Direct-current power supply protection device
By combining a dual analog-to-digital converter unit with a digitally controlled DC power supply protection device, the integration and cost issues of surge suppressor equipment in airborne systems are solved, achieving highly flexible and reliable power supply protection suitable for airborne environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF RADIO METROLOGY & MEASUREMENT
- Filing Date
- 2025-12-08
- Publication Date
- 2026-04-17
AI Technical Summary
When facing complex aerospace environments, existing DC airborne systems have different surge suppressor device interface definitions and physical dimensions, resulting in high development costs and technical risks, making it difficult to achieve highly integrated and fully functional surge suppression.
By combining dual analog-to-digital converters with digital control, and through direct drive of error amplifiers and switching transistors, the feedback loop is made software configurable. Combining the real-time nature of analog regulation with the intelligence of digital control, a digital closed loop is formed, which is suitable for airborne DC power supply protection.
It improves the system's flexibility and adaptability, achieves highly reliable and adjustable DC power supply protection, is particularly suitable for airborne environments, and has higher output quality and electromagnetic compatibility.
Smart Images
Figure CN121886282A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of DC power supply protection systems. More specifically, it relates to a DC power supply protection device. Background Technology
[0002] Currently, in the field of DC airborne systems, aircraft engines may generate surge voltages of 80V, 50ms, 60V, and 550ms in the DC power supply circuit when switching power supplies or changing loads. The downstream stages of aircraft engines often still directly use DC 28V or use a secondary power supply for voltage conversion. To prevent surge voltages from damaging downstream products, an adjustable surge suppression output circuit is added. Furthermore, since different models of downstream products may use different voltages, designing an adjustable surge suppression output circuit with an adjustable input undervoltage point is particularly important.
[0003] Surge suppression output adjustable circuits and undervoltage protection circuits play a crucial role in the safety of airborne electronic equipment. They accurately capture transient changes in airborne voltage while effectively suppressing airborne surge voltages. Adjusting voltages according to the requirements of downstream products is also essential for current products. However, due to the complex and diverse airborne application environments, the interface definitions and dimensions of the surge suppressors used vary considerably. With the rapid development of my country's aerospace industry, the types of surge suppressors are increasing. There is a need to develop a highly integrated and comprehensive surge suppressor that can reuse the same design methods to reduce the development cost of DC airborne surge suppressors, while avoiding the technical and schedule risks associated with the development of DC power supply protection systems. Summary of the Invention
[0004] The purpose of this disclosure is to provide a simple and low-cost DC power supply protection system with surge suppressor to solve at least one of the problems existing in the prior art.
[0005] To achieve the above objectives, the present disclosure adopts the following technical solution: The first aspect of this disclosure provides a DC power supply protection device, comprising: The system includes a control unit, a first digital-to-analog converter, a second digital-to-analog converter, a first voltage divider network unit, a first switching transistor, an error amplifier, an output interface, and an input interface. The control unit is used to output a target voltage to the first terminal of the error amplifier through a first digital-to-analog converter unit; to obtain an output voltage by acquiring the voltage of the output interface through a first voltage divider network unit; to obtain a feedback voltage based on the output voltage and output the feedback voltage to the second terminal of the error amplifier through a second digital-to-analog converter unit, so that the error amplifier dynamically adjusts its output voltage according to the target voltage and the feedback voltage and outputs it to the control electrode of the first switching transistor to control the conduction degree of the first switching transistor. The first switching transistor, in response to the control of the error amplifier, adjusts the voltage input from the input interface and outputs it to an external load through the output interface.
[0006] Furthermore, the first output terminal of the control unit is connected to the input terminal of the first digital-to-analog converter unit, the output terminal of the first digital-to-analog converter unit is connected to the first input terminal of the error amplifier, the second output terminal of the control unit is connected to the input terminal of the second digital-to-analog converter unit, the output terminal of the second digital-to-analog converter unit is connected to the second input terminal of the error amplifier, and the output terminal of the error amplifier is connected to the control electrode of the first switching transistor; the first electrode of the first switching transistor is connected to the input interface, and the second electrode is connected to the output interface; the first acquisition terminal of the control unit is connected to the output terminal of the first voltage divider network unit, and the input terminal of the first voltage divider network unit is connected to the output interface.
[0007] Furthermore, the first switching transistor is a MOSFET; The DC power supply protection device also includes a constant current unit; the first switching transistor is a MOSFET, the fourth output terminal of the control unit is connected to the control terminal of the constant current unit, the input terminal of the constant current unit is connected to the external power supply terminal, and the output terminal is connected to the drain of the first switching transistor.
[0008] Furthermore, the first switching transistor is an N-channel MOSFET.
[0009] Furthermore, the DC power supply protection device also includes a comparator, a first resistor, a second resistor, a third resistor, a fourth resistor, and a second switching transistor; One end of the first resistor, one end of the second resistor, one end of the third resistor, one end of the fourth resistor, and the first input terminal of the comparator are connected to the first node; The output terminal of the comparator and the other end of the fourth resistor are connected to the control electrode of the second switching transistor, the other end of the first resistor is connected to the input interface, and the second input terminal of the comparator is connected to the reference voltage. The second terminal of the second switch is connected to the input interface, and the first terminal is connected to the first terminal of the first switch.
[0010] Furthermore, the third resistor is a potentiometer.
[0011] Furthermore, the DC power supply protection device also includes a second voltage divider network module, a fifth resistor, a sixth resistor, a second switching transistor, and a third switching transistor; One end of the fifth resistor, one end of the sixth resistor, the first electrode of the third switch, and the control electrode of the second switch are connected to the second node. The input terminal of the second voltage divider network module, the other end of the sixth resistor, and the second electrode of the second switch are respectively connected to the input interface. The first electrode of the second switch is connected to the first electrode of the first switch. The output terminal of the second voltage divider network module is connected to the second acquisition terminal of the control unit. The third output terminal of the control unit is respectively connected to the control electrode of the third switch and the other end of the fifth resistor.
[0012] Furthermore, the second switch is a P-channel MOSFET.
[0013] Furthermore, the third switch is an N-channel MOSFET.
[0014] Furthermore, the control unit is a microcontroller unit.
[0015] The beneficial effects of this disclosure are as follows: This invention employs a combination of dual analog-to-digital converters and digital control, making the parameters and protection thresholds of the feedback loop fully configurable in software, thus improving the system's flexibility and adaptability. Simultaneously, the direct drive of the analog error amplifier and power switch ensures the loop's speed, balancing the intelligence of digital control with the real-time performance of analog adjustment. This makes it particularly suitable for high-reliability, highly adjustable DC power supply protection scenarios, such as airborne applications. It is especially suitable for digital surge suppression output adjustable systems, where the error amplifier and switch enable higher output quality and better electromagnetic compatibility. Attached Figure Description
[0016] The specific embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.
[0017] Figure 1 A schematic diagram of the structure of a DC power supply protection device according to a first embodiment of the present disclosure is shown.
[0018] Figure 2 A schematic diagram of the structure of a DC power supply protection device according to a second embodiment of the present disclosure is shown.
[0019] Figure 3 A schematic diagram of the undervoltage protection circuit according to the first embodiment of this disclosure is shown.
[0020] Figure 4 A schematic diagram of the undervoltage protection circuit according to a second embodiment of the present disclosure is shown. Detailed Implementation
[0021] To more clearly illustrate this disclosure, the following description, in conjunction with embodiments and accompanying drawings, provides further insight. Similar components in the drawings are indicated by the same reference numerals. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of this disclosure.
[0022] One embodiment of the present invention discloses a DC power supply protection device, comprising: The control unit, the first digital-to-analog converter, the second digital-to-analog converter, the first voltage divider network unit, the first switching transistor, the error amplifier, the output interface Vout, and the input interface Vin; The control unit is used to output a target voltage to the first terminal of the error amplifier through the first digital-to-analog converter unit; to obtain the output voltage by acquiring the voltage of the output interface Vout through the first voltage divider network unit; to obtain a feedback voltage based on the output voltage and output the feedback voltage to the second terminal of the error amplifier through the second digital-to-analog converter unit, so that the error amplifier dynamically adjusts its output voltage according to the target voltage and the feedback voltage and outputs it to the control electrode of the first switching transistor to control the conduction degree of the first switching transistor. The first switching transistor, in response to the control of the error amplifier, adjusts the voltage input from the input interface Vin and outputs it to an external load through the output interface Vout. The error amplifier may be an operational amplifier.
[0023] This invention combines a dual analog-to-digital converter (ADC) with digital control, improving the system's flexibility and adaptability. Simultaneously, the direct drive of the analog error amplifier and power switch ensures loop speed, balancing the intelligence of digital control with the real-time performance of analog adjustment. This makes it particularly suitable for high-reliability, highly adjustable DC power supply protection scenarios, such as airborne applications. It is especially suitable for digital surge suppression output adjustable systems, where the error amplifier and switch enable higher output quality and better electromagnetic compatibility.
[0024] In one possible implementation, such as Figure 1 As shown, the first output terminal of the control unit is connected to the input terminal of the first digital-to-analog converter unit, the output terminal of the first digital-to-analog converter unit is connected to the first input terminal of the error amplifier, the second output terminal of the control unit is connected to the input terminal of the second digital-to-analog converter unit, the output terminal of the second digital-to-analog converter unit is connected to the second input terminal of the error amplifier, and the output terminal of the error amplifier is connected to the control electrode of the first switching transistor; the first electrode of the first switching transistor is connected to the input interface Vin, and the second electrode is connected to the output interface Vout; the first acquisition terminal of the control unit is connected to the output terminal of the first voltage divider network unit, and the input terminal of the first voltage divider network unit is connected to the output interface Vout.
[0025] In a specific example, the control unit presets a target voltage value and outputs the corresponding target voltage to the non-inverting input of the error amplifier through the first digital-to-analog converter. Simultaneously, the control unit acquires the output voltage of the output interface Vout in real time through the first voltage divider network unit, obtains a feedback voltage based on the output voltage, and outputs the feedback voltage to the inverting input of the error amplifier through the second digital-to-analog converter. The error amplifier compares the target voltage with the feedback voltage and outputs an error voltage to the control electrode of the first switching transistor, adjusting its conduction level. The first switching transistor is connected in series between the input interface Vin and the output interface Vout, and its equivalent resistance is controlled by the output error voltage, thereby adjusting the voltage drop from input to output to make the output voltage tend towards the target value. This forms a digital closed loop, achieving high-precision voltage regulation.
[0026] Following the example above, the control unit acquires the actual voltage of the output interface Vout in real time through the first voltage divider network unit. After obtaining the digital feedback quantity through internal analog-to-digital conversion, it calculates the feedback voltage according to a preset control algorithm, which can be a PID algorithm. When a surge voltage occurs at the input interface Vin, the output voltage tends to rise. The control unit quickly detects this change through the first voltage divider network unit and rapidly reduces the output feedback voltage of the second digital-to-analog converter unit through the algorithm, causing the voltage at the inverting input of the error amplifier to decrease. The error amplifier then increases the output error voltage, causing the control electrode voltage of the first switching transistor to rise, deepening its conduction and reducing its equivalent resistance, thereby consuming more surge energy on the first switching transistor and maintaining a stable output voltage. Conversely, if the load increases and causes the output voltage to drop, the control unit increases the feedback voltage. This causes the error amplifier to reduce its error voltage, while the equivalent resistance of the first switching transistor increases, reducing its own voltage drop and thus increasing the output voltage. The entire adjustment process is completed collaboratively by digital algorithms and analog loops, resulting in fast response and high voltage regulation accuracy.
[0027] This embodiment employs a combination of dual analog-to-digital converters and digital control, making the parameters and protection thresholds of the feedback loop fully configurable in software, thus improving the system's flexibility and adaptability. Simultaneously, the direct drive of the analog error amplifier and power switching transistors ensures the loop's speed, balancing the intelligence of digital control with the real-time performance of analog adjustment. This makes it particularly suitable for high-reliability, highly adjustable DC power supply protection scenarios, such as airborne applications.
[0028] In another example, the control unit acquires the actual voltage of the output interface Vout in real time through the first voltage divider network unit, obtains the feedback quantity in digital form through internal analog-to-digital conversion, and directly uses the feedback quantity as the feedback voltage.
[0029] In one possible implementation, the first switch is a metal-oxide-semiconductor field-effect transistor (MOSFET). In a specific example, the first switch, the second switch, and the third switch are all MOSFETs, with the control electrode being the gate, the first electrode being the drain, and the second electrode being the source.
[0030] In one possible implementation, such as Figure 2 As shown, the DC power supply protection device also includes a constant current unit; the first switching transistor is a MOSFET, the fourth output terminal of the control unit is connected to the control terminal of the constant current unit, the input terminal of the constant current unit is connected to the external power supply terminal Vcc, and the output terminal is connected to the drain of the first switching transistor.
[0031] Specifically, if the MOSFET is an N-channel MOSFET, the drain of the first switching transistor is connected to the input interface Vin.
[0032] In this example, the constant current unit and the control unit work together to achieve self-testing. The control unit controls the device to enter a test state with no load and no output, and then turns on the constant current source through the fourth output terminal.
[0033] The constant current output from the constant current unit flows into the drain of the first switching transistor. At this time, the error amplifier loop is still working and will attempt to adjust the gate voltage of the first switching transistor to maintain a dummy balance.
[0034] The first switch samples the gate voltage at this time through its analog-to-digital converter.
[0035] Under normal conditions, the control unit operates in the linear region (variable resistance region), and the gate voltage will stabilize in a medium range, such as 2V-10V, so that the resistance of the control unit can withstand the voltage drop generated by the constant current.
[0036] Fault - Open circuit: If the control unit is open, the constant current cannot flow, and the error amplifier will continuously output the maximum voltage in an attempt to turn it on, causing the detected gate voltage to be close to the power supply voltage of the op-amp.
[0037] Fault - Short circuit or op-amp failure: If the control unit is short-circuited or the op-amp fails and there is no output, the gate voltage will be close to 0V.
[0038] In a specific example, a constant current unit is a circuit module capable of outputting a constant current. Its core function is to maintain a stable output current when the load device, power supply voltage, or ambient temperature changes. It typically includes an input terminal that connects to an external power supply to provide the operating voltage for the constant current unit; an output terminal that outputs a constant current; and a control terminal that dynamically adjusts the current.
[0039] In one possible implementation, the first switch is an N-channel MOSFET.
[0040] In one possible implementation, such as Figure 3 As shown, the DC power supply protection device also includes a comparator 1Z, a sixth resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a second switching transistor. One end of the sixth resistor R1, one end of the second resistor R2, one end of the third resistor R3, one end of the fourth resistor R4, and the first input terminal of the comparator 1Z are connected to the first node. The output terminal of comparator 1Z and the other end of the fourth resistor R4 are connected to the control electrode of the second switching transistor, the other end of the sixth resistor R1 is connected to the input interface Vin, and the second input terminal of comparator 1Z is connected to the reference voltage Vref. The second terminal of the second switch is connected to the input interface Vin, and the first terminal is connected to the first terminal of the first switch. The other ends of the second resistor R2 and the third resistor R3 are grounded.
[0041] In one possible implementation, the third resistor R3 is a potentiometer. The undervoltage protection operating voltage is adjusted by adjusting the potentiometer.
[0042] In one possible implementation, such as Figure 4 The DC power supply protection device shown also includes a second voltage divider network module, a fifth resistor R5, a sixth resistor R6, a second switch, and a third switch. One end of the fifth resistor R5, one end of the sixth resistor R6, the first terminal of the third switch, and the control terminal of the second switch are connected to the second node. The input terminal of the second voltage divider network module, the other end of the sixth resistor R6, and the second terminal of the second switch are respectively connected to the input interface Vin. The first terminal of the second switch is connected to the first terminal of the first switch. The output terminal of the second voltage divider network module is connected to the second acquisition terminal of the control unit. The third output terminal of the control unit is connected to the control terminal of the third switch and the other end of the fifth resistor R5. The second terminal of the third switch is grounded.
[0043] In a specific example, the working principle of this embodiment is as follows: In this embodiment, the second switch is a P-channel MOSFET and the third switch is an N-channel MOSFET.
[0044] Status 1: Input voltage is normal, system is powered normally. The second voltage divider network continuously samples the input interface Vin voltage. The control unit reads and calculates this data through its internal analog-to-digital converter module, confirming that the input interface Vin voltage is higher than the set undervoltage threshold. The third output of the control unit is a general-purpose input / output (GPIO) port, which outputs a high level. This high level fully turns on the third switch, pulling its drain voltage down to near ground. This pulls the gate of the second switch low. The second switch turns on when its voltage is lower than its source voltage. Since the turn-on condition is met, the second switch turns on.
[0045] In a specific example, the first and second outputs are either the Serial Peripheral Interface (SPI) or the Inter-Integrated Circuit (I2C) bus, respectively. The fourth interface is a GPIO port.
[0046] The input interface Vin voltage is successfully supplied to the first switching transistor through the conducting second switching transistor, and the system works normally.
[0047] State 2: Input voltage undervoltage, system trips protection. The control unit calculates and finds that the input interface Vin voltage is lower than the set undervoltage threshold. The control unit immediately outputs a low level at its third output terminal. This low level turns off the third switch, causing its drain to become high-impedance. Because the third switch is off, the input interface Vin voltage pulls the control voltage of the second switch high through the sixth resistor R6. The gate voltage of the second switch is pulled up to be approximately equal to its source voltage, resulting in the second switch being completely turned off.
[0048] The main power path is completely cut off, the subsequent circuit loses power, and the output interface Vout is zero, thus protecting the subsequent load from operating under abnormally low voltage.
[0049] In this embodiment, the undervoltage protection point is entirely set by the control unit, and can be adjusted by modifying the program without replacing any hardware resistors, greatly enhancing the versatility and adaptability of the equipment. The control unit can add complex logic such as hysteresis comparison, fault timing, and status indication to prevent frequent jitter at critical points and improve system stability. The undervoltage protection function is seamlessly integrated into a digital control system centered on the control unit, simplifying the system architecture. The input undervoltage protection circuit of this invention can be designed with a wide range of undervoltage points to adapt to different working environments.
[0050] In one possible implementation, the second switch is a P-channel MOSFET.
[0051] In one possible implementation, the third switch is an N-channel MOSFET.
[0052] In one possible implementation, the control unit is a microcontroller unit (MCU).
[0053] In summary, this invention achieves a wide-range voltage regulation design by utilizing an input voltage divider network module circuit, along with potentials, switches, a reference source, and comparator 1Z, thereby improving product versatility. The digital input undervoltage protection system, designed based on the input voltage divider network module, offers faster response and higher reliability. The digital surge suppression output adjustable system, utilizing an error amplifier and MOSFETs, achieves higher output quality and better electromagnetic compatibility. The self-test circuit enables self-testing of the surge suppression MOSFETs and error amplifier, enhancing circuit reliability.
[0054] Compared to existing technologies, DC power supply protection system design offers certain advantages in airborne and other fields, particularly in terms of flexible configuration, reliability, fault warning, and simplicity. Its protection thresholds and surge suppression slopes are implemented in software, eliminating the need for hardware replacements and offering high configurability. Adding custom circuitry can improve product reliability and provide early warnings before faults occur. Simplified hardware and enhanced functionality integrate undervoltage protection, surge suppression, adjustable output, and self-testing into a single circuit, achieving a synergistic effect greater than the sum of its parts.
[0055] In the description of this disclosure, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; they can be internal connections between two elements. For those skilled in the art, the specific meaning of the above terms in this disclosure can be understood according to the specific circumstances.
[0056] It should also be noted that, in the description of this disclosure, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0057] Obviously, the above embodiments of this disclosure are merely examples for clearly illustrating this disclosure, and are not intended to limit the implementation of this disclosure. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all implementation methods here. Any obvious variations or modifications derived from the technical solutions of this disclosure are still within the protection scope of this disclosure.
Claims
1. A direct current power supply protection device, characterized by, include: The system includes a control unit, a first digital-to-analog converter, a second digital-to-analog converter, a first voltage divider network unit, a first switching transistor, an error amplifier, an output interface, and an input interface. The control unit is used to output a target voltage to the first terminal of the error amplifier through a first digital-to-analog converter unit; to obtain an output voltage by acquiring the voltage of the output interface through a first voltage divider network unit; to obtain a feedback voltage based on the output voltage and output the feedback voltage to the second terminal of the error amplifier through a second digital-to-analog converter unit, so that the error amplifier dynamically adjusts its output voltage according to the target voltage and the feedback voltage and outputs it to the control electrode of the first switching transistor to control the conduction degree of the first switching transistor. The first switching transistor, in response to the control of the error amplifier, adjusts the voltage input from the input interface and outputs it to an external load through the output interface.
2. The DC power supply protection device according to claim 1, characterized in that, The first output terminal of the control unit is connected to the input terminal of the first digital-to-analog converter unit, the output terminal of the first digital-to-analog converter unit is connected to the first input terminal of the error amplifier, the second output terminal of the control unit is connected to the input terminal of the second digital-to-analog converter unit, the output terminal of the second digital-to-analog converter unit is connected to the second input terminal of the error amplifier, and the output terminal of the error amplifier is connected to the control electrode of the first switching transistor. The first electrode of the first switching transistor is connected to the input interface, and the second electrode is connected to the output interface. The first acquisition terminal of the control unit is connected to the output terminal of the first voltage divider network unit, and the input terminal of the first voltage divider network unit is connected to the output interface.
3. The DC power supply protection device according to claim 2, characterized in that, The DC power supply protection device also includes a constant current unit; the first switching transistor is a MOSFET, the fourth output terminal of the control unit is connected to the control terminal of the constant current unit, the input terminal of the constant current unit is connected to the external power supply terminal, and the output terminal is connected to the drain of the first switching transistor.
4. The DC power supply protection device according to claim 3, characterized in that, The first switch is an N-channel MOSFET.
5. The DC power supply protection device according to claim 2, characterized in that, The DC power supply protection device also includes a comparator, a first resistor, a second resistor, a third resistor, a fourth resistor, and a second switching transistor; One end of the first resistor, one end of the second resistor, one end of the third resistor, one end of the fourth resistor, and the first input terminal of the comparator are connected to the first node; The output terminal of the comparator and the other end of the fourth resistor are connected to the control electrode of the second switching transistor, the other end of the first resistor is connected to the input interface, and the second input terminal of the comparator is connected to the reference voltage. The second terminal of the second switch is connected to the input interface, and the first terminal is connected to the first terminal of the first switch.
6. The DC power supply protection apparatus according to claim 5, wherein The third resistor is a potentiometer.
7. The DC power supply protection device according to claim 2, characterized in that, The DC power supply protection device also includes a second voltage divider network module, a fifth resistor, a sixth resistor, a second switching transistor, and a third switching transistor; One end of the fifth resistor, one end of the sixth resistor, the first electrode of the third switch, and the control electrode of the second switch are connected to the second node. The input terminal of the second voltage divider network module, the other end of the sixth resistor, and the second electrode of the second switch are respectively connected to the input interface. The first terminal of the second switching transistor is connected to the first terminal of the first switching transistor; the output terminal of the second voltage divider network module is connected to the second acquisition terminal of the control unit; the third output terminal of the control unit is connected to the control terminal of the third switching transistor and the other end of the fifth resistor.
8. The DC power supply protection device according to claim 7, characterized in that, The second switch is a P-channel MOSFET.
9. The DC power supply protection device according to claim 8, characterized in that, The third switch is an N-channel MOSFET.
10. The DC power supply protection device according to claim 1, characterized in that, The control unit is a microcontroller unit.