Surge voltage suppression circuit based on isolated DCDC converter driving

Abstract

The invention provides a surge voltage suppression circuit based on isolated DCDC converter driving, which relates to the technical field of suppression circuits and comprises an input port, an NMOS tube, a protection circuit, a DC / DC converter, a filter, a voltage clamping circuit and an output port. The VIN + and the VIN-are connected to the input end of the DC / DC converter through the protection circuit; the output end of the DC / DC converter is connected to an output port VOUT through a filter, and the filter ensures the stability of the output voltage; the NMOS tube is connected with the DC / DC converter through a control signal, so that the on-off state of the DC / DC converter is controlled; when abnormal current is detected, the current is cut off through the NMOS tube; the DC / DC converter is connected with the voltage clamp circuit through a voltage detection signal, and when the voltage exceeds a set value, the voltage clamp circuit is switched on to limit the voltage rise and protect the safety of downstream equipment. The invention has the advantages of higher reliability and lower cost, and can effectively solve the problem of insufficient driving capability under the condition of high-power application.

Description

Technical Field

[0001] The present invention relates to the technical field of suppression circuits, and in particular to a surge voltage suppression circuit driven by an isolated DCDC converter. Background Art

[0002] The surge voltage suppression circuit clamps the short-term spike voltage that exceeds the normal voltage range of the input power supply to within the normal voltage range to prevent the spike voltage from damaging the downstream equipment. There are relevant standard requirements in the military aviation and automotive fields, such as GJB181 Aircraft Power Supply Characteristics and GJB298 Military Vehicle 28V DC Electrical System Characteristics, which have corresponding provisions on surge voltage requirements. Regarding how to suppress surge voltage, the most commonly used methods are as follows:

[0003] 1. Connect voltage clamping devices in parallel to the input port, such as transient suppression diodes (TVS tubes), gas / solid discharge tubes, varistors, etc. However, these clamping devices have too small clamping power and are usually used for spike voltages at the us level. They cannot meet the requirements of tens of ms for GJB and automotive grade applications;

[0004] 2. Use the charge pump to generate a voltage about 12V higher than the input voltage, and combine it with the output feedback circuit to drive the positive line NMOS tube to work in the linear region to suppress the peak voltage. This circuit is relatively complex, and the charge pump driving capability is weak (small current, usually only 100mA). For high-power application scenarios that require multiple NMOS tubes to be used in parallel, it cannot meet the NMOS driving requirements and will cause the NMOS tube to burn out.

[0005] 3. Use a dedicated surge voltage suppression chip and NMOS tube to form a surge suppression circuit to suppress it. The internal mechanism of the dedicated surge voltage suppression chip is also composed of a charge pump plus a feedback loop. Compared with the above, it only optimizes the peripheral circuit and is more convenient to use, but it also has the problem of weak driving ability and cannot meet high-power applications. Summary of the invention

[0006] The purpose of the present invention is to provide a surge voltage suppression circuit based on an isolated DCDC converter drive to improve the above problems. In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present application provides a surge voltage suppression circuit based on an isolated DCDC converter drive, comprising:

[0008] Input port, NMOS tube, protection circuit, DC / DC converter, filter, voltage clamping circuit and output port;

[0009] The input port includes VIN+ and VIN-, which are used to receive external power input; the NMOS tube is used to control the switch state of the circuit, and the voltage is controlled by its conduction and cutoff;

[0010] The protection circuit includes anti-backflow and current limiting functions, which are used to prevent reverse current and limit excessive current. The protection circuit includes two parts, which are respectively located between VIN+ and VIN- and the DC / DC converter, and between the DC / DC converter and the output port VOUT;

[0011] The DC / DC converter is used to convert the input voltage into the required output voltage, and realizes voltage conversion and stable output through internal switches and control logic;

[0012] The filter is located at the output end of the DC / DC converter and is used to smooth the output voltage and reduce noise and fluctuations;

[0013] The voltage clamp circuit is located at the output port and is used to limit the output voltage to a certain value to prevent the voltage from being too high and damaging the downstream equipment.

[0014] Wherein, VIN+ and VIN- are connected to the input end of the DC / DC converter through a protection circuit, and the anti-backflow and current limiting functions of the protection circuit ensure the correct flow direction and magnitude of the current; wherein, the output end of the DC / DC converter is connected to the output port VOUT through a filter, and the filter ensures the stability of the output voltage; the voltage clamp circuit is located at the VOUT end to ensure that the output voltage does not exceed the set safety value;

[0015] Among them, the NMOS tube is connected to the DC / DC converter through a control signal to realize the control of the switching state of the DC / DC converter; the DC / DC converter is connected to the voltage clamp circuit through a voltage detection signal to monitor the output voltage in real time. When the voltage exceeds the set value, the voltage clamp circuit intervenes to limit the voltage rise and protect the safety of downstream equipment.

[0016] Preferably, the DC / DC converter comprises an isolated DC / DC converter N1, wherein the isolated DC / DC converter N1 is used to provide a driving voltage VGS of the NMOS tube;

[0017] The voltage at the output port of the isolated DC / DC converter N1 is applied to the gate-source port of the NMOS tube to achieve driving, and the output voltage is electrically isolated from the ground line GND;

[0018] When the input voltage of the NMOS tube is a normal working voltage, the GS terminal receives the output voltage of the isolated DC / DC converter N1 to normally drive the NMOS tube to conduct;

[0019] The protection circuit also includes a clamping voltage regulator V3. When the input voltage generates a surge voltage and exceeds the voltage of V3, V3 clamps the GS voltage, thereby clamping the output voltage to the regulated voltage Vz of V3.

[0020] Preferably, the input end of the protection circuit is connected to an input filter circuit, and the input filter circuit includes a capacitor C1 and a capacitor C3, wherein the capacitor C1 and the capacitor C3 serve as filter input capacitors to filter input noise, thereby stabilizing circuit operation.

[0021] Preferably, the protection circuit includes a first protection circuit and a second protection circuit;

[0022] The first protection circuit includes a resistor R1 and a diode V2, wherein the resistor R1 is used to limit the current flowing through the first protection circuit to protect the voltage-stabilizing diode V3, and the diode V2 is used to prevent the output current of the isolated DC / DC converter N1 from flowing back to the input power supply;

[0023] The second protection circuit includes a resistor R3 and a diode V4, wherein the resistor R3 is used to limit the current flowing through the second protection circuit to protect the NMOS tube, and the diode V4 is used to prevent the current of the input power supply from flowing back into the isolated DC / DC converter N1.

[0024] Preferably, the voltage clamp circuit adopts a voltage regulator tube for clamping, and the voltage clamp circuit includes a voltage regulator tube V3 for clamping and controlling the gate-source voltage GS of the NMOS tube;

[0025] The voltage regulator tube V3 is started when the input voltage exceeds its operating voltage threshold, and the gate-source voltage GS of the NMOS tube is limited to not exceed the set voltage regulator voltage Vz of the voltage regulator tube V3, thereby ensuring that the NMOS tube operates stably within a safe operating range.

[0026] Preferably, the input and output ends of the converter N1 are electrically isolated, so that the port of the output end is connected to the port of the gate-source end GS of the NMOS tube to provide a driving voltage, and the output voltage range of the isolated DC / DC converter N1 is 10V to 15V.

[0027] Preferably, the output end of the protection circuit is connected to an output filter circuit, and the output filter circuit includes a capacitor C2 and a capacitor C4, wherein the capacitor C2 and the capacitor C4 serve as filter output capacitors to filter the output noise, thereby stabilizing the circuit operation.

[0028] The beneficial effects of the present invention are:

[0029] The isolated DC / DC converter N1 in the present invention can select DC / DC converters with different output capabilities according to the number and parameters of NMOS selected under different powers, which is different from the charge pump and the dedicated driver chip and has stronger flexibility; the voltage regulator diode in the voltage clamping circuit is only used as a control device, with extremely low power consumption, and is not in the main power loop, which is different from the voltage clamping device connected in parallel to the input port, which needs to consider power, and has stronger versatility; this circuit is simpler and has lower cost, and is different from the charge pump and the dedicated driver chip which also need a feedback circuit. This circuit directly uses the voltage regulator as a clamping circuit and has higher reliability.

[0030] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by practicing the embodiments of the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a principle block diagram of a surge voltage suppression circuit based on an isolated DCDC converter drive according to an embodiment of the present invention;

[0033] Figure 2 The schematic diagram is a schematic diagram of a surge voltage suppression circuit based on an isolated DCDC converter drive according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0036] With the increasing requirements of electronic devices for power management, traditional power management technologies have gradually failed to meet the requirements of modern electronic devices for high efficiency, high stability and low power consumption. In current technologies, power management and protection circuits usually use simple linear regulators or basic switching regulators. Although these technologies can achieve basic voltage conversion and voltage regulation functions, they often have problems such as low efficiency, slow response speed and imperfect protection mechanism when facing complex circuit environments and high dynamic load changes. In addition, these traditional technologies often lack effective protection measures when dealing with high current or high voltage shocks, which can easily lead to circuit damage or equipment failure. In order to solve these problems, the prior art attempts to improve the stability and safety of the circuit by adding external protection components and optimizing circuit design, but these methods often increase the complexity and cost of the circuit, and it is still difficult to completely avoid circuit failures caused by power supply fluctuations or external interference in practical applications. The present invention mainly solves the surge voltage suppression requirements of 50ms, 100ms, etc. required in GJB and automotive standards. In high-power application scenarios, the driving capability of the NMOS tube on the positive line is improved to avoid the burning of the NMOS tube, as follows:

[0037] Example:

[0038] like Figure 1 and 2 As shown, this embodiment provides a surge voltage suppression circuit based on an isolated DCDC converter drive, including an input port, an NMOS tube, a protection circuit, a DC / DC converter, a filter, a voltage clamping circuit and an output port;

[0039] The input port includes VIN+ and VIN-, which are used to receive external power input; the NMOS tube is used to control the switch state of the circuit, and the voltage is controlled by its conduction and cutoff;

[0040] The protection circuit includes anti-backflow and current limiting functions, which are used to prevent reverse current and limit excessive current. The protection circuit includes two parts, which are respectively located between VIN+ and VIN- and the DC / DC converter, and between the DC / DC converter and the output port VOUT;

[0041] The DC / DC converter is used to convert the input voltage into the required output voltage, and realizes voltage conversion and stable output through internal switches and control logic;

[0042] The filter is located at the output end of the DC / DC converter and is used to smooth the output voltage and reduce noise and fluctuations;

[0043] The voltage clamp circuit is located at the output port and is used to limit the output voltage to a certain value to prevent the voltage from being too high and damaging the downstream equipment.

[0044] Wherein, VIN+ and VIN- are connected to the input end of the DC / DC converter through a protection circuit, and the anti-backflow and current limiting functions of the protection circuit ensure the correct flow direction and magnitude of the current; wherein, the output end of the DC / DC converter is connected to the output port VOUT through a filter, and the filter ensures the stability of the output voltage; the voltage clamp circuit is located at the VOUT end to ensure that the output voltage does not exceed the set safety value;

[0045] Among them, the NMOS tube and the DC / DC converter are connected through a control signal to realize the control of the switching state of the DC / DC converter; the DC / DC converter and the voltage clamp circuit are connected through a voltage detection signal to monitor the output voltage in real time. When the voltage exceeds the set value, the voltage clamp circuit intervenes to limit the voltage rise and protect the safety of downstream equipment.

[0046] It should be noted that the output of the isolated DC / DC converter N1 is used as the driving voltage VGS of the NMOS tube. The output of the isolated DC / DC converter N1 is not grounded with GND, but is directly added to both ends of the NMOS tube GS as a driver. When the input is a normal working voltage, GS is the output voltage of the DC / DC converter N1, and the NMOS is normally driven to be fully turned on; when the input voltage generates a surge voltage (exceeding the voltage of the clamping Zener tube V3), the Zener tube V3 clamps the GS voltage, thereby clamping the output voltage to the Zener tube regulated voltage Vz.

[0047] It should be noted that the NMOS tube plays the role of a switch in the circuit. By controlling its on and off states, the current can be precisely controlled. In actual research, the selection and configuration of the NMOS tube need to consider its threshold voltage, on-resistance and maximum current carrying capacity to ensure reliability and efficiency under various working conditions. The protection circuit consists of two parts, located at the input and output ends respectively, providing anti-backflow and current limiting functions. In actual applications, it can effectively prevent reverse current and overcurrent conditions and protect the circuit from damage. The technical effect is to enhance the robustness of the circuit and extend the life of the equipment. The DC / DC converter is the core of the circuit and is responsible for converting the input voltage into the required output voltage. Among them, the efficiency, stability and noise level of the converter are key considerations. The DC / DC converter is connected to the voltage clamp circuit through a voltage detection signal to monitor the output voltage in real time. This design enables the circuit to respond quickly when the voltage is abnormal, protect downstream equipment, achieve real-time voltage monitoring and rapid response, and improve the reliability of the circuit.

[0048] Specifically, the DC / DC converter includes an isolated DC / DC converter N1, wherein the isolated DC / DC converter N1 is used to provide a driving voltage VGS of the NMOS tube;

[0049] The voltage at the output port of the isolated DC / DC converter N1 is applied to the gate-source port of the NMOS tube to achieve driving, and the output voltage is electrically isolated from the ground line GND;

[0050] When the input voltage of the NMOS tube is a normal working voltage, the GS terminal receives the output voltage of the isolated DC / DC converter N1 to normally drive the NMOS tube to conduct;

[0051] The protection circuit also includes a clamping voltage regulator V3. When the input voltage generates a surge voltage and exceeds the voltage of V3, V3 clamps the GS voltage, thereby clamping the output voltage to the regulated voltage Vz of V3.

[0052] It should be noted that the isolated DC / DC converter N1 is the core component in the circuit. It is responsible for converting the input voltage into a voltage VGS suitable for NMOS tube driving. The isolated design means that the input and output of the converter are electrically isolated, which can effectively prevent the noise and voltage fluctuations at the input end from affecting the output end, thereby protecting the downstream circuit and improving the safety and reliability of the circuit, especially in high-voltage or noisy application environments. The gate-source voltage VGS of the NMOS tube is a key parameter for controlling its switching state. The VGS provided by the isolated DC / DC converter N1 ensures that the NMOS tube can be fully turned on under normal operating voltage, thereby controlling the current flow of the circuit. The clamping voltage regulator V3 plays a key role in the protection circuit. It can protect the NMOS tube when the input voltage surges. When the input voltage exceeds the rated voltage of V3, V3 clamps the GS voltage to a safe regulated voltage Vz to prevent the NMOS tube from being damaged due to excessive voltage. This protection mechanism is particularly important when the power supply fluctuates or external interference occurs. It can ensure the continuous and stable operation of the circuit and enhance the circuit's anti-interference and self-protection capabilities.

[0053] Specifically, the input end of the protection circuit is connected to an input filter circuit, and the input filter circuit includes a capacitor C1 and a capacitor C3, wherein the capacitor C1 and the capacitor C3 are used as filter input capacitors to filter input clutter, thereby stabilizing circuit operation.

[0054] Specifically, the protection circuit includes a first protection circuit and a second protection circuit;

[0055] The first protection circuit includes a resistor R1 and a diode V2, wherein the resistor R1 is used to limit the current flowing through the first protection circuit to protect the voltage-stabilizing diode V3, and the diode V2 is used to prevent the output current of the isolated DC / DC converter N1 from flowing back to the input power supply;

[0056] The second protection circuit includes a resistor R3 and a diode V4, wherein the resistor R3 is used to limit the current flowing through the second protection circuit to protect the NMOS tube, and the diode V4 is used to prevent the current of the input power supply from flowing back into the isolated DC / DC converter N1.

[0057] It should be noted that the two protection circuits work together to ensure the stability and safety of the circuit under normal working conditions, while preventing equipment damage due to current backflow or overcurrent.

[0058] It can be understood that the resistor R1 and the diode V2 are used as current limiting and backflow protection in the protection circuit 1. The resistor R1 limits the current to protect the voltage regulator diode V3, and the diode V2 prevents the output of the isolated DC / DC converter N1 from backflowing to the input power supply to avoid damage to the input power supply or the isolated DC / DC converter N1. The resistor R3 and the diode V4 are used as current limiting and backflow protection in the protection circuit 2. The resistor R1 limits the current to protect the NMOS tube, and the diode V4 prevents the input power supply from backflowing into the isolated DC / DC converter N1 to avoid damage to the isolated DC / DC converter N1.

[0059] Specifically, the voltage clamp circuit adopts a voltage regulator tube for clamping, and the voltage clamp circuit includes a voltage regulator tube V3 for clamping and controlling the gate-source voltage GS of the NMOS tube;

[0060] The voltage regulator tube V3 is started when the input voltage exceeds its operating voltage threshold, and the gate-source voltage GS of the NMOS tube is limited to not exceed the set voltage regulator voltage Vz of the voltage regulator tube V3, thereby ensuring that the NMOS tube operates stably within a safe operating range.

[0061] It should be noted that in the present application, the voltage regulator V3 is used to clamp the gate-source voltage GS of the NMOS tube. When the input voltage is normal, the voltage regulator V3 does not participate in the operation of the circuit, but when the input voltage exceeds its operating voltage threshold, the voltage regulator V3 starts immediately to limit the GS voltage to below the set voltage regulator voltage Vz of the voltage regulator. The start-up of the voltage regulator V3 is triggered by the input voltage exceeding its operating voltage threshold, which usually involves a special structure inside the voltage regulator, such as a Zener diode, which can be turned on when a specific voltage is reached, thereby clamping the voltage to a predetermined value. In practical applications, this startup mechanism needs to be precisely designed to ensure that the voltage regulator can work reliably under various conditions.

[0062] Therefore, by limiting the gate-source voltage GS of the NMOS tube to not exceed the set voltage regulator voltage Vz of the voltage regulator tube V3, the voltage clamp circuit effectively protects the NMOS tube and prevents it from being damaged due to excessive voltage; the voltage clamp circuit ensures that the NMOS tube operates stably within a safe working range, and can maintain the stability and reliability of the circuit even when the input voltage fluctuates.

[0063] Specifically, the input and output ends of the converter N1 are electrically isolated, so that the port of the output end is connected to the port of the gate-source end GS of the NMOS tube to provide a driving voltage; the output voltage range of the isolated DC / DC converter N1 is 10V to 15V;

[0064] The output end of the protection circuit is connected to an output filter circuit, and the output filter circuit includes a capacitor C2 and a capacitor C4, wherein the capacitor C2 and the capacitor C4 are used as filter output capacitors to filter the output clutter, thereby stabilizing the circuit operation.

[0065] It should be noted that the output voltage range of the isolated DC / DC converter N1 is 10V to 15V. This voltage range is carefully selected to meet the driving requirements of the NMOS tube while ensuring the stability and efficiency of the circuit. Within this voltage range, the NMOS tube can be effectively turned on, providing sufficient driving current while avoiding damage caused by overvoltage.

[0066] In this embodiment, the output filter circuit includes capacitor C2 and capacitor C4, which serve as filter output capacitors to filter the output noise. Filtering is a key step to ensure stable operation of the circuit. It can reduce noise and fluctuations on the power line and improve the quality of the power supply.

[0067] In practical power management applications, such as data centers, industrial control systems, and electric vehicles, the stability and safety of power supply are crucial. The combination of isolated DC / DC converter N1 and output filter circuit provides an effective solution that can maintain stable operation of the circuit under various working conditions. In addition, this design can also implement more advanced power management strategies such as dynamic voltage adjustment and load balancing through software control, further improving energy efficiency and system performance.

[0068] Therefore, the circuit design in the present invention provides an efficient, stable and safe power management solution through the coordinated work of the isolated DC / DC converter N1 and the output filter circuit. By accurately controlling the output voltage and filtering processing, the circuit can maintain stable operation under various working conditions while providing effective overvoltage protection, and has broad application prospects in practical applications, and can achieve more advanced power management functions through further research and development.

[0069] Therefore, the present invention optimizes the traditional surge voltage, the circuit is simpler, the reliability is higher, the cost is lower, and it can effectively solve the problem of insufficient driving ability under high-power application conditions, and can also meet the requirements of surge voltage such as GJB and vehicle regulations; the present invention uses an isolated DC / DC converter N1 to achieve electrical isolation between the input and output ends, effectively enhance the safety and reliability of the circuit, and at the same time provide a precise driving voltage range of 10V to 15V, optimize the driving efficiency of the NMOS tube and flexibly adapt to different application requirements. In addition, the combination of the protection circuit and the output filter circuit effectively suppresses the voltage fluctuation and clutter at the output end through the filtering effect of capacitors C2 and C4, and improves the circuit stability; and the introduction of the voltage clamping mechanism, through the voltage regulator tube V3, responds quickly when the input voltage is abnormal, limits the gate-source voltage GS of the NMOS tube, prevents the voltage spike from damaging the tube, and protects the downstream equipment. At the same time, the comprehensive application of these technical means realizes the efficient, stable and safe operation of the power management and protection circuit, which is suitable for various application scenarios requiring high-reliability power management.

[0070] In summary, the present invention adopts a power management and protection circuit based on NMOS tubes and DC / DC converters to address the deficiencies of the prior art. The circuit integrates advanced NMOS tube control technology and efficient DC / DC converters to achieve accurate management and efficient conversion of power. At the same time, the present application also innovatively introduces a multi-level protection circuit and a voltage clamp circuit, which not only improves the stability and safety of the circuit, but also effectively prevents circuit damage caused by power supply fluctuations or external interference. In addition, the circuit design of the present application takes into account the cost and complexity of practical applications. By optimizing the circuit structure and control algorithm, the performance of the power management and protection circuit is significantly improved without increasing too much cost. Through the technology of the present application, electronic equipment can achieve higher energy efficiency and longer service life, meeting the high standards of power management for modern electronic equipment.

[0071] It should be noted that, regarding the device in the above embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment of the method, and will not be elaborated here.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0073] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A surge voltage suppression circuit based on an isolated DCDC converter drive, characterized in that: It includes input port, NMOS tube, protection circuit, DC / DC converter, filter, voltage clamping circuit and output port; The input port includes VIN+ and VIN-, which are used to receive external power input; the NMOS tube is used to control the switch state of the circuit, and the voltage is controlled by its conduction and cutoff; The protection circuit includes anti-backflow and current limiting functions, which are used to prevent reverse current and limit excessive current. The protection circuit includes two parts, which are respectively located between VIN+ and VIN- and the DC / DC converter, and between the DC / DC converter and the output port VOUT; The DC / DC converter is used to convert the input voltage into the required output voltage, and realizes voltage conversion and stable output through internal switches and control logic; The filter is located at the output end of the DC / DC converter and is used to smooth the output voltage and reduce noise and fluctuations; The voltage clamp circuit is located at the output port and is used to limit the output voltage to a certain value to prevent the voltage from being too high and damaging the downstream equipment. Wherein, VIN+ and VIN- are connected to the input end of the DC / DC converter through a protection circuit, and the anti-backflow and current limiting functions of the protection circuit ensure the correct flow direction and magnitude of the current; wherein, the output end of the DC / DC converter is connected to the output port VOUT through a filter, and the filter ensures the stability of the output voltage; the voltage clamping circuit is located at the VOUT end to ensure that the output voltage does not exceed the set safety value; Among them, the NMOS tube is connected to the DC / DC converter through a control signal to realize the control of the switching state of the DC / DC converter; the DC / DC converter is connected to the voltage clamp circuit through a voltage detection signal to monitor the output voltage in real time. When the voltage exceeds the set value, the voltage clamp circuit intervenes to limit the voltage rise and protect the safety of downstream equipment.

2. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 1, characterized in that: The DC / DC converter includes an isolated DC / DC converter N1, wherein the isolated DC / DC converter N1 is used to provide a driving voltage VGS of the NMOS tube; The voltage at the output port of the isolated DC / DC converter N1 is applied to the gate-source port of the NMOS tube to achieve driving, and the output voltage is electrically isolated from the ground line GND; When the input voltage of the NMOS tube is a normal working voltage, the GS terminal receives the output voltage of the isolated DC / DC converter N1 to normally drive the NMOS tube to conduct; The protection circuit also includes a clamping voltage regulator V3. When the input voltage generates a surge voltage and exceeds the voltage of V3, V3 clamps the GS voltage, thereby clamping the output voltage to the regulated voltage Vz of V3.

3. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 1, characterized in that: The input end of the protection circuit is connected to an input filter circuit, and the input filter circuit includes a capacitor C1 and a capacitor C3, wherein the capacitor C1 and the capacitor C3 are used as filter input capacitors to filter input clutter, thereby stabilizing circuit operation.

4. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 1, characterized in that: The protection circuit includes a first protection circuit and a second protection circuit; The first protection circuit includes a resistor R1 and a diode V2, wherein the resistor R1 is used to limit the current flowing through the first protection circuit to protect the voltage-stabilizing diode V3, and the diode V2 is used to prevent the output current of the isolated DC / DC converter N1 from flowing back to the input power supply; The second protection circuit includes a resistor R3 and a diode V4, wherein the resistor R3 is used to limit the current flowing through the second protection circuit to protect the NMOS tube, and the diode V4 is used to prevent the current of the input power supply from flowing back into the isolated DC / DC converter N1.

5. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 1, characterized in that: The voltage clamp circuit adopts a voltage regulator tube for clamping, and the voltage clamp circuit includes a voltage regulator tube V3 for clamping and controlling the gate-source voltage GS of the NMOS tube; The voltage regulator tube V3 is started when the input voltage exceeds its operating voltage threshold, and the gate-source voltage GS of the NMOS tube is limited to not exceed the set voltage regulator voltage Vz of the voltage regulator tube V3, thereby ensuring that the NMOS tube operates stably within a safe operating range.

6. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 2, characterized in that: The input and output ends of the converter N1 are electrically isolated, so that the port of the output end is connected to the port of the gate-source end GS of the NMOS tube to provide a driving voltage.

7. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 6, characterized in that: The output voltage range of the isolated DC / DC converter N1 is 10V to 15V.

8. The surge voltage suppression circuit based on isolated DCDC converter drive according to claim 1, characterized in that: The output end of the protection circuit is connected to an output filter circuit, and the output filter circuit includes a capacitor C2 and a capacitor C4, wherein the capacitor C2 and the capacitor C4 are used as filter output capacitors to filter the output clutter, thereby stabilizing the circuit operation.

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