Switching power supply protection circuit and application equipment thereof

Abstract

A switching power supply protection circuit and an application device thereof relate to the technical field of control circuits, the switching power supply protection circuit comprises a switch driving circuit, a sampling circuit and a feedback circuit, the output end of the switch driving circuit is connected with the sampling circuit, and the output end of the sampling circuit is connected with the feedback circuit. According to the embodiment of the utility model, the switch driving circuit, the sampling circuit and the feedback circuit are integrated, so that the output power under an overload condition can be effectively managed and adjusted, and when the output power of the power amplifier is about to exceed a safety threshold value, the feedback circuit is switched on, and the output power is output. The sampling circuit detects and converts an overload condition into an overload signal, then the signal is fed back to the switch driving circuit, and the switch driving circuit immediately adjusts the output of the signal to prevent the power supply from being automatically turned off, so that the shutdown of the application equipment is avoided, and the real-time feedback mechanism not only ensures the continuous operation of the application equipment, but also ensures the safety of the application equipment. And the equipment is protected from potential damage caused by overload.

Description

Technical Field

[0001] The utility model relates to the technical field of control circuits, in particular to a switching power supply protection circuit and application equipment thereof. Background Art

[0002] With the rapid development of digital technology, digital power amplifiers have become a core component of audio products. Due to their high efficiency, excellent sound quality control and programmability, digital power amplifiers have been rapidly popularized and widely used. The design of digital power amplifiers enables audio equipment to process audio signals more accurately, thereby providing clearer sound quality and more powerful output capabilities.

[0003] However, in existing technologies, when the output power of a digital amplifier is severely overloaded, the overload protection function of the switching power supply is triggered. At this time, to prevent damage, the switching power supply will automatically shut down the power supply, causing the amplifier to suddenly stop working and the sound to be cut off, which directly affects the smooth progress of the entire performance and the audience's experience. Such sound cut problems not only cause embarrassment on the scene, but may also damage the reputation of the audio equipment provider. Utility Model Content

[0004] The purpose of the present utility model is to address the defects and shortcomings of the prior art. On the one hand, it provides a switching power supply protection circuit, including a switch drive circuit, a sampling circuit and a feedback circuit, wherein the output end of the switch drive circuit is connected to the sampling circuit, the output end of the sampling circuit is connected to the feedback circuit, and the feedback circuit is connected to the feedback end of the switch drive circuit, wherein:

[0005] The switch drive circuit is used to convert direct current into analog alternating current through high-frequency switching operation, the sampling circuit is used to convert the overload power at the output end of the switch drive circuit into an overload signal, and the feedback circuit is used to output the overload signal to the feedback end of the switch drive circuit.

[0006] The switching power supply protection circuit further includes an energy conversion isolation module and an output port, the sampling circuit includes a first sampling circuit and a second sampling circuit, the first sampling circuit is electrically connected to the second sampling circuit, the output end of the second sampling circuit is connected to the feedback circuit, the output end of the switch drive circuit is connected to the first sampling circuit, the first sampling circuit and the switch drive circuit are connected to the primary side of the energy conversion isolation module, and the output port, the second sampling circuit and the feedback circuit are connected to the secondary side of the energy conversion isolation module, wherein:

[0007] The transducer isolation module is used to convert the input voltage into the voltage required by the output port; the first sampling circuit is used to convert the overload power at the output end of the switch drive circuit into an overload signal, and the second sampling circuit is used to output the overload signal from the first sampling circuit to the feedback circuit.

[0008] The first sampling circuit includes a first resistor R1, a sampling resistor RS, a first switch tube D1, and a primary isolation transmission switch tube. One end of the sampling resistor RS is connected to the output end of the switch drive circuit and the anode of the first switch tube D1. The other end of the sampling resistor RS and one end of the primary isolation transmission switch tube are commonly connected to the primary ground terminal PGND. The other end of the primary isolation transmission switch tube is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the cathode of the first switch tube D1.

[0009] A first implementation of the second sampling circuit includes a first sampling branch, a second resistor R2, and a secondary isolation transmission switch tube, that is, the photosensitive side U1A of the first optocoupler switch tube. The input end of the first sampling branch is connected to the secondary side of the energy conversion isolation module; the output end of the first sampling branch is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the secondary isolation transmission switch tube, and the other end of the secondary isolation transmission switch tube is connected to the controlled end of the feedback circuit; the ground end of the first sampling branch and the ground end of the feedback circuit are commonly connected to the secondary ground end AGND, and the primary isolation transmission switch tube transmits the overload signal to the secondary isolation transmission switch tube.

[0010] The primary isolation transmission switch tube is the light-emitting side U1B of the first optocoupler switch tube or the primary winding CT1A of the current transformer, and the secondary isolation transmission switch tube is the photosensitive side U1A of the first optocoupler switch tube or the secondary winding CT1B of the current transformer.

[0011] A second implementation of the second sampling circuit includes a second sampling branch, a second resistor R2 and a parallel capacitor thereof, a third resistor R3, a second switch tube Q2, and a secondary isolation transmission switch tube. The secondary isolation transmission switch tube, that is, the secondary winding CT1B of the current transformer, is connected in parallel with the second resistor R2 and its parallel capacitor, one end of which is connected to one end of the third resistor R3, and the other end is connected to the secondary ground terminal AGND together with the ground terminal of the feedback circuit. The other end of the third resistor R3 is connected to the control terminal of the second switch tube Q2, and the conduction terminal of the second switch tube Q2 is connected to the output terminal of the second sampling branch and the controlled terminal of the feedback circuit.

[0012] The switching power supply protection circuit also includes an input port, which includes a fourth resistor R4, a second capacitor C2 and a third switch tube D2. After the fourth resistor R4 and the second capacitor C2 are connected in parallel, one end is connected to the input voltage and the primary side of the energy conversion isolation module, and the other end is connected to the cathode of the third switch tube D2. The anode of the third switch tube D2 is connected to the primary side of the energy conversion isolation module.

[0013] The switch driving circuit includes a fourth switch tube Q1 and a switch driving chip U4. The switch driving chip U4 includes a pin 6, which is connected to the control end of the fourth switch tube Q1; the conduction end of the fourth switch tube Q1 is connected to the anode of the third switch tube D2 and the sampling resistor RS; the switch driving chip U4 controls the on / off of the fourth switch tube Q1 through the pin 6.

[0014] The feedback circuit includes a second optocoupler switch tube photosensitive side U2A, a second optocoupler switch tube light-emitting side U2B, a first voltage regulator U3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10 and a third capacitor C3. The switch driver chip U4 also includes a pin 2, and the switch driver chip U4 receives the overload signal of the feedback circuit through the pin 2; one end of the fifth resistor R5 and the seventh resistor R7 is connected to the output port, and the other end of the fifth resistor R5 is connected to one end of the third capacitor C3, the controlled end of the first voltage regulator U3 and the sixth resistor R6. R6; the other end of the sixth resistor R6 and the ground end of the first voltage regulator U3 are commonly connected to the secondary ground terminal AGND; the output end of the first voltage regulator U3 is connected to one end of the ninth resistor R9, one end of the eighth resistor R8 and one end of the light-emitting side U2B of the second optocoupler switch tube; the other end of the ninth resistor R9 is connected to the other end of the third capacitor C3; the other end of the seventh resistor R7 is connected to the other end of the eighth resistor R8 and the other end of the light-emitting side U2B of the second optocoupler switch tube; the photosensitivity side U2A of the second optocoupler switch tube is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected to pin 2.

[0015] The switching power supply protection circuit also includes a first rectifier module, a second rectifier module, a driver chip power supply module and a voltage stabilizing module, wherein the input end of the first rectifier module is connected to the primary side of the energy conversion isolation module, and the output end of the first rectifier module is connected to the driver chip power supply module and the switch drive circuit; the driver chip power supply module is connected to the switch drive circuit, the input end of the second rectifier module is connected to the secondary side of the energy conversion isolation module, and the output end of the second rectifier module is connected to the input end of the voltage stabilizing module; the voltage stabilizing module is connected to the feedback circuit and the output port, wherein the first rectifier module is used to convert the alternating current output from the primary side of the energy conversion isolation module into direct current, the second rectifier module is used to rectify the alternating current output from the secondary side of the energy conversion isolation module into direct current again, the driver chip power supply module is used to supply power to the switch drive circuit, and the voltage stabilizing module is used to receive the direct current output from the second rectifier module and perform voltage regulation and stabilization.

[0016] On the other hand, the present invention also provides a power amplifier application device, including the switching power supply protection circuit of the above technical solution.

[0017] The embodiment of the present utility model can effectively manage and adjust the power output under overload conditions by integrating a switch drive circuit, a sampling circuit and a feedback circuit. When the output power of the power amplifier is about to exceed the safety threshold, the sampling circuit detects and converts the overload condition into an overload signal, which is then fed back to the switch drive circuit. The switch drive circuit then adjusts its output to prevent the power supply from automatically shutting down, thereby avoiding the occurrence of shutdown of the application device. This real-time feedback mechanism not only ensures the continuous operation of the application device, but also protects the device from potential damage caused by overload.

[0018] In addition, by maintaining the continuity and stability of the performance, it not only significantly improves the reliability of professional audio equipment and the overall user experience, but also maintains the clarity and intensity of the sound quality, ensuring the reputation and market competitiveness of the audio equipment provider. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a structural block diagram of a switching power supply protection circuit according to a first embodiment of the present invention;

[0021] Figure 2This is a structural block diagram of a switching power supply protection circuit according to a second embodiment of the present invention;

[0022] Figure 3 This is a structural block diagram of a switching power supply protection circuit according to a third embodiment of the present invention;

[0023] Figure 4 1 is a circuit diagram of a switching power supply protection circuit according to another embodiment of the present invention;

[0024] Figure 5 This is a circuit diagram of a switching power supply protection circuit according to yet another embodiment of the present invention.

[0025] Reference numerals:

[0026] DETAILED DESCRIPTION

[0027] The present invention will be described in further detail below with reference to the accompanying drawings.

[0028] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Reference Figure 1 The first embodiment of the present invention provides a switching power supply protection circuit, comprising a switch driving circuit 100, a sampling circuit 200, and a feedback circuit 300. The output end of the switch driving circuit 100 is connected to the sampling circuit 200, the output end of the sampling circuit 200 is connected to the feedback circuit 300, and the feedback circuit 300 is connected to the feedback end of the switch driving circuit 100.

[0032] The switch driving circuit 100 is used to convert direct current into analog alternating current through high-frequency switching operation, the sampling circuit 200 is used to convert the overload power at the output end of the switch driving circuit 100 into an overload signal, and the feedback circuit 300 is used to output the overload signal to the feedback end of the switch driving circuit 100.

[0033] The embodiment of the present utility model can effectively manage and adjust the power output under overload conditions by integrating a switch drive circuit, a sampling circuit and a feedback circuit. When the output power of the power amplifier is about to exceed the safety threshold, the sampling circuit detects and converts the overload condition into an overload signal, which is then fed back to the switch drive circuit. The switch drive circuit then adjusts its output to prevent the power supply from automatically shutting down, thereby avoiding the occurrence of shutdown of the application device. This real-time feedback mechanism not only ensures the continuous operation of the application device, but also protects the device from potential damage caused by overload.

[0034] In addition, by maintaining the continuity and stability of the performance, it not only significantly improves the reliability of professional audio equipment and the overall user experience, but also maintains the clarity and intensity of the sound quality, ensuring the reputation and market competitiveness of the audio equipment provider.

[0035] Reference Figure 2 A second embodiment of the present invention provides a switching power supply protection circuit. Specifically, in one possible implementation, the switching power supply protection circuit further includes an energy conversion isolation module 400 and an output port 12. The sampling circuit 200 includes a first sampling circuit 210 and a second sampling circuit 220. The first sampling circuit 210 is electrically connected to the second sampling circuit 220. The output end of the second sampling circuit 220 is connected to the feedback circuit 300. The output end of the switch driving circuit 100 is connected to the first sampling circuit 210. The first sampling circuit 210 and the switch driving circuit 100 are connected to the primary side of the energy conversion isolation module 400. The output port 12, the second sampling circuit 220, and the feedback circuit 300 are connected to the secondary side of the energy conversion isolation module 400.

[0036] The energy conversion isolation module 400 is used to convert the input voltage into the voltage required by the output port 12; the first sampling circuit 210 is used to convert the overload power at the output end of the switch driving circuit 100 into an overload signal, and the second sampling circuit 220 is used to output the overload signal from the first sampling circuit 210 to the feedback circuit 300.

[0037] In the second embodiment, compared with the first embodiment, a first sampling circuit 210, a second sampling circuit 220 and a transducer isolation module 400 are newly added. These newly added circuits and modules improve the flexibility and safety of the overall circuit. Specifically, the design of the first sampling circuit 210 and the second sampling circuit 220 allows for more precise processing of overload signals, and can process and optimize signals separately at different stages, thereby improving response speed and accuracy; the transducer isolation module 400 ensures electrical isolation between the input and output ends while providing the necessary voltage conversion, thereby enhancing the safety of the system and preventing voltage fluctuations or overload conditions from negatively affecting the output device. Through the above settings, the second embodiment can provide higher stability and reliability in complex power supply application environments.

[0038] In the second embodiment of the present invention, the switch drive circuit 100 is the core, responsible for converting the input direct current into analog alternating current through high-frequency switching operations. This conversion is achieved through the rapid switching of transistors. The switching frequency of the transistors directly affects the frequency and quality of the AC signal, which not only ensures the continuous supply of current, but also provides a basic guarantee for subsequent voltage regulation and signal processing.

[0039] The first sampling circuit 210 is directly connected to the output of the switch driver circuit. Its main function is to monitor the output power in real time. When an overload condition is detected, it immediately converts the excess power into an overload signal and transmits it to the second sampling circuit 220. The second sampling circuit further processes these overload signals and sends the processed signals to the feedback circuit. This hierarchical processing method allows the system to respond to overload conditions more quickly and accurately, effectively preventing equipment damage caused by excessive power.

[0040] The feedback circuit 300 is to feed back the overload signal processed by the second sampling circuit to the switch drive circuit. This closed-loop feedback mechanism is the key to the protection circuit function. It ensures that when the sampling circuit detects an overload, the switch drive circuit can adjust its output in time and reduce power, thereby avoiding power shutdown or equipment damage due to overload. In this way, the system can self-regulate and protect without interrupting power supply. The transducer isolation module 400 is not only responsible for converting the input voltage into an output voltage suitable for the output port 12, but also provides electrical isolation between the input and output ends, so that the mutual influence between the input and output ends is minimized, thereby reducing the risk of output devices being affected by voltage fluctuations or overloads. The transducer isolation module not only ensures the independent operation of the primary and secondary circuits, but also ensures the integrity of the signal and the safety of the system.

[0041] Through the above-described circuit configuration, the switching power supply protection circuit of the second embodiment can achieve efficient power management and excellent system protection. During normal system operation, the switch drive circuit continuously supplies stable analog AC power. When the system is overloaded, the sampling circuit immediately detects and processes the overload condition, and quickly adjusts the output of the switch drive circuit through the feedback circuit, thereby ensuring that the power supply does not accidentally shut down due to overload protection, thereby ensuring the continuous operation and stability of the audio equipment. This design not only improves the performance and reliability of the audio equipment, but also enhances user trust and satisfaction with the audio equipment provider.

[0042] Reference Figure 3-Figure 5 A third embodiment of the present invention provides another switching power supply protection circuit. Specifically, in one possible implementation, a first sampling circuit 210 includes a first resistor R1, a sampling resistor RS, a first switch transistor D1, and a primary isolation transmission switch transistor. One end of the sampling resistor RS is connected to the output end of the switch drive circuit 100 and the anode of the first switch transistor D1. The other end of the sampling resistor RS and one end of the primary isolation transmission switch transistor are commonly connected to the primary ground terminal PGND. The other end of the primary isolation transmission switch transistor is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the cathode of the first switch transistor D1.

[0043] A first implementation of the second sampling circuit 220 includes a first sampling branch 221, a second resistor R2, and a secondary isolation transmission switch tube, namely, the photosensitive side U1A of the first optocoupler switch tube. The input end of the first sampling branch 221 is connected to the secondary side of the transducer isolation module 400; the output end of the first sampling branch 221 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the secondary isolation transmission switch tube, and the other end of the secondary isolation transmission switch tube is connected to the controlled end of the feedback circuit 300; the ground end of the first sampling branch 221 and the ground end of the feedback circuit 300 are commonly connected to the secondary ground end AGND, and the primary isolation transmission switch tube transmits the overload signal to the secondary isolation transmission switch tube.

[0044] This embodiment optimizes the circuit response speed and system stability through a sophisticated signal sampling and isolated transmission mechanism. Specifically, the first sampling circuit 210 and the second sampling circuit 220 implement efficient signal processing and transmission through two isolated transmission switches. In the first sampling circuit 210, the first resistor R1 and the sampling resistor RS are key signal processing components. One end of the sampling resistor RS is connected to the output end of the switch drive circuit 100, and the other end is connected to the primary ground terminal PGND. This enables the sampling resistor RS to detect current changes under overload conditions and generate an overload signal reflecting the overload state. This signal is transmitted to the second sampling circuit 220 through the primary isolated transmission switch. This ensures signal clarity and accuracy while isolating the high voltage portion to protect sensitive components in the secondary circuit.

[0045] The second sampling circuit 220 further processes the overload signal transmitted from the first sampling circuit 210. Specifically, the secondary isolation transmission switch tube is responsible for receiving the signal, and the first sampling branch 221 and the second resistor R2 participate in collaborative control to ensure that the overload signal is properly adjusted before being transmitted to the feedback circuit 300. The secondary isolation transmission switch tube is not only used to transmit signals, but also protects the feedback circuit 300 from potential electrical interference.

[0046] In general, the working principle of this embodiment is based on efficient signal acquisition and precise isolation transmission strategy. Through careful circuit design, it realizes effective detection and processing of overload signals, while ensuring the safe and effective transmission of signals between the independent circuits of the primary and secondary parts. This method not only improves the overall performance of the circuit system, but also enhances the stability and reliability of the system in the face of extreme working conditions.

[0047] This embodiment significantly improves the response speed and accuracy of overload protection by introducing signal sampling and isolated transmission design: through the use of first and second sampling circuits and isolated transmission switching tubes, this circuit can accurately detect and quickly respond to overload conditions, preventing power shutdown or equipment damage caused by overload. This protection mechanism can ensure that the equipment operates stably within a safe operating range, thereby extending the service life of the equipment and maintaining stable performance.

[0048] Optionally, the primary isolation transmission switch tube is the light-emitting side U1B of the first optocoupler switch tube or the primary winding CT1A of the current transformer, and the secondary isolation transmission switch tube is the photosensitive side U1A of the first optocoupler switch tube or the secondary winding CT1B of the current transformer.

[0049] In this embodiment, the light-emitting side U1B of the first optocoupler switch tube or the primary winding CT1A of the current transformer is used as the primary isolation transmission switch tube, and the photosensitive side U1A of the first optocoupler switch tube or the secondary winding CT1B of the current transformer is used as the secondary isolation transmission switch tube, thereby achieving electrical isolation. This not only significantly improves the safety of the entire circuit and the accurate transmission of signals, but also effectively prevents high voltage or high current interference from propagating from the primary input side to the secondary output side, thereby ensuring the purity of the signal and the stable operation of the system.

[0050] In addition, the application of optocoupler switches and current transformers improves the accuracy and response speed of signal processing, enabling the circuit system to respond to overload conditions more quickly and effectively, preventing equipment damage or operational interruptions caused by overload, thereby ensuring the reliability, continuity and stability of the performance of high-power equipment such as professional audio systems.

[0051] Optionally, a second implementation of the second sampling circuit 220 includes a second sampling branch 222, a second resistor R2 and a parallel capacitor thereof, a third resistor R3, a second switch tube Q2 and a secondary isolation transmission switch tube. The secondary isolation transmission switch tube, that is, the secondary winding CT1B of the current transformer, is connected in parallel with the second resistor R2 and its parallel capacitor, one end of which is connected to one end of the third resistor R3, and the other end is connected to the secondary ground terminal AGND together with the ground terminal of the feedback circuit 300. The other end of the third resistor R3 is connected to the control end of the second switch tube Q2, and the conduction end of the second switch tube Q2 is connected to the output end of the second sampling branch 222 and the controlled end of the feedback circuit 300.

[0052] In this embodiment, the design of the second sampling circuit 220 adds a second sampling branch 222, a second resistor R2 and its parallel capacitor, a third resistor R3 and a second switch tube Q2. These components work together to optimize and enhance the circuit system's ability to handle overload conditions. The key to this embodiment lies in how to accurately control the feedback signal and how to use the characteristics of electronic components to achieve this goal. Specifically, the second resistor R2 and its parallel capacitor form a low-pass filter for smoothing the overload signal received by the secondary winding CT1B of the current transformer from the primary winding CT1A of the current transformer, eliminating high-frequency noise and ensuring the quality of the overload signal. The processed overload signal passes through the third resistor R 3 is transmitted to the control terminal of the second switch tube Q2; the third resistor R3 plays the role of current limiting and voltage dividing, ensuring that the voltage transmitted to the control terminal of the second switch tube Q2 is within a safe range; whether the second switch tube Q2 is on or off is determined by the voltage at its control terminal. When the voltage exceeds a certain threshold, Q2 is turned on, allowing the signal to pass, thereby affecting the feedback circuit 300 and realizing the regulation of the switch drive circuit 100. In this way, the circuit system can dynamically adjust the output to cope with different load conditions, thereby preventing the occurrence of overload. The connection between the output of the second sampling branch 222 and the second switch tube Q2 ensures the consistency, controllability and stability of signal transmission, making the response of the entire system more rapid and accurate.

[0053] This embodiment significantly improves the reliability, continuity, and stability of the switching power supply protection circuit performance by introducing a comprehensive filtering and control mechanism: the low-pass filter composed of the second parallel resistor R2 and its parallel capacitor effectively smoothes the input signal, reduces high-frequency noise interference, and improves the stability of the system; and the introduction of the second switch tube Q2 and the second sampling branch 222 allows fine adjustment of the feedback signal, thereby achieving more accurate overload protection, which not only enhances the circuit system's ability to respond to sudden high loads, but also protects the audio equipment from damage caused by overload, ensuring the long-term stable operation of the equipment and the user's satisfactory experience.

[0054] Optionally, the switching power supply protection circuit also includes an input port 11, which includes a fourth resistor R4, a second capacitor C2 and a third switch tube D2. After the fourth resistor R4 and the second capacitor C2 are connected in parallel, one end is connected to the input voltage and the primary side of the energy conversion isolation module 400, and the other end is connected to the cathode of the third switch tube D2, and the anode of the third switch tube D2 is connected to the primary side of the energy conversion isolation module 400.

[0055] In this embodiment, an input port 11 including a fourth resistor R4, a second capacitor C2 and a third switch tube D2 is introduced, which is mainly used to optimize the power input and protect the circuit from the influence of unstable input voltage and high-frequency noise generated during the on / off process of the fourth switch tube Q1.

[0056] Specifically, the fourth resistor R4, the second capacitor C2, and the third switch D2 together form an RCD absorption circuit, which is used to absorb and clamp the voltage spike on the drain of the fourth switch Q1, thereby protecting the power supply from damage. When the fourth switch Q1 is turned off, the leakage inductance of the transducer isolation module 400 and the parasitic capacitance of the fourth switch Q1 generate a voltage spike. This voltage spike is then charged to the second capacitor C2 through the third switch D2. The second capacitor C2 is much larger than the parasitic capacitance of the fourth switch Q1 and therefore divides most of the current, slowing the charging process of the parasitic capacitance of the fourth switch Q1. This suppresses the voltage spike between the drain and source of the fourth switch Q1. When the charging process of the second capacitor C2 is completed, the voltage spike begins to discharge through the fourth resistor R4. The fourth resistor R4 consumes the energy stored in the leakage inductance of the transducer isolation module 400, causing the resonant waveform to stabilize as quickly as possible. In this way, the RCD absorption circuit effectively reduces voltage spikes and electromagnetic interference by absorbing and dissipating energy, protecting the power supply from damage.

[0057] Optionally, the switch driving circuit 100 further includes a fourth switch tube Q1 and a switch driving chip U4, wherein the switch driving chip U4 includes a pin 6, wherein the pin 6 is connected to the control end of the fourth switch tube Q1; the conduction end of the fourth switch tube Q1 is connected to the anode of the third switch tube D2 and the sampling resistor RS; the switch driving chip U4 controls the on / off of the fourth switch tube Q1 through the pin 6.

[0058] In this embodiment, the fourth switch tube Q1 and the switch driver chip U4 are added to enhance the control accuracy and response speed of the circuit. The switch driver chip U4 is the core control unit of the entire circuit. Its pin 6 is directly connected to the control end of the fourth switch tube Q1, enabling the chip to accurately control the opening and closing of the fourth switch tube Q1.

[0059] Specifically, one end of the conduction end of the fourth switch tube Q1 is connected to the primary side of the transducer isolation module 400, and the other end is connected to the sampling resistor RS. The sampling resistor RS monitors and samples the primary current of the transducer isolation module 400, and transmits the sampling result to the switch driver chip U4. The switch driver chip U4 adjusts the control signal output by its pin 6 according to the received sampling result to accurately control the on and off time of the fourth switch tube Q1. By measuring, monitoring and sampling the current through the sampling resistor RS, the system can monitor the load status of the circuit in real time and detect whether there is an overload. The switch driver chip U4 accurately controls the on and off of the fourth switch tube Q1 by adjusting the control signal output by its pin 6, thereby finely adjusting the current size and output power of the circuit. This control mechanism not only improves the response speed of the circuit, but also enhances the circuit system's adaptability to changing load conditions, ensuring that the circuit can maintain stability and safety under various operating conditions.

[0060] This embodiment significantly improves the control accuracy and operational flexibility of the system by integrating the fourth switch tube Q1 and the switch driver chip U4. The precise control of the fourth switch tube Q1 enables the system to quickly respond to load changes, timely adjust the circuit current and output power, and effectively prevent the harm of overload.

[0061] In addition, the introduction of the switch driver chip U4 and its control pin design further enhances the intelligence of the circuit, allowing the circuit to more intelligently adjust automatically according to the actual current load conditions, ensuring that the device operates within a safe current range. This not only improves the safety of the device, but also optimizes the performance of the device, ensuring long-term stable operation, and providing users with a more reliable power supply solution.

[0062] Optionally, the feedback circuit 300 includes a photosensitive side U2A and a light-emitting side U2B of a second optocoupler switch tube, a first voltage regulator U3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10 and a third capacitor C3, and the switch driver chip U4 further includes a pin 2, and the switch driver chip U4 receives the overload signal of the feedback circuit 300 through the pin 2; one end of the fifth resistor R5 and the seventh resistor R7 is connected to the output port 12, and the other end of the fifth resistor R5 is connected to one end of the third capacitor C3, the controlled end of the first voltage regulator U3 and the sixth resistor R7. One end of the resistor R6; the other end of the sixth resistor R6 and the ground end of the first voltage regulator U3 are commonly connected to the secondary ground terminal AGND; the output end of the first voltage regulator U3 is connected to one end of the ninth resistor R9, one end of the eighth resistor R8 and one end of the light-emitting side U2B of the second optocoupler switch tube; the other end of the ninth resistor R9 is connected to the other end of the third capacitor C3; the other end of the seventh resistor R7 is connected to the other end of the eighth resistor R8 and the other end of the light-emitting side U2B of the second optocoupler switch tube; the photosensitivity side U2A of the second optocoupler switch tube is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected to pin 2.

[0063] The core of the feedback circuit 300 of this embodiment is the first voltage regulator U3, which works in conjunction with the photosensitive side U2A and the light-emitting side U2B of the second optocoupler switch tube, a group of resistors (R5 to R10) and the third capacitor C3 to form a complex signal processing and transmission network.

[0064] Specifically, the fifth resistor R5 and the seventh resistor R7 sample the output voltage signal of the output port 12 and transmit the sampled signal to a complex filtering, voltage division, and current shunting feedback network. When the output voltage of the output port 12 changes due to a change in the load, it will cause the current flowing through the light-emitting side U2B of the second optocoupler switch tube to change, and the current on the photosensitive side U2A of the second optocoupler switch tube will also change accordingly. The change signal is transmitted to pin 2 of the switch driver chip U4 through the tenth resistor R10. The switch driver chip U4 adjusts the control signal output from its pin 6 accordingly, thereby accurately controlling the on and off time of the fourth switch tube Q1, thereby stabilizing the output voltage of the output port 12.

[0065] This embodiment effectively isolates the high voltage environment and protects sensitive electronic components by using the photosensitive side U2A and the light-emitting side U2B of the second optocoupler switch tube. This isolated transmission ensures the safety and accuracy of the signal during the transmission process. The ninth resistor R9 and the third capacitor C3 together form a filtering link to further eliminate noise and stabilize the signal to ensure the quality of the feedback signal. Finally, these processed signals are sent back to the switch driver chip U4 and read through pin 2, thereby achieving precise control and stable regulation of the entire switching power supply system.

[0066] Optionally, the switching power supply protection circuit further includes a first rectifier module 13, a second rectifier module 14, a driver chip power supply module 16 and a voltage stabilizing module 15, wherein the input end of the first rectifier module 13 is connected to the primary side of the transducer isolation module 400, and the output end of the first rectifier module 13 is connected to the driver chip power supply module 16 and the switch drive circuit 100; the driver chip power supply module 16 is connected to the switch drive circuit 100, the input end of the second rectifier module 14 is connected to the secondary side of the transducer isolation module 400, and the output end of the second rectifier module 14 is connected to the secondary side of the transducer isolation module 400. The end is connected to the input end of the voltage stabilizing module 15; the voltage stabilizing module 15 is connected to the feedback circuit 300 and the output port 12, wherein the first rectifier module 13 is used to convert the alternating current output from the primary side of the energy conversion isolation module 400 into direct current, and the second rectifier module 14 is used to rectify the alternating current output from the secondary side of the energy conversion isolation module 400 into direct current again, the driving chip power supply module 16 is used to supply power to the switch driving circuit 100, and the voltage stabilizing module 15 is used to receive the direct current output from the second rectifier module 14, and perform voltage regulation and stabilization.

[0067] The switching power supply protection circuit of the present invention has multiple key modules, including a first rectifier module 13, a second rectifier module 14, a driver chip power supply module 16, and a voltage regulator module 15. These modules work together to ensure the stability and reliability of the entire power supply system. Starting from receiving a DC signal at the input port 11, the operation flow of the entire circuit is as follows:

[0068] The first rectifier module 13 mainly converts the alternating current output from the primary side of the energy conversion isolation module 400 into direct current (DC). The rectification process is completed by using diodes to provide stable DC power supply for the driver chip power supply module 16.

[0069] The driver chip power supply module 16 is used to receive the DC power output by the first rectifier module 13 and provide necessary power to the switch drive circuit 100 to ensure that the switch drive circuit 100 obtains the voltage and current for stable operation.

[0070] Under the control signal output from pin 6 of the switch driver chip U4, the switch driver circuit 100 adjusts the output frequency and duty cycle to control the on and off time of the fourth switch tube Q1 to drive the transducer isolation module 400 to meet the requirements of the next stage.

[0071] Under the high-frequency switch control of the switch drive circuit 100, the primary side of the transducer isolation module 400 converts the DC power from the input port 11 into AC power after isolation and transformation, which is output by the secondary side of the transducer isolation module 400 and then rectified into DC power by the second rectifier module 14.

[0072] The second rectifier module 14 receives the AC output of the transducer isolation module and converts it back into DC power, which is used for further power applications or additional processing.

[0073] The voltage stabilizing module 15 receives the DC power processed by the second rectifier module 14 and performs necessary voltage regulation and stabilization to provide a stable and reliable power supply to the feedback circuit 300 and the output port 12 .

[0074] This embodiment can provide the circuit with a pure, stable DC output. The use of the voltage stabilizing module 15, the feedback circuit 300, and the switch drive circuit 100 ensures precise control and adaptability of the output voltage regardless of whether the power supply load is stable or changing. The application of the first sampling circuit 210 and the second sampling circuit 220 can effectively monitor the output power. With the cooperation of the switch drive circuit 100 and the feedback circuit 300, the output power under overload conditions can be effectively managed and regulated, which not only ensures the continuous operation of the circuit system but also protects the equipment from potential damage caused by overload.

[0075] The above is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A switching power supply protection circuit, characterized in that: The invention comprises a switch driving circuit (100), a sampling circuit (200) and a feedback circuit (300), wherein the output end of the switch driving circuit (100) is connected to the sampling circuit (200), the output end of the sampling circuit (200) is connected to the feedback circuit (300), and the feedback circuit (300) is connected to the feedback end of the switch driving circuit (100), wherein: The switch drive circuit (100) is used to convert direct current into analog alternating current through high-frequency switching operation, the sampling circuit (200) is used to convert overload power at the output end of the switch drive circuit (100) into an overload signal, and the feedback circuit (300) is used to output the overload signal to the feedback end of the switch drive circuit (100).

2. A switching power supply protection circuit according to claim 1, characterized in that: The switching power supply protection circuit further comprises an energy conversion isolation module (400) and an output port (12); the sampling circuit (200) comprises a first sampling circuit (210) and a second sampling circuit (220); the first sampling circuit (210) is electrically connected to the second sampling circuit (220); the output end of the second sampling circuit (220) is connected to the feedback circuit (300); the output end of the switch drive circuit (100) is connected to the first sampling circuit (210); the first sampling circuit (210) and the switch drive circuit (100) are connected to the primary side of the energy conversion isolation module (400); the output port (12), the second sampling circuit (220) and the feedback circuit (300) are connected to the secondary side of the energy conversion isolation module (400); wherein: The energy conversion isolation module (400) is used to convert the input voltage into the voltage required by the output port (12); the first sampling circuit (210) is used to convert the overload power at the output end of the switch drive circuit (100) into an overload signal; and the second sampling circuit (220) is used to output the overload signal from the first sampling circuit (210) to the feedback circuit (300).

3. A switching power supply protection circuit according to claim 2, characterized in that: The first sampling circuit (210) comprises a first resistor R1, a sampling resistor RS, a first switch tube D1, and a primary isolation transmission switch tube, one end of the sampling resistor RS is connected to the output end of the switch drive circuit (100) and the anode of the first switch tube D1, the other end of the sampling resistor RS and one end of the primary isolation transmission switch tube are connected to the primary ground terminal PGND, the other end of the primary isolation transmission switch tube is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the cathode of the first switch tube D1. A first implementation of the second sampling circuit (220) includes a first sampling branch (221), a second resistor R2, and a secondary isolation transmission switch tube, namely, a photosensitive side U1A of a first optocoupler switch tube, wherein the input end of the first sampling branch (221) is connected to the secondary side of the energy conversion isolation module (400); the output end of the first sampling branch (221) is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the secondary isolation transmission switch tube, and the other end of the secondary isolation transmission switch tube is connected to the controlled end of the feedback circuit (300); the ground end of the first sampling branch (221) and the ground end of the feedback circuit (300) are commonly connected to the secondary ground end AGND, and the primary isolation transmission switch tube transmits the overload signal to the secondary isolation transmission switch tube.

4. A switching power supply protection circuit according to claim 3, characterized in that: The primary isolation transmission switch tube is the light-emitting side U1B of the first optocoupler switch tube or the primary winding CT1A of the current transformer, and the secondary isolation transmission switch tube is the photosensitive side U1A of the first optocoupler switch tube or the secondary winding CT1B of the current transformer.

5. A switching power supply protection circuit according to claim 4, characterized in that: A second implementation of the second sampling circuit (220) includes a second sampling branch (222), a second resistor R2 and a parallel capacitor thereof, a third resistor R3, a second switch tube Q2, and a secondary isolation transmission switch tube. The secondary isolation transmission switch tube, i.e., the secondary winding CT1B of the current transformer, is connected in parallel with the second resistor R2 and the parallel capacitor thereof, one end of which is connected to one end of the third resistor R3, and the other end of which is connected together with the ground end of the feedback circuit (300) to the secondary grounding terminal AGND. The other end of the third resistor R3 is connected to the control end of the second switch tube Q2, and the conduction end of the second switch tube Q2 is connected to the output end of the second sampling branch (222) and the controlled end of the feedback circuit (300).

6. A switching power supply protection circuit according to claim 5, characterized in that: The switching power supply protection circuit further includes an input port (11), the input port (11) including a fourth resistor R4, a second capacitor C2, and a third switch tube D2. After the fourth resistor R4 and the second capacitor C2 are connected in parallel, one end of the fourth resistor R4 is connected to the input voltage and the primary side of the energy conversion isolation module (400), and the other end is connected to the cathode of the third switch tube D2. The anode of the third switch tube D2 is connected to the primary side of the energy conversion isolation module (400).

7. A switching power supply protection circuit according to claim 6, characterized in that: The switch drive circuit (100) comprises a fourth switch tube Q1 and a switch drive chip U4, wherein the switch drive chip U4 comprises a pin 6, wherein the pin 6 is connected to the control end of the fourth switch tube Q1; the conduction end of the fourth switch tube Q1 is connected to the anode of the third switch tube D2 and the sampling resistor RS; and the switch drive chip U4 controls the on / off of the fourth switch tube Q1 via the pin 6.

8. The switching power supply protection circuit according to claim 7, characterized in that: The feedback circuit (300) includes a photosensitive side U2A and a light-emitting side U2B of a second optocoupler switch tube, a first voltage regulator U3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and a third capacitor C3. The switch driver chip U4 also includes a pin 2, and the switch driver chip U4 receives an overload signal of the feedback circuit (300) through the pin 2. One end of the fifth resistor R5 and the seventh resistor R7 are connected to the output port (12), and the other end of the fifth resistor R5 is connected to one end of the third capacitor C3, the controlled end of the first voltage regulator U3, and the One end of the sixth resistor R6; the other end of the sixth resistor R6 and the ground end of the first voltage regulator U3 are commonly connected to the secondary ground terminal AGND; the output end of the first voltage regulator U3 is connected to one end of the ninth resistor R9, one end of the eighth resistor R8 and one end of the light-emitting side U2B of the second optocoupler switch tube; the other end of the ninth resistor R9 is connected to the other end of the third capacitor C3; the other end of the seventh resistor R7 is connected to the other end of the eighth resistor R8 and the other end of the light-emitting side U2B of the second optocoupler switch tube; the photosensitivity side U2A of the second optocoupler switch tube is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected to pin 2.

9. The switching power supply protection circuit according to claim 8, characterized in that: The switching power supply protection circuit further comprises a first rectifier module (13), a second rectifier module (14), a driver chip power supply module (16) and a voltage stabilizing module (15), wherein the input end of the first rectifier module (13) is connected to the primary side of the energy conversion isolation module (400), and the output end of the first rectifier module (13) is connected to the driver chip power supply module (16) and the switch drive circuit (100); the driver chip power supply module (16) is connected to the switch drive circuit (100), the input end of the second rectifier module (14) is connected to the secondary side of the energy conversion isolation module (400), and the output end of the second rectifier module (14) is connected to the secondary side of the energy conversion isolation module (400). The output end is connected to the input end of the voltage stabilizing module (15); the voltage stabilizing module (15) is connected to the feedback circuit (300) and the output port (12), wherein the first rectifier module (13) is used to convert the alternating current output from the primary side of the energy conversion isolation module (400) into direct current, the second rectifier module (14) is used to rectify the alternating current output from the secondary side of the energy conversion isolation module (400) into direct current again, the driver chip power supply module (16) is used to supply power to the switch drive circuit (100), and the voltage stabilizing module (15) is used to receive the direct current output from the second rectifier module (14) and perform voltage regulation and stabilization.

10. An application device, characterized in that: The invention comprises a switching power supply protection circuit as described in any one of claims 1 to 9.

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