preset charging time, the breakdown conduction module breaks down and outputs a conduction voltage, driving the switching module to close the output switch terminal. The full-wave working circuit is then turned on, and the half-wave working circuit is simultaneously cut off, allowing the load to switch to full-wave working mode for full-power normal operation. Through the above scheme, the protection circuit achieves slow load start-up, reduces the damage of the power-on surge current to the load and power supply system, extends the service life of the load, and improves the overall reliability of the system. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0016] Figure 1 This is a structural block diagram of a protection circuit provided in an embodiment of this application;

[0017] Figure 2 This is a circuit diagram of the protection circuit provided in the embodiments of this application;

[0018] Figure 3 This is another protection circuit structure diagram provided in the embodiments of this application;

[0019] Figure 4 This is a structural block diagram of another protection circuit provided in the embodiments of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be described clearly and in detail below with reference to the accompanying drawings. Obviously, the embodiments in this application are only some embodiments, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0021] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0022] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0023] In a first aspect, embodiments of this application provide a protection circuit 100, see reference. Figure 1 It includes: a first unidirectional conduction module 10, a voltage-stabilized energy storage module 20, a breakdown conduction module 30, a switch module 40, and a second unidirectional conduction module 50.

[0024] The first unidirectional conduction module 10 is connected to the first terminal GRID-L of the AC power supply. The first unidirectional conduction module 10 is used to unidirectionally conduct the AC power supply to obtain a positive voltage signal. The voltage-regulated energy storage module 20 is connected to the first unidirectional conduction module 10. The voltage-regulated energy storage module 20 is used for charging based on the positive voltage signal. The breakdown conduction module 30 is connected to the voltage-regulated energy storage module 20. The control terminal of the switching module 40 is connected to the breakdown conduction module 30. The output switch terminal of the switching module 40 is used to conduct the connection between the first terminal of the load 200 and the second terminal GRID-N of the AC power supply. The second terminal of the load 200 is connected to the first terminal GRID-L of the AC power supply. The second unidirectional conduction module 50 is connected in parallel to the output switch terminal of the switching module 40. The second unidirectional conduction module 50 is used to unidirectionally conduct the half-wave band signal of the AC power supply within a preset charging time of the voltage-regulated energy storage module 20, so as to conduct the half-wave working circuit of the load 200 and the AC power supply. The breakdown conduction module 30 is used to break down and conduct after the voltage-stabilized energy storage module 20 has been charged for a preset charging time, so as to output the conduction voltage; the switching module 40 is used to close the output switch terminal based on the conduction voltage, so as to conduct the full-wave working circuit of AC power and load 200 and cut off the half-wave working circuit, so that load 200 can work in the full-wave band of AC power.

[0025] Alternating current (AC) refers to electrical energy sources whose amplitude and direction change periodically over time. In this embodiment, it specifically refers to AC provided by the mains power grid, including the first terminal GRID-L (e.g., the live wire terminal) and the second terminal GRID-N (e.g., the neutral wire terminal). The AC provides working power to the load 200 and the protection circuit 100.

[0026] Load 200 refers to an electrical device or equipment connected to alternating current that consumes electrical energy to perform a specific function, such as a resistive load, an inductive load, or a capacitive load. Load 200 has a first terminal and a second terminal, which are used to connect to the protection circuit 100.

[0027] The first unidirectional conduction module 10 refers to a circuit module that allows current to flow in only one direction. It is connected to the first terminal GRID-L of the AC power supply and is used to rectify the AC power supply, converting the AC signal into a positive voltage signal to provide a stable DC drive power supply for the voltage-stabilized energy storage module 20.

[0028] The voltage-regulated energy storage module 20 refers to a circuit module capable of regulating the input voltage and charging and storing energy through internal energy storage devices. The voltage-regulated energy storage module 20 charges based on the positive voltage signal output by the first unidirectional conduction module 10. Its charging voltage gradually increases over time, and after reaching a preset charging time, it provides sufficient trigger voltage to break down the conduction module 30. The preset charging time refers to the length of time from the start of charging to the point where the charging voltage reaches the threshold voltage required to trigger the breakdown of the conduction module 30. The preset charging time can be flexibly set by adjusting the parameters of the internal energy storage devices (such as resistance and capacitance values), which determines the delay time for the load 200 to switch from half-wave operating mode to full-wave operating mode, i.e., the soft-start time.

[0029] The breakdown conduction module 30 refers to a circuit module that undergoes reverse breakdown and conduction when the voltage across its terminals reaches a preset breakdown threshold, thereby outputting a conduction voltage to the control terminal of the switching module 40. The breakdown conduction module 30 remains in a cutoff state and does not output any drive signal to the switching module 40 until the regulated energy storage module 20 has reached the preset charging time. When the charging reaches the preset charging time, the voltage reaches the breakdown threshold of the breakdown conduction module 30, causing it to break down and conduct, outputting a conduction voltage to drive the switching module 40 to operate.

[0030] Switching module 40 refers to a circuit module driven by the voltage of the control terminal and capable of controlling the on / off state of its output switching terminal. Before the conduction module 30 is broken down and outputs a conduction voltage, the output switching terminal of switching module 40 remains in the open state; after receiving the conduction voltage, the output switching terminal of switching module 40 closes, conducting the full-wave working circuit and simultaneously cutting off the half-wave working circuit.

[0031] The second unidirectional conduction module 50 is a circuit module that allows current to flow in only one direction and is connected in parallel across the output switch terminals of the switch module 40. When the switch module 40 is open, the second unidirectional conduction module 50 provides a half-wave operating current path for the load 200; when the switch module 40 is closed, the second unidirectional conduction module 50 is short-circuited by the output switch terminals of the switch module 40, the half-wave operating circuit is cut off, and the load 200 operates in full-wave mode.

[0032] The half-wave operating circuit refers to the unidirectional conduction circuit formed by the AC power, load 200, and second unidirectional conduction module 50 during the period when the switching module 40 is disconnected. In this circuit, the second unidirectional conduction module 50 only allows half-wave current (such as positive half-wave current) of the AC power to flow through the load 200, while the other half-wave current (such as negative half-wave current) is cut off. Therefore, the load 200 operates in half-wave operating mode, reducing the inrush current at the moment of power-on and protecting the load 200 and the power supply system.

[0033] A full-wave operating circuit refers to the conducting circuit formed by the AC power supply, the load 200, and the switch module 40 after the switch module 40 is closed. In this circuit, both the positive and negative half-wave currents of the AC power supply can flow through the load 200, and the load 200 operates at full power.

[0034] In the protection circuit 100, when the AC power and load 200 are connected to the protection circuit 100, firstly, the output switch terminal of the switch module 40 is in the open state. The AC power forms a half-wave working circuit through the load 200 and the second unidirectional conduction module 50. The load 200 operates in half-wave working mode and only receives half the power supply provided by half the half-wave of the AC power. At the same time, the first unidirectional conduction module 10 rectifies the AC power, and the obtained positive voltage signal drives the voltage-stabilized energy storage module 20 to start charging. The charging voltage gradually increases over time. After a preset charging time, the charging voltage of the voltage-stabilized energy storage module 20 reaches the breakdown threshold of the conduction module 30. The conduction module 30 breaks down and conducts, and outputs a conduction voltage to the control terminal of the switch module 40. In response to the conduction voltage, the switch module 40 closes the output switch terminal, and the full-wave working circuit is turned on. At the same time, the second unidirectional conduction module 50 is short-circuited, the half-wave working circuit is cut off, and the load 200 switches to the full-wave working mode to operate normally at full power.

[0035] In this protection circuit 100, a half-wave operating circuit is constructed using the second unidirectional conduction module 50 before the switching module 40 closes. This ensures that the load 200 operates at half power during the initial power-on phase, effectively preventing the large current surge that would occur if the load 200 directly entered full-power operation. After a preset charging time delay by the voltage regulation and energy storage module 20, the load 200 smoothly transitions to full-wave operating mode, reducing the risk of damage to the load 200 and the power supply system from power-on surges. Furthermore, the switching of the load 200 from half-wave to full-wave operating mode is entirely autonomous, requiring no external control commands or manual operation, exhibiting a high degree of automation and suitability for various applications requiring automatic soft-start. This soft-start mechanism reduces the impact stress during each power-on, fundamentally lowering the probability of accelerated aging of the load 200 due to repeated large current surges, thereby effectively extending the service life of the load 200 and reducing equipment maintenance and replacement costs.

[0036] In some of these embodiments, see Figure 2 The first unidirectional conduction module 10 includes a diode D1; the anode of the diode D1 is connected to the first terminal GRID-L of the AC power supply, and the cathode of the diode D1 is connected to the voltage regulator energy storage module 20. The diode D1 is used to rectify the AC power supply to output a positive voltage signal to the voltage regulator energy storage module 20.

[0037] Diode D1 utilizes its unidirectional conduction characteristic to perform half-wave rectification of AC power, allowing only the current during the positive half-wave period of AC power to pass through and blocking the reverse current during the negative half-wave period. This converts the alternating voltage of AC power into a unidirectional pulsating positive voltage signal, which is then output to the voltage-regulated energy storage module 20, providing a stable DC drive power supply for the voltage-regulated energy storage module 20.

[0038] In this embodiment, the first unidirectional conduction module 10 is composed of a single diode D1. The circuit structure is extremely simple and can complete the half-wave rectification of the AC power supply without any auxiliary devices, providing a stable positive voltage signal for the subsequent voltage regulation and energy storage module 20. Moreover, as a basic semiconductor device, the diode has a mature and reliable working principle and a low failure rate, which effectively ensures the long-term stable operation of the rectification stage.

[0039] In some of these embodiments, see Figure 2 The protection circuit 100 also includes a capacitor CE1. The first terminal of the capacitor CE1 is connected to the cathode of the diode D1, and the second terminal of the capacitor CE1 is grounded to GND. The capacitor CE1 is configured to filter the forward voltage signal output by the diode D1, using the charging and discharging characteristics of the capacitor to smooth the pulsating voltage waveform and suppress the high-frequency ripple components in the forward voltage signal, thereby outputting a more stable DC voltage signal to the voltage regulator energy storage module 20.

[0040] In some of these embodiments, see Figure 3 The voltage-regulated energy storage module 20 includes a voltage divider unit 21, a voltage-regulated output unit 22, and an energy storage unit 23. The voltage divider unit 21 is connected to the first unidirectional conduction module 10 and is used to obtain a first voltage divider signal based on a positive voltage signal. The voltage-regulated output unit 22 is connected to the voltage divider unit 21 and is used to output a constant voltage signal based on the first voltage divider signal. The energy storage unit 23 is connected to the voltage-regulated output unit 22 and the breakdown conduction module 30. The energy storage unit 23 is used for charging and energy storage based on the constant voltage signal, and is used to conduct the breakdown conduction module 30 after a preset charging time, so that the breakdown conduction module 30 outputs a conduction voltage to the control terminal of the switching module 40.

[0041] Voltage divider unit 21 refers to a voltage divider network composed of several resistors connected in series in a certain proportion. The magnitude of the first voltage divider signal is determined by the resistance ratio of each resistor in voltage divider unit 21. By adjusting the resistance value of each resistor, the voltage range of the first voltage divider signal can be flexibly set, thereby controlling the working state of the voltage regulator output unit 22 and the stable value of the output voltage.

[0042] The voltage regulator output unit 22 refers to a circuit module that can regulate the input voltage and maintain a constant output voltage. Specifically, the voltage regulator output unit 22 controls the conduction and cutoff of its internal switching device 221 based on a first voltage divider signal. When the first voltage divider signal is lower than a preset voltage threshold, the voltage regulator output unit 22 conducts and outputs current to the energy storage unit 23. When the first voltage divider signal reaches or exceeds the preset voltage threshold, the voltage regulator output unit 22 limits the further increase of the output voltage through a feedback regulation mechanism, thereby ensuring a stable constant voltage signal output to the energy storage unit 23, avoiding instability in the charging voltage of the energy storage unit 23 due to grid voltage fluctuations, and ensuring the consistency and reliability of the preset charging time.

[0043] Energy storage unit 23 refers to a circuit module that charges and stores energy from a constant voltage signal using internal energy storage devices (such as capacitors). Energy storage unit 23 is connected between the voltage regulator output unit 22 and the breakdown conduction module 30. Upon receiving the constant voltage signal, it begins charging, and the voltage across its terminals gradually increases over time. When the charging time reaches the preset charging duration and the charging voltage rises to the breakdown threshold of the breakdown conduction module 30, energy storage unit 23 conducts through the breakdown conduction module 30, triggering the subsequent switching module 40. By adjusting the parameters of the internal energy storage devices in energy storage unit 23 (such as capacitor value and series resistor value), the preset charging duration, i.e., the delay time for the soft start of load 200, can be precisely controlled.

[0044] When AC power is connected, the first unidirectional conduction module 10 rectifies the AC power and outputs a positive voltage signal to the voltage divider unit 21. The voltage divider unit 21 divides the positive voltage signal to obtain a first voltage divider signal and transmits it to the voltage regulation output unit 22. The voltage regulation output unit 22 regulates the voltage based on the first voltage divider signal and continuously outputs a stable constant voltage signal to the energy storage unit 23. The energy storage unit 23 starts charging under the drive of the constant voltage signal. After a preset charging time, the charging voltage of the energy storage unit 23 reaches the trigger threshold of the breakdown conduction module 30. The breakdown conduction module 30 then breaks down and conducts, outputting a conduction voltage to the control terminal of the switch module 40, driving the switch module 40 to close. The load 200 smoothly switches from half-wave working mode to full-wave working mode, completing the soft start process.

[0045] By introducing a voltage regulator output unit 22 into the voltage regulator energy storage module 20, the first voltage divider signal output by the voltage divider unit 21 is regulated, ensuring that the constant voltage signal charging the energy storage unit 23 is not affected by grid voltage fluctuations. This guarantees the stability of the charging process of the energy storage unit 23 and the consistency of the preset charging time. Furthermore, the charging time constant of the energy storage unit 23 is determined by the parameters of its internal energy storage devices. The preset charging time can be precisely set by adjusting the relevant device parameters, allowing the protection circuit 100 to flexibly configure the charging time for AC loads 200 with different power levels and characteristics. This provides good adaptability and versatility, meeting the needs of different application scenarios without requiring a complete circuit redesign.

[0046] In some of these embodiments, see Figure 2 The voltage divider unit 21 includes resistors R1, R6, and R11. The first end of resistor R1 is connected to the first unidirectional conduction module 10, the second end of resistor R1 is connected to the first end of resistor R6 and the voltage regulation output unit 22, the second end of resistor R6 is connected to the first end of resistor R11, and the second end of resistor R11 is grounded to GND.

[0047] In this configuration, resistors R1, R6, and R11 are connected in series between the output terminal of the first unidirectional conduction module 10 and ground, forming a series voltage divider network. The series connection of resistors R1 and R6 serves as the first voltage divider terminal of the voltage divider unit 21, outputting the first voltage divider signal to the voltage regulation output unit 22.

[0048] In this embodiment, the voltage value of the first voltage divider signal is determined by the ratio of the resistance values ​​of resistors R1, R6, and R11. Designers can calculate the required resistance values ​​according to actual needs, making parameter design convenient and efficient.

[0049] In some of these embodiments, see Figure 2 The voltage regulator output unit 22 includes a switching device 221 and a voltage regulator 222. The first terminal of the switching device 221 is connected to the voltage divider unit 21, the second terminal of the switching device 221 is connected to the first terminal of the voltage regulator 222 and the energy storage unit 23, and the third terminal of the switching device 221 is connected to the second terminal of the voltage regulator 222. The switching device 221 is configured to connect the voltage divider unit 21 and the energy storage unit 23 based on a first voltage divider signal, and output a constant voltage signal to the voltage regulator 222. The voltage regulator 222 is configured to control the connection between the voltage divider unit 21 and the energy storage unit 23 when the constant voltage signal is greater than or equal to a preset voltage threshold.

[0050] Switching device 221 refers to a controllable switching circuit capable of controlling the on / off state between its first and second terminals. In this embodiment, switching device 221 is driven by both the first voltage divider signal and the feedback signal from voltage regulator 222. In the on state, it provides a charging current path for energy storage unit 23, and in the off state, it cuts off the electrical connection between voltage divider unit 21 and energy storage unit 23, thereby working with voltage regulator 222 to achieve dynamic adjustment and voltage regulation control of the output voltage.

[0051] The voltage regulator 222 refers to a voltage regulation circuit that can sample the constant voltage signal output by the switching device 221 in real time and output a feedback signal to the switching device 221 when the constant voltage signal reaches a preset voltage threshold. By continuously monitoring and adjusting the output voltage, the voltage regulator 222 ensures that the output voltage of the regulated output unit 22 is stably maintained near the preset voltage threshold, thus ensuring a stable and consistent constant voltage signal is provided to the energy storage unit 23. The preset voltage threshold can be flexibly set by adjusting the internal parameters of the voltage regulator 222 to meet the differentiated charging voltage requirements of different application scenarios.

[0052] In the voltage regulation output unit 22, when AC power is connected, the first unidirectional conduction module 10 outputs a positive voltage signal. After being divided by the voltage divider unit 21, a first voltage divider signal is obtained and transmitted to the first terminal of the switching device 221. In the initial state, the switching device 221 is in the conducting state based on the first voltage divider signal. The voltage divider unit 21 continuously outputs charging current to the energy storage unit 23 through the switching device 221, and the charging voltage of the energy storage unit 23 gradually increases over time. Meanwhile, the voltage regulator 222 monitors the voltage of the constant voltage signal output from the second terminal of the switching device 221 in real time. When the voltage of the constant voltage signal is less than the preset voltage threshold, the voltage regulator 222 does not output a feedback signal to the switching device 221, the switching device 221 remains in the on state, the energy storage unit 23 continues to charge, and the output voltage continues to rise. When the output voltage reaches the preset voltage threshold, the voltage regulator 222 outputs a feedback signal to the third terminal of the switching device 221, driving the switching device 221 to turn off. The connection between the voltage divider unit 21 and the energy storage unit 23 is cut off, and the output voltage stops rising. This stabilizes the voltage of the constant voltage signal output by the voltage regulator output unit 22 near the preset voltage threshold, continuously providing a stable constant voltage signal to the energy storage unit 23, ensuring the stability of the charging process of the energy storage unit 23 and the consistency with the preset charging time.

[0053] In this embodiment, the voltage regulation output unit 22 samples and adjusts the output voltage in real time through the voltage regulator 222 to form a closed-loop voltage regulation circuit, so that the voltage of the output constant voltage signal is always kept stable near the preset voltage threshold and is not affected by the fluctuation of the grid voltage.

[0054] In some of these embodiments, see Figure 3 The switching device 221 includes switching transistors Q1, Q2, and Q4, resistors R2 and R5. The first end of switching transistor Q1 is connected to the first voltage divider terminal of voltage divider unit 21, the first end of resistor R2, and the first end of resistor R5. The second end of switching transistor Q1 is connected to the first end of voltage regulator 222 and energy storage unit 23. The first end of resistor R2 is connected to the first end of switching transistor Q2. The third end of switching transistor Q1 is connected to the second end of switching transistor Q2. The second end of resistor R5 is connected to the third end of switching transistor Q2 and the first end of switching transistor Q4. The second end of switching transistor Q4 is grounded to GND, and the third end of switching transistor Q4 is connected to the second end of voltage regulator 222.

[0055] Switches Q1, Q2, and Q4 can be any controllable switch, such as an Insulated Gate Bipolar Transistor (IGBT), an Integrated Gate Commutated Thyristor (IGCT), a Gate Turn-Off Thyristor (GTO), a Silicon Controlled Rectifier (SCR), a Junction Gate Field-Effect Transistor (JFET), or a MOS-controlled Thyristor (MCT). Specifically, switches Q1, Q2, and Q4 are all NPN transistors, with the first terminal being the collector, the second terminal being the emitter, and the third terminal being the base.

[0056] In the switching device 221, when AC power is connected, the first voltage divider terminal of the voltage divider unit 21 outputs a first voltage divider signal, driving the switching transistors Q2 and Q1 to conduct. After the switching transistor Q1 conducts, the voltage divider unit 21 outputs a constant voltage signal to the energy storage unit 23 and the first terminal of the voltage regulator 222 via the switching transistor Q1, and the energy storage unit 23 begins charging, with the charging voltage gradually increasing over time. As the constant voltage signal continues to rise, the voltage regulator 222 samples the constant voltage signal in real time, and when the constant voltage signal reaches a preset voltage threshold, it outputs a feedback signal to the base of the switching transistor Q4 via the second terminal of the voltage regulator 222, driving the switching transistor Q4 to conduct. After the switching transistor Q4 conducts, the switching transistor Q2 is turned off, causing the switching transistor Q1 to turn off, the charging path between the voltage divider unit 21 and the energy storage unit 23 is cut off, and the constant voltage signal stops rising. Subsequently, the voltage regulator 222 drives the switch Q4 to dynamically adjust between on and off through the above-mentioned feedback adjustment mechanism, so as to maintain the constant voltage signal stably near the preset voltage threshold and continuously provide a stable constant voltage charging signal to the energy storage unit 23.

[0057] In this embodiment, by cascading switching transistors Q2 and Q1, the first voltage divider signal output by the voltage divider unit 21 first drives switching transistor Q2 to conduct, and then switching transistor Q2 drives switching transistor Q1 to conduct, enabling switching transistor Q1 to obtain sufficient base drive current, ensuring that it can reliably and fully conduct, and stably output charging current to the energy storage unit 23. Switching transistor Q4 is used to receive the feedback signal from the voltage regulator 222 and control the on / off state of switching transistors Q1 and Q2. The independent feedback control path makes the voltage regulation response rapid and the operation reliable, effectively avoiding the problem of mutual coupling interference between the feedback signal and the drive signal, and improving the accuracy and stability of the voltage regulation control.

[0058] In some of these embodiments, see Figure 3 The voltage regulator 222 includes resistors R4, R12 and R10; the first end of resistor R4 is connected to the second end of the switching device 221 and the energy storage unit 23, the second end of resistor R4 is connected to the first end of resistor R10 and the first end of resistor R12, the second end of resistor R10 is connected to the third end of the switching device 221, and the second end of resistor R12 is grounded to GND.

[0059] Specifically, the first end of resistor R4 is connected to the second end of switch Q1, and the second end of resistor R10 is connected to the third end of switch Q4. In this voltage regulator 222, when switch Q1 is turned on and outputs charging current to energy storage unit 23, the voltage of the constant voltage signal output by switching device 221 is proportionally sampled through a series voltage divider network formed by resistors R4 and R12. A voltage divider signal proportional to the voltage is generated at the series node of resistors R4 and R12, and this voltage divider signal is transmitted to switch Q4 through resistor R10. When the voltage of the constant voltage signal is less than a preset voltage threshold, the voltage divider at the series node of resistors R4 and R12 is less than the conduction threshold of switch Q4, switch Q4 is turned off, switch Q1 remains on, and energy storage unit 23 continues to charge. When the voltage of the constant voltage signal is greater than or equal to the preset voltage threshold, the voltage drop at the series node of resistors R4 and R12 reaches the conduction threshold of switch Q4, causing switch Q4 to conduct and switch Q2 and switch Q1 to turn off, thus stopping the voltage of the constant voltage signal from rising. Subsequently, the voltage regulator 222 continuously samples and adjusts the constant voltage signal to drive switch Q4 to dynamically adjust between conduction and cutoff, thereby controlling switch Q1 and switch Q2 to dynamically switch between conduction and cutoff, thus stabilizing the constant voltage signal near the preset voltage threshold and continuously providing a stable constant voltage charging signal to the energy storage unit 23.

[0060] In this embodiment, resistor R10 provides current limiting protection for the switching transistor Q4 to prevent damage from excessive current. When the voltage divider signal output by the voltage regulator 222 is unstable, the switching device 221 is reliably grounded to GND through resistor R12, ensuring that the switching transistor Q4 is reliably turned off. In this embodiment, the magnitude of the constant voltage signal V1 = VH1 / R12 × (R12 + R4), where VH1 is the conduction threshold of the switching transistor Q4, which is the voltage difference between the base and emitter that the switching transistor Q4 must satisfy when it is turned on. By simply adjusting the resistance value of resistor R4 or resistor R12, the magnitude of the constant voltage signal output by the voltage regulator output unit 22 can be easily changed without modifying the overall circuit topology. This allows the voltage regulator 222 to quickly adapt to the differentiated charging voltage requirements of different application scenarios, significantly reducing the design workload for product series development and demonstrating good versatility and product adaptability.

[0061] In some of these embodiments, see Figure 2 The energy storage unit 23 includes a resistor R3 and a capacitor CE2; the first end of the resistor R3 is connected to the voltage regulation output unit 22, the second end of the resistor R3 is connected to the first end of the capacitor CE2, and the second end of the capacitor CE2 is grounded to GND; the breakdown conduction module 30 is connected to the first end of the resistor R3; the capacitor CE2 is used for charging and energy storage based on a constant voltage signal, and is used to conduct the breakdown conduction module 30 after a preset charging time.

[0062] When the voltage regulator output unit 22 starts outputting a constant voltage signal to the energy storage unit 23, current charges the capacitor CE2 through resistor R3. Due to the current limiting effect of resistor R3, the charging process of capacitor CE2 is not instantaneous, but gradually charged according to the RC time constant determined by the resistance value of resistor R3 and the capacitance value of capacitor CE2, and the voltage across its terminals rises slowly according to an exponential law. Before the charging voltage reaches the breakdown threshold of the breakdown conduction module 30, the breakdown conduction module 30 remains in the off state, the output switch terminal of the switch module 40 remains open, and the load 200 continues to operate in half-wave mode. When the charging time reaches the preset charging duration and the voltage across capacitor CE2 rises to the breakdown threshold of the breakdown conduction module 30, the breakdown conduction module 30 breaks down and conducts, outputting a conduction voltage to the control terminal of the switch module 40, and the switch module 40 immediately closes, the load 200 switches to full-wave mode, and the soft start process is completed.

[0063] In this embodiment, the energy storage unit 23 consists of only two basic passive components, resistor R3 and capacitor CE2, without any active components or complex control logic. The circuit structure is simple, and both components are general standard components that are widely available and inexpensive, which helps to reduce the overall material cost of the protection circuit 100 and is suitable for mass industrial production.

[0064] In some of these embodiments, see Figure 3 The second unidirectional conduction module 50 includes diode D3. The anode of diode D3 is connected to the first terminal of the output switch, and the cathode of diode D3 is connected to the second terminal of the output switch. The first terminal of the output switch is connected to the first terminal of the load 200, and the second terminal of the output switch is connected to the second terminal GRID-N of the AC power supply. The first terminal GRID-L of the AC power supply, the second terminal of the load 200, the first terminal of the load 200, the anode of diode D3, and the cathode of diode D3 are sequentially connected to form a half-wave operating circuit. Diode D3 is used to unidirectionally conduct the half-wave signal of the AC power supply during a preset charging time for the voltage-stabilized energy storage module 20, thereby maintaining the half-wave operating circuit of the load 200 and the AC power supply.

[0065] Diode D3 is configured to conduct in the forward direction in response to the positive half-wave period of the AC current and to cut off in the reverse direction in response to the negative half-wave period of the AC current. During the preset charging time of the voltage-stabilized energy storage module 20, the output switch of the switch module 40 remains open, and diode D3 conducts the positive half-wave current of the AC current in one direction, maintaining the half-wave working circuit of the load 200 and the AC current, so that the load 200 operates in half-power mode and achieves slow start-up. When the voltage-stabilized energy storage module 20 reaches the preset charging time, the breakdown and conduction module 30 breaks down and conducts, the output switch of the switch module 40 closes, diode D3 is short-circuited by the output switch, the half-wave working circuit is cut off, and the load 200 switches to full-wave working mode to operate normally at full power.

[0066] In this embodiment, the second unidirectional conduction module 50 is composed of a single diode D3, and the circuit structure is extremely simple. It does not require any auxiliary control devices, which effectively reduces the risk of protection function failure due to device failure and improves the reliability of the protection circuit 100.

[0067] In some of these embodiments, see Figure 2 The switching module 40 includes a relay RLY1. The first coil pin of relay RLY1 is connected to the breakdown conduction module 30, the second coil pin of relay RLY1 is grounded (GND), the common contact terminal of relay RLY1 is connected to the second terminal of the AC power supply (GRID-N), the normally open terminal of relay RLY1 is connected to the load 200, and the second terminal of the output switch of relay RLY1 is connected to the second terminal of the AC power supply (GRID-N). The second unidirectional conduction module 50 is connected in parallel to the common contact terminal and the normally open terminal. The first terminal of the AC power supply (GRID-L), the second terminal of the load 200, the first terminal of the load 200, the normally open terminal of relay RLY1, the common contact terminal of relay RLY1, and the second terminal of the AC power supply (GRID-N) are sequentially connected to form a full-wave operating circuit. Relay RLY1 is used to close the common contact terminal and the normally open terminal when the conduction voltage output by the breakdown conduction module 30 is reached, thereby conducting the full-wave operating circuit and cutting off the half-wave operating circuit.

[0068] Relay RLY1 is configured such that when the breakdown conduction module 30 outputs a conduction voltage to its first coil pin, the coil is energized to generate an electromagnetic attraction force, driving the common terminal of the contacts to close with the normally open terminal, and the full-wave operating circuit is turned on. At the same time, the second unidirectional conduction module 50 is short-circuited by the common terminal of the contacts and the normally open terminal, the half-wave operating circuit is cut off, and the load 200 switches to the full-wave operating mode to operate normally at full power. When the breakdown conduction module 30 is turned off and the conduction voltage disappears, the coil of relay RLY1 is de-energized, the electromagnetic attraction force disappears, the common terminal of the contacts and the normally open terminal are disconnected, the full-wave operating circuit is cut off, the second unidirectional conduction module 50 is turned on again, the half-wave operating circuit is restored, and the load 200 switches back to the half-wave operating mode.

[0069] In this embodiment, the relay RLY1 uses a low-voltage DC control signal on the coil side to drive the AC high-voltage circuit on the contact side to switch on and off, thereby achieving electrical isolation between the control circuit and the AC load 200 circuit. This effectively prevents the AC high-voltage power from interfering with and impacting the low-voltage control circuit, and improves the safety and anti-interference capability of the protection circuit 100.

[0070] In some of these embodiments, see Figure 2 The switching module 40 also includes a capacitor C1, a resistor R13 and a diode D2; the first end of the capacitor C1 is connected to the breakdown conduction module 30 and the first end of the resistor R13, the second end of the resistor R13 is connected to the cathode of the diode D2 and the first coil pin of the relay RLY1, and the anode of the diode D2 is grounded to GND.

[0071] Capacitor C1 filters the conduction voltage output from the breakdown conduction module 30, removing high-frequency ripples and transient spikes to provide a more stable drive voltage to the coil of relay RLY1, ensuring reliable engagement of relay RLY1. Resistor R13 provides current-limiting protection for the current flowing into the coil of relay RLY1, preventing damage to the coil due to overcurrent. Together with capacitor C1, it forms an RC filter network to further smooth the conduction voltage waveform and improve the stability of relay RLY1's drive. Diode D2 absorbs the reverse induced electromotive force (RFF) generated by the sudden current change in the coil when the relay RLY1 coil is de-energized (freewheeling protection), providing a freewheeling path for the coil current and preventing the reverse induced RF from damaging the conduction module 30 and other downstream circuit components.

[0072] In some of these embodiments, see Figure 2 The breakdown conduction module 30 includes a reverse breakdown Zener diode DZ1, the cathode of the reverse breakdown Zener diode DZ1 is connected to the voltage regulation and energy storage module 20, and the anode of the reverse breakdown Zener diode DZ1 is connected to the control terminal of the switch module 40.

[0073] When the charging voltage of the voltage-regulated energy storage module 20 is less than its reverse breakdown voltage, the reverse breakdown Zener diode DZ1 remains in the off state and does not output any signal to the control terminal of the switching module 40. The output switch terminal of the switching module 40 remains open, and the load 200 continues to operate in half-wave mode. When the charging voltage of the voltage-regulated energy storage module 20 rises to the reverse breakdown voltage of the reverse breakdown Zener diode DZ1, the reverse breakdown Zener diode DZ1 undergoes reverse breakdown and enters the regulated conduction state. Current flows through the reverse breakdown Zener diode DZ1. The anode of Z1 flows to the control terminal of the switching module 40, outputting a conduction voltage to the switching module 40, driving the switching module 40 to close the output switch terminal, and the full-wave working circuit is turned on, and the load 200 switches to the full-wave working mode; when the charging voltage of the voltage-stabilized energy storage module 20 drops below the reverse breakdown voltage due to the overvoltage protection triggering rapid discharge, the reverse breakdown voltage regulator DZ1 exits the breakdown state, returns to cutoff, the conduction voltage disappears, the switching module 40 disconnects the output switch terminal, and the load 200 switches back to the half-wave working mode.

[0074] The reverse breakdown voltage of the reverse breakdown Zener diode DZ1 is the conduction voltage threshold required to trigger the closing of the switch module 40. By selecting reverse breakdown Zener diodes DZ1 with different breakdown voltage specifications, the trigger threshold of the breakdown conduction module 30 can be flexibly set to meet the differentiated requirements of conduction voltage for different application scenarios.

[0075] In this embodiment, the breakdown conduction module 30 is composed of a single reverse breakdown Zener diode DZ1. The circuit structure is simple and does not require any auxiliary devices, thus realizing the functions of threshold detection of charging voltage and stable output of conduction voltage.

[0076] Specifically, see Figure 2 The protection circuit 100 also includes a switch KEY1. When switch KEY1 is closed, the first terminal GRID-L and the second terminal GRID-N of the AC power supply are connected to the protection circuit 100, and the relay RLY1 is in the normally open state. After the voltage of the constant voltage signal VCC stabilizes, the capacitor CE2 is continuously charged through the current-limiting resistor R3. The voltage across the capacitor CE2 rises slowly according to the law determined by the RC time constant. By adjusting the resistance value of resistor R3 and the capacitance of capacitor CE2, the charging time constant of capacitor CE2 can be flexibly set. During the charging process of capacitor CE2, when the voltage at the first terminal of resistor R3 has not yet reached the reverse breakdown voltage of the reverse breakdown Zener diode DZ1, the reverse breakdown Zener diode DZ1 remains in the cut-off state, no current flows through the coil of relay RLY1, the common terminal of the relay RLY1 contacts is disconnected from the normally open terminal, and the load 200 continues to maintain a half-wave operating state (the load operates at the positive half-cycle signal of the power grid).

[0077] Specifically, after capacitor CE2 has been charging for a preset time, the voltage at the first terminal of resistor R3 rises above the reverse breakdown voltage of Zener diode DZ1. Zener diode DZ1 then undergoes reverse breakdown and enters a regulated conduction state. The constant voltage signal VCC flows sequentially through Zener diode DZ1, resistor R13, and the coil of relay RLY1 to ground GND. The common and normally open contacts of relay RLY1 close, short-circuiting diode D3. The half-wave operating circuit is then interrupted. The first terminal of AC power GRID-L, switch KEY1, load 200, the common terminal of relay RLY1, the normally open terminal of relay RLY1, and the second terminal of AC power GRID-N form a full-wave operating circuit. Afterward, load 200 can operate normally in both the positive and negative half-cycles of the power grid, entering a full-wave operating state and running at full power. Because the switching process of the above operating mode depends on the charging delay of capacitor CE2, load 200 can smoothly transition from the half-wave state to the full-wave state, achieving a slow start-up.

[0078] In this protection circuit, the load 200 operates in half-wave mode during the initial power-on stage, effectively suppressing the large current surge at the moment of power-on. After the capacitor CE2 charges and delays, the load 200 smoothly transitions to full-wave operation, achieving a slow start-up. The soft-start duration can be flexibly set by adjusting the parameters of resistor R3 and capacitor CE2, making it highly adaptable.

[0079] In some of these embodiments, see Figure 4 The protection circuit 100 also includes an overvoltage protection module 60. The control terminal of the overvoltage protection module 60 is connected to the voltage divider unit 21, and the output terminal of the overvoltage protection module 60 is connected to the energy storage unit 23. The voltage divider unit 21 is also used to output a second voltage divider signal to the control terminal of the overvoltage protection module 60 based on the positive voltage signal. The overvoltage protection module 60 is used to conduct when the second voltage divider signal exceeds a preset voltage value. The conducting overvoltage protection module 60 and the voltage divider unit 21 cooperate to form a discharge channel for the energy storage unit 23, so that the breakdown conduction module 30 is turned off. The switching module 40 is also used to disconnect the full-wave operating circuit when the breakdown conduction module 30 is turned off.

[0080] The second voltage divider signal refers to the voltage signal output by the voltage divider unit 21 based on the positive voltage signal output by the first unidirectional conduction module 10, which is proportionally divided by the internal voltage divider network and then output to the control terminal of the overvoltage protection module 60. The second voltage divider signal is proportional to the voltage amplitude of the AC power and can reflect the changes in the grid voltage in real time. When the grid voltage is within the normal range, the second voltage divider signal is less than the preset voltage value, the overvoltage protection module 60 remains off, and the charging process of the energy storage unit 23 is not affected, so the protection circuit 100 operates normally. When the grid voltage is greater than or equal to the set overvoltage protection threshold, the second voltage divider signal is greater than or equal to the preset voltage value, triggering the overvoltage protection module 60 to conduct. The conducted overvoltage protection module 60 cooperates with the voltage divider unit 21 to form a rapid discharge channel for the energy storage unit 23. The charge stored in the energy storage unit 23 is rapidly released through this discharge channel, and the voltage across the energy storage unit 23 drops rapidly. The breakdown conduction module 30 is turned off because the voltage across it is lower than the breakdown threshold. The switch module 40 loses its conduction voltage drive, disconnects the output switch, and the full-wave operating circuit is cut off. The load 200 switches to half-wave operating mode, realizing overvoltage protection. When the grid voltage returns to the normal range, the second voltage divider signal drops below the preset voltage value, the overvoltage protection module 60 turns off, the discharge channel is disconnected, the voltage-stabilized energy storage module 20 is recharged, and after a preset charging time, the breakdown conduction module 30 conducts again, the switch module 40 closes again, and the load 200 automatically returns to full-wave operating mode.

[0081] In this embodiment, by setting an overvoltage protection module 60, the protection circuit 100 can monitor changes in the grid voltage in real time. Once the grid voltage exceeds the set overvoltage protection threshold, the overvoltage protection module 60 is immediately triggered, driving the switch module 40 to disconnect the full-wave operating circuit and automatically switch the load 200 to half-wave operating mode. This reduces the actual operating voltage borne by the load 200, thereby reducing the phenomenon of accelerated aging or direct damage to the load 200 due to long-term exposure to excessively high voltage, effectively extending the service life of the load 200. Furthermore, when the grid voltage returns to normal, the overvoltage protection module 60 automatically shuts off, the energy storage unit 23 recharges, and the load 200 automatically switches back to full-wave operating mode. The entire overvoltage protection triggering and recovery process is completed autonomously by the circuit without manual reset, exhibiting a high degree of automation and significantly improving the system's ease of use and maintenance efficiency. When the AC voltage rises abnormally, the overvoltage protection module 60 is automatically triggered, driving the load 200 back to the half-wave operating state, reducing the possibility of damage to the load 200 due to excessive voltage; after the voltage returns to normal, the circuit automatically resets without manual intervention, effectively extending the service life of the load 200.

[0082] Specifically, the voltage divider unit 21 uses the series connection of resistor R6 and resistor R11 as the second voltage divider terminal of the voltage divider unit 21, and outputs the second voltage divider signal to the control terminal of the overvoltage protection module 60 to reflect the changes in the grid voltage in real time, and as the trigger control signal of the overvoltage protection module 60.

[0083] In some of these embodiments, see Figure 3 The overvoltage protection module 60 includes resistors R7 and R8 and a switching transistor Q3. The first end of resistor R7 is connected to the second end of resistor R3 and the first end of capacitor CE2. The second end of resistor R7 is connected to the first end of switching transistor Q3. The second end of switching transistor Q3 is grounded to GND. The third end of switching transistor Q3 is connected to the first end of resistor R8. The second end of resistor R8 is connected to the second voltage divider terminal of voltage divider unit 21.

[0084] The switching transistor Q3 can be any controllable switch, such as an insulated-gate bipolar transistor (IGBT), an integrated gate commutated thyristor (IGCT), a gate turn-off thyristor (GTO), a silicon controlled rectifier (SCR), a junction-gate field-effect transistor (JFET), or a MOS-controlled thyristor (MCT). Specifically, the switching transistor Q3 is an NPN transistor, with its first terminal being the collector, its second terminal being the emitter, and its third terminal being the base. The second terminal of resistor R8 is connected to the second terminal of resistor R6 and the first terminal of resistor R11. Resistor R8 is used to limit the current output from voltage divider unit 21 to switching transistor Q3. Resistor R7, when switching transistor Q3 is turned on, together with switching transistor Q3, forms a fast discharge channel for capacitor CE2, allowing the charge stored in capacitor CE2 to be quickly discharged to ground GND through resistor R7 and switching transistor Q3.

[0085] It should be noted that resistor R7 is preferably a power resistor to withstand the transient large current generated during the rapid discharge of capacitor CE2, preventing the resistor from being damaged due to overcurrent and ensuring the reliability and durability of the discharge path. At the same time, the lower impedance characteristics of the power resistor help to accelerate the discharge speed of capacitor CE2, improving the response time of overvoltage protection.

[0086] In this embodiment, the overvoltage protection threshold is set by adjusting the resistance values ​​of resistor R6 and resistor R11. The overvoltage protection threshold V2 = VH2 / R11 × (R11 + R6), where VH2 is the conduction threshold of switch Q3, which is the voltage difference between the base and emitter that switch Q3 needs to satisfy when it is turned on.

[0087] In this embodiment, the voltage value of the second voltage divider signal is determined by the resistance ratio of resistors R1, R6, and R11. Designers can calculate the required resistance values ​​based on the target regulated output voltage and the overvoltage protection trigger threshold, making parameter design convenient and efficient. At the same time, in the voltage divider unit 21, adjusting the resistance value of a single resistor can simultaneously affect the output of the two voltage divider signals, making parameter adjustment flexible and facilitating rapid circuit debugging and parameter optimization.

[0088] Specifically, when the AC voltage is normal, the second voltage divider signal at the series connection of resistors R6 and R11 is less than the conduction threshold of switch Q3, so switch Q3 remains off. The overvoltage protection module 60 does not intervene in the circuit operation, and the protection circuit 100 maintains the full-wave operation state normally. When the mains voltage is in an abnormal range, the second voltage divider signal rises and reaches the conduction threshold of switch Q3. Switch Q3 conducts, and the charge stored in capacitor CE2 is quickly discharged to ground GND through resistor R7 and switch Q3. The reverse breakdown voltage regulator DZ1 cannot be reversed, and the reverse breakdown voltage regulator DZ1 returns to the off state. The coil of relay RLY1 is de-energized, the common terminal of the contacts is disconnected from the normally open terminal, the full-wave operating circuit is cut off, the circuit returns to the half-wave operating circuit, the load 200 re-enters the half-wave operating state, and the actual operating voltage it withstands decreases accordingly, thereby achieving overvoltage protection for the load 200. When the AC voltage returns to the normal range, the second voltage divider signal drops below the conduction threshold of the switch Q3, the switch Q3 is turned off again, the discharge channel is disconnected, and the constant voltage signal VCC recharges the capacitor CE2 through the resistor R3. After a preset charging time, the positive voltage of the capacitor CE2 reaches the reverse breakdown voltage of the reverse breakdown regulator DZ1 again. The reverse breakdown regulator DZ1 breaks down and conducts, the relay RLY1 is energized and energized again, the load 200 automatically returns to the full-wave working state, and the protection circuit 100 completes automatic reset without manual intervention.

[0089] As can be seen, when the AC voltage rises abnormally, the overvoltage protection module 60 is automatically triggered, driving the load 200 back to the half-wave operating state to prevent the load 200 from being damaged due to excessive voltage; after the voltage returns to normal, the circuit automatically resets without manual intervention, effectively extending the service life of the load 200.

[0090] Secondly, embodiments of this application provide an electrical device that includes a protection circuit as described in any of the first aspects.

[0091] In this embodiment, the protection circuit has the same structure and function as the protection circuit described in any embodiment of the first aspect, and will not be repeated here.

[0092] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0093] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A protection circuit, characterized in that, include: The first unidirectional conduction module is connected to the first terminal of the AC power supply and is used to conduct the AC power supply unidirectionally to obtain a positive voltage signal. A voltage-regulated energy storage module includes a voltage divider unit, a voltage-regulated output unit, and an energy storage unit. The voltage divider unit is connected to a first unidirectional conduction module and is used to obtain a first voltage divider signal based on the positive voltage signal. The voltage-regulated output unit is connected to the voltage divider unit and is used to output a constant voltage signal based on the first voltage divider signal. The voltage-regulated output unit includes a switching device and a voltage regulator. A first terminal of the switching device is connected to the voltage divider unit, a second terminal of the switching device is connected to the first terminal of the voltage regulator and the energy storage unit, and a third terminal of the switching device is connected to the second terminal of the voltage regulator. The switching device is configured to conduct the connection between the voltage divider unit and the energy storage unit based on the first voltage divider signal and output the constant voltage signal to the voltage regulator. The voltage regulator is configured to control the switching device to disconnect the connection between the voltage divider unit and the energy storage unit when the constant voltage signal is greater than or equal to a preset voltage threshold. The energy storage unit is used for charging and energy storage based on the constant voltage signal. Break down the conduction module to connect the energy storage unit; A switching module, wherein the control terminal of the switching module is connected to the breakdown conduction module, and the output switching terminal of the switching module is used to conduct a connection between the first terminal of the load and the second terminal of the AC power, wherein the second terminal of the load is connected to the first terminal of the AC power; The second unidirectional conduction module is connected in parallel to the output switch terminal of the switch module; The second unidirectional conduction module is used to unidirectionally conduct the half-wave signal of the AC power during the preset charging time of the energy storage unit, so as to conduct the half-wave working circuit of the load and the AC power; the breakdown conduction module is used to break down and conduct after the energy storage unit has been charged for the preset charging time, so as to output the conduction voltage to the control terminal of the switching module; the switching module is used to close the output switch terminal based on the conduction voltage, so as to conduct the full-wave working circuit of the AC power and the load and cut off the half-wave working circuit, so that the load operates in the full-wave band of the AC power.

2. The protection circuit according to claim 1, characterized in that, The energy storage unit includes a resistor R3 and a capacitor CE2; The first end of the resistor R3 is connected to the second end of the switching device, the second end of the resistor R3 is connected to the first end of the capacitor CE2, and the second end of the capacitor CE2 is grounded; the breakdown conduction module is connected to the first end of the resistor R3. The capacitor CE2 is used for charging and energy storage based on the constant voltage signal, and is used to turn on the breakdown conduction module after charging for the preset charging time.

3. The protection circuit according to claim 1, characterized in that, The protection circuit also includes an overvoltage protection module; The control terminal of the overvoltage protection module is connected to the voltage divider unit, and the output terminal of the overvoltage protection module is connected to the energy storage unit. The voltage divider unit is also used to output a second voltage divider signal to the control terminal of the overvoltage protection module based on the positive voltage signal. The overvoltage protection module is used to conduct when the second voltage divider signal exceeds a preset voltage value. The conducted overvoltage protection module and the voltage divider unit are used to cooperate to form a discharge channel for the energy storage unit, so that the breakdown conduction module is turned off. The switching module is also used to disconnect the full-wave working circuit when the breakdown conduction module is turned off.

4. The protection circuit according to claim 1, characterized in that, The first unidirectional conduction module includes a diode D1; The anode of diode D1 is connected to the first terminal of the AC power, and the cathode of diode D1 is connected to the voltage divider unit. Diode D1 is used to rectify the AC power to output the positive voltage signal to the voltage-stabilized energy storage module.

5. The protection circuit according to claim 1, characterized in that, The second unidirectional conduction module includes diode D3; The anode of diode D3 is connected to the first terminal of the output switch, the cathode of diode D3 is connected to the second terminal of the output switch, the first terminal of the output switch is connected to the first terminal of the load, and the second terminal of the output switch is connected to the second terminal of the AC power supply. The first terminal of the AC power supply, the second terminal of the load, the first terminal of the load, the anode of the diode D3, and the cathode of the diode D3 are connected in sequence to form the half-wave working circuit; the diode D3 is used to unidirectionally conduct the half-wave band signal of the AC power supply during the preset charging time of the energy storage unit to maintain the half-wave working circuit of the load and the AC power supply.

6. The protection circuit according to claim 1, characterized in that, The switching module includes a relay; The first coil pin of the relay is connected to the breakdown conduction module, the second coil pin of the relay is grounded, the common contact terminal of the relay is connected to the second terminal of the AC power supply, the normally open terminal of the relay is connected to the load, and the second terminal of the output switch terminal of the relay is connected to the second terminal of the AC power supply; the second unidirectional conduction module is connected in parallel to the common contact terminal and the normally open terminal; The first terminal of the AC power supply, the second terminal of the load, the first terminal of the load, the normally open terminal of the relay, the common contact terminal of the relay, and the second terminal of the AC power supply are connected in sequence to form the full-wave working circuit; The relay is used to close the common terminal of the contacts and the normally open terminal when the conduction voltage output by the breakdown conduction module is reached, so as to conduct the full-wave working circuit and cut off the half-wave working circuit.

7. The protection circuit according to claim 1, characterized in that, The breakdown conduction module includes a reverse breakdown Zener diode DZ1, the cathode of which is connected to the energy storage unit, and the anode of which is connected to the control terminal of the switching module.

8. An electrical appliance, characterized in that, Includes the protection circuit as described in any one of claims 1-7.

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