Current limiting circuit suitable for low-temperature starting of airborne electronic equipment

Abstract

The invention provides a current limiting circuit suitable for low-temperature starting of airborne electronic equipment. Comprising a charging current-limiting module used for suppressing a starting current when airborne electronic equipment is started at a low temperature or a capacitive load is too large, a power supply and discharge protection module used for guaranteeing circuit power supply continuity and blocking a reverse current when an external 28V power supply of the equipment is instantaneously disconnected or fluctuates, and a filtering module used for suppressing electromagnetic interference of the circuit. And the charging current-limiting module, the power supply and discharge protection module and the filtering module are connected to form a power supply loop of the airborne electronic equipment. The starting current in a low-temperature environment or when a capacitive load is too large is effectively suppressed, the suppression of the starting current of an electronic circuit and an integrated circuit is realized, the circuit power supply continuity when a power supply is instantaneously disconnected or fluctuates is ensured by adjusting the current-limiting resistor, and the starting current suppression circuit has good electromagnetic interference suppression capability and is suitable for popularization and application. Stable starting and operation of airborne electronic equipment under extreme working conditions are ensured, and the problem that starting of electronic products is difficult in the low-temperature starting process and the capacitive load is too large is solved.

Description

Technical Field

[0001] This invention belongs to the field of electronic circuit technology, specifically relating to a current limiting circuit suitable for low-temperature startup of airborne electronic equipment. Background Technology

[0002] In today's rapidly developing aerospace technology, airborne electronic equipment (AFEE) serves as the core support for navigation, communication, flight control, and mission execution modules in modern aircraft. Its reliability directly impacts flight safety and mission completion quality. With the continuous iteration and upgrading of electronic technology, the operational scenarios for aircraft are constantly expanding, extending from plains airspace with normal temperatures to extreme low-temperature environments such as high altitudes, polar regions, and near-space. Simultaneously, to meet the demands for higher precision and multi-functional missions, the integration of AFEE is continuously increasing, and the scale of internal capacitive loads is also expanding. This places more stringent requirements on the environmental adaptability and reliable startup of AFEE. In practical applications, when equipment is in a low-temperature environment, the physical characteristics of its internal electronic components change significantly. For example, the on-resistance of semiconductor devices increases, and the equivalent series resistance of capacitors rises, leading to a sharp increase in the instantaneous current required for startup, a significant increase in startup power consumption, and even failure to start normally. To solve these problems, it is necessary to design a current-limiting circuit suitable for low-temperature startup of airborne electronic equipment. Summary of the Invention

[0003] The technical problem solved by this invention is to provide a current-limiting circuit suitable for low-temperature startup of airborne electronic equipment. This circuit effectively suppresses the startup current in low-temperature environments or under excessive capacitive loads, thereby suppressing the startup current of electronic circuits and integrated circuits. By adjusting the current-limiting resistor, it ensures the continuity of power supply to the load circuit when the external power supply to the equipment experiences momentary interruptions or fluctuations. Simultaneously, it possesses excellent electromagnetic interference suppression capabilities, ensuring reliable startup and operation of airborne electronic equipment under extreme conditions. This effectively solves the problem of startup difficulties caused by low temperatures and excessive capacitive loads in electronic products, guaranteeing the product's temperature application range. The implementation process is simple and reliable, with low cost, and the circuit parameters are easy to adjust. The startup operating current can be flexibly adjusted, and further iterations can achieve circuits with larger startup currents, resulting in a wide range of applications.

[0004] The technical solution adopted in this invention is a current-limiting circuit suitable for low-temperature startup of airborne electronic equipment. It includes a charging current-limiting module for suppressing the startup current when the airborne electronic equipment is starting at low temperatures or under excessive capacitive load; a power supply and discharge protection module for ensuring the continuity of power supply and blocking reverse current when the external 28V power supply to the equipment experiences momentary interruptions or fluctuations; and a filtering module for suppressing electromagnetic interference in the circuit. The charging current-limiting module, power supply and discharge protection module, and filtering module are connected to form the power supply circuit of the airborne electronic equipment. The charging current-limiting module is composed of a unidirectional diode D1, a current-limiting resistor R2, and an energy storage tantalum capacitor C3. The diode D1, the energy storage tantalum capacitor C3, the unidirectional diode D3, and the DC / DC converter U1 constitute a power supply and discharge protection module. The anode of the unidirectional diode D1 is connected to the external 28V power supply of the device, and the cathode of the unidirectional diode D1 is connected to one end of the current limiting resistor R2. The positive terminal of the energy storage tantalum capacitor C3 is connected to the other end of the current limiting resistor R2 and the anode of the unidirectional diode D3, and the negative terminal of the energy storage tantalum capacitor C3 is grounded. The cathode of the unidirectional diode D3 is connected to the positive input terminal of the DC / DC converter U1, and the negative input terminal and the ground terminal of the DC / DC converter U1 are both connected to the common ground.

[0005] The filtering module includes filter capacitors C1, C2, and C4. Filter capacitor C1 is connected in parallel between the positive terminal of the power supply circuit and the common ground to filter out electromagnetic EMI interference on the input side of the power supply circuit. Filter capacitors C2 and C4 are connected in parallel between the output terminal of the DC / DC converter U1 and the common ground to filter out EMI interference noise on the output side after power conversion.

[0006] Furthermore, when the external 28V power supply of the device is powered on normally, it can charge the energy storage tantalum capacitor C3 through the unidirectional diode D1 and the current limiting resistor R2, and suppress the starting current by adjusting the value of the current limiting resistor R2.

[0007] Furthermore, when the external 28V power supply to the device experiences a momentary interruption or fluctuation, it discharges through the energy storage tantalum capacitor C3, and the unidirectional diode D1 prevents the energy storage tantalum capacitor C3 from flowing back into the external 28V power supply during discharge.

[0008] Advantages of this invention compared to existing technologies: 1. This technical solution uses the current-limiting resistor R2 in the charging current-limiting module to flexibly adjust the resistance value according to the characteristics of the components and the scale of the capacitive load in low-temperature environments, effectively suppressing the instantaneous large current during startup, solving the problem of startup difficulties caused by excessive startup current in airborne electronic equipment in low-temperature and frigid environments, and ensuring reliable startup of equipment in extreme temperature zones. 2. In this technical solution, the energy storage tantalum capacitor C3 in the power supply protection module discharges rapidly when the power supply is interrupted or fluctuates, providing temporary power to the circuit. Combined with the reverse blocking function of the unidirectional diode D1, it not only avoids the damage of the external 28V power supply and circuit caused by current backflow, but also ensures the continuous operation of airborne electronic equipment under complex flight conditions, thereby improving the environmental adaptability and mission reliability of the equipment. 3. The filtering module of this technical solution uses the synergistic effect of filter capacitors C1, C2 and C4 to filter out electromagnetic interference on the power supply input side and noise on the output side after voltage conversion. At the same time, the reasonable grounding design reduces ground loop interference, effectively reduces the impact of the complex electromagnetic environment of the aircraft on the circuit, ensures the stability of the output voltage, and improves the operating accuracy and stability of airborne electronic equipment. 4. This technical solution has a simple and compact structure, is easy to integrate and install, and has low electronic component costs. It does not require complex control chips or special customized components, making it easy for mass production and engineering applications, and has high practicality and economy. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the circuit structure of the present invention. Detailed Implementation

[0010] The following will be based on embodiments of the present invention. Figure 1 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0011] It should be noted that, unless otherwise stated herein, the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0012] In this document, the terms "comprising," "including," or any other variations thereof are intended to cover a 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 limitation, 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.

[0013] Current-limiting circuits suitable for low-temperature startup of airborne electronic equipment, such as Figure 1 As shown, the system includes a charging current limiting module 1 for suppressing the starting current of airborne electronic equipment during low-temperature startup or when the capacitive load is too large; a power supply and discharge protection module 2 for ensuring the continuity of circuit power supply and blocking reverse current when the external 28V power supply to the equipment is interrupted or fluctuates; and a filtering module 3 for suppressing electromagnetic interference in the circuit. The charging current limiting module 1, the power supply and discharge protection module 2, and the filtering module 3 are connected to form the power supply circuit of the airborne electronic equipment. The charging current limiting module 1 is composed of a unidirectional diode D1, a current limiting resistor R2, and an energy storage tantalum capacitor C3. C3, unidirectional diode D3, and DC / DC converter U1 constitute the power supply and discharge protection module 2. The anode of the unidirectional diode D1 is connected to the external 28V power supply of the device, and the cathode of the unidirectional diode D1 is connected to one end of the current limiting resistor R2. The positive terminal of the energy storage tantalum capacitor C3 is connected to the other end of the current limiting resistor R2 and the anode of the unidirectional diode D3, and the negative terminal of the energy storage tantalum capacitor C3 is grounded. The cathode of the unidirectional diode D3 is connected to the positive input terminal of the DC / DC converter U1, and the negative input terminal and the ground terminal of the DC / DC converter U1 are both connected to the common ground. In the above structure, the current-limiting resistor R2 in the charging current-limiting module can flexibly adjust its resistance value according to the characteristics of the components and the scale of the capacitive load in low-temperature environments, effectively suppressing the instantaneous large current during startup. This solves the problem of startup difficulties caused by excessive startup current in airborne electronic equipment in low-temperature and frigid environments, ensuring reliable startup of the equipment in extreme temperature zones. The energy storage tantalum capacitor C3 in the power supply and discharge protection module discharges rapidly when the power supply is interrupted or fluctuates, providing temporary power to the circuit. Combined with the reverse blocking function of the unidirectional diode D1, it not only avoids the damage of current backflow to the external 28V power supply and circuit, but also ensures the continuous operation of airborne electronic equipment under complex flight conditions, improving the environmental adaptability and mission reliability of the equipment. The filtering module 3 is specifically as follows: The filtering module 3 includes filter capacitors C1, C2, and C4. Filter capacitor C1 is connected in parallel between the positive terminal of the power supply / discharge circuit and the common ground to filter out electromagnetic EMI interference from the power supply / discharge input side. Filter capacitors C2 and C4 are connected in parallel between the output terminal of the DC / DC converter U1 and the common ground to filter out EMI interference noise from the output side after power conversion. In the above structure, the filtering module 3, through the synergistic effect of filter capacitors C1, C2, and C4, filters out electromagnetic interference from the power supply input side and noise from the output side after voltage conversion, respectively. Simultaneously, a reasonable grounding design reduces ground loop interference, effectively reducing the impact of the complex electromagnetic environment of the aircraft on the circuit, ensuring the stability of the output voltage, and improving the operating accuracy and stability of airborne electronic equipment. By adjusting the parameters of the current-limiting resistor R2 and the energy storage tantalum capacitor C3, the current magnitude can be adjusted, allowing for flexible configuration of the device's starting current value. By adjusting the parameters of filter capacitors C1, C2, and C4, the EMI efficiency of the overall working circuit is further optimized.

[0014] When the external 28V power supply of the device is powered on normally, it can charge the energy storage tantalum capacitor C3 through the unidirectional diode D1 and the current limiting resistor R2. By adjusting the size of the current limiting resistor R2, the starting current is suppressed, ensuring that the starting current of the airborne electronic equipment is within the maximum allowable range when starting at low temperature or with a large capacitive load, and the device can start up and work smoothly. When the current limiting resistor R2 is larger, the current during the device startup process is smaller, and the easier it is for the device to start up normally.

[0015] When the external 28V power supply to the device experiences a momentary interruption or fluctuation, the energy storage tantalum capacitor C3 discharges, ensuring that the device continues to operate normally for a certain period of time. The unidirectional diode D1 prevents the energy storage tantalum capacitor C3 from flowing back into the external 28V power supply during discharge, thus avoiding damage to other onboard equipment. The unidirectional diode D3 also protects the energy storage tantalum capacitor C3 from repeated charging when other capacitive loads inside the device discharge.

[0016] In operation, when the airborne electronic equipment starts up, the external 28V power supply is normally powered on. After the unidirectional diode D1 conducts, the current flows through the current-limiting resistor R2 to the energy storage tantalum capacitor C3 to charge it. If the equipment is in a low-temperature environment and has a large internal capacitive load, the peak value of the instantaneous starting current is high. The current-limiting resistor R2 limits the rate of current rise through its own resistance, suppressing the peak starting current within the range that meets the safe starting current requirements of the airborne electronic equipment. At the same time, the filter capacitor C1 filters out electromagnetic interference from the +28V power supply to ensure stable input current. During flight, if the external 28V power supply to the equipment experiences a momentary interruption or fluctuation due to turbulence or other reasons, the energy storage tantalum capacitor C3 immediately discharges, supplying power to the input terminal of the DC / DC converter U1 through the unidirectional diode D3. This ensures the stability of the input voltage of the DC / DC converter U1 and prevents the airborne electronic equipment from shutting down due to power interruption. The unidirectional diode D1 is reverse-biased to prevent the discharge current of C3 from flowing back to the external 28V power supply side of the equipment, thus protecting the power module from damage. DC / DC converter U1 steps down the external 28V power supply input voltage to a stable +5V voltage. The output side filter capacitor C2 (10μF) filters out low-frequency noise, and the filter capacitor C4 (0.1μF) filters out high-frequency noise. Finally, it outputs a clean and stable +5V voltage to the airborne electronic equipment, ensuring stable operation of the equipment in complex environments such as low temperature and electromagnetic interference.

[0017] This technical solution has a simple and compact structure, is easy to integrate and install, and has low electronic component costs. It does not require complex control chips or special customized components, making it easy for mass production and engineering applications. It has high practicality and economy, and can be applied to circuits with large internal capacitive loads and high reliability requirements.

[0018] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0019] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A current-limiting circuit suitable for low-temperature startup of airborne electronic equipment, characterized in that: The system includes a charging current limiting module (1) for suppressing the starting current of airborne electronic equipment during low-temperature startup or when the capacitive load is too large; a power supply and discharge protection module (2) for ensuring the continuity of circuit power supply and blocking reverse current when the external 28V power supply to the equipment is interrupted or fluctuates; and a filtering module (3) for suppressing electromagnetic interference in the circuit. The charging current limiting module (1), the power supply and discharge protection module (2), and the filtering module (3) are connected to form the power supply circuit of the airborne electronic equipment. The charging current limiting module (1) is composed of a unidirectional diode D1, a current limiting resistor R2, and an energy storage tantalum capacitor C3. The energy storage tantalum capacitor C3, the unidirectional diode D3, and the DC / DC converter U1 constitute the power supply and discharge protection module (2). The anode of the unidirectional diode D1 is connected to the external 28V power supply of the device, and the cathode of the unidirectional diode D1 is connected to one end of the current limiting resistor R2. The positive terminal of the energy storage tantalum capacitor C3 is connected to the other end of the current limiting resistor R2 and the anode of the unidirectional diode D3, and the negative terminal of the energy storage tantalum capacitor C3 is grounded. The cathode of the unidirectional diode D3 is connected to the positive input terminal of the DC / DC converter U1, and the negative input terminal and the ground terminal of the DC / DC converter U1 are both connected to the common ground.

2. The current limiting circuit for low-temperature startup of airborne electronic equipment according to claim 1, characterized in that: The filtering module (3) includes a filter capacitor C1, a filter capacitor C2 and a filter capacitor C4. The filter capacitor C1 is connected in parallel between the positive terminal of the power supply circuit and the common ground to filter out electromagnetic EMI interference on the input side of the power supply circuit. The filter capacitors C2 and C4 are connected in parallel between the output terminal of the DC / DC converter U1 and the common ground to filter out EMI interference noise on the output side after power conversion.

3. The current limiting circuit for low-temperature startup of airborne electronic equipment according to claim 1, characterized in that: When the external 28V power supply of the device is powered on normally, it can charge the energy storage tantalum capacitor C3 through the unidirectional diode D1 and the current limiting resistor R2, and suppress the starting current by adjusting the value of the current limiting resistor R2.

4. The current limiting circuit for low-temperature startup of airborne electronic equipment according to claim 1, characterized in that: When the external 28V power supply to the device experiences a momentary interruption or fluctuation, it discharges through the energy storage tantalum capacitor C3, and the unidirectional diode D1 prevents the energy storage tantalum capacitor C3 from flowing back into the external 28V power supply during discharge.

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