Isolated return difference-adjustable output overvoltage protection circuit and power supply system

Abstract

The utility model discloses an isolated return difference-adjustable output overvoltage protection circuit and a power supply system. According to the output overvoltage protection circuit, one end of a first acquisition module is connected with an output voltage end, the other end is grounded, and the first acquisition module is used for acquiring output voltage; one end of the second acquisition module is connected with the reference voltage end, the other end is grounded, and the second acquisition module is used for acquiring reference voltage; the inverting input end of the comparison module is connected with the first acquisition module, and the non-inverting input end of the comparison module is connected with the second acquisition module; the first end of the return difference adjusting module is connected with the in-phase input end of the comparison module, and the second end is connected with the output end of the comparison module; the optocoupler isolation module is connected with the output end of the comparison module. According to the technical scheme, the overvoltage protection circuit can be effectively simplified, the reliability of the circuit is improved, the circuit is easy to maintain, meanwhile, the space occupied by elements on a circuit board is reduced, the integration degree is improved, and miniaturization design is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, specifically to an isolated adjustable hysteresis output overvoltage protection circuit and power supply system. Background Technology

[0002] In communication power supply applications, the performance of output overvoltage protection circuits is crucial. With the rapid development of the communication industry, communication power supplies are constantly evolving towards higher power density and higher efficiency, which places increasingly stringent requirements on output overvoltage protection circuits.

[0003] Conventional output overvoltage protection circuits employ multiple independent functional modules, resulting in a complex overall circuit structure. This complexity not only increases the difficulty of circuit design and debugging but also reduces circuit reliability, as more components and connection points mean a higher risk of failure. Consequently, in actual production and maintenance, technicians need to spend more time and effort troubleshooting and resolving circuit faults.

[0004] Moreover, the numerous components and complex wiring structure mean that conventional output overvoltage protection circuits require a significant amount of space on the printed circuit board (PCB). With the trend of pursuing high power density in communication power supplies, PCB space has become increasingly precious. Such space-consuming overvoltage protection circuits severely limit the integration and miniaturization of power supply systems, failing to meet the increasingly compact device layout requirements. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides an isolated adjustable hysteresis output overvoltage protection circuit that effectively simplifies the overvoltage protection circuit, improves the reliability of the circuit, makes it easier to maintain, reduces the space occupied by components on the circuit board, improves integration, and facilitates miniaturization design.

[0006] This application provides an isolated adjustable hysteresis output overvoltage protection circuit, the output overvoltage protection circuit comprising:

[0007] The first acquisition module has one end connected to the output voltage terminal and the other end grounded. The first acquisition module is used to acquire the output voltage.

[0008] The second acquisition module has one end connected to the reference voltage terminal and the other end grounded. The second acquisition module is used to acquire the reference voltage.

[0009] A comparison module, wherein the inverting input terminal of the comparison module is connected to the first acquisition module, and the non-inverting input terminal of the comparison module is connected to the second acquisition module;

[0010] A hysteresis adjustment module, wherein the first end of the hysteresis adjustment module is connected to the non-inverting input of the comparison module, and the second end is connected to the output of the comparison module;

[0011] An optocoupler isolation module is connected to the output terminal of the comparator module;

[0012] When the voltage at the inverting input terminal of the comparator module is greater than the voltage at the non-inverting input terminal, the output terminal of the comparator module provides a low level, the potential at the second terminal of the hysteresis adjustment module decreases, and the current of the hysteresis adjustment module flows from the first terminal to the second terminal, pulling down the voltage at the non-inverting input terminal of the comparator module to increase the time the output terminal of the comparator module provides a low level, while simultaneously increasing the current of the light-emitting diode in the optocoupler.

[0013] In one aspect, the first acquisition module includes a first voltage divider resistor and a second voltage divider resistor, one end of the first voltage divider resistor is connected to the output voltage terminal, the other end of the first voltage divider resistor is connected to one end of the second voltage divider resistor, the other end of the second voltage divider resistor is grounded, and the inverting input terminal of the comparison module is connected to the line between the first voltage divider resistor and the second voltage divider resistor.

[0014] In one aspect, the first acquisition module further includes a first voltage-stabilizing capacitor, one end of which is connected to the line between the first voltage divider resistor and the second voltage divider resistor, and the other end of which is grounded.

[0015] In one aspect, the second acquisition module includes a third voltage divider resistor and a fourth voltage divider resistor. One end of the third voltage divider resistor is connected to the reference voltage terminal, and the other end of the third voltage divider resistor is connected to one end of the fourth voltage divider resistor. The other end of the fourth voltage divider resistor is grounded, and the non-inverting input terminal of the comparison module is connected to the line between the third voltage divider resistor and the fourth voltage divider resistor.

[0016] In one aspect, the second acquisition module further includes a second voltage-stabilizing capacitor, one end of which is connected to the line between the third voltage-dividing resistor and the fourth voltage-dividing resistor, and the other end of which is grounded.

[0017] In one aspect, the hysteresis adjustment module includes a first diode and a fifth voltage divider resistor. One end of the fifth voltage divider resistor is connected between the third and fourth voltage divider resistors and the non-inverting input of the comparator module. The other end of the fifth voltage divider resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the output of the comparator module.

[0018] In one aspect, the output overvoltage protection circuit further includes a second diode disposed in the line between the optocoupler isolation module and the comparator module, the anode of the second diode being connected to the optocoupler isolation module and the cathode of the second diode being connected to the output terminal of the comparator.

[0019] In one aspect, the optocoupler isolation module includes an optocoupler, a pulse width controlled current mirror network, and a secondary-side feedback network, wherein the collector of the optocoupler is connected to an auxiliary power supply.

[0020] The optocoupler includes a light-emitting element and a light-receiving element. The pulse width controlled current mirror network is connected to the emitter of the light-receiving element. The pulse width controlled current mirror network is used to receive the signal transmitted by the optocoupler. The secondary-side feedback network is connected to the cathode of the light-emitting element. The anode of the second diode is connected between the cathode of the light-emitting element and the secondary-side feedback network.

[0021] In one aspect, the optocoupler isolation module further includes a current-limiting resistor, one end of which is connected to the reference voltage terminal and the other end of which is connected to the anode of the light-emitting element of the optocoupler.

[0022] In addition, to solve the above problems, this application also provides a power supply system, which includes the output overvoltage protection circuit as described above.

[0023] The beneficial effects of this invention are reflected in the following aspects: By integrating voltage acquisition, comparison, hysteresis adjustment, and feedback control functions into a circuit composed of a first acquisition module, a second acquisition module, a comparison module, a hysteresis adjustment module, and an optocoupler isolation module, the signal transmission path and intermediate links are simplified through the collaboration between the hysteresis adjustment module and the comparison module, and by using the output signal control of the comparison module. The close cooperation of each module reduces unnecessary connection nodes and line crossings, resulting in a simpler circuit layout. The simplified circuit structure makes the connections between components more robust, reducing faults caused by loose connections or poor soldering. The simple circuit structure makes troubleshooting easier. The reduced number of components occupies less space on the printed circuit board. This space saving allows for the integration of more functional modules onto a single circuit board, improving the integration of the power supply system and meeting the needs of miniaturization design. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0025] Figure 1 This is a schematic diagram of the component connections for the overvoltage protection circuit of this application.

[0026] Figure Descriptions: 100, First acquisition module; 200, Second acquisition module; 300, Comparison module; 400, Hysteresis adjustment module; 500, Optocoupler isolation module; Vo+, Output voltage terminal; VSCC, Reference voltage terminal; VREF, Auxiliary power supply; N1, Comparator; N2, Optocoupler; 510, Pulse width control current mirror network; 520, Secondary-side feedback network; 501, Light-emitting element; 502, Light-receiving element;

[0027] R1, first voltage divider resistor; R2, second voltage divider resistor; R3, third voltage divider resistor; R4, fourth voltage divider resistor; R5, fifth voltage divider resistor; R6, current limiting resistor; VD1, first diode; VD2, second diode; C1, first voltage stabilizing capacitor; C2, second voltage stabilizing capacitor. Detailed Implementation

[0028] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0029] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0030] See Figure 1 As shown, this application provides an output overvoltage protection circuit, which includes: a first acquisition module 100, a second acquisition module 200, a comparison module 300, a hysteresis adjustment module 400, and an optocoupler isolation module 500.

[0031] One end of the first acquisition module 100 is connected to the output voltage terminal Vo+, and the other end is grounded. The first acquisition module 100 is used to acquire the output voltage. This connection method allows the first acquisition module 100 to directly and proportionally acquire the output voltage signal. In the entire overvoltage protection circuit, the output voltage is a key parameter that needs to be monitored in real time. The first acquisition module 100 acquires the output voltage and transmits it to the subsequent comparison module 300 for comparison with a reference voltage to determine whether the output voltage exceeds the safe range. For example, in a switching power supply circuit, the output voltage may change due to factors such as load changes and input voltage fluctuations. The first acquisition module 100 can capture these changes in real time and transmit the proportionally scaled voltage value to the comparison module 300.

[0032] The second acquisition module 200 is connected at one end to the reference voltage terminal VSCC and at the other end to ground. The second acquisition module 200 is used to acquire the reference voltage; the reference voltage is typically a stable reference voltage provided by a dedicated voltage reference source. The function of the second acquisition module 200 is to acquire a proportionally scaled reference voltage. The reference voltage is a pre-set standard value representing the safe upper limit of the output voltage. The second acquisition module 200 transmits the acquired reference voltage to the non-inverting input terminal of the comparison module 300 as a reference for comparison. For example, in a power supply circuit designed to output 5V, a 5.5V overvoltage protection voltage might be set. When the output voltage exceeds 5.5V, the overvoltage protection mechanism needs to be triggered. The overvoltage protection voltage can be adjusted as needed.

[0033] The inverting input of the comparator module 300 is connected to the first acquisition module 100, and the non-inverting input is connected to the second acquisition module 200. The comparator module 300 primarily compares the input proportionally scaled output voltage with the proportionally scaled reference voltage. When the voltage at the inverting input (i.e., the output voltage) is greater than the voltage at the non-inverting input (the preset comparison voltage), the output of the comparator module 300 will provide a low level. This is the overvoltage protection trigger signal, indicating that the output voltage has exceeded the safety threshold and appropriate protective measures need to be taken. The comparator module 300 mainly includes comparator N1.

[0034] The first terminal of the hysteresis adjustment module 400 is connected to the non-inverting input terminal of the comparator module 300, and the second terminal is connected to the output terminal of the comparator module 300. When the comparator module 300 determines that the output voltage exceeds the overvoltage protection point and provides a low level at its output terminal, the hysteresis adjustment module 400 begins to function. At this time, the potential at the second terminal of the hysteresis adjustment module 400 decreases, and current flows from the first terminal to the second terminal. Since the first terminal is connected to the non-inverting input terminal of the comparator module 300, the current flow will lower the voltage at the non-inverting input terminal of the comparator module 300. The purpose of this is to increase the time that the comparator module 300 provides a low level at its output terminal, that is, to increase the duration of the overvoltage protection signal, and to avoid frequent operation of the protection circuit when the output voltage fluctuates near the overvoltage protection point. The hysteresis adjustment module 400 can make the protection circuit more stable and reliable, and reduce the possibility of false triggering.

[0035] The optocoupler isolation module 500 is connected to the output of the comparator module 300. The main function of the optocoupler isolation module 500 is to achieve electrical isolation and signal feedback. When the comparator module 300 outputs a low level, the current to the LED in the optocoupler isolation module 500 increases. Simultaneously, due to the hysteresis adjustment module 400, the time for current to flow to the comparator module 300 is also increased. The optocoupler N2, as an isolation element, can isolate the output signal from the input signal.

[0036] It should be noted that when the voltage at the inverting input terminal of the comparator module 300 is greater than the voltage at the non-inverting input terminal, the output terminal of the comparator module 300 provides a low level, the potential at the second terminal of the hysteresis adjustment module 400 decreases, and the current of the hysteresis adjustment module 400 flows from the first terminal to the second terminal, pulling down the voltage at the non-inverting input terminal of the comparator module 300. This increases the time for the output terminal of the comparator module 300 to provide a low level, and at the same time increases the current flowing from the optocoupler isolation module 500 to the comparator module 300, thereby extending the overvoltage protection state, even if the output voltage is already lower than the standard voltage at this time.

[0037] Existing conventional output overvoltage protection circuits employ multiple independent functional modules, typically requiring separate optocouplers for isolation, resulting in a complex structure. This embodiment integrates output overvoltage acquisition, comparison, hysteresis adjustment, and feedback control functions into a circuit comprised of a first acquisition module 100, a second acquisition module 200, a comparison module 300, a hysteresis adjustment module 400, and an optocoupler isolation module 500. It cleverly integrates the output voltage negative feedback optocoupler with the overvoltage protection optocoupler. In traditional circuits, overvoltage comparison signal transmission usually requires a separate optocoupler, leading to a complex structure. However, this embodiment's circuit, through the collaboration of the hysteresis adjustment module 400 and the comparison module 300, directly utilizes the output signal of the comparison module 300 to control the optocoupler isolation module 500, simplifying the signal transmission path and intermediate steps.

[0038] In terms of connectivity, the modules work closely together, avoiding the complex wiring found in traditional circuits. Moreover, by reducing the number of components and the complex wiring structure, the simplified circuit structure results in more robust connections between components, reducing malfunctions caused by loose connections or poor soldering.

[0039] Furthermore, the simple circuit structure makes troubleshooting easier for technicians. Compared to traditional complex circuits where determining the fault point may require checking multiple functional modules one by one, which is time-consuming and labor-intensive, the circuit modules in this application are clearly divided. If a fault occurs, the faulty module can be quickly located by checking the input and output signals of each module. If the output of the comparison module 300 is abnormal, it is possible to directly check whether the input signals of the first acquisition module 100 and the second acquisition module 200 are normal, and whether the hysteresis adjustment module 400 affects the operation of the comparison module 300.

[0040] The reduction in the number of components not only lowers procurement costs but also reduces the types and quantities of components that need to be replaced during maintenance. Furthermore, the increased circuit reliability and reduced maintenance frequency further save on maintenance costs.

[0041] By simplifying the circuit structure, the number of required components is reduced, and the space occupied on the printed circuit board (PCB) is correspondingly reduced. The circuit can be more compactly arranged, leaving more space for other circuit modules. In the PCB design of power systems, space savings facilitate the integration of more functional modules onto a single board, improving the overall integration of the power system. Utilizing the circuit's space-saving characteristics allows it to better adapt to this trend and meet the demands of miniaturization design. In some distributed power applications with stringent size requirements, such as small base station power modules, this circuit can effectively reduce the size of the power module, improving the overall miniaturization of the device.

[0042] In one embodiment of this application, the first acquisition module 100 includes a first voltage divider resistor R1 and a second voltage divider resistor R2. One end of the first voltage divider resistor R1 is connected to the output voltage terminal Vo+, and the other end of the first voltage divider resistor R1 is connected to one end of the second voltage divider resistor R2. The other end of the second voltage divider resistor R2 is grounded. The inverting input terminal of the comparison module 300 is connected to the line between the first voltage divider resistor R1 and the second voltage divider resistor R2. The first acquisition module 100 uses a voltage divider circuit to acquire the output voltage. The first voltage divider resistor R1 and the second voltage divider resistor R2 form a series voltage divider structure, and the output voltage is applied across the two resistors connected in series. According to the principle of series resistor voltage division, in a series circuit, the voltage across each resistor is proportional to its resistance value. Therefore, the first voltage divider resistor R1 and the second voltage divider resistor R2 will divide the output voltage according to the ratio of their own resistance values. The inverting input terminal of the comparison module 300 is connected to the line between the two resistors, and the obtained value is the output voltage sample value after voltage division. This converts a potentially high output voltage into a voltage value suitable for the input range of the comparator module 300 according to a certain ratio, making it easier to compare with a proportionally reduced reference voltage, thereby determining whether the output voltage is overvoltage.

[0043] In one embodiment of this application, the first acquisition module 100 further includes a first voltage-stabilizing capacitor C1. One end of the first voltage-stabilizing capacitor C1 is connected to the line between the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2, and the other end of the first voltage-stabilizing capacitor C1 is grounded. In actual circuit environments, the output voltage may be affected by various high-frequency noises, which may be generated by other nearby electronic devices, power supply noise, etc. One end of the first voltage-stabilizing capacitor C1 is connected to the sampling line between the first voltage-dividing resistor R1 and the second voltage-dividing resistor R2, and the other end is grounded. Utilizing the characteristic of a capacitor to "pass AC and block DC," high-frequency noises are bypassed and filtered. High-frequency noises can flow to ground through the capacitor without affecting the transmission of the sampled voltage to the comparison module 300, ensuring that the sampled voltage transmitted to the inverting input terminal of the comparison module 300 is stable and reliable, avoiding misjudgment by the comparison module 300 due to noise interference, and thus improving the anti-interference capability of the entire overvoltage protection circuit.

[0044] The first voltage-regulating capacitor C1 stabilizes the sampling voltage. During circuit operation, changes in load or fluctuations in the power supply itself may cause momentary fluctuations in the output voltage. The first voltage-regulating capacitor C1 can store and release charge, and it can respond quickly when the sampling voltage fluctuates. If the sampling voltage rises, the capacitor charges, absorbing some charge and suppressing the voltage rise; if the sampling voltage drops, the capacitor discharges, replenishing charge and maintaining voltage stability. In this way, the sampling voltage is stabilized, ensuring that the comparator module 300 can accurately compare the sampling voltage with the reference voltage, thus improving the accuracy of overvoltage protection.

[0045] In one embodiment of this application, the second acquisition module 200 includes a third voltage divider resistor R3 and a fourth voltage divider resistor R4. One end of the third voltage divider resistor R3 is connected to the reference voltage terminal VSCC, and the other end of the third voltage divider resistor R3 is connected to one end of the fourth voltage divider resistor R4. The other end of the fourth voltage divider resistor R4 is grounded. The non-inverting input terminal of the comparison module 300 is connected to the line between the third voltage divider resistor R3 and the fourth voltage divider resistor R4. The third voltage divider resistor R3 and the fourth voltage divider resistor R4 are connected in series between the reference voltage terminal VSCC and ground, forming a voltage divider circuit. The non-inverting input terminal of the comparison module 300 is connected between them, and the sampled value of the reference voltage after voltage division is obtained. Through this voltage division method, the reference voltage can be adjusted to a suitable amplitude, which facilitates accurate comparison with the output voltage after voltage division by the first acquisition module 100 in the comparison module 300. In addition, by reasonably selecting the resistance values ​​of the third voltage divider resistor R3 and the fourth voltage divider resistor R4, the voltage at the non-inverting input terminal of the comparison module 300 can accurately represent a preset threshold. When the output voltage sample value transmitted by the first acquisition module 100 is compared with it, if the output voltage sample value exceeds the preset threshold, the comparison module 300 can react in time and output a corresponding signal to trigger the overvoltage protection mechanism to ensure the safe operation of the circuit.

[0046] In one embodiment of this application, the second acquisition module 200 further includes a second voltage-stabilizing capacitor C2. One end of the second voltage-stabilizing capacitor C2 is connected to the line between the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4, and the other end of the second voltage-stabilizing capacitor C2 is grounded. The working principle of the second voltage-stabilizing capacitor C2 is the same as that of the first voltage-stabilizing capacitor C1. The second voltage-stabilizing capacitor C2 is connected between the line between the third voltage-dividing resistor R3 and the fourth voltage-dividing resistor R4 and ground, using the characteristics of a capacitor to stabilize the voltage. When the reference voltage fluctuates, if the voltage rises, the capacitor stores charge to suppress the voltage rise; if the voltage falls, the capacitor releases charge to compensate for the voltage drop. This ensures that the reference voltage sampling signal transmitted to the non-inverting input terminal of the comparison module 300 is more stable, reduces the comparison error caused by reference voltage fluctuations, and enables the overvoltage protection circuit to more accurately determine whether the output voltage is overvoltage. It also enhances the anti-interference capability of the entire second acquisition module 200 and the overvoltage protection circuit, improves the reliability and stability of the circuit, avoids misjudgment due to interference, and ensures that the overvoltage protection function is accurate and effective.

[0047] In one embodiment of this application, the hysteresis adjustment module 400 includes a first diode VD1 and a fifth voltage divider resistor R5. One end of the fifth voltage divider resistor R5 is connected between the third voltage divider resistor R3 and the fourth voltage divider resistor R4, and to the non-inverting input terminal of the comparison module 300. The other end of the fifth voltage divider resistor R5 is connected to the anode of the first diode VD1, and the cathode of the first diode VD1 is connected to the output terminal of the comparison module 300. In a non-overvoltage state, the output terminal of the comparison module 300 is at a high level. Because the cathode of the first diode VD1 is connected to the output terminal of the comparison module 300, and the anode is connected to the fifth voltage divider resistor R5, the first diode VD1 is in a reverse bias state, equivalent to an open circuit. Therefore, the fifth voltage divider resistor R5 has virtually no impact on the reference voltage acquired by the second acquisition module 200. The voltage at the non-inverting input terminal of the comparison module 300 is the reference voltage after being divided by the third voltage divider resistor R3 and the fourth voltage divider resistor R4. The comparison module 300 compares this reference voltage with the output voltage acquired by the first acquisition module 100.

[0048] When the output voltage is too high, and the output voltage acquired by the first acquisition module 100 is greater than the reference voltage, the output of the comparator module 300 becomes low. At this time, the first diode VD1 becomes forward biased and is in a conducting state. Current will flow from one end of the fifth voltage divider resistor R5 (the line connecting the third voltage divider resistor R3 and the fourth voltage divider resistor R4), through the fifth voltage divider resistor R5 and the conducting first diode VD1, to the output of the comparator module 300. At this time, it is equivalent to the hysteresis module 400 being connected to the fourth voltage divider R4, thereby pulling down the voltage at the non-inverting terminal of the comparator module 300. This voltage drop allows the comparator module 300 to output a low potential for a longer period of time, even if the output voltage is far below the overvoltage protection point.

[0049] When the output voltage drops, because the voltage at the non-inverting input of the comparator module 300 has already been pulled low, the output voltage needs to drop to a value lower than the original reference voltage before the output of the comparator module 300 will change from low to high. This phenomenon, where the voltage values ​​triggering the change in the output state of the comparator module 300 differ when the output voltage rises and falls, is called hysteresis. The existence of hysteresis can prevent the output of the comparator module 300 from frequently switching between high and low levels when the output voltage fluctuates near the reference voltage, thereby preventing frequent activation of the protection circuit and enhancing the stability and reliability of the circuit.

[0050] In summary, the hysteresis adjustment module 400 achieves the hysteresis function through the cooperation of the first diode VD1 and the fifth voltage divider resistor R5, effectively improving the performance of the overvoltage protection circuit.

[0051] In one embodiment of this application, the output overvoltage protection circuit further includes a second diode VD2. The second diode VD2 is disposed in the line between the optocoupler isolation module 500 and the comparator module 300. The anode of the second diode VD2 is connected to the optocoupler isolation module 500, and the cathode of the second diode VD2 is connected to the output terminal of the comparator N1. The unidirectional conductivity of the second diode VD2 determines that current can only flow from its positive terminal to its negative terminal. During normal circuit operation, when the comparator module 300 outputs a high level, since the negative terminal of the second diode VD2 is connected to the output terminal of the comparator module 300, the diode is in a reverse cutoff state, preventing current from flowing back into the comparator module 300 from the optocoupler isolation module 500. This ensures that the optocoupler isolation module 500 is not affected by the high-level output state of the comparator module 300. Only when there is an output overvoltage will the comparator module 300 be triggered to output a low potential to take over the working state of the optocoupler N2, causing it to exit the normal negative feedback working mode, thereby reliably realizing the overvoltage protection function and ensuring the logical correctness of the overvoltage protection circuit.

[0052] When the output voltage reaches the overvoltage protection threshold, the comparator module 300 outputs a low level, and the second diode VD2 is forward-biased. At this time, the optocoupler isolation module 500 can work in conjunction with the comparator module 300. The current in the optocoupler isolation module 500 can flow to the comparator module 300 through the conducting second diode VD2, realizing the feedback regulation effect of the optocoupler N2 on the comparator module 300. Under overvoltage conditions, the optocoupler isolation module 500 increases the current flowing through the light-emitting diode of the optocoupler, which is basically determined by the value of R6 and the supply voltage. At the same time, the hysteresis adjustment module 400 will lower the voltage at the non-inverting terminal of the comparator module 300, thereby further extending the duration of the overvoltage protection signal.

[0053] The second diode VD2 acts as a signal isolation barrier, allowing forward current conforming to the overvoltage protection logic to pass through. Its function is to prevent the high level output of the comparator module 300 from affecting the normal operation of the secondary feedback network when there is no overvoltage protection. It plays the role of isolating the high potential output of the overvoltage protection. Only when the comparator module 300 outputs a low potential can the signal of the overvoltage protection circuit be effectively transmitted through VD2.

[0054] In one embodiment of this application, the optocoupler isolation module 500 includes an optocoupler N2, a pulse width controlled current mirror network 510, and a secondary side feedback network 520.

[0055] In one embodiment of this application, the optocoupler isolation module 500 further includes a current-limiting resistor R6. One end of the current-limiting resistor R6 is connected to the reference voltage terminal VSCC, and the other end is connected to the anode of the light-emitting element 501 of the optocoupler N2. The light-emitting element 501 of the optocoupler N2 is usually sensitive to current. If the current passing through it is too large, it may damage the light-emitting element 501, affecting the normal operation of the optocoupler N2 or even causing it to fail. The current-limiting resistor R6 is connected in series between the reference voltage terminal VSCC and the anode of the light-emitting element 501 of the optocoupler N2, which can limit the current flowing into the light-emitting element 501. When the comparator module 400 outputs a low potential, the current-limiting resistor R6 will limit the current according to its own resistance value. The resistance value of the current-limiting resistor R6 cannot be too small, otherwise the current on the light-emitting side of the optocoupler will be too large, nor can it be too large, otherwise it will not be able to effectively enter the overvoltage protection mode. By setting the value of R6, the current of the light-emitting element 501 is kept within its safe operating range, thereby effectively protecting the light-emitting element 501, extending the service life of the optocoupler N2, and also achieving the function of overvoltage protection.

[0056] This application also provides a power supply system including the aforementioned output overvoltage protection circuit. The power supply system typically consists of multiple distributed power supply units, and the output voltage of each unit may fluctuate due to load changes, environmental factors, etc. The output overvoltage protection circuit can monitor the output voltage of each unit in real time, and quickly activate the protection mechanism once an overvoltage condition is detected. The output overvoltage protection circuit has a compact structure, providing necessary support for achieving high power density. Its high integration means it occupies little space in the power supply system, facilitating system integration design. Moreover, its relatively simple structure and fewer components reduce system costs. By reducing equipment damage and maintenance costs caused by overvoltage problems, the system's economic efficiency is further improved.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An isolated adjustable backoff output overvoltage protection circuit, characterized by, The output overvoltage protection circuit includes: The first acquisition module has one end connected to the output voltage terminal and the other end grounded. The first acquisition module is used to acquire the output voltage. The second acquisition module has one end connected to the reference voltage terminal and the other end grounded. The second acquisition module is used to acquire the reference voltage. A comparison module, wherein the inverting input terminal of the comparison module is connected to the first acquisition module, and the non-inverting input terminal of the comparison module is connected to the second acquisition module; A hysteresis adjustment module, wherein the first end of the hysteresis adjustment module is connected to the non-inverting input of the comparison module, and the second end is connected to the output of the comparison module; An optocoupler isolation module is connected to the output terminal of the comparator module; When the voltage at the inverting input terminal of the comparator module is greater than the voltage at the non-inverting input terminal, the output terminal of the comparator module provides a low level, the potential at the second terminal of the hysteresis adjustment module decreases, and the current of the hysteresis adjustment module flows from the first terminal to the second terminal, pulling down the voltage at the non-inverting input terminal of the comparator module to increase the time the output terminal of the comparator module provides a low level, while simultaneously increasing the current of the light-emitting diode in the optocoupler.

2. The output overvoltage protection circuit of claim 1, wherein The first acquisition module includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to the output voltage terminal, and the other end of the first voltage divider resistor is connected to one end of the second voltage divider resistor. The other end of the second voltage divider resistor is grounded. The inverting input terminal of the comparison module is connected to the line between the first voltage divider resistor and the second voltage divider resistor.

3. The output overvoltage protection circuit of claim 2, wherein, The first acquisition module further includes a first voltage-stabilizing capacitor, one end of which is connected to the line between the first voltage divider resistor and the second voltage divider resistor, and the other end of which is grounded.

4. The output overvoltage protection circuit of claim 1, wherein The second acquisition module includes a third voltage divider resistor and a fourth voltage divider resistor. One end of the third voltage divider resistor is connected to the reference voltage terminal, and the other end of the third voltage divider resistor is connected to one end of the fourth voltage divider resistor. The other end of the fourth voltage divider resistor is grounded. The non-inverting input terminal of the comparison module is connected to the line between the third voltage divider resistor and the fourth voltage divider resistor.

5. The output overvoltage protection circuit of claim 4, wherein, The second acquisition module also includes a second voltage-stabilizing capacitor. One end of the second voltage-stabilizing capacitor is connected to the line between the third voltage-dividing resistor and the fourth voltage-dividing resistor, and the other end of the second voltage-stabilizing capacitor is grounded.

6. The output overvoltage protection circuit of claim 4, wherein, The hysteresis adjustment module includes a first diode and a fifth voltage divider resistor. One end of the fifth voltage divider resistor is connected between the third and fourth voltage divider resistors and the non-inverting input terminal of the comparator module. The other end of the fifth voltage divider resistor is connected to the positive terminal of the first diode, and the negative terminal of the first diode is connected to the output terminal of the comparator module.

7. The output overvoltage protection circuit according to any one of claims 1 to 6, characterized in that, The output overvoltage protection circuit also includes a second diode, which is disposed in the line between the optocoupler isolation module and the comparator module. The positive terminal of the second diode is connected to the optocoupler isolation module, and the negative terminal of the second diode is connected to the output terminal of the comparator module.

8. The output overvoltage protection circuit of claim 7, wherein, The optocoupler isolation module comprises an optocoupler, a pulse width control current mirror network and a secondary side feedback network, a collector of the optocoupler is connected with an auxiliary power supply; The optocoupler comprises a light emitting element and a light receiving element, the pulse width control current mirror network is connected with an emitter of the light receiving element, the pulse width control current mirror network is used for receiving a signal transmitted by the optocoupler, the secondary side feedback network is connected with a cathode of the light emitting element, and a positive electrode of the second diode is connected between the cathode of the light emitting element and the secondary side feedback network.

9. The output overvoltage protection circuit of claim 8, wherein, The optocoupler isolation module further comprises a current limiting resistor, one end of the current limiting resistor is connected with the reference voltage end, and the other end of the current limiting resistor is connected with an anode of the light emitting element of the optocoupler. 10.A power supply system, comprising the output overvoltage protection circuit according to any one of claims 1 to 9.

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