Switching power supply, bleeding method, storage medium and program product

Abstract

The invention discloses a switching power supply, a discharge method, a storage medium and a program product, and relates to the technical field of power supplies, and the switching power supply comprises an input filter capacitor which is connected in parallel between a live line and a zero line of an AC source and is used for suppressing electromagnetic interference; the bleeder circuit unit is connected to the two ends of the input filter capacitor in parallel and used for releasing charges stored in the input filter capacitor under the condition that the switching power supply is in an abnormal power-off state so as to ensure that the input filter capacitor is discharged to a safe voltage level within a specified time range; the non-leakage circuit unit is used for collecting the output voltage of the alternating current source; and the processing unit is used for disconnecting the bleeder circuit unit under the condition that the output voltage of the alternating current source represents that the switching power supply is in a normal power supply state, thereby solving the problem that the overall efficiency of the power supply is reduced because a bleeder resistor consumes too much power when the power supply works normally in the prior art.

Description

Technical Field

[0001] This application relates to the technical field of power supplies, and in particular, to a switching power supply, a discharging method, a storage medium, and a program product. Background Art

[0002] As an efficient and stable power conversion device, a switching power supply is widely used in various electronic devices. In the design of a switching power supply, an input filter capacitor (such as a safety capacitor, also known as an X capacitor) is used to suppress electromagnetic interference (EMI). However, these capacitors may store a relatively high voltage after power-off, posing a potential safety risk to users and devices. To solve this problem, a bleeder resistor is usually added to the circuit. The function of the bleeder resistor is to quickly release the charge stored in the capacitor after the power supply is turned off, ensuring that the capacitor can quickly discharge to a safe voltage level and the safety of the device and avoiding the risk of electric shock.

[0003] However, to meet safety requirements (such as IEC 62368-1), the resistance value of the bleeder resistor is usually low, resulting in excessive power consumption during normal operation and a decrease in the overall efficiency of the power supply. Summary of the Invention

[0004] This application provides a switching power supply, a discharging method, a storage medium, and a program product to at least solve the problem in the related art that the bleeder resistor consumes excessive power during normal operation of the power supply, resulting in a decrease in the overall efficiency of the power supply.

[0005] This application provides a switching power supply, including: an input filter capacitor, connected in parallel between the live wire and the neutral wire of an AC source, for suppressing electromagnetic interference; a discharging circuit unit, connected in parallel across the input filter capacitor, for releasing the charge stored in the input filter capacitor when the switching power supply is in an abnormal power-off state to ensure that the input filter capacitor discharges to a safe voltage level within a specified time range; a non-discharging circuit unit, for collecting the output voltage of the AC source; and a processing unit, for disconnecting the discharging circuit unit when the output voltage of the AC source indicates that the switching power supply is in a normal power supply state.

[0006] The present application also provides a discharging method, including: collecting the output voltage of an AC source through a non-discharging circuit unit, and disconnecting the discharging circuit unit when the output voltage of the AC source indicates that the switching power supply is in a normal power supply state; the discharging circuit unit is connected in parallel across both ends of an input filter capacitor and is used to release the charge stored in the input filter capacitor when the switching power supply is in an abnormal power-off state, so as to ensure that the input filter capacitor discharges to a safe voltage level within a specified time range; the input filter capacitor is connected in parallel between the live wire and the neutral wire of the AC source and is used to suppress electromagnetic interference.

[0007] The present application also provides an electronic device, including: a memory for storing a computer program; a processor for implementing the steps of any of the above discharging methods when executing the computer program.

[0008] The present application also provides a computer-readable storage medium storing a computer program, wherein the computer program implements the steps of any of the above discharging methods when executed by a processor.

[0009] The present application also provides a computer program product including a computer program, and the computer program implements the steps of any of the above discharging methods when executed by a processor.

[0010] Through the present application, the processing unit intelligently switches between the discharging circuit unit and the non-discharging circuit unit according to the state of the switching power supply. When the switching power supply is in a normal power supply state, the discharging circuit unit is disconnected, so that the loss of the discharging circuit unit is 0, and it is realized that the discharging circuit is completely turned off when the power supply is turned on and is only activated at the moment of power-off, greatly reducing the continuous power consumption of the system, solving the problem in the related art that the discharging resistor consumes too much power when the power supply is working normally, resulting in a decrease in the overall efficiency of the power supply, and at the same time ensuring safe discharging after power-off and improving the energy utilization efficiency of the switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0012] Figure 1 It is a structural diagram of a discharging circuit in a related art provided by an embodiment of the present application.

[0013] Figure 2 It is a structural diagram of a switching power supply provided by an embodiment of the present application.

[0014] Figure 3Another structural diagram of the switching power supply provided by the embodiment of the present application.

[0015] Figure 4 Another structural diagram of the switching power supply provided by the embodiment of the present application.

[0016] Figure 5 It is another structural diagram of the switching power supply provided by the embodiment of the present application.

[0017] Figure 6 Structural diagram of the voltage sampling unit and the processing unit provided by the embodiment of the present application.

[0018] Figure 7 Circuit diagram of a switching power supply provided by the embodiment of the present application.

[0019] Figure 8 A discharge flow chart provided by the embodiment of the present application. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0021] It should be noted that in the description of the present application, the terms "include", "comprise" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. The terms "first", "second", etc. in the present application are used to distinguish similar objects and are not used to describe a specific order or sequence.

[0022] Glossary: IEC 62368 is a safety standard issued by the International Electrotechnical Commission (IEC for short), which is applicable to audio, video, information and communication technology equipment, as well as commercial and office machines. This standard aims to provide a unified safety framework for these types of products to ensure their safety during design, manufacturing and use.

[0023] As an efficient and stable power conversion device, the switching power supply is widely used in various electronic devices. In the design of the switching power supply, input filter capacitors (such as safety capacitors, also known as X capacitors) are used to suppress electromagnetic interference (EMI). However, these capacitors may store a relatively high voltage after power-off, posing a potential safety risk to users and equipment. Therefore, there are mandatory requirements in safety regulations regarding the discharge of the residual voltage of the switching power supply to a safe voltage and its discharge time. For example, the international standard (IEC 62368-1:2023 Ed.4) requires the following: within 1 second after power-off, the voltage of accessible terminals should be reduced to below 60V (the requirement was shortened from the original 2 seconds to 1 second after the update in 2024); within 10 seconds after power-off, the voltage should decay to below 30V (more stringent requirements for medical equipment, need to drop to 30V within <5 seconds); while China's national standard (GB 4943.1-2022): introduces "dual energy-time determination": when the capacitor energy > 0.5J, the energy needs to be discharged to <0.1J within 5 seconds.

[0024] To solve this problem, a bleeder resistor is usually added to the circuit. The function of the bleeder resistor is to quickly release the charge stored in the capacitor after the power supply is turned off, ensuring that the capacitor can be quickly discharged to a safe voltage level after power-off and the safety of the equipment and avoiding the risk of electric shock. Figure 1 The structural diagram of a bleeder circuit in a related technology provided by an embodiment of the present application is as Figure 1 shown. After the switching power supply is powered off, the energy of the X capacitor Cx1 inside the power supply is consumed by connecting bleeder resistors R1', R2', R3', and R4' in series across the capacitor terminals. The bleeder resistor R = R1' + R2' + R3' + R4'. According to the input voltage of the switching power supply, the required safe voltage value to be discharged, the required discharge time, and the capacitance value of the X capacitor selected for the input of the switching power supply, the size of the bleeder resistor can be obtained as shown in the following formula (1):

[0025]

[0026] where R is the bleeder resistor, t is the required discharge time, C is the capacitance value of the X capacitor for the input of the switching power supply, Vo is the initial voltage, Vt is the voltage after discharging for t time, subject to the safety requirements of IEC62328. During normal operation, the bleeder resistor does not need to discharge, but there will be losses. V is the voltage value superimposed on the X capacitor Cx1 during normal operation; its losses are shown in the following formula (2):

[0027] (2)

[0028] In summary, for a traditional bleeder resistor to meet safety requirements (such as IEC 62368-1), the resistance value of the bleeder resistor is usually low, resulting in excessive power consumption during normal operation and a decrease in the overall efficiency of the power supply.

[0029] To solve the problem in the related art that the bleeder resistor consumes too much power during the normal operation of the power supply, resulting in a decrease in the overall efficiency of the power supply, an embodiment of the present application provides a switching power supply that monitors the power-on and power-off states of the power supply, and determines whether to call the bleeder circuit unit of the power supply according to different states (power-on or power-off) of the power supply. When the power supply is normally powered, it switches from the bleeder circuit unit to the non-bleeder circuit unit, achieving device reuse, reducing the volume and saving efficiency, and reducing losses.

[0030] To enable those skilled in the art of the present technology to better understand the solution of the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] According to one aspect of the embodiments of the present application, a switching power supply is provided, as Figure 2 shown, including:

[0032] An input filter capacitor (Cx1) is connected in parallel between the live wire (L line) and the neutral wire (N line) of the AC source to suppress electromagnetic interference. The input filter capacitor stores energy during the normal operation of the power supply, and after power-off, the charge needs to be quickly released through the bleeder circuit unit to reach a safe voltage level.

[0033] A bleeder circuit unit is connected in parallel at both ends of the input filter capacitor and is used to release the charge stored in the input filter capacitor in the case where the switching power supply is in an abnormal power-off state, so as to ensure that the input filter capacitor discharges to a safe voltage level within a specified time range. In the embodiments of the present application, the bleeder circuit unit is a circuit design, and its purpose is to quickly consume the energy stored in the capacitor through a resistor network or a switch connected in parallel at both ends of the input filter capacitor (Cx1) after the switching power supply is powered off.

[0034] A non-bleeder circuit unit is used to collect the output voltage of the AC source. The non-bleeder circuit unit is a circuit part for collecting the output voltage of the AC source (L line and N line) during the normal operation of the switching power supply, and converts the high voltage output by the AC source into a signal that can be processed by the processing unit without triggering the operation of the bleeder circuit unit. It can be understood that only one of the bleeder circuit unit and the non-bleeder circuit unit can be conducting, and the other is in an off state.

[0035] The processing unit is used to disconnect the discharge circuit unit when the output voltage of the AC source indicates that the switching power supply is in a normal power supply state. The processing unit is the control core in the entire switching power supply system. It determines whether the power supply is in a normal power supply state by monitoring the output voltage of the AC source. To reduce the excessive power consumption of the discharge circuit unit during the normal operation of the power supply, improve the overall efficiency of the power supply, and at the same time ensure safe discharge after power-off, when the processing unit detects normal power supply of the power supply, it controls the disconnection of the discharge circuit unit to avoid power consumption of the discharge circuit unit during the normal operation of the power supply. When detecting power-off of the power supply, the processing unit will control the disconnection of the non-discharge circuit unit and activate the discharge circuit unit to ensure the safe discharge of the input filter capacitor Cx1.

[0036] Through this embodiment, the processing unit intelligently switches the discharge circuit unit and the non-discharge circuit unit according to the state of the switching power supply. In the normal power supply state of the switching power supply, the discharge circuit unit is disconnected, so that the loss of the discharge circuit unit is 0, and the discharge circuit is completely turned off when the power supply is turned on, and is only activated at the moment of power-off, greatly reducing the continuous power consumption of the system, solving the problem in the related technology that the discharge resistor consumes too much power during the normal operation of the power supply, resulting in a decrease in the overall efficiency of the power supply, and at the same time ensuring safe discharge after power-off, and improving the energy utilization efficiency of the switching power supply.

[0037] In an exemplary embodiment, the processing unit is further used to disconnect the non-discharge circuit unit and conduct the discharge circuit unit when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state.

[0038] Among them, when the processing unit detects power-off of the AC source, the primary task is to ensure the electric shock safety of users and the safety of equipment. The processing unit immediately executes the action of disconnecting the non-discharge circuit unit and conducting the discharge circuit unit, switching the non-discharge circuit unit originally used for voltage sampling to the discharge circuit unit, so as to quickly discharge the input filter capacitor and rapidly reduce the voltage across the capacitor to a safe level, preventing the danger of electric shock to users and protecting the subsequent circuit from high voltage damage.

[0039] Through this embodiment, the processing unit automatically completes the switching from the non-discharge circuit unit to the discharge circuit unit by monitoring the state of the AC source. Without manual intervention, it can ensure the safe handling of the switching power supply in the case of power-off.

[0040] In an exemplary embodiment, the discharge resistor in the related art fails to reduce the voltage of the input filter capacitor to a safe range within the specified time, affecting the user experience and safety. Therefore, to solve the above problems, in this embodiment, a discharge circuit unit is provided, which includes a first discharge unit and a second discharge unit, and the resistance of the first discharge unit is less than that of the second discharge unit. By dynamically switching between the first discharge unit and the second discharge unit, the function of discharging energy using discharge units with different resistance values according to the voltage level across the input filter capacitor is achieved, solving the problem of slow response speed of the discharge resistor in the related art.

[0041] Figure 3 The structure diagram of another switching power supply provided by the embodiment of the present application is as Figure 3 shown, and the discharge circuit unit includes:

[0042] A first discharge unit, connected in parallel across the input filter capacitor, is configured to release the charge stored in the input filter capacitor when the voltage across the input filter capacitor is greater than or equal to a first voltage threshold. Herein, the first voltage threshold is a preset high-voltage threshold. When the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, it indicates that the voltage across the input filter capacitor is in the high-voltage stage, and at this time, rapid discharge is required to ensure discharge safety and ensure that the input filter capacitor is discharged to a safe level within the specified time range. When the voltage across the input filter capacitor is less than the first voltage threshold, it indicates that the voltage across the input filter capacitor is in the low-voltage stage, and at this time, the remaining charge needs to be discharged in a low-power consumption manner. It can be seen that in this embodiment, the first voltage threshold is used to distinguish between the high-voltage stage and the low-voltage stage. When the voltage across the input filter capacitor Cx1 is greater than or equal to the first voltage threshold, the first discharge unit is activated; conversely, when it is lower than the first voltage threshold, the second discharge unit starts to work. The first voltage threshold is set according to safety standards and performance requirements, such as the requirements for voltage discharge time after power-off in IEC 62368-1. The fast discharge circuit where the first discharge unit is connected in parallel across the input filter capacitor Cx1 mainly includes a low-resistance resistor and a switch. When the voltage across the input filter capacitor Cx1 reaches or exceeds the first voltage threshold, the first discharge unit is activated, and the capacitor voltage is rapidly reduced through a large current to meet the fast discharge requirements after the switching power supply is powered off. The goal of the first discharge unit is to quickly and safely consume the energy in the capacitor in the high-voltage stage.

[0043] The second discharge unit, which is connected in parallel across the input filter capacitor, is used to discharge the charge stored in the input filter capacitor when the voltage across the input filter capacitor is less than the first voltage threshold. The second discharge unit partially reuses the first discharge unit, that is, when the voltage across the input filter capacitor Cx1 is lower than the first voltage threshold, by changing the switching states of the first discharge unit and the second discharge unit, the original first discharge unit is changed into a high-resistance steady-state discharge circuit. The main purpose of the second discharge unit is to reduce power consumption and extend the discharge time in the low-voltage stage, while ensuring that the residual voltage meets the safety standards. The reuse of the first discharge unit by the second discharge unit means that after the power supply is cut off, the second discharge unit can utilize a part of the resistance network originally belonging to the first discharge unit by adjusting the switching states of its internal switching components, so as to achieve the conversion from fast discharge to steady-state discharge at different voltage thresholds, thereby saving hardware resources, reducing costs and occupied space. The resistance of the first discharge unit is less than that of the second discharge unit because when the power supply is just cut off, the input filter capacitor Cx1 may carry a relatively high voltage and energy. In order to quickly release this energy to a safe level to meet the requirements of the safety standards for the voltage discharge time and the final voltage after power-off (such as the IEC 62368-1 standard), the first discharge unit adopts a low-resistance resistance network. The low-resistance resistor can carry a larger current, thus achieving fast and effective energy consumption and accelerating the decline rate of the capacitor voltage. As the voltage of the capacitor Cx1 gradually decreases, continuing to use the low-resistance resistor for discharge will result in excessive power consumption, especially in the steady-state and lower voltage stages. To avoid this unnecessary energy loss and improve the overall efficiency of the power supply, the second discharge unit is designed as a high-resistance resistance network. The high-resistance resistor in the network can maintain low power consumption even during a long discharge process, while still meeting the attenuation requirements of the capacitor residual voltage.

[0044] The processing unit is also used to select one of the first discharge unit and the second discharge unit to conduct according to the voltage across the input filter capacitor when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state. In this embodiment, the processing unit is responsible for monitoring the AC source state and the voltage across the input filter capacitor Cx1, and intelligently selecting to activate the first discharge unit or the second discharge unit based on the voltage across the input filter capacitor Cx1. When the power supply is cut off, the processing unit decides to use fast large-current discharge (the first discharge unit) or low-power steady-state discharge (the second discharge unit) by detecting the voltage across the input filter capacitor Cx1, so as to optimally meet various safety and performance indicators.

[0045] Through this embodiment, it is set that the discharge circuit unit includes a first discharge unit and a second discharge unit, and the resistance of the first discharge unit is less than that of the second discharge unit. Threshold segmentation control is performed according to the magnitude of the voltage across the input filter capacitor. That is, when the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, the first discharge unit is turned on and the second discharge unit is turned off. The low-resistance design of the first discharge unit enables the rapid reduction of the capacitor voltage at the initial stage of power-off of the power supply, meeting the requirement of rapid discharge; when the voltage across the input filter capacitor is less than the first voltage threshold, the first discharge unit is turned off and the second discharge unit is turned on. The second discharge unit switches to a high resistance after the voltage drops to a relatively low level, reducing the power consumption in the steady state and improving the overall efficiency, solving the problems of excessive power consumption and slow response speed in the related art; in addition, the second discharge unit reuses part of the resistance network of the first discharge unit, so that the same circuit components can assume different functional roles at different times; in the high-voltage stage, the first discharge unit forms a low-resistance channel, while in the low-voltage stage, by changing the circuit connection state of the first discharge unit, the same components constitute a high-resistance steady-state discharge circuit. This reuse method reduces the use of hardware resources, lowers the cost, and at the same time overcomes the cost and volume problems caused by the use of high-power resistors in the traditional design; the processing unit intelligently selects to turn on the first discharge unit or the second discharge unit according to the power-off state of the AC source and the real-time voltage of the input filter capacitor Cx1. This intelligent selection mechanism based on the voltage threshold ensures that the most suitable discharge strategy is adopted at any time, neither causing excessive energy consumption nor being able to respond quickly when necessary, ensuring safety.

[0046] In an exemplary embodiment, as Figure 3 shown, the switching power supply further includes: a voltage sampling unit, connected in parallel across the input filter capacitor, for collecting the voltage across the input filter capacitor.

[0047] Among them, the voltage sampling unit refers to a group of circuit components, mainly including resistors, operational amplifiers and other signal conditioning elements, which are connected in parallel across the input filter capacitor Cx1. Its function is to accurately measure and monitor the voltage on the input filter capacitor Cx1, and convert this voltage signal into a form suitable for the processing unit to read. The voltage sampling unit is used to monitor the input voltage during normal power supply, and assist in detecting the residual voltage of the capacitor after power-off to realize the timely control of the discharge circuit unit, ensure that the energy of the capacitor is properly released according to safety standards, and cooperate with the decision-making of the processing unit to perform intelligent switching of the fast or steady-state discharge circuit.

[0048] Through this embodiment, the close cooperation between the voltage sampling unit and the processing unit enables the switching power supply to automatically adjust the discharge strategy according to the real-time change of the capacitor voltage.

[0049] In an exemplary embodiment, Figure 4 is a structural diagram of another switching power supply provided by an embodiment of the present application. As Figure 4 shown, the first discharge unit includes: a first discharge resistor component and a first switch component; wherein, the first discharge resistor component and the first switch component are connected in series and then connected in parallel across both ends of the input filter capacitor.

[0050] In this embodiment, the first discharge unit refers to a circuit module in which the first discharge resistor component and the first switch component are connected in series and then connected in parallel across both ends of the input filter capacitor. Its main task is to, when the voltage across the input filter capacitor reaches or exceeds the first voltage threshold, activate the first switch component by using the first discharge resistor component to quickly release the energy stored in the capacitor, ensuring that the capacitor voltage can quickly drop to a safe range after the power supply is powered off, so as to meet the requirements of rapid discharge.

[0051] The first switch component refers to an electronic switch that can control the on / off of the first discharge unit, such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). When the switching power supply is powered off and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, the processing unit will send a signal to turn on the first switch component, causing the first discharge unit to start working; conversely, when the voltage across the input filter capacitor is less than the first voltage threshold, the first switch component will be turned off, stopping the rapid discharge and switching to the steady-state discharge mode or completely turning off the discharge circuit to prevent unnecessary power consumption.

[0052] The first discharge resistor component includes a group of low-resistance resistors, which are used to provide a high-current path to accelerate the discharge process of the capacitor when the voltage across the input filter capacitor is relatively high. By cooperating with the first switch component, it can significantly reduce the capacitor voltage within a short time, meeting the rapid discharge time requirements specified by the safety standards.

[0053] The processing unit is further configured to turn on the first switching component when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold; and turn off the first switching component when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold. In this embodiment, the processing unit is responsible for monitoring and analyzing the power supply state and the voltage of the input filter capacitor. When it detects that the switching power supply is abnormally powered off and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, it automatically turns on the first switching component to activate the fast discharge process; once the voltage across the input filter capacitor is less than the first voltage threshold, it will turn off the first switching component, switch to the steady state or stop discharging, ensuring fast and economical release of the capacitor energy.

[0054] Through this embodiment, the first discharge unit forms a controllable discharge circuit through the series-connected first switching component and the first discharge resistance component. The first discharge unit is connected in parallel across the input filter capacitor. When the AC source is powered off and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, the processing unit automatically turns on the first switching component, connects the low-resistance first discharge resistance component to the discharge path of the capacitor, and realizes fast charge release.

[0055] In an exemplary embodiment, when the switching power supply is powered off and it is necessary to quickly release the energy stored in the filter capacitor to reach the safe voltage level, the first discharge unit may generate a large amount of heat due to the instantaneous large current passing through it. If the heat accumulates too fast and cannot be effectively dissipated, the temperature of the circuit components will rise sharply, resulting in the fusing of the components in the discharge circuit unit, the rupture of the package, or the deformation of the circuit board, thus damaging the entire discharge circuit and even the switching power supply system, increasing the risk of equipment failure. Therefore, to solve the above problems, as Figure 4 shown, the first discharge unit further includes: a temperature sampling unit, connected in series between the first discharge resistance component and the first switching component, for collecting the temperature of the discharge path of the input filter capacitor and cutting off the first discharge unit when the temperature is greater than the preset temperature threshold.

[0056] Among them, the temperature sampling unit is part of the first discharging unit, and its main responsibility is to monitor the temperature of the capacitor discharging path in real time during the discharging process. Once it is found that the temperature exceeds the preset threshold, the temperature sampling unit will immediately cut off the first discharging unit to avoid circuit damage or safety hazards caused by overheating. The preset temperature threshold is a set maximum safety temperature limit used to guide the operation of the temperature sampling unit. When the temperature of the discharging path of the input filter capacitor exceeds this threshold, the temperature sampling unit will trigger the protection mechanism and automatically disconnect the first discharging unit to prevent serious consequences such as circuit damage or fire caused by high temperature. In this embodiment, the temperature sampling unit can use a temperature switch that automatically cuts off the power, or transmit the collected temperature to the processing unit, and the processing unit shuts off the first switch component in the first discharging unit.

[0057] Through this embodiment, by setting the temperature sampling unit, the temperature of the discharging path can be monitored in real time. Once it is detected that the temperature exceeds the preset threshold, the first discharging unit will be immediately cut off to prevent the current from continuing to flow, thereby preventing the temperature from rising further. This mechanism effectively solves the potential thermal runaway problem caused by rapid discharging, ensures that the discharging circuit can work efficiently and stably within a safe temperature range, avoids component damage and safety hazards, and at the same time maintains the overall performance and service life of the switching power supply.

[0058] In an exemplary embodiment, in the related art, the design of the discharging circuit often dissipates the energy stored in the capacitor in the form of heat, which not only causes energy waste but also may increase the thermal load of the components. Therefore, to solve the above problems, as Figure 4 shown, the first discharging unit further includes: an energy feedback unit, connected in series between the first discharging resistor component and the first switch component, for storing the discharging voltage of the input filter capacitor and feeding it back to the AC source after the switching power supply is turned on.

[0059] Among them, the energy feedback unit refers to a circuit module designed to collect and store the energy discharged from the input filter capacitor when the switching power supply is turned off, rather than simply dissipating it as heat. When the switching power supply is restarted, the energy feedback unit can feed back the stored energy to the power supply system and convert it back into electrical energy for use, thereby realizing the recovery and reuse of energy, significantly improving the power conversion efficiency, and reducing energy consumption. The energy feedback unit usually consists of a flyback transformer, a rectifier diode, a current-limiting resistor, and a constant-current DC source, etc., and they work together to ensure the efficient collection and safe feedback of energy.

[0060] Figure 5 is the structural diagram of another switching power supply provided by the embodiment of the present application, as Figure 5As shown, the non-discharging circuit unit collects the output voltage of the AC source and transmits the output voltage to the processing unit. The processing unit also receives the voltages at both ends of the input filter capacitor collected by the voltage sampling unit. If the output voltage of the AC source indicates that the switching power supply is in a normal power supply state, the non-discharging circuit unit is turned on and the discharging circuit unit is turned off. Otherwise, one of the first discharging unit and the second discharging unit is selected to be turned on according to the voltages at both ends of the input filter capacitor. If the first discharging unit is selected to be turned on, not only can rapid discharging be performed through the low-resistance network, but also temperature acquisition can be performed through the temperature sampling unit. When the temperature exceeds the preset temperature threshold, the first discharging unit is turned off, and the discharging voltage of the input filter capacitor is fed back to the system through the energy feedback unit for reuse next time.

[0061] Through this embodiment, the energy feedback unit can effectively collect the energy discharged from the filter capacitor after power-off and reuse it when the power supply is started next time, rather than completely wasting it as heat. This significantly improves the energy utilization efficiency of the system and reduces energy loss.

[0062] In an exemplary embodiment, in the related art, in order to achieve the purpose of rapid discharging and steady-state discharging, high-power discharging resistors are often used. However, high-power discharging resistors are often large in size and high in cost, which limits their application in miniaturized devices. Therefore, to solve this problem, as Figure 4 shown, the second discharging unit includes: a first discharging resistor component, a second discharging resistor component, a first switch component, and a second switch component; the first discharging resistor component is connected in series with the first switch component and then connected in parallel across both ends of the input filter capacitor; the second discharging resistor component is connected in series with the second switch component and then connected in parallel across both ends of the first switch component.

[0063] Among them, the first discharging resistor component and the first switch component are the structures of the first discharging unit. In this embodiment, the second discharging unit reuses the first discharging resistor component in the first discharging unit, reducing the need to purchase and install high-resistance steady-state discharging resistors additionally, thereby reducing the cost of the circuit and avoiding occupying extra space. The first discharging component and the first switch component have been explained in the above embodiment and will not be repeated here.

[0064] The second discharging resistor component refers to a high-resistance steady-state discharging network, which is used to maintain the continuous stability of the capacitor voltage with lower power consumption after the voltage at both ends of the input filter capacitor is less than the first voltage threshold, avoiding unnecessary energy loss. The second switch component is connected in series with the second discharging resistor component and is used to control the on-off of the high-resistance steady-state discharging path. When the voltage of the input filter capacitor drops below the first voltage threshold, the processing unit activates the second switch component to switch to the steady-state discharging mode.

[0065] The processing unit is further configured to, when the output voltage of the AC power source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, disconnect the non-discharging circuit unit, turn off the second switching component, turn on the first switching component, so as to turn on the first discharging unit for rapid discharging; when the output voltage of the AC power source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold, disconnect the non-discharging circuit unit, turn on the second switching component, turn off the first switching component, so as to turn on the second discharging unit for steady-state discharging, so as to reduce power consumption and improve efficiency.

[0066] Through this embodiment, the discharging circuit unit is dynamically configured to adapt to different stages of the voltage across the input filter capacitor. That is, when the voltage across the input filter capacitor is greater than or equal to the first voltage threshold (i.e., in the high-voltage stage), the processing unit disconnects the non-discharging circuit unit, turns off the second switching component, turns on the first switching component, enables the first discharging unit to work, and uses the low-resistance characteristic of the first discharging resistor component for rapid discharging to meet the requirement of rapid and safe discharging after power-off; when the voltage across the input filter capacitor is less than the first voltage threshold, the second switching component is turned on and the first switching component is turned off to activate the second discharging unit, and a high-resistance resistor network formed by the first discharging resistor component and the second discharging resistor component is used for steady-state discharging, effectively solving the contradiction between rapid response and low-power consumption requirements pointed out in the related art; in addition, the second discharging unit reuses the first discharging resistor component and the first switching component in the first discharging unit, avoiding the additional introduction of components with the same function in the second discharging unit, saving material costs and manufacturing costs, reducing the number of components on the circuit board, contributing to a more compact and smaller design, and being beneficial to the overall miniaturization of the device.

[0067] In an exemplary embodiment, in order to further reduce costs and volume, as Figure 4 shown, the non-discharging circuit unit includes: a first discharging resistor component, a second discharging resistor component, a third switching component, a fourth switching component, a first voltage sampling component, and a second voltage sampling component; one end of the second switching component is grounded through the series-connected third switching component and the first voltage sampling component; the other end of the second switching component is grounded through the series-connected fourth switching component and the second voltage sampling component; the first voltage sampling component is used to collect the output voltage of the live wire; the second voltage sampling component is used to collect the output voltage of the neutral wire.

[0068] Among them, the first discharge resistor component and the second discharge resistor component have been explained in the above embodiments and will not be repeated here. It can be seen that the non-discharge circuit unit multiplexes the discharge circuit unit, that is, the non-discharge circuit unit multiplexes the first discharge resistor component and the second discharge resistor component in the discharge circuit unit. When the switching power supply is normally powered, the first discharge resistor component and the second discharge resistor component are multiplexed by the non-discharge circuit unit as adopted components. When the switching power supply is abnormally powered off, the first discharge resistor component and the second discharge resistor component act as discharge resistors, effectively reducing the cost and power consumption and reducing the volume of the device.

[0069] The third switch component is connected in series with the first voltage sampling component and is connected to one end of the second switch component and finally grounded. When the switching power supply is in a normal power supply state, the third switch component cooperates with the first voltage sampling component to perform voltage sampling; when the switching power supply is in an abnormal power-off state, the third switch component is disconnected by the processing unit to support the activation of the discharge circuit unit.

[0070] The fourth switch component is connected in series with the second voltage sampling component in the non-discharge circuit unit and is connected to the other end of the second switch component and finally grounded. The function of the fourth switch component is similar to that of the third switch component, but it cooperates with different resistors and sampling components in the circuit. When the switching power supply is in an abnormal power-off state, the fourth switch component is disconnected by the processing unit to support the activation of the discharge circuit unit.

[0071] The first voltage sampling component is used to monitor the voltage of the L line when the switching power supply is in a normal power supply state, and the sampling result is transmitted to the processing unit to judge the power supply state and the capacitor voltage level, and then determine whether it is necessary to activate the discharge circuit unit.

[0072] The second voltage sampling component is used to monitor the voltage of the N line when the switching power supply is in a normal power supply state. The sampling result is also transmitted to the processing unit to judge the power supply state and the capacitor voltage level, and then determine whether it is necessary to activate the discharge circuit unit.

[0073] In this embodiment, the processing unit is further configured to disconnect the first switch component and the second switch component to disconnect the discharge circuit unit, save power consumption and improve power efficiency, and conduct the third switch component and the fourth switch component to collect and monitor the voltages of the L and N lines when the output voltage of the AC source indicates that the switching power supply is in a normal power supply state; when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state, according to the voltage across the input filter capacitor, select to conduct one of the first switch component and the second switch component, and disconnect the third switch component and the fourth switch component to disconnect the non-discharge circuit unit and switch the non-discharge circuit unit to the discharge circuit unit to achieve rapid or steady-state release of the capacitor energy.

[0074] Through this embodiment, by controlling the on / off states of the first switch component, the second switch component, the third switch component, and the fourth switch component, the dynamic switching between the non-discharging circuit unit and the discharging circuit unit is achieved; when the switching power supply is in the normal power supply state, the non-discharging circuit unit reuses the first discharging resistor component and the second discharging resistor component in the discharging circuit unit as sampling resistors, avoiding the need to additionally add resistors in the non-discharging circuit unit and reducing the hardware cost; when the switching power supply is in the abnormal power-off state, the third switch component and the fourth switch component are disconnected to prevent the first voltage sampling component and the second voltage sampling component from consuming additional energy when the discharging circuit unit is working, avoiding the problem of unnecessary power consumption, reducing energy loss, and improving the overall energy utilization efficiency.

[0075] In an exemplary embodiment, Figure 6 is a structural diagram of the voltage sampling unit and the processing unit provided by the embodiment of the present application. As Figure 6 shown, the voltage sampling unit includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a voltage-dividing resistor Rx, and an operational amplifier IC1; wherein, the negative electrode of the input filter capacitor is connected to the negative input terminal of the operational amplifier IC1 through the second resistor R2, and the positive electrode of the input filter capacitor is connected to the positive input terminal of the operational amplifier IC1 through the third resistor R3; the output terminal of the operational amplifier IC1 is connected to the processing unit; one end of the first resistor R1 is connected to the negative input terminal of the operational amplifier IC1, and the other end of the first resistor R1 is connected to the output terminal of the operational amplifier IC1; one end of the fourth resistor R4 is connected to the voltage source, and the other end of the fourth resistor is connected to the positive input terminal of the operational amplifier IC1; one end of the voltage-dividing resistor Rx is connected to the positive input terminal of the operational amplifier IC1, and the other end of the voltage-dividing resistor Rx is grounded.

[0076] Among them, the first resistor R1 is a feedback resistor. When the output signal of the operational amplifier IC1 changes, the first resistor R1 can ensure that the signal is correctly fed back to the negative input terminal of the operational amplifier IC1, thereby forming a closed-loop amplifier circuit. The resistance value of the first resistor R1 is directly related to the feedback strength, and thus affects the amplification factor and stability of the voltage sampling voltage.

[0077] The second resistor R2 is connected in series between the negative electrode of the input filter capacitor Cx1 and the negative input terminal of the operational amplifier IC1. Its function is to introduce the voltage signal (VCx-) on the negative electrode of the input filter capacitor Cx1 into the negative-phase input terminal of the operational amplifier IC1, providing a reference voltage for the operational amplifier IC1 to compare with the signal at the positive-phase input terminal of the operational amplifier IC1.

[0078] The third resistor R3 is responsible for feeding the voltage signal (VCx+) on the positive terminal of the input filter capacitor Cx1 into the non-inverting input terminal of the operational amplifier IC1. The third resistor R3 and the second resistor R2 cooperate to jointly achieve voltage division and sampling, ensuring that the operational amplifier IC1 can accurately measure the voltage difference across the input filter capacitor Cx1. By adjusting the resistance value of the third resistor R3, the voltage sampling accuracy can be adjusted.

[0079] The fourth resistor R4 is used to provide a reference voltage for the input filter capacitor Cx1, ensuring that even under power supply fluctuations, the non-inverting input terminal of the operational amplifier IC1 can still receive a stable and accurate reference voltage.

[0080] The voltage dividing resistor Rx and the fourth resistor R4 together form a voltage dividing network to further adjust and stabilize the voltage at the non-inverting input terminal of the operational amplifier IC1.

[0081] The operational amplifier IC1 receives the input signals from the second resistor R2 and the third resistor R3, is feedback through the first resistor R1, and the reference voltage provided by the fourth resistor R4 and the voltage dividing resistor Rx. It amplifies and preliminarily processes the voltage signal across the input filter capacitor Cx1 to obtain the voltage VCx across the filter capacitor Cx1, and then outputs the processed VCx signal to the processing unit.

[0082] As Figure 6 shown, the processing unit includes an MCU (Microcontroller Unit) processor. The signal processed by the operational amplifier IC1 is output to the MCU processor. The MCU processor analyzes it to obtain the voltage across the input filter capacitor. When the voltage across the input filter capacitor is greater than the first voltage threshold, it controls the first switch component to conduct, and the second, third, and fourth switch components to disconnect.

[0083] Through this embodiment, the voltage across the input filter capacitor Cx1 is divided by the second resistor R2 and the third resistor R3 and led to the input terminal of the operational amplifier IC1, realizing real-time monitoring of the capacitor voltage; the first resistor R1 constitutes the feedback loop of the operational amplifier IC1. By feeding back a part of the output signal to the inverting input terminal of the operational amplifier IC1 to form a closed-loop control, the stability of the entire voltage sampling unit is enhanced; the fourth resistor R4 and the voltage dividing resistor Rx work together to provide a stable reference voltage for the non-inverting input terminal of the operational amplifier IC1, ensuring that even under power supply voltage fluctuations, IC1 can still perform voltage comparison and amplification based on an accurate reference, improving the sampling accuracy.

[0084] In an exemplary embodiment, Figure 7 is a circuit diagram of a switching power supply provided by an embodiment of the present application. AsFigure 7 As shown, the first discharge resistor assembly includes a fifth resistor R5 and a sixth resistor R6, and the first switch assembly includes a first switch S1; one end of the fifth resistor R5 is connected to the neutral line, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 through the first switch S1, and the other end of the sixth resistor R6 is connected to the live line.

[0085] Among them, in the first discharge unit, the first switch S1 plays a key role in controlling the opening and closing of the first discharge resistor assembly. When the processing unit detects that the switching power supply is in a power-off state and the voltage across the input filter capacitor is higher than the set first voltage threshold, the first switch S1 is turned on, connecting the series resistor formed by the fifth resistor R5 and the sixth resistor R6 into the circuit to accelerate the discharge process of the capacitor. When the voltage across the input filter capacitor is less than the set first voltage threshold (i.e., entering the low-voltage stage), the first switch S1 will be turned off, cutting off the discharge loop and switching to the steady-state discharge mode to reduce power consumption.

[0086] On the AC power line, the voltage between the live line and the neutral line changes periodically, reaching peaks and valleys. If only one discharge resistor is directly connected across the live line and the neutral line, then when the power supply is disconnected, this resistor will bear the full AC voltage, which may lead to excessive power consumption and heat generation, not only increasing energy consumption but also potentially causing component overheating and damage. Therefore, in this embodiment, the first discharge resistor assembly includes the fifth resistor R5 and the sixth resistor R6 instead of a single resistor, and the fifth resistor R5 and the sixth resistor R6 are respectively placed between the live line and the neutral line and the input filter capacitor, which can disperse the voltage and power consumption while ensuring the discharge path, avoid a single component from bearing excessive pressure, and improve the thermal stability and safety of the circuit.

[0087] In this embodiment, the fifth resistor R5 and the sixth resistor R6 together constitute the first discharge resistor assembly. They are connected in series and form a loop with the live line and the neutral line through the first switch S1. This series structure design allows the charge in the input filter capacitor to be discharged after power-off and controls the discharge rate of the capacitor. The resistance values of R5 and R6 directly affect the discharge speed and efficiency. At the same time, the series connection provides a more flexible resistance adjustment ability, enabling it to play an effective role in both the rapid discharge and steady-state discharge stages and meeting the discharge requirements under different safety standards.

[0088] The processing unit is further configured to, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, disconnect the non-discharging circuit unit and turn on the first switch S1 to turn on the first discharging unit. In this embodiment, the processing unit is further configured to, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold, disconnect the non-discharging circuit unit and turn off the first switch S1 to turn off the first discharging unit. As Figure 6 shown, the processing unit includes an MCU processor. A pin of the MCU processor is used to control the first switch S1. The MCU processor outputs a control signal to the first switch S1 through this pin to control the on / off of the first switch S1.

[0089] Through this embodiment, the combination of the first discharging resistor components (the fifth resistor R5 and the sixth resistor R6) and the first switch S1 realizes the function of dynamically adjusting the resistance value according to the voltage of the input filter capacitor. Compared with the solution in the related art where a fixed low-resistance resistor is often used in the discharging circuit to meet the requirement of rapid discharging, in this embodiment, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold (i.e., the high-voltage stage), the processing unit controls the first switch S1 to turn on, and the fifth resistor R5 and the sixth resistor R6 form a low-resistance discharging network to achieve rapid discharging. And when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold, the processing unit controls the first switch S1 to turn off, switches to a high-resistance steady-state discharging, reduces the steady-state power consumption, and solves the problem of excessive power consumption.

[0090] In an exemplary embodiment, as Figure 7 shown, the temperature sampling unit includes: a temperature switch T1, which is connected in series in the link between the fifth resistor R5 and the first switch S1, and is used to detect the temperature of the discharging path of the input filter capacitor and disconnect when the temperature is greater than the preset temperature threshold to cut off the first discharging unit.

[0091] Among them, the temperature switch T1 is the core component of the temperature sampling unit. It is connected in series in the path of the discharging circuit unit, such as between the fifth resistor R5 and the first switch S1. The temperature switch T1 can detect the temperature change caused by large-current discharging in the path. Once the temperature exceeds the preset temperature threshold (such as 130 °C), the temperature switch T1 will automatically disconnect to cut off the first discharging unit, prevent thermal runaway, and avoid damage to the first discharging unit caused by high current and high temperature.

[0092] In this embodiment, the temperature switch T1 is connected in series in the link between the fifth resistor R5 and the first switch S1, and is located on the critical path of the discharge circuit. This means that when the discharge circuit is working, the temperature switch T1 can directly sense the temperature change of this path. When the temperature exceeds the preset threshold, the temperature switch T1 will automatically disconnect, cutting off the path of the first discharge unit, thereby preventing the large current in the overheat state from flowing further, playing a protective role. This design solves the problem of damage to the discharge circuit caused by the high temperature caused by the large current.

[0093] In an exemplary embodiment, the energy feedback unit includes: a transformer T2, a diode D1, a seventh resistor R7, and a constant current source DC; the primary coil of the transformer T2 is connected in series in the link between the first switch S1 and the sixth resistor R6; one end of the secondary coil of the transformer T2 is connected to the positive pole of the constant current source DC through the diode D1 and the seventh resistor R7 connected in series in sequence; the other end of the secondary coil of the transformer T2 is connected to the negative pole of the constant current source DC; the transformer T2 is used to collect the discharge voltage of the input filter capacitor and store the discharge voltage in the constant current source DC.

[0094] Among them, the transformer T2 plays a key role in energy transfer in the energy feedback unit. It is connected in series in the link between the first switch S1 and the sixth resistor R6. When the discharge circuit unit is working, the primary coil of the transformer T2 receives the discharge voltage, and the secondary coil transfers the energy to the constant current source DC for storage through rectification and current limiting.

[0095] The diode D1 is used for the rectification link in the energy feedback unit to ensure that the energy transmitted from the secondary coil of the transformer T2 can flow unidirectionally into the constant current source DC, prevent the energy from flowing backward, and protect the stability of the circuit. D1 is connected in series with the seventh resistor R7 and together constitutes a part of the energy feedback path.

[0096] The seventh resistor R7 serves as a current limiting resistor in the energy feedback unit to limit the energy current flowing into the constant current source DC and avoid overloading the constant current source. R7 is connected in series with the diode D1 to ensure the stability of the current during the energy storage process, protecting both the constant current source DC and improving the efficiency of energy feedback.

[0097] The constant current source DC is the energy storage element of the energy feedback unit. It receives the energy transmitted through the transformer T2 and the current limiting resistor R7, converts it into electrical energy and stores it. When the power supply starts normally next time, the energy in the constant current source DC can be used to assist the system startup, save energy, reduce the dependence on the external power supply at the same time, and realize the closed-loop recycling of energy. The positive pole of the constant current source DC is connected to one end of the secondary coil of the transformer T2 through D1 and R7, and the negative pole is directly connected to the other end of the secondary coil of T2, forming a closed circuit for energy storage and use.

[0098] In this embodiment, the diode D1 and the seventh resistor R7 are connected in series between the secondary coil of the transformer T2 and the constant current source DC, forming a rectifying and current-limiting path. The diode D1 ensures that energy can only flow into the constant current source DC unidirectionally, preventing energy backflow and protecting the circuit; the seventh resistor R7 plays a role in current limiting, avoiding overload of the constant current source DC, and ensuring the stability and safety of energy storage.

[0099] In an exemplary embodiment, the second discharging unit includes: a first discharging resistor assembly, a second discharging resistor assembly, a first switch assembly, and a second switch assembly. As Figure 7 shown, the first discharging resistor assembly includes a fifth resistor R5 and a sixth resistor R6, and the second discharging resistor assembly includes an eighth resistor R8 and a ninth resistor R9; the first switch assembly includes a first switch S1; the second switch assembly includes a second switch S2; as Figure 7 shown, one end of the fifth resistor R5 is connected to the neutral line, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 through the first switch S1, and the other end of the sixth resistor R6 is connected to the live line; one end of the eighth resistor R8 is connected to the other end of the fifth resistor R5, the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9 through the second switch S2, and the other end of the ninth resistor R9 is connected to the other end of the sixth resistor.

[0100] Among them, the first discharging resistor assembly and the first switch assembly have been explained in the above embodiment and will not be repeated here. The second discharging resistor assembly is a resistor network composed of the eighth resistor R8 and the ninth resistor R9. Its main function is to be enabled when the residual voltage of the electrical input filter capacitor Cx1 enters the low-voltage stage, forming a high-resistance steady-state discharging circuit, which is used to reduce the steady-state power consumption while meeting the requirements of the safe residual voltage, and avoid unnecessary energy waste.

[0101] In the second discharging unit, the second switch S2, like the first switch S1, is controlled by the processing unit, and its main role is to switch the working mode of the discharging circuit. In the high-voltage stage, the first switch S1 is turned on and the second switch S2 is turned off to avoid interfering with the fast discharging; while in the low-voltage stage, the first switch S1 is turned off and the second switch S2 is turned on, so that the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 form a high-resistance discharging path for steady-state discharging and reduce the continuous power consumption. In this embodiment, the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 together form the high-resistance discharging network of the second discharging unit. Among them, the reason why the second discharging resistor assembly includes the eighth resistor R8 and the ninth resistor R9 instead of a single resistor is the same as the reason why the first discharging resistor assembly includes the fifth resistor R5 and the sixth resistor R6 instead of a single resistor, which will not be repeated here.

[0102] In this embodiment, the processing unit is further configured to, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold (high-voltage stage), disconnect the non-discharging circuit unit, turn off the second switch S2, and turn on the first switch S1 to turn on the first discharging unit. At this time, the discharging voltage of the input filter capacitor starts from the sixth resistor R6, passes through the first switch S1, and then through the fifth resistor R5 to achieve rapid discharging; when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold (low-voltage stage), disconnect the non-discharging circuit unit, turn off the first switch S1, and turn on the second switch S2 to turn on the second discharging unit. At this time, the discharging voltage of the input filter capacitor starts from the sixth resistor R6, passes through the ninth resistor R9, the second switch S2, and then through the eighth resistor R8 and the fifth resistor R5 to achieve rapid discharging. As Figure 6 shown, the processing unit includes an MCU processor. Two pins of the MCU processor are respectively used to control the first switch S1 and the second switch S2. The MCU processor outputs a control signal to the first switch S1 through one pin to control the on / off of the first switch S1, and outputs a control signal to the second switch S2 through the other pin to control the on / off of the second switch S2.

[0103] Through this embodiment, when the switching power supply is in a normal power supply state, the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 serve as part of the high-voltage sampling path. When the switching power supply is in an abnormal power-off state, these resistor components can be quickly converted into part of the discharging circuit through the control of the first switch S1 and the second switch S2. This circuit multiplexing not only reduces the number of hardware components, but also saves space and reduces the cost of the device.

[0104] In an exemplary embodiment, the non-discharging circuit unit includes: a first discharging resistor component, a second discharging resistor component, a third switch component, a fourth switch component, a first voltage sampling component, and a second voltage sampling component. Among them, the first discharging resistor component and the second discharging resistor component have been explained in the above embodiment and will not be repeated here. As Figure 7 shown, the third switch component includes a first power switch Q1, and the fourth switch component includes a second power switch Q2; the first voltage sampling component includes a tenth resistor R10, and the second voltage sampling component includes an eleventh resistor R11.

[0105] As Figure 7As shown, the drain of the first power switch Q1 is connected to one end of the ninth resistor R9, and the source of the first power switch Q1 is grounded through the tenth resistor R10; the gate of the first power switch Q1 is connected to the processing unit; the source of the second power switch Q2 is connected to the other end of the eighth resistor R8, and the drain of the second power switch Q2 is grounded through the tenth resistor R10; the gate of the second power switch Q2 is connected to the processing unit; the source of the first power switch Q1 and the drain of the second power switch Q2 are respectively connected to the processing unit.

[0106] Among them, the first power switch Q1 and the second power switch Q2 are control components. When the switching power supply is in an abnormal power-off state, they are turned off by the processing unit to switch from the non-discharge circuit unit to the discharge circuit unit; when the switching power supply is in a normal power supply state, they are turned on by the processing unit to switch from the discharge circuit unit to the non-discharge circuit unit. The tenth resistor R10 and the eleventh resistor R11 are both sampling resistors. The tenth resistor R10 is used to sample the voltage on the live wire, and the eleventh resistor R11 is used to sample the voltage on the neutral wire.

[0107] In this embodiment, the processing unit is further configured to collect the first voltage of the source of the first power switch Q1 and the second voltage of the drain of the second power switch Q2, and determine the output voltage of the AC source according to the first voltage and the second voltage; when the output voltage of the AC source is greater than or equal to the second voltage threshold, it is determined that the switching power supply is in a normal power supply state, the first switch S1 and the second switch S2 are turned off, and the first power switch Q1 and the second power switch Q2 are turned on; when the output voltage of the AC source is less than the second voltage threshold, it is determined that the switching power supply is in an abnormal power-off state, the first power switch Q1 and the second power switch Q2 are turned off, and one of the first switch S1 and the second switch S2 is selected to be turned on according to the voltage across the input filter capacitor.

[0108] Figure 8 It is a discharge flow chart provided by an embodiment of the present application. As Figure 8 shown, in the initial state, the first power switch Q1 and the second power switch Q2 are in the on state, and the first switch S1 and the second switch S2 are in the off state. Therefore, the non-discharge circuit unit samples the voltage on the live wire through voltage division by the fifth resistor R5, the eighth resistor R8, and the eleventh resistor R11 and transmits it to the processing unit, samples the voltage on the neutral wire through voltage division by the sixth resistor R6, the ninth resistor R9, and the tenth resistor R10, and transmits the output voltage Vac of the AC source to the processing unit. As Figure 6 and Figure 7As shown, the processing unit determines whether the switching power supply is powered off according to the voltage transmitted by the non-discharging circuit unit. If the output voltage Vac of the AC source is greater than or equal to 90V, it is considered that the switching power supply is in a normal power supply state, and a high-level signal of AC OK (Alternating Current OK, alternating current normal signal) is sent to the first power switch Q1 and the second power switch Q2 to continue to maintain the conduction of the first power switch Q1 and the second power switch Q2, and two AC fail (Alternating Current Failure, alternating current failure signal) signals are sent to the first switch S1 and the second switch S2 respectively to control the first switch S1 and the second switch S2 to remain off to disconnect the discharging circuit unit. At this time, the discharging circuit unit is switched to a non-discharging circuit unit, and the non-discharging circuit unit multiplexes the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 in the discharging circuit unit, which can save the continuous loss of the discharging resistor when the switching power supply is in a normal power supply state. The power consumption saved can be calculated according to the following formula (3):

[0109] (3)

[0110] As Figure 8 shown, if the output voltage Vac of the AC source (such as 80V) is less than 90V, it is considered that the switching power supply is in an abnormal power-off state. The processing unit sends a low-level signal of the AC OK signal to the first power switch Q1 and the second power switch Q2 to turn off the first power switch Q1 and the second power switch Q2, and switches the non-discharging circuit unit to a discharging circuit unit. At the same time, the processing unit collects the voltage VCx (including VCx+ and VCx-) at both ends of the input filter capacitor through the voltage sampling unit. The processing unit performs voltage threshold segmentation control according to the voltage VCx at both ends of the input filter capacitor, which specifically includes the following two scenarios:

[0111] Scenario 1: When the voltage at both ends of the input filter capacitor is greater than the first voltage threshold (i.e., the low-voltage stage), the processing unit sends an AC fail signal (high level) to the first switch S1 to control the first switch S1 to conduct, and sends another AC fail signal (low level) to the second switch S2 to control the second switch S2 to turn off, enabling a low-resistance discharging channel, that is Figure 7 the fifth resistor R5 and the sixth resistor R6 in, and uses a large current for rapid discharging to shorten the duration of the high-energy stage and meet the discharging time requirement from the start of discharging to the safe voltage according to the safety regulations. It can be obtained according to the following formula (4) that the smaller the discharging resistor, the shorter its discharging time.

[0112] (4)

[0113] Assume that the initial voltage is the mains voltage of 230 Vac, and the initial voltage Vo of the input filter capacitor Cx1 = 230 V * = 325 V. With the capacitance of the input filter capacitor Cx1 fixed at 2.5 μF, according to the discharge requirements of IEC62368 mentioned above: within 1 second after power-off, the voltage of the accessible terminal needs to drop below 60 V. t1 = 1 s, Vo = 325 V, Vt1 = 60 V; calculated according to the following formula (5), the maximum calculated value of the discharge resistance of the first discharge unit shall not exceed 236 kΩ, that is, the resistance value of the first discharge unit (the sum of the fifth resistor R5 and the sixth resistor R6) is less than 236 kΩ.

[0114] (5)

[0115] At the same time, when the first discharge unit is working, through the flyback transformer T2 and rectification by the diode D1, the energy of the rapid discharge of the input filter capacitor Cx1 is fed back to the constant current source DC for storage and utilization, so that it can be directly used in the system when starting up.

[0116] At the same time, a temperature switch T1 is added to detect the temperature in the first discharge unit. For example, when the temperature switch T1 > 130 °C, the temperature switch T1 is turned off, the path where the first switch S1 is located is disconnected, and the rapid discharge path is cut off to prevent thermal runaway and avoid damage to the discharge circuit unit due to high current and high temperature.

[0117] Scenario 2: When the voltage across the input filter capacitor is greater than the first voltage threshold (i.e., the low-voltage stage), the processing unit sends an AC fail signal (low level) to the first switch S1 to control the first switch S1 to disconnect, and sends another AC fail signal (high level) to the second switch S2 to control the second switch S2 to conduct, enabling a high-resistance discharge channel, so that the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 form a high-resistance discharge network, using the second discharge unit to reduce the steady-state power consumption, while meeting the safety residual voltage requirements (such as the 1 V / s attenuation rate specified in UL60950-1).

[0118] Through this embodiment, compared with the fixed-resistance scheme in the related technology, the overall energy consumption of this embodiment can be reduced by more than 60%, and it can ensure the normal operation of the discharge circuit, avoid the problem of overheating and burning due to large current during rapid discharge. At the same time, the devices of the switching power supply can be reused, allowing the discharge and sampling circuits to share the discharge resistance. Through the judgment and processing of the processing unit, it is ensured that the safety performance of each port is not affected, reducing the hardware cost and shrinking the device volume.

[0119] In an exemplary embodiment, different types of devices where the switching power supply is located have different requirements for the discharge time. For example, for general devices, it is required that the voltage decays to below 30V within 10 seconds after the switching power supply is powered off, while for medical devices, it is required to drop to 30V within 5 seconds after power-off. If a discharge circuit unit with a fixed resistance value and a fixed discharge strategy is used, it cannot meet the discharge requirements of various devices. Therefore, to solve the above problems, in this embodiment, a method for dynamically adjusting the resistance value of the discharge circuit unit is provided. When the power supply is started or during operation, the signal data collected is analyzed in real time by a trained model to identify the type of the connected load, and the discharge strategy is automatically adjusted according to the load type. For example, for highly sensitive medical devices, a faster discharge rate is adopted.

[0120] In this embodiment, the processing unit is further configured to: identify the load type of the device connected to the switching power supply; determine the fastest safe discharge rate required by the device connected to the switching power supply according to the load type; the fastest safe discharge rate represents discharging the voltage of the input filter capacitor to the safe voltage level within the fastest safe time range; calculate the first discharge resistance required by the first discharge unit and the second discharge resistance required by the second discharge unit according to the fastest safe discharge rate; adjust the resistance value of the first discharge unit to the first discharge resistance and adjust the resistance value of the second discharge unit to the second discharge resistance.

[0121] Among them, the load type refers to the category of the terminal device connected to the switching power supply, such as medical devices, servers, personal computers, etc. Each device has specific requirements for the safe discharge rate of the switching power supply due to differences in its application characteristics and safety standards. By identifying the load type, this embodiment can specifically optimize the design of the discharge circuit to meet the safety requirements of different devices. In this embodiment, the connected load type is identified through a reinforcement learning model. For example, the working state data of the switching power supply is collected, such as input voltage, current, temperature, and the voltage signal of the input filter capacitor, etc.; the working state data of the switching power supply is input into a pre-trained model. This model can be trained using machine learning or pattern recognition techniques, such as Support Vector Machine (SVM), decision tree, neural network, etc. By inputting the working state data of the switching power supply, the load type currently connected to the switching power supply is output. This model is pre-defined with different load type characteristics and stores a load type feature library, which includes various load types and their characteristics for comparing the real-time monitored data. This model processes the working state data of the switching power supply through techniques such as statistical analysis, determines key indicators such as the load power curve, switching frequency, and required discharge time of the load connected to the switching power supply, and compares these key indicators with the characteristics in the load type feature library to obtain the load type currently connected to the switching power supply.

[0122] The fastest safe discharge rate defines the highest discharge speed within the time range required to reduce the voltage on the input filter capacitor (Cx1) to a safe level after the power supply is disconnected. This is set according to the specific safety standards of various loads. For example, medical equipment requires a faster discharge rate to ensure user safety. This rate is one of the key parameters in designing the discharge circuit.

[0123] The fastest safe time range refers to the time interval during which the input filter capacitor must reach a safe voltage level after the power supply of the device is disconnected. This time range is determined by safety regulations. For example, IEC 62368 requires the voltage to be reduced below 60V within 1 second, or medical equipment requires it to be reduced to 30V within 5 seconds after power-off.

[0124] In this embodiment, both the first discharge resistance component in the first discharge unit and the second discharge resistance component in the second discharge unit adopt adjustable resistors or digital potentiometers to achieve the purpose of making the resistance values of the first discharge unit and the second discharge unit adjustable.

[0125] For example, assume that it is recognized that a medical device is connected. Due to the special nature of such devices, a shorter discharge time is required. The processing unit sets the resistance values of R5 and R6 to lower values through a digital potentiometer. R8 and R9 remain unchanged or are appropriately adjusted according to the calculation results to accelerate the discharge speed. During the discharge process, the temperature switch T1 and the voltage VCx across the input filter capacitor are continuously monitored. Once the temperature exceeds the preset threshold or the voltage reaches the safe range, it is immediately adjusted back to the steady-state discharge mode, or the discharge circuit is completely turned off to avoid unnecessary power consumption.

[0126] Through this embodiment, the load type is identified. According to the load type, the fastest safe discharge rate required by the device connected to the switching power supply is determined. And according to the fastest safe discharge rate, the first discharge resistance required by the first discharge unit and the second discharge resistance required by the second discharge unit are calculated. The resistance value of the first discharge unit is adjusted to the first discharge resistance, and the resistance value of the second discharge unit is adjusted to the second discharge resistance, so as to realize the dynamic adjustment of the resistance value of the discharge circuit unit according to the load type, enabling the switching power supply to discharge safely within its corresponding discharge time when connected to devices of different load types, and improving the adaptability of the switching power supply to devices of different load types.

[0127] According to one aspect of the embodiments of the present application, a discharge method is provided. Optionally, in this embodiment, a discharge method can be but is not limited to being applied to a processing unit as Figure 2 shown. The embodiments of the present application provide a discharge method, including the following steps:

[0128] The output voltage of the AC source is collected through a non-discharging circuit unit. When the output voltage of the AC source indicates that the switching power supply is in a normal power supply state, the discharging circuit unit is disconnected. The discharging circuit unit is connected in parallel across the input filter capacitor and is used to release the charge stored in the input filter capacitor when the switching power supply is in an abnormal power-off state, so as to ensure that the input filter capacitor discharges to a safe voltage level within a specified time range. The input filter capacitor is connected in parallel between the live wire and the neutral wire of the AC source and is used to suppress electromagnetic interference.

[0129] Since the above method has been described in the embodiments of the above switching power supply, it will not be repeated here.

[0130] In an exemplary embodiment, the above method further includes: when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state, disconnecting the non-discharging circuit unit and turning on the discharging circuit unit.

[0131] In an exemplary embodiment, the discharging circuit unit includes a first discharging unit and a second discharging unit; the second discharging unit reuses the first discharging unit; the resistance of the first discharging unit is less than the resistance of the second discharging unit; turning on the discharging circuit unit includes: when the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, turning on the first discharging unit and turning off the second discharging unit; when the voltage across the input filter capacitor is less than the first voltage threshold, turning off the first discharging unit and turning on the second discharging unit.

[0132] Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method.

[0133] An embodiment of the present application further provides an electronic device, including a memory and a processor. A computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any of the above embodiments of the discharging method.

[0134] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored. The computer program is configured to execute the steps in any of the above embodiments of the discharging method when running.

[0135] In an exemplary embodiment, the above computer-readable storage medium may include, but is not limited to: USB flash drive, read-only memory (abbreviated as ROM), random access memory (abbreviated as RAM), mobile hard disk, magnetic disk or optical disc and other various media that can store computer programs.

[0136] An embodiment of the present application also provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the steps in any of the above-described discharge method embodiments are implemented.

[0137] An embodiment of the present application also provides another computer program product, including a non-volatile computer-readable storage medium. The non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in any of the above-described discharge method embodiments are implemented.

[0138] Those skilled in the art can further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Skilled professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0139] The above has introduced in detail a switching power supply, a discharge method, a storage medium, and a program product provided by this application. Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A switching power supply, characterized in that, Comprising: An input filter capacitor, connected in parallel between the live wire and the neutral wire of the AC source, for suppressing electromagnetic interference; A discharge circuit unit, connected in parallel across the two ends of the input filter capacitor, for releasing the charge stored in the input filter capacitor when the switching power supply is in an abnormal power-off state, so as to ensure that the input filter capacitor discharges to a safe voltage level within a specified time range; A non-discharge circuit unit, for collecting the output voltage of the AC source; A processing unit, for disconnecting the discharge circuit unit when the output voltage of the AC source indicates that the switching power supply is in a normal power supply state.

2. The switching power supply according to claim 1, characterized in that, The processing unit is further configured to disconnect the non-discharge circuit unit and turn on the discharge circuit unit when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state.

3. The switching power supply according to claim 1, characterized in that, The discharge circuit unit includes: A first discharge unit, connected in parallel across the two ends of the input filter capacitor, for releasing the charge stored in the input filter capacitor when the voltage across the two ends of the input filter capacitor is greater than or equal to a first voltage threshold; A second discharge unit, connected in parallel across the two ends of the input filter capacitor, for releasing the charge stored in the input filter capacitor when the voltage across the two ends of the input filter capacitor is less than the first voltage threshold; the second discharge unit multiplexes the first discharge unit; the resistance of the first discharge unit is less than the resistance of the second discharge unit; The processing unit is further configured to select to turn on one of the first discharge unit and the second discharge unit according to the voltage across the two ends of the input filter capacitor when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state.

4. The switching power supply according to claim 3, characterized in that, The switching power supply further includes: A voltage sampling unit, connected in parallel across the two ends of the input filter capacitor, for collecting the voltage across the two ends of the input filter capacitor.

5. The switching power supply according to claim 3, characterized in that, The first discharge unit includes: a first discharge resistor assembly and a first switch assembly; The first discharge resistor assembly and the first switch assembly are connected in series and then connected in parallel across the two ends of the input filter capacitor; The processing unit is further configured to turn on the first switch assembly when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the two ends of the input filter capacitor is greater than or equal to the first voltage threshold; and turn off the first switch assembly when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the two ends of the input filter capacitor is less than the first voltage threshold.

6. The switching power supply according to claim 5, characterized in that, The first discharge unit further includes: A temperature sampling unit, connected in series between the first discharge resistor assembly and the first switch assembly, for collecting the temperature of the discharge path of the input filter capacitor and cutting off the first discharge unit when the temperature is greater than a preset temperature threshold.

7. The switching power supply according to claim 6, characterized in that, The first discharge unit further includes: An energy feedback unit, connected in series between the first discharge resistor assembly and the first switch assembly, for storing the discharge voltage of the input filter capacitor and feeding it back to the AC source after the switching power supply is turned on.

8. The switching power supply according to any one of claims 3 to 7, characterized in that, The second discharge unit includes: a first discharge resistor assembly, a second discharge resistor assembly, a first switch assembly, and a second switch assembly; The first discharge resistor assembly and the first switch assembly are connected in series and then connected in parallel across both ends of the input filter capacitor; the second discharge resistor assembly and the second switch assembly are connected in series and then connected in parallel across both ends of the first switch assembly; The processing unit is further configured to, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold, disconnect the non-discharge circuit unit, turn off the second switch assembly, and turn on the first switch assembly to turn on the first discharge unit; when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold, disconnect the non-discharge circuit unit, turn on the second switch assembly, and turn off the first switch assembly to turn on the second discharge unit.

9. The switching power supply according to claim 8, characterized in that, The non-discharge circuit unit includes: the first discharge resistor assembly, the second discharge resistor assembly, a third switch assembly, a fourth switch assembly, a first voltage sampling assembly, and a second voltage sampling assembly; One end of the second switch assembly is grounded through the series-connected third switch assembly and the first voltage sampling assembly; the other end of the second switch assembly is grounded through the series-connected fourth switch assembly and the second voltage sampling assembly; The first voltage sampling assembly is configured to collect the output voltage of the live wire; the second voltage sampling assembly is configured to collect the output voltage of the neutral wire; The processing unit is further configured to, when the output voltage of the AC source indicates that the switching power supply is in a normal power supply state, disconnect the first switch assembly and the second switch assembly to disconnect the discharge circuit unit, and turn on the third switch assembly and the fourth switch assembly; when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state, select to turn on one of the first switch assembly and the second switch assembly according to the voltage across the input filter capacitor, and disconnect the third switch assembly and the fourth switch assembly to disconnect the non-discharge circuit unit.

10. The switching power supply according to claim 4, characterized in that, The voltage sampling unit includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a voltage-dividing resistor Rx, and an operational amplifier IC1; The negative electrode of the input filter capacitor is connected to the negative electrode of the operational amplifier IC1 through the second resistor R2, and the positive electrode of the input filter capacitor is connected to the positive electrode of the operational amplifier IC1 through the third resistor R3; the output terminal of the operational amplifier IC1 is connected to the processing unit; one end of the first resistor R1 is connected to the negative electrode of the operational amplifier IC1, and the other end of the first resistor R1 is connected to the output terminal of the operational amplifier IC1; one end of the fourth resistor R4 is connected to the voltage source, and the other end of the fourth resistor is connected to the positive electrode of the operational amplifier IC1; one end of the voltage dividing resistor Rx is connected to the positive electrode of the operational amplifier IC1, and the other end of the voltage dividing resistor Rx is grounded.

11. The switching power supply according to claim 7, characterized in that, The first discharge resistor assembly includes a fifth resistor R5 and a sixth resistor R6, and the first switch assembly includes a first switch S1; One end of the fifth resistor R5 is connected to the neutral line, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 through the first switch S1, and the other end of the sixth resistor R6 is connected to the live line; The processing unit is further configured to disconnect the non-discharge circuit unit and turn on the first switch S1 to turn on the first discharge unit when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold.

12. The switching power supply according to claim 11, wherein The temperature sampling unit includes: A temperature switch T1, which is connected in series in the link between the fifth resistor R5 and the first switch S1, is used to detect the temperature of the discharge path of the input filter capacitor, and disconnects when the temperature is greater than the preset temperature threshold to cut off the first discharge unit.

13. The switching power supply according to claim 11, wherein The energy feedback unit includes: a transformer T2, a diode D1, a seventh resistor R7, and a constant current source DC; The primary coil of the transformer T2 is connected in series in the link between the first switch S1 and the sixth resistor R6; one end of the secondary coil of the transformer T2 is connected to the positive electrode of the constant current source DC through the diode D1 and the seventh resistor R7 connected in series in sequence; the other end of the secondary coil of the transformer T2 is connected to the negative electrode of the constant current source DC; The transformer T2 is used to collect the discharge voltage of the input filter capacitor and store the discharge voltage in the constant current source DC.

14. The switching power supply according to claim 9, wherein The first discharge resistor assembly includes a fifth resistor R5 and a sixth resistor R6, the second discharge resistor assembly includes an eighth resistor R8 and a ninth resistor R9; the first switch assembly includes a first switch S1; the second switch assembly includes a second switch S2; One end of the fifth resistor R5 is connected to the neutral line, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 through the first switch S1, and the other end of the sixth resistor R6 is connected to the live line; one end of the eighth resistor R8 is connected to the other end of the fifth resistor R5, the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9 through the second switch S2, and the other end of the ninth resistor R9 is connected to the other end of the sixth resistor; The processing unit is further configured to disconnect the non-discharging circuit unit, turn off the second switch S2, and turn on the first switch S1 to turn on the first discharging unit when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is greater than or equal to the first voltage threshold; When the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state and the voltage across the input filter capacitor is less than the first voltage threshold, disconnect the non-discharging circuit unit, turn off the first switch S1, and turn on the second switch S2 to turn on the second discharging unit.

15. The switching power supply according to claim 14, wherein The third switch component includes a first power switch Q1, and the fourth switch component includes a second power switch Q2; the first voltage sampling component includes a tenth resistor R10, and the second voltage sampling component includes an eleventh resistor R11; The drain of the first power switch Q1 is connected to one end of the ninth resistor R9, the source of the first power switch Q1 is grounded through the tenth resistor R10; the gate of the first power switch Q1 is connected to the processing unit; the source of the second power switch Q2 is connected to the other end of the eighth resistor R8, the drain of the second power switch Q2 is grounded through the tenth resistor R10; the gate of the second power switch Q2 is connected to the processing unit; the source of the first power switch Q1 and the drain of the second power switch Q2 are respectively connected to the processing unit; The processing unit is further configured to collect a first voltage at the source of the first power switch Q1 and a second voltage at the drain of the second power switch Q2, and determine the output voltage of the AC source according to the first voltage and the second voltage; when the output voltage of the AC source is greater than or equal to a second voltage threshold, determine that the switching power supply is in a normal power supply state, turn off the first switch S1 and the second switch S2, and turn on the first power switch Q1 and the second power switch Q2; when the output voltage of the AC source is less than the second voltage threshold, determine that the switching power supply is in an abnormal power-off state, turn off the first power switch Q1 and the second power switch Q2, and select to turn on one of the first switch S1 and the second switch S2 according to the voltage across the input filter capacitor.

16. A discharging method, wherein Including: The output voltage of an AC source is collected through a non-discharging circuit unit. When the output voltage of the AC source indicates that the switching power supply is in a normal power supply state, the discharging circuit unit is disconnected. The discharging circuit unit is connected in parallel across both ends of the input filter capacitor and is used to release the charge stored in the input filter capacitor when the switching power supply is in an abnormal power-off state, so as to ensure that the input filter capacitor discharges to a safe voltage level within a specified time range. The input filter capacitor is connected in parallel between the live wire and the neutral wire of the AC source and is used to suppress electromagnetic interference.

17. The method according to claim 16, wherein The method further includes: When the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state, the non-discharging circuit unit is disconnected and the discharging circuit unit is turned on.

18. The method according to claim 17, wherein The discharging circuit unit includes a first discharging unit and a second discharging unit; the second discharging unit reuses the first discharging unit; the resistance of the first discharging unit is less than the resistance of the second discharging unit; Turning on the discharging circuit unit includes: When the voltage across both ends of the input filter capacitor is greater than or equal to a first voltage threshold, the first discharging unit is turned on and the second discharging unit is turned off; When the voltage across both ends of the input filter capacitor is less than the first voltage threshold, the first discharging unit is turned off and the second discharging unit is turned on.

19. A computer-readable storage medium, wherein A computer program is stored in the computer-readable storage medium, wherein when the computer program is executed by a processor, the steps of the discharging method according to any one of claims 16 to 18 are implemented.

20. A computer program product, comprising a computer program, wherein When the computer program is executed by a processor, the steps of the discharging method according to any one of claims 16 to 18 are implemented.

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