Short-circuit protection circuit and method suitable for wide-range input auxiliary power supply

Abstract

The invention relates to a short-circuit protection circuit and method suitable for a wide-range input auxiliary power supply. The circuit comprises an AC input and fuse circuit, an EMI filter circuit, a rectification filter circuit, an RCD absorption circuit, a transformer, an output rectification filter circuit, a driving and switching tube, a power management chip, a power management chip power supply circuit, a short circuit protection circuit and a feedback circuit. The alternating current input and fuse circuit is connected with the EMI filter circuit, and the alternating current input and fuse circuit is used for receiving an external input power supply and protecting the circuit from being influenced by a power supply fault or overload; the EMI filter circuit is connected with the rectification filter circuit, and the EMI filter circuit is used for reducing electromagnetic interference in an input power supply and ensuring the stability of a power supply signal; omnibearing protection of the auxiliary power supply can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of protection circuits, and in particular to a short-circuit protection circuit and method for auxiliary power supply with wide input range. Background Art

[0002] At present, the traditional auxiliary power supply design mainly focuses on voltage regulation and efficiency, while the research on short-circuit protection is relatively insufficient. Existing short-circuit protection schemes often only consider a single protection mechanism, such as overcurrent protection or thermal protection, and fail to build a complete protection system. Especially under wide-range input conditions, the existing short-circuit protection method may not be able to adapt to different input voltages and load conditions, resulting in unstable protection effects, or even complete failure in some cases. Existing short-circuit protection schemes have obvious deficiencies in response speed, sensitivity, and reliability. When the auxiliary power supply output is short-circuited or the circuit components are damaged and short-circuited, if the protection mechanism cannot respond quickly and effectively, it may cause the power management chip to continue to work in an abnormal state, eventually causing damage to the circuit components and even causing safety hazards. It is of great significance to study a method for auxiliary power supply short-circuit protection under wide-range input conditions, build a complete protection mechanism, and improve the response speed and reliability of short-circuit protection, which is of great significance to improving the safety and stability of electronic equipment. Summary of the invention

[0003] The main purpose of the present invention is to provide a short-circuit protection circuit and method for auxiliary power supply with wide input range, which can realize all-round protection of the auxiliary power supply and significantly improve the reliability and safety of the circuit.

[0004] To achieve the above object, the present invention provides a short-circuit protection circuit for auxiliary power supply with wide input range, comprising: AC input and fuse circuit, EMI filter circuit, rectifier filter circuit, RCD absorption circuit, transformer, output rectifier filter circuit, driver and switch tube, power management chip, power management chip power supply circuit, short circuit protection circuit and feedback circuit; The AC input and fuse circuit is connected to the EMI filter circuit, and the AC input and fuse circuit is used to receive external input power and protect the circuit from power failure or overload; The EMI filter circuit is connected to the rectifier filter circuit, and the EMI filter circuit is used to reduce electromagnetic interference in the input power supply to ensure the stability of the power supply signal; The rectifier and filter circuit is connected to the RCD absorption circuit, and the rectifier and filter circuit converts the AC power supply into a DC power supply, provides it to the subsequent circuit, and converts the AC fluctuation into a smooth DC output; The RCD absorption circuit is connected to the transformer, and the RCD absorption circuit is used to suppress high-frequency noise and overvoltage to ensure stable operation of the transformer; The transformer is connected to the output rectifier and filter circuit and the drive and switch tube respectively, and the transformer is used to isolate and convert the voltage and provide the transformed voltage to the drive circuit and the rectifier circuit; The short-circuit protection circuit is respectively connected to the output rectifier filter circuit, the feedback circuit and the power management chip. The short-circuit protection circuit is used to quickly cut off the circuit or adjust the power management chip when an abnormal voltage or a short-circuit fault is detected, and monitor the voltage and current status in real time through the feedback circuit; The power management chip is connected to the power management chip power supply circuit and the feedback circuit respectively. The power management chip is used to adjust the output voltage and control the working state of the auxiliary power supply, and perform real-time monitoring and adjustment through the feedback circuit.

[0005] Furthermore, the short circuit protection circuit comprises: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2, a seventh resistor R7, a ninth resistor R9, a second optical coupler U2, an eighth resistor R8, a third voltage reference chip U3 and an eleventh resistor R11; One end of the fifth resistor R5 is connected to the third pin of the second transistor Q2 and one end of the seventh resistor R7 respectively, and the other end of the fifth resistor R5 is connected to the power supply circuit of the power management chip; The second pin of the second transistor Q2 is respectively connected to the second end of the third voltage reference chip U3, one end of the ninth resistor R9 and the third pin of the second optical coupler U2, and the first pin of the second transistor Q2 is respectively connected to the other end of the seventh resistor R7 and one end of the eighth resistor R8; The other end of the eighth resistor R8 is connected to the third end of the third voltage reference chip U3; The first end of the third voltage reference chip U3 is respectively connected to one end of the third resistor R3, the other end of the ninth resistor R9 and the fourth pin of the second optical coupler U2, and the other end of the third resistor R3 is connected to the power management chip; The first pin of the second optical coupler U2 is connected to one end of the fourth resistor R4 and one end of the eleventh resistor R11 respectively, and the second pin of the second optical coupler U2 is connected to the other end of the eleventh resistor R11; The other end of the fourth resistor R4 is connected to the output rectification and filtering circuit and the feedback circuit respectively.

[0006] Furthermore, the output rectification and filtering circuit comprises: A first diode D1, a third capacitor C3, a fourth capacitor C4 and an electrolytic capacitor EC1; One end of the first diode D1 is respectively connected to one end of the third capacitor C3, one end of the fourth capacitor C4 and the first pin of the electrolytic capacitor EC1; The other end of the first diode D1 is connected to the transformer; The other end of the third capacitor C3, the other end of the fourth capacitor C4 and the second pin of the electrolytic capacitor EC1 are connected to the transformer; One end of the third capacitor C3 is also connected to the short-circuit protection circuit and the feedback circuit short-circuit protection circuit respectively.

[0007] Furthermore, the power management chip power supply circuit includes: A sixth resistor R6, a tenth resistor R10, a second electrolytic capacitor EC2, a sixth capacitor C6, a fourth rectifier bridge D4 and a second transformer T1B; One end of the tenth resistor R10 is respectively connected to one end of the sixth resistor R6, one end of the sixth capacitor C6 and one end of the second electrolytic capacitor EC2, and one end of the sixth resistor is also connected to the power management chip; One end of the second electrolytic capacitor EC2 is respectively connected to one end of the fourth rectifier bridge D4 and the short-circuit protection circuit; The other end of the fourth rectifier bridge D4 is connected to the third end of the second transformer T1B; A first end of the second transformer T1B is respectively connected to the other end of the tenth resistor R10 , the other end of the second electrolytic capacitor EC2 , and the other end of the sixth capacitor C6 .

[0008] Furthermore, the feedback circuit comprises: A twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifth voltage reference chip U5 and a fourth optical coupler U4; One end of the twelfth resistor R12 and one end of the thirteenth resistor R13 are connected to the short-circuit protection circuit; The other end of the thirteenth resistor R13 is respectively connected to one end of the fourteenth resistor R14 and the first end of the fifth voltage reference chip U5, and the other end of the fourteenth resistor R14 is connected to the second end of the fifth voltage reference chip U5; The third end of the fifth voltage reference chip U5 is connected to the second pin of the fourth optocoupler U4, the first pin of the fourth optocoupler U4 is connected to the other end of the twelfth resistor R12, the fourth pin of the fourth optocoupler U4 is connected to the power management chip, and the third pin of the fourth optocoupler U4 is grounded.

[0009] The present invention further provides a method for short-circuit protection of an auxiliary power supply with a wide input range, which is applied to any of the above-mentioned short-circuit protection circuits for auxiliary power supply with a wide input range, comprising: When AC power is input, the AC input and fuse circuit perform overcurrent protection, the EMI filter circuit filters high-frequency noise and electromagnetic interference of the AC power, the rectifier filter circuit converts the AC power into a smooth DC power, and provides startup power to the power management chip after filtering by the power management chip power supply circuit; When the power management chip is started, the PWM signal is output to control the drive and switch tube, driving the transformer to convert electric energy. The transformer converts the electric energy and outputs it to the output rectifier and filter circuit. The output rectifier and filter circuit outputs a stable DC voltage and outputs a part of the voltage to the power management chip power supply circuit to provide auxiliary power supply for the power management chip. The feedback circuit samples the output voltage and feeds back the sampled signal to the control pin of the power management chip. The power management chip adjusts the PWM output according to the feedback signal to achieve the stability of the output voltage. When the output load is short-circuited or the circuit device is damaged and short-circuited, the output voltage drops to near zero volts, the sampling voltage of the sampling resistor in the short-circuit protection circuit decreases, the optocoupler current decreases or even cuts off, and the transistor in the short-circuit protection circuit is turned on, and the power supply pin voltage of the power management chip is discharged through the transistor conduction path, so that the power supply capacitor voltage of the power management chip is reduced to the undervoltage protection value, triggering the undervoltage protection, thereby achieving output short-circuit protection.

[0010] The present invention provides a circuit and method for short-circuit protection of auxiliary power supply with wide input range, which has the following beneficial effects: By setting up a complete short-circuit protection system, including multiple protection mechanisms such as AC input and fuse circuit, EMI filter circuit, rectifier filter circuit, etc., all-round protection of the auxiliary power supply is achieved, and the reliability and safety of the circuit are significantly improved. The collaborative working mechanism of the short-circuit protection circuit, power management chip, and feedback circuit can quickly respond to abnormal conditions such as output short circuit or device damage. Through real-time monitoring and control, the circuit can be effectively prevented from continuing to work in an abnormal state to avoid causing greater damage. Through the cooperation of the rectifier filter circuit and the RCD absorption circuit, effective processing of a wide range of input voltages is achieved, so that the protection circuit can maintain stable operation under different input conditions, improving the adaptability and reliability of the circuit. Based on the design of transformer isolation and voltage conversion, combined with the intelligent control of the power management chip, the output voltage is accurately adjusted, ensuring the stability of the auxiliary power supply in normal working and protection states. Through real-time monitoring of the feedback circuit and dynamic adjustment of the power management chip, a closed-loop control system is constructed, which not only improves the reliability of short-circuit protection, but also achieves rapid response and processing of abnormal conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a general circuit diagram of a short-circuit protection circuit for auxiliary power supply with wide input range provided by the present invention; Figure 2 It is a short-circuit protection circuit structure diagram of a short-circuit protection circuit suitable for a wide-range input auxiliary power supply provided by the present invention; Figure 3 This is one of the flow charts of a method for short-circuit protection of auxiliary power supply applicable to wide-range input provided by the present invention.

[0012] Figure 4 This is the second flow chart of a method for short-circuit protection of auxiliary power supply applicable to wide-range input provided by the present invention.

[0013] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0015] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0016] Reference Figure 1 As shown, the present invention provides a short-circuit protection circuit for auxiliary power supply with wide input range, comprising: AC input and fuse circuit, EMI filter circuit, rectifier filter circuit, RCD absorption circuit, transformer, output rectifier filter circuit, driver and switch tube, power management chip, power management chip power supply circuit, short circuit protection circuit and feedback circuit; The AC input and fuse circuit is connected to the EMI filter circuit, and the AC input and fuse circuit is used to receive external input power and protect the circuit from power failure or overload; The EMI filter circuit is connected to the rectifier filter circuit. The EMI filter circuit is used to reduce electromagnetic interference in the input power supply and ensure the stability of the power supply signal; The rectifier and filter circuit is connected to the RCD absorption circuit. The rectifier and filter circuit converts the AC power into a DC power supply, provides it to the subsequent circuits, and converts the AC fluctuation into a smooth DC output. The RCD absorption circuit is connected to the transformer. The RCD absorption circuit is used to suppress high-frequency noise and overvoltage to ensure the stable operation of the transformer; The transformer is connected to the output rectifier filter circuit and the driver and switch tube respectively. The transformer is used to isolate and convert the voltage and provide the transformed voltage to the driver circuit and the rectifier circuit. The short-circuit protection circuit is connected to the output rectifier filter circuit, the feedback circuit and the power management chip respectively. The short-circuit protection circuit is used to quickly cut off the circuit or adjust the power management chip when an abnormal voltage or short-circuit fault is detected, and monitor the voltage and current status in real time through the feedback circuit; The power management chip is connected to the power management chip power supply circuit and the feedback circuit respectively. The power management chip is used to adjust the output voltage and control the working state of the auxiliary power supply, and performs real-time monitoring and adjustment through the feedback circuit.

[0017] The invention provides a short-circuit protection circuit for auxiliary power supply with wide input range. By setting a complete short-circuit protection system, including multiple protection mechanisms such as AC input and fuse circuit, EMI filter circuit, rectifier filter circuit, etc., all-round protection of auxiliary power supply is realized, and the reliability and safety of the circuit are significantly improved. The short-circuit protection circuit, power management chip, and feedback circuit are used to work together to quickly respond to abnormal conditions such as output short circuit or device damage. Through real-time monitoring and control, the circuit is effectively prevented from continuously working in an abnormal state to avoid causing greater damage. Through the cooperation of the rectifier filter circuit and the RCD absorption circuit, effective processing of wide-range input voltage is realized, so that the protection circuit can maintain stable operation under different input conditions, and the adaptability and reliability of the circuit are improved. Based on the design of transformer isolation and voltage conversion, combined with the intelligent control of the power management chip, the accurate adjustment of the output voltage is realized, and the stability of the auxiliary power supply in normal working and protection states is ensured. Through real-time monitoring of the feedback circuit and dynamic adjustment of the power management chip, a closed-loop control system is constructed, which not only improves the reliability of short-circuit protection, but also realizes rapid response and processing of abnormal states.

[0018] Reference Figure 2 As shown, in one embodiment, the short circuit protection circuit includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2, a seventh resistor R7, a ninth resistor R9, a second optical coupler U2, an eighth resistor R8, a third voltage reference chip U3 and an eleventh resistor R11; One end of the fifth resistor R5 is connected to the third pin of the second transistor Q2 and one end of the seventh resistor R7 respectively, and the other end of the fifth resistor R5 is connected to the power supply circuit of the power management chip; The second pin of the second transistor Q2 is respectively connected to the second end of the third voltage reference chip U3, one end of the ninth resistor R9 and the third pin of the second optical coupler U2, and the first pin of the second transistor Q2 is respectively connected to the other end of the seventh resistor R7 and one end of the eighth resistor R8; The other end of the eighth resistor R8 is connected to the third end of the third voltage reference chip U3; A first end of the third voltage reference chip U3 is respectively connected to one end of the third resistor R3, the other end of the ninth resistor R9 and the fourth pin of the second optical coupler U2, and the other end of the third resistor R3 is connected to the power management chip; The first pin of the second optical coupler U2 is connected to one end of the fourth resistor R4 and one end of the eleventh resistor R11 respectively, and the second pin of the second optical coupler U2 is connected to the other end of the eleventh resistor R11; The other end of the fourth resistor R4 is connected to the output rectification and filtering circuit and the feedback circuit respectively.

[0019] This embodiment realizes effective monitoring and short-circuit protection of the circuit by using an accurate voltage reference chip and an optocoupler in the short-circuit protection circuit. In this embodiment, the close connection between the second optocoupler U2 and the third voltage reference chip U3 ensures real-time detection and feedback of the circuit state, greatly enhancing the stability and reliability of the system. Through the reasonable configuration of the second transistor Q2 and each resistor, it is possible to respond to abnormal current changes in a timely manner, and to accurately switch the short-circuit protection by adjusting the signal path, thereby effectively avoiding the risk of equipment damage. In addition, the combined application of multiple resistors not only optimizes the distribution of current, but also reduces the power consumption of the system through current limitation, making the overall system more efficient and energy-saving. This design enables the short-circuit protection circuit to have high adaptability and safety, and can provide stable protection under different working conditions, significantly improving the service life and stability of the circuit.

[0020] In one embodiment, the AC input and fuse circuit and the EMI filter circuit include: The first safety X capacitor CX1, AC power supplies AC-L and AC-N, fuse F1, the second safety Y capacitor CY2, the first safety Y capacitor CY1, the common mode inductor LF1 and the power input socket M1.

[0021] At the input end, AC power sources AC-L and AC-N provide input voltages respectively, where AC-L is the live wire and AC-N is the neutral wire. One end of the fuse F1 is connected to AC-L, and the other end is connected to the subsequent part of the circuit and is also connected to the first safety X capacitor CX1 to provide overcurrent protection.

[0022] The first pin of the power input socket M1 is connected to AC-N, the second pin is connected to AC-L, and the third pin is grounded.

[0023] One end of the first safety X capacitor CX1 is connected to AC-L, and the other end is connected to AC-N and the other end of the second safety Y capacitor CY2. The main function is to filter out the high-frequency noise at the input end of the AC power supply. One end of the first safety Y capacitor CY1 is connected to one end of the first safety X capacitor CX1, and the other end of the first safety Y capacitor CY1 and one end of the second safety Y capacitor CY2 are grounded respectively and connected to the other end of the first safety X capacitor CX1. The main function is to suppress electromagnetic interference and reduce common mode noise.

[0024] The fourth pin of the common mode inductor LF1 is connected to one end of the first safety Y capacitor CY1, and the second pin is respectively connected to the other end of the second safety Y capacitor CY2 and AC-N, for further suppressing the common mode noise from the power supply and enhancing the anti-interference ability of the circuit.

[0025] The entire input end part ensures the stability of the input power supply through the cooperation of the above components, and effectively filters and isolates noise to prevent power supply interference from having adverse effects on the circuit.

[0026] This embodiment uses components such as the first safety X capacitor, the second safety Y capacitor, the common mode inductor and the fuse, which can effectively filter out the high-frequency noise and common-mode interference at the input end of the AC power supply, and significantly improve the stability and anti-interference ability of the power supply. By combining the first safety X capacitor with the safety Y capacitor, the electromagnetic interference EMI at the input end of the power supply can be effectively reduced, the reliability and safety of the power supply under different voltage and load conditions can be ensured, and the negative impact of high-frequency noise on the circuit system can be avoided. The addition of the common mode inductor further enhances the suppression ability of the power supply end to the common mode noise, reduces the interference of the power input to other circuit parts, and improves the overall anti-interference performance of the system. The protective effect of the fuse ensures that the circuit can cut off the power supply in time in the case of overcurrent, thereby increasing the safety and stability of the circuit. Through the optimized coordination of these components, the common noise interference problem of the power input part is solved, and the adaptability and long-term operation stability of the power module in a complex power grid environment are effectively improved.

[0027] In one embodiment, the output rectification and filtering circuit includes: A first diode D1, a third capacitor C3, a fourth capacitor C4 and an electrolytic capacitor EC1; One end of the first diode D1 is respectively connected to one end of the third capacitor C3, one end of the fourth capacitor C4 and the first pin of the electrolytic capacitor EC1; The other end of the first diode D1 is connected to the transformer; The other end of the third capacitor C3, the other end of the fourth capacitor C4 and the second pin of the electrolytic capacitor EC1 are connected to the transformer; One end of the third capacitor C3 is also connected to the short-circuit protection circuit and the feedback circuit short-circuit protection circuit respectively.

[0028] This embodiment can effectively balance the output voltage fluctuation, reduce the current ripple, and improve the stability of the output voltage by using the configuration of the first diode D1, the third capacitor C3, the fourth capacitor C4 and the electrolytic capacitor EC1 in the output rectifier filter circuit. By connecting the first diode D1 with multiple capacitors, not only the filtering effect is optimized, but also the power supply can be kept stable when the voltage fluctuation is large, ensuring the efficient operation of the circuit. At the same time, the connection of the third capacitor C3 with the short-circuit protection circuit and the feedback circuit further enhances the anti-interference ability of the circuit, avoids the damage to the equipment caused by current overload, and helps to improve the reliability and safety of the system. In addition, the introduction of the electrolytic capacitor EC1 improves the capacitor energy storage capacity, so that the circuit can respond more quickly when the load changes, and provide a more lasting stable output, thereby improving the performance and reliability of the overall circuit and meeting the use requirements under various load conditions.

[0029] In one embodiment, a power management chip power supply circuit includes: A sixth resistor R6, a tenth resistor R10, a second electrolytic capacitor EC2, a sixth capacitor C6, a fourth rectifier bridge D4 and a second transformer T1B; One end of the tenth resistor R10 is respectively connected to one end of the sixth resistor R6, one end of the sixth capacitor C6 and one end of the second electrolytic capacitor EC2, and one end of the sixth resistor is also connected to the power management chip; One end of the second electrolytic capacitor EC2 is respectively connected to one end of the fourth rectifier bridge D4 and the short-circuit protection circuit; The other end of the fourth rectifier bridge D4 is connected to the third end of the second transformer T1B; A first end of the second transformer T1B is connected to the other end of the tenth resistor R10 , the other end of the second electrolytic capacitor EC2 , and the other end of the sixth capacitor C6 , respectively.

[0030] This embodiment can realize efficient and stable operation of the power supply circuit by reasonably configuring the connection of the sixth resistor, the tenth resistor, the sixth capacitor, the second electrolytic capacitor, the fourth rectifier bridge and the second transformer in the power supply circuit of the power management chip. First, through the cooperation of the tenth resistor and the sixth resistor, the accurate distribution of current is achieved, and the stability of the power supply system is guaranteed. The series design of the sixth capacitor and the second electrolytic capacitor not only optimizes the voltage stability, but also effectively reduces the impact of power supply fluctuations on the circuit, ensuring a more stable power output. In addition, the combination of the fourth rectifier bridge and the second transformer ensures the rectification function of the power supply circuit, avoids the fluctuations that may be caused by the AC power supply, and improves the reliability of power management. Through this configuration, a stable power supply can be provided under different working environments to ensure the normal operation of the power management chip, thereby improving the performance and stability of the overall system, reducing the probability of failure, and extending the service life of the equipment.

[0031] In one embodiment, the feedback circuit comprises: A twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifth voltage reference chip U5 and a fourth optical coupler U4; One end of the twelfth resistor R12 and one end of the thirteenth resistor R13 are connected to the short-circuit protection circuit; The other end of the thirteenth resistor R13 is respectively connected to one end of the fourteenth resistor R14 and the first end of the fifth voltage reference chip U5, and the other end of the fourteenth resistor R14 is connected to the second end of the fifth voltage reference chip U5; The third end of the fifth voltage reference chip U5 is connected to the second pin of the fourth optocoupler U4, the first pin of the fourth optocoupler U4 is connected to the other end of the twelfth resistor R12, the fourth pin of the fourth optocoupler U4 is connected to the power management chip, and the third pin of the fourth optocoupler U4 is grounded.

[0032] This embodiment can achieve precise voltage control and stable signal transmission by reasonably configuring the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, the fifth voltage reference chip U5 and the fourth optical coupler U4 in the feedback circuit, thereby enhancing the anti-interference ability and reliability of the circuit. The combination of the thirteenth resistor R13 and the fourteenth resistor R14 can effectively adjust the current distribution, ensure the stability of the feedback circuit, and optimize the current conduction path, reduce power consumption and improve efficiency. Through the precise voltage reference function of the fifth voltage reference chip U5, the stability of the feedback voltage can be guaranteed, so that the system can maintain good performance under different working conditions. The introduction of the fourth optical coupler U4 effectively avoids mutual interference between circuits by isolating the signal path, and improves the safety and stability of the system. This design not only improves the adaptability of the circuit, but also ensures the high efficiency and low power consumption of power management by optimizing signal feedback and voltage control.

[0033] In one embodiment, the connection relationship between the rectifier filter circuit, the RCD absorption circuit, the transformer, the driver and the switch tube includes: In the rectifier and filter circuit, the second rectifier bridge D2 and the first capacitor C1 are key components. The first pin of the second rectifier bridge D2 is connected to the first pin of the common mode inductor LF1, and the third pin of the second rectifier bridge D2 is connected to the third pin of the common mode inductor LF1 to convert AC into DC. The fourth pin of the second rectifier bridge D2 is grounded, and the second pin is connected to the first pin of the first capacitor C1, that is, one end of the first capacitor C1 is connected to the output end of the second rectifier bridge D2, and the second pin of the first capacitor C1 is grounded PGND. The function of the first capacitor C1 is to smooth the rectified DC, reduce voltage fluctuations, and ensure the stability of the power supply voltage.

[0034] In the RCD absorption circuit, one end of the first resistor R1 is respectively connected to the first pin of the first capacitor C1, one end of the second capacitor C2 and the fifth pin of the first transformer T1G.

[0035] One end of the third diode D3 is connected to the other end of the first resistor R1 and the other end of the second capacitor C2 respectively, and the other end of the third diode D3 is connected to the second pin of the main switch Q1 and the seventh pin of the first transformer T1G respectively.

[0036] In the driver and switch tube and transformer, the primary side of the first transformer T1G is connected to the output end of the rectifier bridge to provide the required voltage conversion.

[0037] The eleventh pin of the first transformer T1G is connected to the other end of the fourth capacitor C4, and the zeroth pin is connected to the other end of the first diode D1. The first end of the main switch tube Q1 is connected to the drive circuit DR1 through the second resistor R2 to control the switch state of Q1. The second end of the main switch tube Q1 is connected to the primary side of the transformer, and the third end and the resistor RS1 are connected to the ground PGND to control the current flow. The drive circuit DR1 monitors the current through current sampling so as to feed back to the power management chip U1 to achieve overcurrent protection. Through this main switch part, the input DC current is converted into high-frequency AC, and then isolated by the transformer to provide a stable voltage for the output circuit.

[0038] In the T1G section, the auxiliary transformer T1B is connected to the secondary end of the main transformer T1. The secondary end of T1B is used for the voltage regulation feedback circuit of the power management chip U1. Through this auxiliary transformer T1B, the power management chip can monitor the output voltage in real time and adjust the working state. Optocouplers U2 and U4 are used to transmit the feedback signal from the output end to the power management chip to ensure the stability of the output voltage. The design of the auxiliary transformer section can effectively achieve voltage regulation and improve the stability of the power supply through current monitoring and feedback loops.

[0039] This embodiment can effectively convert AC into stable DC by adopting the second rectifier bridge D2 and the first capacitor C1 design in the rectifier filter circuit, and smooth the output voltage through the first capacitor C1 to reduce voltage fluctuations, thereby improving the stability of the power supply voltage and ensuring the reliable operation of the power supply under various load conditions. The design of the RCD absorption circuit, combined with the first resistor R1, the second capacitor C2 and the third diode D3, can effectively absorb the transient overvoltage during the switching process of the switch tube, avoid the circuit from being damaged by voltage overshoot, and improve the durability and safety of the power supply. By combining the configuration of the main switch tube Q1 and the transformer T1G in the drive and switch tube circuit, the input DC current can be converted into high-frequency AC, and voltage isolation can be achieved through the transformer to ensure the stability of the output voltage. The drive circuit DR1 monitors the current through current sampling feedback, and cooperates with the overcurrent protection mechanism of the power management chip U1 to further improve the stability and safety of the power supply. The auxiliary transformer T1B works in conjunction with the optical couplers U2 and U4 to adjust the working state of the power supply in real time to ensure the precise regulation of the output voltage, thereby effectively enhancing the accuracy of power management and the stability of the system. The overall design improves the power supply's anti-interference capability and reliability, and optimizes the power supply's performance.

[0040] Reference Figure 3 As shown, the present invention provides a method for short-circuit protection of an auxiliary power supply with a wide input range, which is applied to a short-circuit protection circuit for an auxiliary power supply with a wide input range according to any one of the above claims, comprising: When AC power is input, the AC input and fuse circuits are protected against overcurrent, the EMI filter circuit filters out high-frequency noise and electromagnetic interference from the AC power, and the rectifier filter circuit converts the AC power into a smooth DC power supply, which is then filtered by the power management chip power supply circuit to provide startup power to the power management chip. When the power management chip is started, it outputs PWM signals to control the drive and switch tube, driving the transformer to convert electric energy. The transformer converts the electric energy and outputs it to the output rectifier and filter circuit. The output rectifier and filter circuit outputs a stable DC voltage and outputs part of the voltage to the power management chip power supply circuit to provide auxiliary power supply for the power management chip. The feedback circuit samples the output voltage and feeds the sampled signal back to the control pin of the power management chip. The power management chip adjusts the PWM output according to the feedback signal to achieve stable output voltage. When the output load is short-circuited or the circuit components are damaged and short-circuited, the output voltage drops to near zero volts, the sampling voltage of the sampling resistor in the short-circuit protection circuit decreases, the optocoupler current decreases or even cuts off, and the transistor in the short-circuit protection circuit is turned on, discharging the power supply pin voltage of the power management chip through the transistor conduction path, reducing the power supply capacitor voltage of the power management chip to the undervoltage protection value, triggering the undervoltage protection, thereby achieving output short-circuit protection.

[0041] The invention provides a short-circuit protection method for auxiliary power supply with wide input range. By setting a complete short-circuit protection system, including multiple protection mechanisms such as AC input and fuse circuit, EMI filter circuit, rectifier filter circuit, etc., all-round protection of auxiliary power supply is realized, and the reliability and safety of the circuit are significantly improved. The short-circuit protection circuit, power management chip, and feedback circuit are used in a coordinated working mechanism, which can quickly respond to abnormal conditions such as output short circuit or device damage. Through real-time monitoring and control, the circuit is effectively prevented from continuously working in an abnormal state to avoid causing greater damage. Through the cooperation of the rectifier filter circuit and the RCD absorption circuit, effective processing of a wide range of input voltage is achieved, so that the protection circuit can maintain stable operation under different input conditions, and the adaptability and reliability of the circuit are improved. Based on the design of transformer isolation and voltage conversion, combined with the intelligent control of the power management chip, the output voltage is accurately adjusted, ensuring the stability of the auxiliary power supply in normal working and protection states. Through real-time monitoring of the feedback circuit and dynamic adjustment of the power management chip, a closed-loop control system is constructed, which not only improves the reliability of short-circuit protection, but also achieves rapid response and processing of abnormal conditions.

[0042] Reference Figure 1-Figure 4 As shown, in one embodiment, it includes: The design and implementation process of the power management system is comprehensively analyzed to obtain the corresponding power management adjustment strategy. The strategy includes: dynamically constructing the AC voltage, filtering, rectification and voltage adjustment process of the input power to obtain a stable DC power output. The input AC voltage range usually includes voltage standards in different countries and regions, such as 110V, 220V, 230V, etc. The system ensures the stability and safety of the power output through circuit structures such as EMI filtering, rectification, and PWM control.

[0043] The connected AC power will enter the system through the protection circuit at the power input end, and the fuse is used to prevent damage caused by current overload. Then, the power passes through the EMI filter circuit to remove high-frequency noise and electromagnetic interference EMI in the AC power. The EMI circuit ensures that the current entering the subsequent processing is a stable low-noise signal. The power management chip executes the control strategy of stable voltage output in the subsequent process.

[0044] The power signal after EMI filtering enters the rectifier filter circuit. At this time, the second rectifier bridge D2 and the first capacitor C1 work together to convert the AC power into a smooth DC current and eliminate high-frequency fluctuations and ripples. In this process, the role of the first capacitor C1 is particularly critical. It can smooth the voltage fluctuations and ensure the provision of a stable DC power supply for the subsequent power management chip.

[0045] The power management chip adjusts the output voltage through PWM control. At this time, the power MOSFET and transformer in the system work, and the transformer is used to increase or decrease the input voltage according to demand. The transformer converts the voltage under the drive of the control circuit based on the principle of current change and outputs the current to the back-end circuit.

[0046] The power supply of the power management chip is provided by the startup circuit. The sixth resistor R6 and the tenth resistor R10 work together with the third capacitor C3 to form a stable power supply to ensure the normal operation of the chip. When the system receives the input voltage signal, the startup circuit provides the required voltage for the power management chip so that it can regulate and control the power system.

[0047] When the power system is working, the output voltage is sampled through the thirteenth resistor R13 and the fourteenth resistor R14, and then fed back to the feedback terminal COMP pin of the power management chip. The power management chip adjusts the PWM signal according to the sampled voltage to achieve stable control of the output voltage. This feedback mechanism ensures that the system adjusts the voltage in real time according to changes in load demand and external environment, ensuring that the output voltage always remains within the specified range.

[0048] It also includes a short-circuit protection function. When the load is short-circuited or there is a problem with the output circuit, the power supply voltage will drop rapidly and almost become zero volts. In this case, the sampling circuit feeds back information to the second optocoupler U2 through the fourth resistor R4 and the eleventh resistor R11, causing the third voltage reference chip U3 to be turned on. At this time, the third voltage reference chip U3 will trigger the second transistor Q2 to turn on, thereby causing the VCC pin voltage of the power management chip to drop and enter the undervoltage protection state. This protection mechanism can cut off the power supply in time when the power supply voltage is too low to avoid damage to the equipment.

[0049] This embodiment can support AC input ranging from 100V to 230V by designing wide voltage adaptability while taking into account global voltage input differences. This design enables the power supply system to automatically adapt and adjust the power supply voltage when used in different regions, ensuring that the power supply system will not be damaged by power grid fluctuations. The short-circuit protection circuit also has wide input voltage adaptability, which can effectively handle voltage instability when the power supply is overloaded or short-circuited, avoiding damage to internal components of the circuit.

[0050] The power supply stability, reliability and safety are ensured by the comprehensive use of EMI filtering, rectification, PWM control, feedback mechanism and short-circuit protection and other technologies. The differences in global voltage ranges are fully considered in the design, so that the system can adapt to different input voltage conditions. In addition, through the precise feedback circuit and protection mechanism, the power output can be adjusted in real time and the circuit can be protected in the event of a fault, avoiding damage to the power management chip and other core components.

[0051] It should be noted that technicians in the relevant technical field can clearly understand that for the convenience and conciseness of description, the specific working process of the system and each module described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0052] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A short-circuit protection circuit for auxiliary power supply with wide input range, characterized in that: include: AC input and fuse circuit, EMI filter circuit, rectifier filter circuit, RCD absorption circuit, transformer, output rectifier filter circuit, driver and switch tube, power management chip, power management chip power supply circuit, short circuit protection circuit and feedback circuit; The AC input and fuse circuit is connected to the EMI filter circuit, and the AC input and fuse circuit is used to receive external input power and protect the circuit from power failure or overload; The EMI filter circuit is connected to the rectifier filter circuit, and the EMI filter circuit is used to reduce electromagnetic interference in the input power supply to ensure the stability of the power supply signal; The rectifier and filter circuit is connected to the RCD absorption circuit, and the rectifier and filter circuit converts the AC power supply into a DC power supply, provides it to the subsequent circuit, and converts the AC fluctuation into a smooth DC output; The RCD absorption circuit is connected to the transformer, and the RCD absorption circuit is used to suppress high-frequency noise and overvoltage to ensure stable operation of the transformer; The transformer is connected to the output rectifier and filter circuit and the drive and switch tube respectively, and the transformer is used to isolate and convert the voltage and provide the transformed voltage to the drive circuit and the rectifier circuit; The short-circuit protection circuit is respectively connected to the output rectifier filter circuit, the feedback circuit and the power management chip. The short-circuit protection circuit is used to quickly cut off the circuit or adjust the power management chip when an abnormal voltage or a short-circuit fault is detected, and monitor the voltage and current status in real time through the feedback circuit; The power management chip is connected to the power management chip power supply circuit and the feedback circuit respectively. The power management chip is used to adjust the output voltage and control the working state of the auxiliary power supply, and perform real-time monitoring and adjustment through the feedback circuit.

2. The auxiliary power supply short-circuit protection circuit applicable to a wide range of input according to claim 1, characterized in that: The short circuit protection circuit comprises: A third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a second triode (Q2), a seventh resistor (R7), a ninth resistor (R9), a second optical coupler (U2), an eighth resistor (R8), a third voltage reference chip (U3) and an eleventh resistor (R11); One end of the fifth resistor (R5) is connected to the third pin of the second transistor (Q2) and one end of the seventh resistor (R7) respectively, and the other end of the fifth resistor (R5) is connected to the power supply circuit of the power management chip; The second pin of the second transistor (Q2) is respectively connected to the second end of the third voltage reference chip (U3), one end of the ninth resistor (R9) and the third pin of the second optical coupler (U2), and the first pin of the second transistor (Q2) is respectively connected to the other end of the seventh resistor (R7) and one end of the eighth resistor (R8); The other end of the eighth resistor (R8) is connected to the third end of the third voltage reference chip (U3); The first end of the third voltage reference chip (U3) is respectively connected to one end of the third resistor (R3), the other end of the ninth resistor (R9) and the fourth pin of the second optical coupler (U2), and the other end of the third resistor (R3) is connected to the power management chip; The first pin of the second optical coupler (U2) is respectively connected to one end of the fourth resistor (R4) and one end of the eleventh resistor (R11), and the second pin of the second optical coupler (U2) is connected to the other end of the eleventh resistor (R11); The other end of the fourth resistor (R4) is connected to the output rectification and filtering circuit and the feedback circuit respectively.

3. The auxiliary power supply short-circuit protection circuit applicable to a wide range of input according to claim 1, characterized in that: The output rectification and filtering circuit comprises: A first diode (D1), a third capacitor (C3), a fourth capacitor (C4) and an electrolytic capacitor (EC1); One end of the first diode (D1) is respectively connected to one end of the third capacitor (C3), one end of the fourth capacitor (C4) and the first pin of the electrolytic capacitor (EC1); The other end of the first diode (D1) is connected to the transformer; The other end of the third capacitor (C3), the other end of the fourth capacitor (C4) and the second pin of the electrolytic capacitor (EC1) are connected to the transformer; One end of the third capacitor (C3) is also connected to the short-circuit protection circuit and the feedback circuit short-circuit protection circuit respectively.

4. The auxiliary power supply short-circuit protection circuit applicable to a wide range of input according to claim 1, characterized in that: The power management chip power supply circuit comprises: a sixth resistor (R6), a tenth resistor (R10), a second electrolytic capacitor (EC2), a sixth capacitor (C6), a fourth rectifier bridge (D4) and a second transformer (T1B); One end of the tenth resistor (R10) is respectively connected to one end of the sixth resistor (R6), one end of the sixth capacitor (C6) and one end of the second electrolytic capacitor (EC2), and one end of the sixth resistor is also connected to the power management chip; One end of the second electrolytic capacitor (EC2) is respectively connected to one end of the fourth rectifier bridge (D4) and the short-circuit protection circuit; The other end of the fourth rectifier bridge (D4) is connected to the third end of the second transformer (T1B); The first end of the second transformer (T1B) is respectively connected to the other end of the tenth resistor (R10), the other end of the second electrolytic capacitor (EC2) and the other end of the sixth capacitor (C6).

5. The auxiliary power supply short-circuit protection circuit applicable to a wide range of input according to claim 1, characterized in that: The feedback circuit comprises: a twelfth resistor (R12), a thirteenth resistor (R13), a fourteenth resistor (R14), a fifth voltage reference chip (U5) and a fourth optical coupler (U4); One end of the twelfth resistor (R12) and one end of the thirteenth resistor (R13) are connected to the short-circuit protection circuit; The other end of the thirteenth resistor (R13) is respectively connected to one end of the fourteenth resistor (R14) and the first end of the fifth voltage reference chip (U5), and the other end of the fourteenth resistor (R14) is connected to the second end of the fifth voltage reference chip (U5); The third end of the fifth voltage reference chip (U5) is connected to the second pin of the fourth optocoupler (U4), the first pin of the fourth optocoupler (U4) is connected to the other end of the twelfth resistor (R12), the fourth pin of the fourth optocoupler (U4) is connected to the power management chip, and the third pin of the fourth optocoupler (U4) is grounded.

6. A method for short-circuit protection of auxiliary power supply with wide input range, applied to the short-circuit protection circuit for auxiliary power supply with wide input range as claimed in any one of claims 1 to 5, characterized in that: include: When AC power is input, the AC input and fuse circuit perform overcurrent protection, the EMI filter circuit filters high-frequency noise and electromagnetic interference of the AC power, the rectifier filter circuit converts the AC power into a smooth DC power, and provides startup power to the power management chip after filtering by the power management chip power supply circuit; When the power management chip is started, the PWM signal is output to control the drive and switch tube, driving the transformer to convert electric energy. The transformer converts the electric energy and outputs it to the output rectifier and filter circuit. The output rectifier and filter circuit outputs a stable DC voltage and outputs a part of the voltage to the power management chip power supply circuit to provide auxiliary power supply for the power management chip. The feedback circuit samples the output voltage and feeds back the sampled signal to the control pin of the power management chip. The power management chip adjusts the PWM output according to the feedback signal to achieve the stability of the output voltage. When the output load is short-circuited or the circuit device is damaged and short-circuited, the output voltage drops to near zero volts, the sampling voltage of the sampling resistor in the short-circuit protection circuit decreases, the optocoupler current decreases or even cuts off, and the transistor in the short-circuit protection circuit is turned on, and the power supply pin voltage of the power management chip is discharged through the transistor conduction path, so that the power supply capacitor voltage of the power management chip is reduced to the undervoltage protection value, triggering the undervoltage protection, thereby achieving output short-circuit protection.

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