Overvoltage protection system and overvoltage protection method

Abstract

The invention discloses an overvoltage protection system and an overvoltage protection method. The system comprises a voltage reduction module, a voltage division module, a comparison module and a control module, commercial power is connected with the voltage division module through the voltage reduction module, the voltage division module is connected with the control module through the comparison module, the voltage reduction module is used for reducing voltage of the commercial power to obtain first voltage, and the first voltage is input voltage of the voltage division module, power supply voltage of the comparison module and driving voltage of the control module. The voltage dividing module is used for dividing the first voltage to obtain a second voltage and a reference voltage; the comparison module is used for obtaining a driving signal according to the second voltage and the reference voltage; the driving signal is used for driving a relay of the control module to cut off power supply between the mains supply and the target object. Damage to the monitoring device in the overvoltage protection process can be relieved, and the system safety is improved. The method can be widely applied to the technical field of power supply safety.

Description

Technical Field

[0001] The present invention relates to the field of power supply safety technology, and in particular to an overvoltage protection system and an overvoltage protection method. Background Art

[0002] A switching power supply is a power converter widely used in electronic devices, converting alternating current (AC) into stable direct current (DC) for power supply. Its technical background stems primarily from the demand for efficient, lightweight, and stable power supplies, and it achieves electrical energy conversion by controlling the on / off switching of switching transistors. The overvoltage protection circuit of a switching power supply is one of the core technologies for ensuring power supply safety and reliability. As electronic devices increasingly demand more stable power supplies, overvoltage protection must respond quickly to abnormal input voltages or sudden load changes to prevent damage to power devices (such as IGBTs and MOSFETs) and downstream circuits due to voltage overload.

[0003] Related technologies rely on voltage sampling and voltage comparators, such as the LM339, to monitor input or output voltages. When the detected value exceeds a preset threshold, overvoltage protection is achieved by blocking the drive signal or disconnecting the main circuit. However, this solution fails to provide overvoltage protection for the monitoring device and can easily damage it, compromising system safety. Summary of the Invention

[0004] The purpose of the present invention is to solve one of the technical problems existing in the prior art to at least a certain extent.

[0005] Therefore, an object of the present invention is to provide a reliable overvoltage protection system and overvoltage protection method.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the embodiments of the present invention include the following aspects:

[0007] On the one hand, an embodiment of the present invention provides an overvoltage protection system, including: a step-down module, a voltage divider module, a comparison module and a control module; the mains power is connected to the voltage divider module through the step-down module, the voltage divider module is connected to the control module through the comparison module, the step-down module is also connected to the comparison module, and the control module is connected to the target object; the step-down module is used to reduce the voltage of the mains power to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the power supply voltage of the comparison module, and the drive voltage of the control module; the voltage divider module is used to divide the first voltage to obtain a second voltage and a reference voltage; the comparison module is used to obtain a drive signal according to the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object. The present application reduces the voltage of the mains power through the step-down module, and then realizes reliable overvoltage protection through the voltage divider module, the comparison module and the control module, which can alleviate the damage to the monitoring device during the overvoltage protection process and improve the safety of the system.

[0008] In addition, the overvoltage protection system according to the above embodiment of the present invention may also have the following additional technical features:

[0009] Furthermore, in the overvoltage protection system of the embodiment of the present invention, the voltage divider module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an adjustable voltage regulator tube;

[0010] The first end of the first resistor is used to connect to the first voltage output end of the step-down module, and the second end of the first resistor is grounded; the first end of the second resistor is connected to the first end of the first resistor, the second end of the second resistor is grounded through the third resistor, and the second end of the second resistor is used to output the second voltage; the first end of the fourth resistor is connected to the first end of the first resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is grounded through the sixth resistor; the anode of the adjustable voltage regulator is grounded, the cathode of the adjustable voltage regulator is connected to the second end of the fourth resistor, and the reference electrode of the adjustable voltage regulator is connected to the second end of the fifth resistor; the cathode of the adjustable voltage regulator is used to generate the reference voltage.

[0011] Furthermore, in one embodiment of the present invention, the voltage divider module also includes: a first voltage regulator tube, the anode of the first voltage regulator tube is connected to the first end of the first resistor, the cathode of the first voltage regulator tube is grounded, and the first voltage regulator tube is used to limit the first voltage.

[0012] Furthermore, in one embodiment of the present invention, the comparison module includes: a first comparator, the reference voltage output end of the voltage divider module is connected to the non-inverting input end of the first comparator, the second voltage output end of the voltage divider module is connected to the inverting input end of the first comparator, and the output end of the first comparator is used to output a relay drive signal.

[0013] Furthermore, in one embodiment of the present invention, the comparison module also includes: a second comparator, the reference voltage output end is connected to the non-inverting input end of the second comparator, the output end of the first comparator is connected to the inverting input end of the second comparator, and the output end of the second comparator is connected to the first voltage output end of the step-down module through a seventh resistor.

[0014] Furthermore, in one embodiment of the present invention, the control module includes a transistor, the output end of the first comparator is connected to the base of the transistor, the emitter of the transistor is connected to the first voltage output end, the collector of the transistor is connected to the coil of the relay, one end of the normally closed switch of the relay is connected to the AC power, and the other end of the normally closed switch is connected to the target object.

[0015] Furthermore, in one embodiment of the present invention, the difference between the resistance of the coil and the resistance of the seventh resistor is less than or equal to a preset difference.

[0016] On the other hand, an embodiment of the present invention provides an overvoltage protection method, which is applied to the above-mentioned overvoltage protection system. The method includes:

[0017] Stepping down the mains power to obtain a first voltage;

[0018] dividing the first voltage to obtain a second voltage and a reference voltage;

[0019] A driving signal is obtained according to the second voltage and the reference voltage; the driving signal is used to drive a relay of a control module to disconnect the power supply between the mains and the target object.

[0020] Furthermore, the overvoltage protection method of the embodiment of the present invention further includes:

[0021] Determining a first value according to a quotient of the mains voltage and the capacitance value of the step-down module;

[0022] determining a first voltage according to a product of the first value and a parallel resistor, wherein the parallel resistor is related to the first resistor, the second resistor, the third resistor, the fourth resistor of the voltage divider module, and the seventh resistor of the comparison module;

[0023] The second voltage is determined according to a voltage division of the first voltage by the third resistor in a series branch of the second resistor and the third resistor.

[0024] Furthermore, the overvoltage protection method of the embodiment of the present invention further includes:

[0025] adjusting the capacitance of the capacitor, the first resistor, the second resistor, the third resistor, the fourth resistor, and the seventh resistor to determine an overvoltage protection threshold for generating the drive signal;

[0026] Alternatively, an adjustable voltage regulator tube is adjusted to determine an overvoltage protection threshold for generating the driving signal.

[0027] In another aspect, an embodiment of the present invention provides an overvoltage protection device, comprising:

[0028] at least one processor;

[0029] at least one memory for storing at least one program;

[0030] When the at least one program is executed by the at least one processor, the at least one processor implements the above-mentioned overvoltage protection method.

[0031] On the other hand, an embodiment of the present invention provides a storage medium storing a program executable by a processor. When the program is executed by the processor, it is used to implement the above-mentioned overvoltage protection method.

[0032] The method provided by the embodiment of the present invention includes: a step-down module, a voltage divider module, a comparison module and a control module; the mains power is connected to the voltage divider module through the step-down module, the voltage divider module is connected to the control module through the comparison module, the step-down module is also connected to the comparison module, and the control module is connected to the target object; the step-down module is used to reduce the voltage of the mains power to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the power supply voltage of the comparison module, and the driving voltage of the control module; the voltage divider module is used to divide the first voltage to obtain a second voltage and a reference voltage; the comparison module is used to obtain a driving signal according to the second voltage and the reference voltage; the driving signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object. The present application reduces the voltage of the mains power through the step-down module, and then realizes reliable overvoltage protection through the voltage divider module, the comparison module and the control module, which can alleviate the damage to the monitoring device during the overvoltage protection process and improve the safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following introduction is made to the drawings of the embodiments of the present invention or the related technical solutions in the prior art. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A schematic structural diagram of an embodiment of an overvoltage protection system provided by the present invention;

[0035] Figure 2 A schematic diagram showing the principle of an embodiment of an overvoltage protection system provided by the present invention;

[0036] Figure 3 A circuit connection diagram of an embodiment of the overvoltage protection system provided by the present invention. DETAILED DESCRIPTION

[0037] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention. The step numbers in the following embodiments are provided for ease of explanation only and do not limit the order of the steps. The order of execution of the steps in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0038] First, the terms used in this application are explained:

[0039] Switching power supply: A high-frequency power conversion device that can convert AC or DC power, such as mains electricity, into stable DC power.

[0040] A bridge rectifier is an electronic component that converts alternating current (AC) into direct current (DC). It consists of four diodes connected in a bridge circuit. During the positive half-cycle of the AC current, two diodes conduct, allowing the current to flow through a specific path and output a positive voltage. During the negative half-cycle, the other two diodes conduct, outputting a negative voltage. This converts AC into DC, ensuring that current flows in only one direction.

[0041] RC step-down circuit: A circuit that uses resistors and capacitors to reduce voltage. Its principle is to use the capacitive reactance generated by capacitors under alternating current. The capacitive reactance of the capacitors limits the current, thereby reducing the voltage.

[0042] Overvoltage: The input voltage is too high.

[0043] A switching power supply is a power converter widely used in electronic devices, converting alternating current (AC) into stable direct current (DC) for power supply. Its technical background stems primarily from the demand for efficient, lightweight, and stable power supplies. It achieves electrical energy conversion by switching a switching transistor on and off. Currently, switching power supplies offer high efficiency, compact size, light weight, and high reliability. Compared to traditional linear power supplies, switching power supplies offer higher efficiency and can deliver high power output in a compact and lightweight package. Therefore, switching power supplies are widely used in many applications requiring stable voltage input.

[0044] The overvoltage protection circuit of a switching power supply is one of the core technologies to ensure the safety and reliability of the power supply. As electronic equipment has increasingly higher requirements for power supply stability, overvoltage protection needs to respond quickly when the input voltage is abnormal or the load changes suddenly, to prevent power devices (such as IGBT, MOSFET) and back-end circuits from being damaged due to voltage exceeding the limit. Traditional solutions are mostly based on voltage division sampling and voltage comparators. For example, comparators such as LM339 are used to monitor the input or output voltage. When the detection value exceeds the preset threshold, protection is achieved by blocking the PWM drive signal or cutting off the main circuit. However, such methods have limitations in response speed and anti-interference ability, which may lead to delayed protection. The present application converts the high voltage of the AC input into a stable DC voltage through a resistor-capacitor step-down circuit, and has the advantages of small size and low cost. Compared with traditional comparison methods, it is not easy to damage the chip due to excessive input voltage.

[0045] The overvoltage protection system and method according to the embodiments of the present invention are described in detail below with reference to the accompanying drawings. First, an overvoltage protection system according to the embodiments of the present invention is described with reference to the accompanying drawings.

[0046] Figure 1 FIG. 1 is a schematic diagram of the structure of an overvoltage protection system according to an embodiment of the present invention. The system specifically includes:

[0047] Buck module, voltage divider module, comparison module and control module;

[0048] The mains is connected to the voltage divider module via the step-down module, the voltage divider module is connected to the control module via the comparison module, the step-down module is also connected to the comparison module, and the control module is connected to the target object;

[0049] The step-down module is used to reduce the voltage of the mains to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the power supply voltage of the comparison module, and the driving voltage of the control module;

[0050] The voltage dividing module is used to divide the first voltage to obtain a second voltage and a reference voltage;

[0051] The comparison module is used to obtain a driving signal according to the second voltage and the reference voltage; the driving signal is used to drive the relay of the control module to disconnect the power supply between the mains and the target object.

[0052] The step-down module in this application includes a rectifier bridge and a resistor-capacitor unit. The second voltage in this application is related to the mains voltage and is less than the mains voltage. The second voltage reflects the mains voltage. When the second voltage is greater than the reference voltage, the power supply between the mains and the target object is disconnected. This application is applicable to any use scenario requiring mains power or AC input.

[0053] Furthermore, in the overvoltage protection system of the embodiment of the present invention, the voltage divider module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an adjustable voltage regulator tube;

[0054] The first end of the first resistor is used to connect to the first voltage output end of the step-down module, and the second end of the first resistor is grounded; the first end of the second resistor is connected to the first end of the first resistor, the second end of the second resistor is grounded through the third resistor, and the second end of the second resistor is used to output a second voltage; the first end of the fourth resistor is connected to the first end of the first resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is grounded through the sixth resistor; the anode of the adjustable voltage regulator is grounded, the cathode of the adjustable voltage regulator is connected to the second end of the fourth resistor, and the reference electrode of the adjustable voltage regulator is connected to the second end of the fifth resistor; the cathode of the adjustable voltage regulator is used to generate a reference voltage.

[0055] Furthermore, in one embodiment of the present invention, the voltage divider module further includes: a first voltage regulator tube, the anode of the first voltage regulator tube is connected to the first end of the first resistor, the cathode of the first voltage regulator tube is grounded, and the first voltage regulator tube is used to limit the first voltage.

[0056] In this application, the first voltage output end of the step-down module is one end of the rectifier bridge, the reference voltage output end of the voltage divider module is the anode of the adjustable voltage regulator tube, and the second voltage output end of the voltage divider module is the second end of the second resistor.

[0057] Furthermore, in one embodiment of the present invention, the comparison module includes: a first comparator, the reference voltage output end of the voltage divider module is connected to the non-inverting input end of the first comparator, the second voltage output end of the voltage divider module is connected to the inverting input end of the first comparator, and the output end of the first comparator is used to output the relay drive signal.

[0058] Furthermore, in one embodiment of the present invention, the comparison module also includes: a second comparator, the reference voltage output end is connected to the non-inverting input end of the second comparator, the output end of the first comparator is connected to the inverting input end of the second comparator, and the output end of the second comparator is connected to the first voltage output end of the step-down module through a seventh resistor.

[0059] Furthermore, in one embodiment of the present invention, the control module includes a transistor, the output end of the first comparator is connected to the base of the transistor, the emitter of the transistor is connected to the first voltage output end, the collector of the transistor is connected to the coil of the relay, one end of the normally closed switch of the relay is connected to the mains, and the other end of the normally closed switch is connected to the target object.

[0060] Furthermore, in one embodiment of the present invention, the difference between the resistance of the coil and the resistance of the seventh resistor is less than or equal to a preset difference.

[0061] On the other hand, an embodiment of the present invention proposes an overvoltage protection method, which is applied to the above-mentioned overvoltage protection system. An overvoltage protection method is provided in an embodiment of the present invention. The overvoltage protection method in the embodiment of the present invention can be applied to a terminal, a server, or software running in a terminal or a server. The terminal can be a tablet computer, a laptop computer, a desktop computer, etc., but is not limited to this. The server can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The method includes:

[0062] Stepping down the mains power to obtain a first voltage;

[0063] Dividing the first voltage to obtain a second voltage and a reference voltage;

[0064] A driving signal is obtained according to the second voltage and the reference voltage; the driving signal is used to drive a relay of the control module to disconnect the power supply between the mains and the target object.

[0065] Furthermore, the overvoltage protection method of the embodiment of the present invention further includes:

[0066] Determining a first value according to a quotient of the mains voltage and the capacitance value of the step-down module;

[0067] Determine a first voltage according to a product of the first value and a parallel resistor; the parallel resistor is related to the first resistor, the second resistor, the third resistor, the fourth resistor of the voltage divider module and the seventh resistor of the comparison module;

[0068] The second voltage is determined according to the voltage division of the first voltage by the third resistor in the series branch of the second resistor and the third resistor.

[0069] Furthermore, the overvoltage protection method of the embodiment of the present invention further includes:

[0070] Adjusting the capacitance value of the capacitor, the first resistor, the second resistor, the third resistor, the fourth resistor, and the seventh resistor to determine an overvoltage protection threshold for generating a drive signal;

[0071] Alternatively, an adjustable voltage regulator tube is adjusted to determine an overvoltage protection threshold for generating a driving signal.

[0072] The overvoltage protection system and overvoltage method of the present application are described in detail below with reference to specific embodiments:

[0073] In view of the above-mentioned defects of the prior art, the present invention provides an input overvoltage protection circuit for a switching power supply. The input overvoltage protection circuit of the switching power supply is composed of Figure 1 As shown, it includes: a RC step-down circuit (i.e., a step-down module), a voltage divider circuit (i.e., a voltage divider module), a comparison circuit (i.e., a comparison module), and a relay control circuit (i.e., a control module). The RC step-down circuit is connected to the voltage divider circuit, which is connected to the comparison circuit, which is connected to the relay control circuit.

[0074] The working principle block diagram of the input overvoltage protection circuit of the switching power supply is as follows Figure 2 As shown, the AC input of the switching power supply is connected to the RC step-down circuit to obtain a stepped-down voltage VCC (i.e., the first voltage) as the input of the voltage divider circuit, the power supply of the comparator chip in the comparison circuit and the drive voltage of the relay control circuit; the voltage divider circuit then divides VCC to obtain a comparison voltage Vcmp (i.e., the second voltage) and a reference voltage of 5V, which are used as the input of the comparison circuit; the comparison circuit compares the input comparison voltage Vcmp with the reference voltage +5V. Since the input voltage is obtained by stepping down the comparison voltage Vcmp, there is a linear relationship between the input voltage and the comparison voltage Vcmp. The overvoltage protection value can be set by adjusting the resistance value of the voltage divider circuit. When Vcmp exceeds +5V, it is regarded as an input overvoltage. The comparison circuit outputs a relay drive signal to the relay control circuit, continuously driving the relay to attract, so that the normally closed contact is disconnected, thereby disconnecting the AC input and the power supply circuit of the switching power supply product, protecting the switching power supply product from overvoltage damage.

[0075] Implementation of input overvoltage protection circuit of switching power supply Figure 3 As shown, it includes: a resistance-capacitance voltage-dropping circuit (1), a voltage-dividing circuit (2), a comparison circuit (3), and a relay control circuit (4). The network connected to the outside includes: a mains input live wire (L) and a mains input neutral wire (N).

[0076] In the RC step-down circuit, the AC input live wire (L) is converted into pulsating DC power by a rectifier bridge consisting of diodes D1, D2, D4, and D5. The specific working process is as follows:

[0077] Positive half cycle: the current path is L→D2→load→D4→step-down capacitor C4→N.

[0078] Negative half-cycle: The current path is N → D5 → load → D1 → step-down capacitor C4 → L. The pulsed DC current passes through filter capacitor C1 to obtain a stable DC voltage (VCC). Among them, step-down capacitor C4 uses the capacitive reactance to limit the AC current and takes on the main task of voltage reduction. In this embodiment, the capacitance of step-down capacitor C4 is 0.8uF, and the formula for capacitive reactance is as follows:

[0079]

[0080] Where f is the frequency of the AC input, C is the capacitance of the step-down capacitor C4, and according to the formula, Xc≈3979Ω.

[0081] The step-down capacitor C4 limits the maximum AC current of the entire circuit. The current calculation formula is as follows:

[0082]

[0083] Vin is the AC effective value voltage of the mains input. Take 220VAC AC voltage input. After full-bridge rectification, the average DC current is about 0.9 times the AC effective value.

[0084] I avg =0.9I rms

[0085] According to the formula, Iavg=49.76mA.

[0086] The bleeder resistor R10 provides a discharge circuit for the step-down capacitor C4 after power failure to avoid the risk of electric shock.

[0087] In the voltage divider circuit, the +5V voltage is provided by an adjustable voltage regulator U1 (i.e., an adjustable voltage regulator diode). In this embodiment, adjustable voltage regulator U1 uses a TL431, and resistors R5 (i.e., the fifth resistor) and R7 (i.e., the sixth resistor) both have a resistance of 10KΩ. Since the dynamic impedance of adjustable voltage regulator U1 is 0.2Ω (refer to the TL431 specification), this is equivalent to short-circuiting resistors R5 and R7, and the resistance here is negligible. The voltage value of VCC is determined by the equivalent resistance Rx (i.e., the parallel resistance) of resistors R1 (i.e., the fourth resistor), R3 (i.e., the second resistor), in series with resistor R8 (i.e., the third resistor), R6 (i.e., the seventh resistor), and R12 (i.e., the first resistor), and the average DC current Iavg. Among them, the resistance of resistor R1 is 1.5KΩ, the resistance of resistor R3 is 3KΩ, the resistance of resistor R8 is 1.2KΩ, the resistance of resistor R6 is 1.5KΩ, and the resistance of resistor R12 is 500Ω. The equivalent resistance Rx after parallel connection is:

[0088]

[0089] According to the formula, Rx = 280Ω.

[0090] The voltage value of VCC can be determined by Ohm's law:

[0091] VCC=I avg ·R x

[0092] According to the formula, we can get VCC=13.9V

[0093] VCC will serve as the power supply voltage and drive voltage for the comparison circuit and relay control circuit. As can be seen from the above formula, VCC will increase as the input voltage Vin increases. To prevent the VCC voltage from being too high and damaging the comparator chip in the comparison circuit, a voltage regulator D3 (i.e., the first voltage regulator) is connected in parallel to VCC. In this embodiment, voltage regulator D3 is a 27V voltage regulator to ensure that the subsequent circuit will not be damaged due to excessive VCC. VCC is divided by resistors R3 and R8 to obtain Vcmp, which is the voltage of resistor R8. Vcmp can be obtained according to the voltage divider formula:

[0094]

[0095] Combining the previous formula, we can get:

[0096]

[0097] Therefore, Vcmp is 3.97V, and there is a linear relationship between the input voltage Vin and the comparison voltage Vcmp. The voltage value of the comparison voltage Vcmp increases as the input voltage Vin increases.

[0098] The comparator circuit primarily consists of two comparators, U1A (i.e., the second comparator) and U1B (i.e., the first comparator). In this embodiment, the comparator chip uses an LM293. The comparison voltage Vcmp serves as U1B's inverting input, and +5V serves as its non-inverting input. Resistors R9 and R11 form the comparator's positive feedback network. In this embodiment, resistor R9 has a resistance of 100KΩ, and resistor R11 has a resistance of 3KΩ. U1B's output is connected to VCC via resistor R2 (i.e., the U1B output is connected to pull-up resistor R2 to VCC) and to the positive terminal of Zener diode D6 via resistor R4. Resistors R2 and R4 have a resistance of 10KΩ and 10KΩ, respectively. The output of U1B controls the activation of the relay: a low-level output activates the relay, and a high-level output deactivates the relay.

[0099] +5V serves as the non-inverting input of U1A, and the output of U1B is connected to the inverting input of U1A. The output of U1A is connected to VCC through resistor R6. When U1B outputs a high level (the output of U1B has a pull-up voltage VCC, and the voltage value of the high level is approximately VCC), U1A outputs a low level, and resistor R6 is equivalent to being connected in parallel to the load of VCC; when U1B is low, U1A outputs a high level, and resistor R6 is equivalent to breaking the loop. The resistance value of resistor R6 here needs to match the impedance of the relay coil to avoid voltage fluctuations of VCC caused by changes in the load of VCC when the relay is energized. In this embodiment, the resistance value of resistor R6 is 1.5KΩ, the relay uses 892-1CC-C-DC12V, and the coil resistance is 1.44KΩ.

[0100] In the relay control circuit, the emitter of PNP transistor Q1 is connected to VCC, the base is connected to the negative terminal of Zener diode D6, and the collector is connected to the relay coil and the negative terminal of diode D7. The other end of the coil is connected to GND and the positive terminal of diode D7, which provides a discharge circuit for the coil. The normally closed contact of the relay is connected to the live mains wire and the live input terminal of the switching power supply. In this embodiment, Zener diode D6 is a 3.3V Zener diode, PNP transistor Q1 is an MMBT4403, and diode D7 is a US1M.

[0101] The working process of the input overvoltage protection circuit composed of the above-mentioned RC step-down circuit, voltage divider circuit, comparison circuit, and relay control circuit is as follows, taking the above-mentioned embodiment as an example:

[0102] As can be seen from the comparator circuit, when Vcmp ≥ 5V (i.e., input voltage Vin ≥ 276VAC), comparator U1B outputs a low level. At this point, the base-emitter voltage Vbe of PNP transistor Q1 ≥ -0.95V meets the conduction condition, causing Zener diode D6 to break down. Resistor R4 serves to limit the base current, turning on PNP transistor Q1. When the voltage across the relay coil reaches the pull-in voltage, the relay closes, opening the normally closed contact and disconnecting the hot wire input of the switching power supply, protecting the internal components from damage due to high voltage. In actual use, the voltage of Vcmp or the +5V reference value can be adjusted as needed to achieve the adjustable input overvoltage threshold (i.e., the overvoltage protection threshold). Zener diode D6 is a 3.3V diode to prevent mis-conduction of the transistor, which could potentially cause Q1 to mis-conduct when interference is applied to the output of U1B.

[0103] In one embodiment, the present invention provides an input overvoltage protection circuit for a switching power supply, capable of preventing damage to the switching power supply due to accidental high voltage connection during operation. The overvoltage protection threshold of the input overvoltage protection circuit can be adjusted according to actual needs, and the circuit can be integrated into the switching power supply. Furthermore, the circuit utilizes relatively common and inexpensive components, including transistors, voltage regulator diodes, and relays, achieving stable functionality while achieving the desired function at a low cost.

[0104] It can be seen that the contents of the above system embodiments are all applicable to the present method embodiments. The functions specifically implemented by the present method embodiments are the same as those of the above system embodiments, and the beneficial effects achieved are also the same as those achieved by the above system embodiments.

[0105] In another aspect, an embodiment of the present invention provides an overvoltage protection device, comprising:

[0106] at least one processor;

[0107] at least one memory for storing at least one program;

[0108] When the at least one program is executed by the at least one processor, the at least one processor is enabled to implement the overvoltage protection method.

[0109] Similarly, the contents of the above method embodiments are applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0110] An embodiment of the present invention further provides a computer-readable storage medium storing a program executable by a processor. The program executable by the processor is used to perform the above-mentioned overvoltage protection method when executed by the processor.

[0111] Similarly, the contents of the above method embodiments are applicable to the present storage medium embodiment. The functions specifically implemented by the present storage medium embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0112] In some optional embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided in an exemplary manner for the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operation and logic flow presented herein. Optional embodiments are contemplated in which the order of the various operations is changed and the sub-operations described as a part of a larger operation are performed independently.

[0113] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It is also understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present invention. More specifically, given the properties, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the module will be understood within the ordinary skill of an engineer. Therefore, a person skilled in the art will be able to implement the present invention set forth in the claims using ordinary skill without undue experimentation. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0114] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several programs for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0115] The logic and / or steps represented in a flowchart or otherwise described herein, for example, may be considered as an ordered list of executable programs for implementing the logical functions, and may be embodied in any computer-readable medium for use by, or in conjunction with, a program execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can retrieve and execute a program from a program execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, a program execution system, apparatus, or device.

[0116] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0117] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable program execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0118] In the above description of this specification, reference to the terms "one embodiment / example," "another embodiment / example," or "certain embodiments / examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0119] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

[0120] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. An overvoltage protection system, characterized in that: The system includes: a voltage reduction module, a voltage division module, a comparison module and a control module; The mains power is connected to the voltage dividing module via the voltage reducing module, the voltage dividing module is connected to the control module via the comparison module, the voltage reducing module is also connected to the comparison module, and the control module is connected to the target object; The voltage reduction module is used to reduce the voltage of the mains to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the power supply voltage of the comparison module, and the driving voltage of the control module; The voltage dividing module is used to divide the first voltage to obtain a second voltage and a reference voltage; The comparison module is used to obtain a driving signal according to the second voltage and the reference voltage; the driving signal is used to drive the relay of the control module to disconnect the power supply between the mains and the target object.

2. The overvoltage protection system according to claim 1, characterized in that: The voltage divider module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an adjustable voltage regulator tube; The first end of the first resistor is used to connect to the first voltage output end of the step-down module, and the second end of the first resistor is grounded; the first end of the second resistor is connected to the first end of the first resistor, the second end of the second resistor is grounded through the third resistor, and the second end of the second resistor is used to output the second voltage; the first end of the fourth resistor is connected to the first end of the first resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is grounded through the sixth resistor; the anode of the adjustable voltage regulator is grounded, the cathode of the adjustable voltage regulator is connected to the second end of the fourth resistor, and the reference electrode of the adjustable voltage regulator is connected to the second end of the fifth resistor; the cathode of the adjustable voltage regulator is used to generate the reference voltage.

3. The overvoltage protection system according to claim 2, characterized in that: The voltage divider module further includes: a first voltage regulator tube, wherein the anode of the first voltage regulator tube is connected to the first end of the first resistor, the cathode of the first voltage regulator tube is grounded, and the first voltage regulator tube is used to limit the first voltage.

4. The overvoltage protection system according to claim 1, characterized in that: The comparison module includes: a first comparator, the reference voltage output end of the voltage divider module is connected to the non-inverting input end of the first comparator, the second voltage output end of the voltage divider module is connected to the inverting input end of the first comparator, and the output end of the first comparator is used to output a relay drive signal.

5. The overvoltage protection system according to claim 4, characterized in that: The comparison module also includes: a second comparator, the reference voltage output end is connected to the non-inverting input end of the second comparator, the output end of the first comparator is connected to the inverting input end of the second comparator, and the output end of the second comparator is connected to the first voltage output end of the step-down module through a seventh resistor.

6. The overvoltage protection system according to claim 5, characterized in that: The control module includes a transistor, the output end of the first comparator is connected to the base of the transistor, the emitter of the transistor is connected to the first voltage output end, the collector of the transistor is connected to the coil of the relay, one end of the normally closed switch of the relay is connected to the mains power, and the other end of the normally closed switch is connected to the target object.

7. The overvoltage protection system according to claim 6, characterized in that: The difference between the resistance of the coil and the resistance of the seventh resistor is less than or equal to a preset difference.

8. An overvoltage protection method, characterized in that: Applied to the overvoltage protection system according to any one of claims 1 to 7, the method comprises: Stepping down the mains power to obtain a first voltage; dividing the first voltage to obtain a second voltage and a reference voltage; A driving signal is obtained according to the second voltage and the reference voltage; the driving signal is used to drive a relay of a control module to disconnect the power supply between the mains and the target object.

9. The overvoltage protection method according to claim 8, characterized in that: The method further comprises: Determining a first value according to a quotient of the mains voltage and the capacitance value of the step-down module; determining a first voltage according to a product of the first value and a parallel resistor, wherein the parallel resistor is related to the first resistor, the second resistor, the third resistor, the fourth resistor of the voltage divider module, and the seventh resistor of the comparison module; The second voltage is determined according to a voltage division of the first voltage by the third resistor in a series branch of the second resistor and the third resistor.

10. The overvoltage protection method according to claim 9, characterized in that: The method further comprises: adjusting the capacitance of the capacitor, the first resistor, the second resistor, the third resistor, the fourth resistor, and the seventh resistor to determine an overvoltage protection threshold for generating the drive signal; Alternatively, an adjustable voltage regulator tube is adjusted to determine an overvoltage protection threshold for generating the driving signal.

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