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

Abstract

The present application discloses a switching power supply, a discharge method, a storage medium and a program product, and relates to the field of power supply technology. The switching power supply includes: an input filter capacitor connected in parallel between the live wire and the neutral wire of an AC source, and used to suppress electromagnetic interference; a discharge circuit unit connected in parallel at both ends of the input filter capacitor, and 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 is discharged to a safe voltage level within a specified time range; a non-discharge circuit unit, used to collect the output voltage of the AC source; and a processing unit, 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, thereby solving the problem in the related art that the discharge resistor consumes too much power when the power supply is working normally, resulting in a decrease in the overall efficiency of the power supply.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a switching power supply, a discharge method, a storage medium, and a program product. Background Art

[0002] Switching power supplies, as efficient and stable power conversion devices, are widely used in various electronic devices. In switching power supply designs, input filter capacitors (such as safety capacitors, also known as X-capacitors) are used to suppress electromagnetic interference (EMI). However, these capacitors can store high voltages after power is removed, posing a potential safety risk to users and equipment. To address this issue, bleeder resistors are often added to the circuit. Bleeder resistors quickly release the charge stored in capacitors after power is turned off, ensuring that the capacitors discharge quickly to a safe voltage level, ensuring equipment safety, and preventing the risk of electric shock.

[0003] However, to meet safety regulations (such as IEC 62368-1), the resistance of the bleeder resistor is usually low, causing it to consume excessive power during normal operation and reducing the overall efficiency of the power supply. Summary of the Invention

[0004] The present application provides a switching power supply, a discharge method, a storage medium and a program product to at least solve the problem in the related art that the discharge resistor consumes too much power when the power supply is operating normally, resulting in a decrease in the overall efficiency of the power supply.

[0005] The present application provides a switching power supply, comprising: an input filter capacitor connected in parallel between the live wire and the neutral wire of an AC power source, for suppressing electromagnetic interference; a discharge 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, so as to ensure that the input filter capacitor is discharged to a safe voltage level within a specified time range; a non-discharge circuit unit for collecting the output voltage of the AC source; and 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.

[0006] The present application also provides a discharge method, comprising: collecting the output voltage of an AC source through a non-discharge circuit unit, and 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; the discharge circuit unit is connected in parallel at 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 is discharged 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, comprising: a memory for storing a computer program; and a processor for implementing the steps of any of the above-mentioned discharge methods when executing the computer program.

[0008] The present application also provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps of any of the above-mentioned discharge methods are implemented.

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

[0010] Through this application, the processing unit intelligently switches the discharge circuit unit and the non-discharge circuit unit according to the state of the switching power supply. When the switching power supply is in normal power supply state, 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 is turned on, and is only activated at the moment of power failure, which greatly reduces the continuous power consumption of the system and solves the problem in the related technology that the discharge resistor consumes too much power when the power supply is working normally, resulting in a decrease in the overall efficiency of the power supply. At the same time, it ensures safe discharge after power failure and improves 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 is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0012] Figure 1 This is a structural diagram of a discharge circuit in a related technology provided in an embodiment of the present application.

[0013] Figure 2 A structural diagram of a switching power supply provided in an embodiment of the present application.

[0014] Figure 3This is a structural diagram of another switching power supply provided in an embodiment of the present application.

[0015] Figure 4 This is a structural diagram of another switching power supply provided in an embodiment of the present application.

[0016] Figure 5 This is a structural diagram of another switching power supply provided in an embodiment of the present application.

[0017] Figure 6 This is a structural diagram of the voltage sampling unit and processing unit provided in an embodiment of the present application.

[0018] Figure 7 A circuit diagram of a switching power supply provided in an embodiment of the present application.

[0019] Figure 8 A discharge flow chart provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

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

[0022] Glossary: ​​IEC 62368 is a safety standard published by the International Electrotechnical Commission (IEC) for audio, video, information and communications 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] Switching power supplies, as efficient and stable power conversion devices, are widely used in various electronic devices. In switching power supply designs, input filter capacitors (such as safety capacitors, also known as X capacitors) are used to suppress electromagnetic interference (EMI). However, these capacitors may store high voltages after power is removed, posing potential safety risks to users and equipment. Therefore, safety regulations mandate that residual voltage in switching power supplies be discharged to a safe voltage and the required discharge time after power is removed. For example, the international standard (IEC 62368-1:2023 Ed.4) requires that the voltage on accessible terminals drop to below 60V within 1 second after power is removed (this requirement will be shortened from 2 seconds to 1 second after the 2024 update). Furthermore, the voltage must decay to below 30V within 10 seconds after power is removed (medical equipment has stricter requirements, requiring a reduction to 30V in less than 5 seconds). Meanwhile, China's national standard (GB 4943.1-2022) introduces a dual energy-time determination: when a capacitor stores energy >0.5J, it must discharge 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 is turned off, ensuring that the capacitor can quickly discharge to a safe voltage level after power is cut off, ensuring the safety of the equipment and avoiding the risk of electric shock. Figure 1 This is a structural diagram of a discharge circuit in a related technology provided in an embodiment of the present application, such as Figure 1 As shown in Figure 1, after the switching power supply is powered off, the energy of the internal X capacitor Cx1 of the power supply is consumed by connecting bleeder resistors R1', R2', R3', and R4' in series across the capacitor. The bleeder resistor R = R1' + R2' + R3' + R4'. Based on the input voltage of the switching power supply, the required safe voltage value for bleeder discharge, the required bleeder time, and the selected capacitance of the switching power supply input X capacitor, 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 bleed time, C is the capacitance of the switching power supply input X capacitor, Vo is the initial voltage, and Vt is the voltage after bleed time t, according 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; the loss is shown in the following formula (2):

[0027] (2)

[0028] In summary, to meet safety regulations (such as IEC 62368-1), traditional bleeder resistors typically have low resistance values. This causes them to consume excessive power during normal operation, reducing the overall efficiency of the power supply.

[0029] In order to solve the problem in the related art that the bleeder resistor consumes too much power when the power supply is operating normally, resulting in a decrease in the overall efficiency of the power supply, the embodiment of the present application provides a switching power supply that monitors the power-on and power-off states of the power supply, and decides whether to call the bleeder circuit unit of the power supply according to the different states of the power supply (on or off). Under normal power supply, the bleeder circuit unit switches to the non-bleeder circuit unit, thereby achieving device reuse, reducing volume, saving efficiency, and reducing losses.

[0030] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

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

[0032] The input filter capacitor (Cx1) is connected in parallel between the live (L) and neutral (N) wires of the AC power source to suppress electromagnetic interference. The input filter capacitor stores energy during normal operation. After a power outage, the charge must be quickly released through the discharge circuit unit to reach a safe voltage level.

[0033] The discharge 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, ensuring that the input filter capacitor discharges to a safe voltage level within a specified time range. In the embodiment of the present application, the discharge circuit unit is a circuit design whose purpose is to quickly dissipate the energy stored in the input filter capacitor (Cx1) after the switching power supply is powered off through a resistor network or switch connected in parallel across the capacitor.

[0034] The non-bleeder circuit unit is used to collect the output voltage of the AC source. When the switching power supply is operating normally, the non-bleeder circuit unit collects the output voltage (L and N lines) of the AC source. This circuit converts the high voltage output of the AC source into a signal that can be processed by the processing unit without triggering the bleeder circuit unit. It should be understood that only one of the bleeder circuit unit and the non-bleeder circuit unit can be turned on; the other can be turned off.

[0035] The processing unit is configured to disconnect the bleeder circuit unit when the AC source's output voltage indicates the switching power supply is operating normally. The processing unit is the control core of the entire switching power supply system and determines whether the power supply is operating normally by monitoring the AC source's output voltage. To reduce excessive power consumption by the bleeder circuit unit during normal operation, improve overall power supply efficiency, and ensure safe discharge after a power outage, the processing unit disconnects the bleeder circuit unit when it detects normal power supply. This prevents the bleeder circuit unit from consuming power during normal operation. If a power outage is detected, the processing unit disconnects the non-bleeder circuit unit and activates the bleeder circuit unit to ensure 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. When the switching power supply is in a normal power supply state, the discharge circuit unit is disconnected, so that the loss of the discharge circuit unit is 0. The discharge circuit is completely turned off when the power is turned on and is only activated at the moment of power failure, which greatly reduces the continuous power consumption of the system. It solves the problem in the related art that the discharge resistor consumes too much power when the power supply is operating normally, resulting in a decrease in the overall efficiency of the power supply. At the same time, it ensures safe discharge after power failure and improves the energy utilization efficiency of the switching power supply.

[0037] In an exemplary embodiment, the processing unit is further configured to disconnect the non-discharge circuit unit and connect 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] When the processing unit detects an AC power outage, its primary priority is to ensure user safety and equipment safety. It immediately disconnects the non-discharging circuit unit and connects the discharging circuit unit, switching the non-discharging circuit unit, originally used for voltage sampling, to the discharging circuit unit. This allows the input filter capacitor to discharge rapidly, quickly reducing the voltage across the capacitor to a safe level, preventing user electric shock and protecting subsequent circuits from high voltage damage.

[0039] Through this embodiment, the processing unit monitors the state of the AC source and automatically completes the switching from the non-discharge circuit unit to the discharge circuit unit when it detects that the switching power supply is in an abnormal power-off state, thereby ensuring the safe processing of the switching power supply in the power-off state without manual intervention.

[0040] In one exemplary embodiment, the bleeder resistor in the related art failed to reduce the voltage of the input filter capacitor to a safe range within the specified time, affecting user experience and safety. Therefore, to address this issue, this embodiment provides a bleeder circuit unit comprising a first bleeder unit and a second bleeder unit, with the resistance of the first bleeder unit being lower than that of the second bleeder unit. By dynamically switching between the first and second bleeder units, energy can be discharged using bleeder units of different resistance values ​​depending on the voltage across the input filter capacitor, resolving the slow response speed of the bleeder resistor in the related art.

[0041] Figure 3 A structural diagram of another switching power supply provided in an embodiment of the present application, such as Figure 3 As shown, the discharge circuit unit includes:

[0042] The first discharge unit is connected in parallel across the input filter capacitor and 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. The first voltage threshold is a pre-set 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 a high-voltage phase. Rapid discharge is required to ensure safe discharge and to ensure that the input filter capacitor is discharged to a safe level within a specified timeframe. 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 a low-voltage phase. At this point, the remaining charge needs to be discharged in a low-power manner. Thus, in this embodiment, the first voltage threshold is used to distinguish between high-voltage and low-voltage phases. 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 the voltage across the input filter capacitor Cx1 is less than the first voltage threshold, the second discharge unit begins operating. The first voltage threshold is set based on safety standards and performance requirements, such as the requirements for voltage discharge time after power failure in IEC 62368-1. The first discharge unit is a fast discharge circuit connected in parallel across the input filter capacitor Cx1. It primarily consists of a low-resistance resistor and a switch. When the voltage across the input filter capacitor Cx1 reaches or exceeds a first voltage threshold, the first discharge unit is activated, rapidly reducing the capacitor voltage with a high current to meet the requirement for rapid discharge after the switching power supply is powered off. The first discharge unit's goal is to quickly and safely dissipate energy from the capacitor during high-voltage phases.

[0043] The second discharge unit, connected in parallel across the input filter capacitor, discharges the charge stored in the input filter capacitor when the voltage across the input filter capacitor falls below a first voltage threshold. The second discharge unit partially reuses the first discharge unit. Specifically, when the voltage across the input filter capacitor Cx1 falls below the first voltage threshold, the first discharge unit is converted into a high-resistance, steady-state discharge circuit by altering the switching states of the first and second discharge units. The second discharge unit's primary purpose is to reduce power consumption and extend discharge time during low-voltage conditions, while ensuring that the residual voltage meets safety standards. Reusing the first discharge unit means that after a power outage, the second discharge unit can utilize a portion of the resistor network originally associated with the first discharge unit by adjusting the switching states of its internal switching components. This allows for a switchover from rapid discharge to steady-state discharge at different voltage thresholds, saving hardware resources, reducing cost, and space. The resistance of the first discharge unit is smaller than that of the second discharge unit because the input filter capacitor Cx1 may carry a significant voltage and energy when the power is immediately lost. To quickly release this energy to a safe level and meet safety standards for voltage discharge time and final voltage after power failure (such as IEC 62368-1), the first discharge unit utilizes a low-resistance resistor network. Low-resistance resistors can carry greater current, enabling rapid and efficient energy dissipation and accelerating the drop in capacitor voltage. As the voltage on capacitor Cx1 gradually decreases, continuing to use low-resistance resistors for discharge would result in excessive power consumption, especially during the steady-state, low voltage phase. 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 resistor network. This high-resistance resistor network maintains low power consumption even during prolonged discharge cycles while still meeting the required attenuation of the capacitor's residual voltage.

[0044] The processing unit is further configured to select, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state, to activate either the first or second bleeder unit based on the voltage across the input filter capacitor. In this embodiment, the processing unit monitors the AC source state and the voltage across the input filter capacitor Cx1, and intelligently selects whether to activate the first or second bleeder unit based on the voltage across the input filter capacitor Cx1. In the event of a power outage, the processing unit determines whether to use a fast, high-current bleeder (the first bleeder unit) or a low-power, steady-state bleeder (the second bleeder unit) by detecting the voltage across the input filter capacitor Cx1, thereby optimally meeting various safety and performance requirements.

[0045] According to this embodiment, a discharge circuit unit is provided, including a first discharge unit and a second discharge unit, wherein the resistance of the first discharge unit is smaller than that of the second discharge unit. Threshold segmented control is performed according to the voltage across the input filter capacitor. Specifically, when the voltage across the input filter capacitor is greater than or equal to a 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 capacitor voltage to be rapidly reduced in the initial stage of power failure, thus 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 lower level, thereby reducing steady-state power consumption and improving overall efficiency. This solves the problems of excessive power consumption and slow response speed in related technologies. 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 phase, the first discharge unit forms a low-resistance channel, while in the low-voltage phase, by changing the circuit connection state of the first discharge unit, the same components form a high-resistance steady-state discharge circuit. This reuse approach reduces hardware resource usage and costs, while also overcoming the cost and size issues associated with the use of high-power resistors in traditional designs. The processing unit intelligently selects whether to turn on the first or second discharger based on the AC source's power-off status and the real-time voltage of the input filter capacitor Cx1. This intelligent selection mechanism, based on voltage thresholds, ensures the most appropriate discharge strategy is used at all times, preventing excessive energy consumption while enabling rapid response when necessary and ensuring safety.

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

[0047] The voltage sampling unit refers to a set of circuit components, primarily resistors, operational amplifiers, and other signal conditioning elements, connected in parallel across the input filter capacitor Cx1. Its function is to accurately measure and monitor the voltage across the input filter capacitor Cx1 and convert this voltage signal into a form suitable for reading by the processing unit. During normal power supply, the voltage sampling unit monitors the input voltage. After power failure, it helps detect the residual voltage on the capacitor to enable timely control of the discharge circuit unit, ensuring that the capacitor's energy is properly discharged according to safety standards. It also coordinates with the processing unit's decisions to intelligently switch between fast and steady-state discharge circuits.

[0048] Through this embodiment, the voltage sampling unit and the processing unit work closely together, so that the switching power supply can automatically adjust the discharge strategy according to the real-time changes in the capacitor voltage.

[0049] In an exemplary embodiment, Figure 4 A structural diagram of another switching power supply provided in an embodiment of the present application is shown in FIG. Figure 4 As 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 to both ends of the input filter capacitor.

[0050] In this embodiment, the first discharge unit refers to a circuit module composed of a first discharge resistor component and a first switch component connected in series and then connected in parallel to the two ends of the input filter capacitor. Its main task is to activate the first switch component when the voltage across the two ends of the input filter capacitor reaches a first voltage threshold or higher, and use the first discharge resistor component to quickly release the energy stored in the capacitor, thereby ensuring that the capacitor voltage can quickly drop to a safe range after the power is cut off, thereby meeting the requirement 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 a first voltage threshold, the processing unit sends a signal to turn on the first switch component, putting the first discharge unit into operation. Conversely, when the voltage across the input filter capacitor is less than the first voltage threshold, the first switch component is turned off, stopping rapid discharge and switching to a steady-state discharge mode or completely shutting down the discharge circuit to prevent unnecessary power consumption.

[0052] The first bleeder resistor assembly, consisting of a set of low-value resistors, provides a high-current path to accelerate the capacitor's discharge when the voltage across the input filter capacitor is high. Working in conjunction with the first switch assembly, it significantly reduces the capacitor voltage in a short period of time, meeting the fast discharge time requirements specified in safety standards.

[0053] The processing unit is further configured to turn on the first switch 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 a first voltage threshold; and to turn off the first switch 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 is detected 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, the first switch component is automatically turned on to activate the rapid discharge process; once the voltage across the input filter capacitor is less than the first voltage threshold, the first switch component is turned off, the capacitor enters a steady state or stops discharging, thereby ensuring both rapid and economical release of capacitor energy.

[0054] Through this embodiment, the first discharge unit forms a controllable discharge circuit by connecting the first switch component and the first discharge resistor component in series. The first discharge unit is connected in parallel to both ends of 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 switch component and connects the low-resistance first discharge resistor component to the discharge path of the capacitor to achieve rapid charge release.

[0055] In an exemplary embodiment, when the switching power supply is powered off and the energy stored in the filter capacitor needs to be quickly released to reach a safe voltage level, the first discharge unit may generate a large amount of heat due to the instantaneous high current passing through it. If the heat accumulates too quickly and cannot be effectively dissipated, the temperature of the circuit components will rise sharply, causing the components in the discharge circuit unit to melt, the package to crack, or the circuit board to deform, thereby damaging the entire discharge circuit and even the switching power supply system, increasing the risk of equipment failure. Therefore, in order to solve the above problem, as Figure 4 As shown, the first discharge unit also includes: a temperature sampling unit, which is connected in series between the first discharge resistor component and the first switch component, and is used to collect the temperature of the discharge path of the input filter capacitor and cut off the first discharge unit when the temperature is greater than a preset temperature threshold.

[0056] Among them, the temperature sampling unit is part of the first discharge unit, and its main responsibility is to monitor the temperature of the capacitor discharge path in real time during the discharge process. Once the temperature is found to exceed the preset threshold, the temperature sampling unit will immediately cut off the first discharge 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 discharge path temperature of the input filter capacitor exceeds this threshold, the temperature sampling unit will trigger the protection mechanism and automatically disconnect the first discharge unit to prevent high temperature from causing serious consequences such as circuit damage or fire. In this embodiment, the temperature sampling unit can use an automatic power-off temperature switch, or it can transmit the collected temperature to the processing unit, and the processing unit will turn off the first switch component in the first discharge unit.

[0057] This embodiment provides a temperature sampling unit to monitor the temperature of the discharge path in real time. Once the temperature exceeds a preset threshold, the first discharge unit is immediately disconnected, preventing further current flow and thus preventing further temperature increases. This mechanism effectively addresses the potential thermal runaway issue caused by rapid discharge, ensuring that the discharge circuit operates efficiently and stably within a safe temperature range, avoiding component damage and safety hazards, while maintaining the overall performance and service life of the switching power supply.

[0058] In an exemplary embodiment, in the related art, the discharge circuit design often consumes 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 component. Therefore, in order to solve the above problem, Figure 4 As shown, the first discharge unit also includes: an energy feedback unit, which is connected in series between the first discharge resistor component and the first switch component, and is used to store the discharge voltage of the input filter capacitor and feed it back to the AC source after the switching power supply is turned on.

[0059] The energy regeneration unit (ERU) is a circuit module designed to collect and store energy released from the input filter capacitor when the switching power supply is powered off, rather than simply dissipating it as heat. When the switching power supply is restarted, the ERU feeds the stored energy back to the power supply system, converting it back into electrical energy for use. This allows for energy recovery and reuse, significantly improving power conversion efficiency and reducing energy consumption. The ERU typically consists of a flyback transformer, rectifier diodes, current-limiting resistors, and a constant-current DC source, all working together to ensure efficient energy collection and safe energy regeneration.

[0060] Figure 5 This is a structural diagram of another switching power supply provided in an embodiment of the present application, such as Figure 5As shown, the non-discharge 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 voltage across 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-discharge circuit unit is turned on and the discharge circuit unit is disconnected. Otherwise, one of the first discharge unit and the second discharge unit is selected to be turned on according to the voltage across the input filter capacitor. If the first discharge unit is selected to be turned on, not only can rapid discharge be performed through the low-resistance network, but temperature can also be collected through the temperature sampling unit. When the temperature exceeds a preset temperature threshold, the first discharge unit is disconnected, and the discharge voltage of the input filter capacitor is fed back to the system through the energy feedback unit for next use.

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

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

[0063] The first bleeder resistor assembly and the first switch assembly form the structure of the first bleeder unit. In this embodiment, the second bleeder unit reuses the first bleeder resistor assembly within the first bleeder unit, eliminating the need to purchase and install additional high-resistance steady-state bleeder resistors, thereby reducing circuit costs and avoiding additional space occupation. The first bleeder assembly and the first switch assembly have been explained in the above embodiments and will not be repeated here.

[0064] The second bleeder resistor component is a high-resistance steady-state discharge network. It is used to maintain the capacitor voltage stable with low power consumption after the voltage across the input filter capacitor falls below a first voltage threshold, thus avoiding unnecessary energy loss. The second switch component is connected in series with the second bleeder resistor component to control the on / off of the high-resistance steady-state discharge path. When the voltage of the input filter capacitor drops below the first voltage threshold, the processing unit activates the second switch component, switching to steady-state discharge mode.

[0065] The processing unit is further configured to disconnect the non-discharge circuit unit and turn off the second switch component, turn on the first switch component, and turn on the first discharge unit for rapid discharge 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 a first voltage threshold; disconnect the non-discharge circuit unit and turn on the second switch component, turn off the first switch component, and turn on the second discharge unit for steady-state discharge 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, so as to reduce power consumption and improve efficiency.

[0066] This embodiment dynamically configures the discharge circuit unit to adapt to different voltage stages across the input filter capacitor. Specifically, when the voltage across the input filter capacitor is greater than or equal to a first voltage threshold (i.e., in a high-voltage stage), the processing unit disconnects the non-discharge circuit unit, turns off the second switch component, and turns on the first switch component, thereby activating the first discharge unit. This utilizes the low-resistance characteristics of the first discharge resistor component for rapid discharge, thereby meeting the requirement for rapid and safe discharge after a power outage. When the voltage across the input filter capacitor is less than the first voltage threshold, the second switch component is turned on and the first switch component is turned off, activating the second discharge unit. Steady-state discharge is performed using the high-resistance resistor network formed by the first and second discharge resistor components. This effectively resolves the conflict between fast response and low power consumption requirements identified in related art. Furthermore, the second discharge unit reuses the first discharge resistor component and the first switch component of the first discharge unit, avoiding the need for additional components with the same function in the second discharge unit. This saves material and manufacturing costs, reduces the number of components on the circuit board, and facilitates a more compact and smaller design, contributing to overall miniaturization of the device.

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

[0068] The first bleeder resistor component and the second bleeder resistor component have been explained in the above embodiment and will not be repeated here. It can be seen that the non-bleeder circuit unit reuses the bleeder circuit unit, that is, the non-bleeder circuit unit reuses the first bleeder resistor component and the second bleeder resistor component in the bleeder circuit unit. When the switching power supply is normally powered, the first bleeder resistor component and the second bleeder resistor component are reused by the non-bleeder circuit unit as sampling components. When the switching power supply is abnormally powered off, the first bleeder resistor component and the second bleeder resistor component serve as bleeder resistors, effectively reducing costs and power consumption and reducing the size of the device.

[0069] The third switch component is connected in series with the first voltage sampling component and to one end of the second switch component, and is ultimately 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 activation of the discharge circuit unit.

[0070] The fourth switch assembly is connected in series with the second voltage sampling assembly in the non-bleeding circuit unit and is connected to the other end of the second switch assembly and ultimately to ground. The fourth switch assembly functions similarly to the third switch assembly, but it utilizes different resistors and sampling components in the circuit. If the switching power supply is abnormally powered off, the processing unit disconnects the fourth switch assembly to enable activation of the bleeder 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 determine the power supply state and the capacitor voltage level, and then decide whether 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 determine the power supply state and the capacitor voltage level, and then decide whether to activate the discharge circuit unit.

[0073] 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 a normal power supply state, disconnect the first switch component and the second switch component to disconnect the discharge circuit unit, thereby saving power consumption and improving power supply efficiency, and turn on 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 an abnormal power-off state, select one of the first switch component and the second switch component to turn on, and disconnect the third switch component and the fourth switch component according to the voltage across the input filter capacitor, to disconnect the non-discharge circuit unit, and switch the non-discharge circuit unit to the discharge circuit unit, thereby achieving rapid or steady-state release of capacitor energy.

[0074] Through this embodiment, the on and off of the first switch component, the second switch component, the third switch component, and the fourth switch component are controlled to achieve dynamic switching between the non-discharge circuit unit and the discharge circuit unit. When the switching power supply is in a normal power supply state, the non-discharge circuit unit reuses the first discharge resistor component and the second discharge resistor component in the discharge circuit unit as sampling resistors, avoiding the need for additional resistors in the non-discharge circuit unit and reducing hardware costs. When the switching power supply is in an abnormal power-off state, the third switch component and the fourth switch component are disconnected to avoid the problem of additional energy consumption by the first voltage sampling component and the second voltage sampling component when the discharge circuit unit is working, thereby increasing unnecessary power consumption, reducing energy loss, and improving overall energy utilization efficiency.

[0075] In an exemplary embodiment, Figure 6 The structure diagram of the voltage sampling unit and the processing unit provided in the embodiment of the present application is as follows: Figure 6 As 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 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 end 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 end 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.

[0076] The first resistor R1 is a feedback resistor. When the output signal of operational amplifier IC1 changes, the first resistor R1 ensures that the signal is correctly fed back to the negative input terminal of operational amplifier IC1, thus forming a closed-loop amplification circuit. The resistance of the first resistor R1 is directly related to the strength of the feedback, which in turn 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 input terminal of the operational amplifier IC1, providing a reference voltage for the operational amplifier IC1 for comparison with the signal at the positive input terminal of the operational amplifier IC1.

[0078] The third resistor R3 is responsible for transmitting the voltage signal (VCx+) at the positive terminal of the input filter capacitor Cx1 to the non-inverting input terminal of the operational amplifier IC1. The third resistor R3 works together with the second resistor R2 to 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 to ensure that the non-inverting input terminal of the operational amplifier IC1 can still receive a stable and accurate reference voltage even in the case of power supply fluctuations.

[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 input signals from the second resistor R2 and the third resistor R3, amplifies and preliminarily processes the voltage signal across the input filter capacitor Cx1 through feedback from the first resistor R1 and the reference voltage provided by the fourth resistor R4 and the voltage divider resistor Rx, obtains the voltage VCx across the filter capacitor Cx1, and then outputs the processed VCx signal to the processing unit.

[0082] like Figure 6 As 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 the voltage across the input filter capacitor and controls the first switch component to be turned on and the second, third, and fourth switch components to be turned off when the voltage across the input filter capacitor is greater than a first voltage threshold.

[0083] In this embodiment, the voltage across the input filter capacitor Cx1 is divided by the second resistor R2 and the third resistor R3 and then directed to the input of the operational amplifier IC1, thereby achieving real-time monitoring of the capacitor voltage. The first resistor R1 constitutes a feedback loop of the operational amplifier IC1, and by feeding back a portion of the output signal to the negative input of the operational amplifier IC1, a closed-loop control is formed, thereby enhancing the stability of the entire voltage sampling unit. The fourth resistor R4 works together with the voltage-dividing resistor Rx to provide a stable reference voltage for the positive input of the operational amplifier IC1, ensuring that even in the case of power supply voltage fluctuations, IC1 can still perform voltage comparison and amplification based on an accurate reference, thereby improving sampling accuracy.

[0084] In an exemplary embodiment, Figure 7 A circuit diagram of a switching power supply provided in an embodiment of the present application is shown in FIG. Figure 7 As shown, the first discharge resistor component includes a fifth resistor R5 and a sixth resistor R6, and the first switch component includes a first switch S1; one end of the fifth resistor R5 is connected to the neutral line, and 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] In the first discharge unit, the first switch S1 plays a key role in controlling the on / off switching of the first discharge resistor component. When the processing unit detects that the switching power supply is powered off and the voltage across the input filter capacitor is above a predetermined 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 to the circuit to accelerate the capacitor's discharge process. When the voltage across the input filter capacitor falls below the predetermined first voltage threshold (i.e., entering a low-voltage phase), the first switch S1 is turned off, severing the discharge circuit and transitioning to a steady-state discharge mode to reduce power consumption.

[0086] On an AC power line, the voltage between the live and neutral wires changes periodically, reaching peak and valley values. If only one bleeder resistor is directly connected across the live and neutral wires, then when the power is disconnected, the resistor will be subjected to the full AC voltage, which may lead to excessive power consumption and heat generation, not only increasing energy consumption but also causing component overheating and damage. Therefore, in this embodiment, the first bleeder resistor assembly includes a fifth resistor R5 and a sixth resistor R6, rather than a single resistor, and the fifth resistor R5 and the sixth resistor R6 are respectively placed between the live and neutral wires and the input filter capacitor. This can disperse the voltage and power consumption while ensuring the discharge path, prevent a single component from being subjected to 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 form a first bleeder resistor assembly. They are connected in series, forming a loop with the live and neutral wires via the first switch S1. This series connection allows the charge in the input filter capacitor to be discharged after a power outage, controlling the capacitor's discharge rate. The resistance values ​​of R5 and R6 directly affect the discharge speed and efficiency. Furthermore, the series connection provides more flexible resistance adjustment, enabling effective operation during both rapid and steady-state discharge phases, meeting discharge requirements under different safety standards.

[0088] 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. In this embodiment, 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 less than the first voltage threshold. Figure 6 As shown, the processing unit includes an MCU processor, and 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 the pin to control the on and off of the first switch S1.

[0089] Through this embodiment, the combination of the first bleeder resistor component (fifth resistor R5 and sixth resistor R6) and the first switch S1 implements the function of dynamically adjusting the resistance value according to the input filter capacitor voltage. Compared with the solution in the related art that the bleeder circuit often uses a fixed low-resistance resistor to meet the fast discharge requirement, 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 bleeder network to achieve rapid discharge. 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, switching to a high-resistance steady-state discharge mode, thereby reducing steady-state power consumption and solving the problem of excessive power consumption.

[0090] In an exemplary embodiment, Figure 7 As 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 discharge path of the input filter capacitor and disconnect when the temperature is greater than a preset temperature threshold to cut off the first discharge unit.

[0091] The temperature switch T1 is a core component of the temperature sampling unit. It is connected in series in the discharge circuit path, for example, between the fifth resistor R5 and the first switch S1. The temperature switch T1 detects temperature changes caused by high current discharge in the path. Once the temperature exceeds a preset threshold (e.g., 130°C), the temperature switch T1 automatically disconnects, disconnecting the first discharge unit. This prevents thermal runaway and protects the first discharge unit from damage 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, located on the critical path of the discharge circuit. This means that when the discharge circuit is operating, the temperature switch T1 can directly sense temperature changes in this path. When the temperature exceeds a preset threshold, the temperature switch T1 automatically disconnects, cutting off the path to the first discharge unit, thereby preventing further flow of high current in an overheated state and providing protection. This design solves the problem of damage to the discharge circuit caused by high temperatures caused by high 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 a 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 via 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.

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

[0095] Diode D1 is used in the rectification phase of the energy feedback unit, ensuring that energy from the secondary winding of transformer T2 flows unidirectionally into the constant current source DC, preventing reverse flow and protecting circuit stability. D1 is connected in series with the seventh resistor, R7, to form part of the energy feedback path.

[0096] Resistor R7 acts as a current-limiting resistor in the energy feedback unit, limiting the energy current flowing into the constant current source DC to prevent overload. Connected in series with diode D1, R7 ensures a stable current during energy storage, protecting the constant current source DC and improving energy feedback efficiency.

[0097] The constant current source DC is the energy storage element of the energy feedback unit. It receives energy transmitted through transformer T2 and current-limiting resistor R7 and converts it into stored electrical energy. The next time the power supply starts up normally, the energy in the constant current source DC can be used to assist in system startup, saving energy while reducing dependence on external power sources and achieving closed-loop energy recycling. The positive electrode of the constant current source DC is connected to one end of the secondary winding of transformer T2 via D1 and R7, while the negative electrode is directly connected to the other end of T2's secondary winding, forming a closed circuit for energy storage and utilization.

[0098] In this embodiment, diode D1 and resistor R7 are connected in series between the secondary winding of transformer T2 and the constant current source DC, forming a rectification and current-limiting path. Diode D1 ensures that energy can flow only in one direction into the constant current source DC, preventing reverse flow and protecting the circuit. Resistor R7 also acts as a current limiter, preventing overload in the constant current source DC and ensuring the stability and safety of energy storage.

[0099] In an exemplary embodiment, the second discharge unit includes: a first discharge resistor component, a second discharge resistor component, a first switch component, and a second switch component. Figure 7 As shown, the first discharge resistor component includes a fifth resistor R5 and a sixth resistor R6, and the second discharge resistor component includes an eighth resistor R8 and a ninth resistor R9; the first switch component includes a first switch S1; the second switch component includes a second switch S2; Figure 7 As 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 wire; 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] The first bleeder resistor assembly and the first switch assembly have been explained in the above embodiments and will not be repeated here. The second bleeder resistor assembly is a resistor network consisting of the eighth resistor R8 and the ninth resistor R9. Its primary function is to activate when the residual voltage on the input filter capacitor Cx1 enters a low-voltage phase, forming a high-resistance steady-state bleeder circuit. This circuit is used to reduce steady-state power consumption while meeting safety residual voltage requirements, thus avoiding unnecessary energy waste.

[0101] In the second discharge unit, the second switch S2, like the first switch S1, is controlled by the processing unit and its main function is to switch the operating mode of the discharge circuit. In the high-voltage stage, the first switch S1 is turned on and the second switch S2 is turned off to avoid interference with rapid discharge; 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 discharge path for steady-state discharge, reducing continuous power consumption. In this embodiment, the fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 together constitute a high-resistance discharge network of the second discharge unit, wherein the second discharge resistor component includes the eighth resistor R8 and the ninth resistor R9 instead of a single resistor for the same reason as the first discharge resistor component includes the fifth resistor R5 and the sixth resistor R6 instead of a single resistor, and will not be repeated here.

[0102] In this embodiment, the processing unit is also used to disconnect the non-discharge circuit unit and turn off the second switch S2 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), and turn on the first switch S1 to turn on the first discharge unit. At this time, the discharge voltage of the input filter capacitor starts from the sixth resistor R6, passes through the first switch S1, and then passes through the fifth resistor R5 to achieve rapid discharge; 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-discharge circuit unit, turn off the first switch S1, and turn on the second switch S2 to turn on the second discharge unit. At this time, the discharge voltage of the input filter capacitor starts from the sixth resistor R6, passes through the ninth resistor R9, the second switch S2, and then passes through the eighth resistor R8 and the fifth resistor R5 to achieve rapid discharge. Figure 6 As shown, the processing unit includes an MCU processor, and two pins of the MCU processor are used to control the first switch S1 and the second switch S2 respectively. The MCU processor outputs a control signal to the first switch S1 through one pin to control the on and off of the first switch S1, and outputs a control signal to the second switch S2 through another pin to control the on and off of the second switch S2.

[0103] According to 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. However, when the switching power supply is in an abnormal power-off state, these resistor elements can be quickly converted into part of the discharge 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 equipment.

[0104] In an exemplary embodiment, the non-discharging circuit unit includes: a first bleeder resistor component, a second bleeder resistor component, a third switch component, a fourth switch component, a first voltage sampling component, and a second voltage sampling component, wherein the first bleeder resistor component and the second bleeder resistor component have been explained in the above embodiment and will not be repeated here. Figure 7 As shown, the third switch component includes a first power switch Q1, 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] like 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 via 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 via 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] The first power switch Q1 and the second power switch Q2 are control elements. When the switching power supply is in an abnormal power-off state, they are shut down by the processing unit to switch from the non-discharging circuit unit to the discharging 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 discharging circuit unit to the non-discharging 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 line, and the eleventh resistor R11 is used to sample the voltage on the neutral line.

[0107] In this embodiment, 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 based on 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; and 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 one of the first switch S1 and the second switch S2 to turn on based on the voltage across the input filter capacitor.

[0108] Figure 8 A discharge flow chart is provided in the embodiment of the present application, such as Figure 8 As 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 line through the fifth resistor R5, the eighth resistor R8 and the eleventh resistor R11, and transmits it to the processing unit. It samples the voltage on the neutral line through 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. Figure 6 and Figure 7As shown, the processing unit determines whether the switching power supply is powered off based on the voltage transmitted by the non-discharge circuit unit. If the output voltage Vac of the AC source is greater than or equal to 90V, the switching power supply is considered to be in a normal power supply state, and a high-level AC OK (Alternating Current OK) 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. Two AC fail (Alternating Current Failure) 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, so as to disconnect the discharge circuit unit. At this time, the discharge circuit unit is switched to the non-discharge circuit unit. The non-discharge circuit unit reuses the fifth resistor R5, the sixth resistor R6, the eighth resistor R8 and the ninth resistor R9 in the discharge circuit unit. When the switching power supply is in a normal power supply state, the continuous loss of the discharge resistor can be saved. According to the following formula (3), the power saving can be calculated as:

[0109] (3)

[0110] like Figure 8 As shown, if the output voltage Vac of the AC source (e.g., 80V) is less than 90V, the switching power supply is considered to be in an abnormal power-off state. The processing unit sends a low-level AC OK signal to the first power switch Q1 and the second power switch Q2, disconnecting the first power switch Q1 and the second power switch Q2 and switching the non-discharging circuit unit to the discharging circuit unit. At the same time, the processing unit collects the voltage VCx (including VCx+ and VCx-) across the input filter capacitor through the voltage sampling unit. The processing unit performs voltage threshold segmentation control based on the voltage VCx across the input filter capacitor, specifically including the following two scenarios:

[0111] Scenario 1: When the voltage across the input filter capacitor is greater than the first voltage threshold (i.e., 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 be turned on, and sends another AC fail signal (low level) to the second switch S2 to control the second switch S2 to be turned off, thereby enabling the low resistance discharge channel. Figure 7 The fifth resistor R5 and the sixth resistor R6 in the circuit utilize high current for rapid discharge, shortening the duration of the high-energy phase and meeting the safety regulations for discharge time from the start of discharge to a safe voltage. According to the following formula (4), the smaller the discharge resistance, the shorter the discharge time.

[0112] (4)

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

[0114] (5)

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

[0116] At the same time, a temperature switch T1 is added to the first discharge unit for temperature detection. For example, when the temperature switch T1 is greater than 130°C, the temperature switch T1 is turned off, the path where the first switch S1 is located is disconnected, and the fast 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 be disconnected, and sends another AC fail signal (high level) to the second switch S2 to control the second switch S2 to be turned on, enabling the high-resistance discharge channel. The fifth resistor R5, the sixth resistor R6, the eighth resistor R8, and the ninth resistor R9 form a high-resistance discharge network. The second discharge unit is used to reduce steady-state power consumption while meeting safety residual voltage requirements (such as the 1V / s decay rate specified in UL60950-1).

[0118] Through this embodiment, compared with the fixed resistance solution used in the related art, the overall energy consumption of this embodiment can be reduced by more than 60%, while ensuring the normal operation of the discharge circuit and avoiding the problem of overheating and burning due to large current during rapid discharge. At the same time, the components of the switching power supply can be reused, allowing the discharge and sampling circuits to share the discharge resistor. Through the judgment and processing switching of the processing unit, the safety performance of each port is ensured to be unaffected, reducing hardware costs and reducing the size of the equipment.

[0119] In one exemplary embodiment, the required discharge time varies depending on the type of device in which the switching power supply is located. For example, general equipment requires that the voltage decay to below 30V within 10 seconds after the switching power supply is powered off, while medical equipment requires that the voltage drop to 30V within 5 seconds after power is off. Using a discharge circuit unit with a fixed resistance value and a fixed discharge strategy would not be suitable for the discharge requirements of various types of equipment. Therefore, to address the above-mentioned issues, this embodiment provides a method for dynamically adjusting the resistance value of the discharge circuit unit. When the power supply is started or during operation, a trained model is used to analyze the collected signal data in real time, identify the connected load type, and automatically adjust the discharge strategy based on the load type. For example, a faster discharge rate is adopted for highly sensitive medical equipment.

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

[0121] Among them, the load type refers to the category of terminal equipment connected to the switching power supply, such as medical equipment, servers, personal computers, etc. Each device has specific requirements for the safe discharge rate of the switching power supply due to its differences in application characteristics and safety standards. By identifying the load type, this embodiment can optimize the discharge circuit design in a targeted manner to meet the safety requirements of different devices. In this embodiment, the connected load type is identified by a reinforcement learning model, such as collecting the working status data of the switching power supply, such as the input voltage, current, temperature and the voltage signal of the input filter capacitor; the working status data of the switching power supply is input into a pre-trained model, which can be trained using machine learning or pattern recognition technology, such as support vector machine (SVM), decision tree, neural network, etc., inputs the working status data of the switching power supply, and outputs the load type currently connected to the switching power supply. The model pre-defines different load type features and stores a load type feature library, which includes various load types and their features for comparing real-time monitoring data. The model processes the working status data of the switching power supply through statistical analysis and other technologies to determine 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 the key indicators with the features 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 maximum discharge speed within the time required to reduce the voltage on the input filter capacitor (Cx1) to a safe level after power is disconnected. This is set based on the specific safety standards of each load. For example, medical equipment requires a faster discharge rate to ensure user safety. This rate is a key parameter when designing the bleeder circuit.

[0123] The fastest safety timeframe is the time interval for the input filter capacitor to reach a safe voltage level after the device's power is disconnected. This timeframe is determined by safety standards. For example, IEC 62368 requires the voltage to drop below 60V within 1 second, or medical equipment requires it to drop to 30V within 5 seconds after a power outage.

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

[0125] For example, if a medical device is identified as connected, a shorter discharge time is required due to its unique characteristics. The processing unit uses a digital potentiometer to set the resistance values ​​of R5 and R6 to lower values, while R8 and R9 remain unchanged or are adjusted appropriately based on calculation results to speed up the discharge process. During the discharge process, the voltage VCx across the temperature switch T1 and the input filter capacitor is continuously monitored. If the temperature exceeds a preset threshold or the voltage reaches a safe range, the circuit immediately switches back to steady-state discharge mode or completely shuts down the discharge circuit to avoid unnecessary power consumption.

[0126] Through this embodiment, the load type is identified, and the fastest safe discharge rate required by the device connected to the switching power supply is determined based on the load type. Based on the fastest safe discharge rate, the first discharge resistor required by the first discharge unit and the second discharge resistor required by the second discharge unit are calculated; the resistance value of the first discharge unit is adjusted to the first discharge resistor, and the resistance value of the second discharge unit is adjusted to the second discharge resistor, so that the resistance value of the discharge circuit unit is dynamically adjusted according to the load type, so that the switching power supply can be safely discharged within the corresponding discharge time when connected to devices with different load types, thereby improving the compatibility of the switching power supply with devices with different load types.

[0127] According to one aspect of the embodiment of the present application, a discharge method is provided. Optionally, in this embodiment, a discharge method can be applied to, but is not limited to, Figure 2 In the processing unit shown. An embodiment of the present application provides a discharge method, comprising the following steps:

[0128] The output voltage of the AC source is collected through the non-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 discharge circuit unit is disconnected; the discharge 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 when 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 input filter capacitor is connected in parallel between the live wire and the neutral wire of the AC source to suppress electromagnetic interference.

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

[0130] In an exemplary embodiment, 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, disconnecting the non-discharge circuit unit and connecting the discharge circuit unit.

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

[0132] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus the necessary general hardware platform, and 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, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the steps in any of the above-mentioned discharge method embodiments.

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

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

[0136] An embodiment of the present application further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps in any of the above-mentioned discharge method embodiments are implemented.

[0137] An embodiment of the present application further provides another computer program product, including a non-volatile computer-readable storage medium, wherein 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-mentioned discharge method embodiments are implemented.

[0138] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0139] The above describes in detail a switching power supply, discharge method, storage medium, and program product provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only intended to help understand the method and core concept of the present application. It should be noted that, for those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application, and such improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A switching power supply, characterized in that: include: Input filter capacitor, connected in parallel between the live wire and the neutral wire of the AC source, is used to suppress electromagnetic interference; a discharge 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, so as to ensure that the input filter capacitor is discharged to a safe voltage level within a specified time range; a non-discharging circuit unit, configured to collect the output voltage of the AC source; the non-discharging circuit unit reuses the first bleeder resistor component and the second bleeder resistor component in the bleeder circuit unit; when the switching power supply is normally powered, the first bleeder resistor component and the second bleeder resistor component are reused by the non-discharging circuit unit as sampling components; when the switching power supply is abnormally powered off, the first bleeder resistor component and the second bleeder resistor component serve as bleeder resistors; The processing unit is configured 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.

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 connect 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, wherein: The discharge circuit unit includes: a first discharge unit connected in parallel to both ends of the input filter capacitor, and 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; a second discharge unit connected in parallel across the input filter capacitor, configured to release 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 reuses the first discharge unit; and 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 and turn on one of the first discharge unit and the second discharge unit 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.

4. The switching power supply according to claim 3, characterized in that: The switching power supply further comprises: The voltage sampling unit is connected in parallel to the two ends of the input filter capacitor and is used to collect 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: the first discharge resistor component and the first switch component; The first discharge resistor component is connected in series with the first switch component and then connected in parallel to both ends of the input filter capacitor; 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, turn on the first switch component; 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, turn off the first switch component.

6. The switching power supply according to claim 5, characterized in that: The first discharge unit further includes: A temperature sampling unit is connected in series between the first discharge resistor component and the first switch component, and is used to collect the temperature of the discharge path of the input filter capacitor and cut 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 is connected in series between the first discharge resistor component and the first switch component, and is used to store the discharge voltage of the input filter capacitor and feed 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: the first discharge resistor component, the second discharge resistor component, a first switch component and a second switch component; The first bleeder resistor component is connected in series with the first switch component and then connected in parallel to both ends of the input filter capacitor; the second bleeder resistor component is connected in series with the second switch component and then connected in parallel to both ends of the first switch component; 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 component, and turn on the first switch component to turn on the first discharge unit; 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, disconnect the non-discharge circuit unit, turn on the second switch component, and turn off the first switch component 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 component, the second discharge resistor component, the third switch component, the fourth switch component, the first voltage sampling component and the second voltage sampling component; One end of the second switch component is grounded through the third switch component and the first voltage sampling component connected in series; the other end of the second switch component is grounded through the fourth switch component and the second voltage sampling component connected in series; The first voltage sampling component is used to collect the output voltage of the live line; the second voltage sampling component is used to collect the output voltage of the neutral line; 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 component and the second switch component to disconnect the discharge circuit unit, and connect the third switch component and the fourth switch component; and, when the output voltage of the AC source indicates that the switching power supply is in an abnormal power-off state, select one of the first switch component and the second switch component to connect based on the voltage across the input filter capacitor, and disconnect the third switch component and the fourth switch component 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 end 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 end 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 divider resistor Rx is connected to the positive electrode of the operational amplifier IC1, and the other end of the voltage divider resistor Rx is grounded.

11. The switching power supply according to claim 7, characterized in that: The first discharge resistor component includes a fifth resistor R5 and a sixth resistor R6, and the first switch component 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 via 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 a first voltage threshold.

12. The switching power supply according to claim 11, characterized in that: The temperature sampling unit includes: The temperature switch T1 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 discharge path of the input filter capacitor and disconnect when the temperature is greater than a 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; 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 bleeder resistor component includes a fifth resistor R5 and a sixth resistor R6, and the second bleeder resistor component includes an eighth resistor R8 and a ninth resistor R9; the first switch component includes a first switch S1; and the second switch component includes a second switch S2; One end of the fifth resistor R5 is connected to the neutral line, and the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 via 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, and the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9 via 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, the non-discharge circuit unit is disconnected, the first switch S1 is turned off, and the second switch S2 is turned on to turn on the second discharge unit.

15. The switching power supply according to claim 14, characterized in that: 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, and the source of the first power switch Q1 is grounded via 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 via 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 an output voltage of the AC source based on the first voltage and the second voltage; determine that the switching power supply is in a normal power supply state when the output voltage of the AC source is greater than or equal to a second voltage threshold, 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; and determine that the switching power supply is in an abnormal power-off state when the output voltage of the AC source is less than the second voltage threshold, turn off the first power switch Q1 and the second power switch Q2, and select one of the first switch S1 and the second switch S2 to turn on based on the voltage across the input filter capacitor.

16. A discharge method, characterized in that: include: The output voltage of the AC source is collected through a non-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 discharge circuit unit is disconnected. The discharge 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 is discharged to a safe voltage level within a specified time range. The non-discharge circuit unit reuses 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 reused by the non-discharge circuit unit as sampling components. When the switching power supply is abnormally powered off, the first discharge resistor component and the second discharge resistor component serve as discharge resistors. The input filter capacitor is connected in parallel between the live wire and the neutral wire of the AC source to suppress electromagnetic interference.

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

18. The method according to claim 17, characterized in that The discharge circuit unit includes a first discharge unit and a second discharge unit; the second discharge unit reuses the first discharge unit; the resistance of the first discharge unit is smaller than the resistance of the second discharge unit; The step of turning on the discharge circuit unit includes: When the voltage across the input filter capacitor is greater than or equal to a first voltage threshold, turning on the first discharge unit and turning off the second discharge unit; 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.

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

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

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