Astronavigation main and standby power supply fault isolation control circuit and control method thereof

Abstract

The invention relates to a main and standby power supply fault automatic isolation control circuit for space navigation and a control method thereof. The circuit comprises a main control unit and a backup control unit, the main control unit comprises a main DC / DC converter, a main fault detection and latch circuit and a main output isolation circuit; the backup control unit comprises a backup DC / DC converter, a backup fault detection and latch circuit and a backup output isolation circuit; the main fault detection and latch circuit comprises a main fault detection circuit and a main fault latch circuit; the backup fault detection and latch circuit comprises a backup fault detection circuit and a backup fault latch circuit. According to the circuit, the switching power supply and the control circuit thereof in the power supply and distribution system are subjected to main and backup design, and when a main power supply system breaks down, faults can be effectively and automatically isolated, a backup power supply system is started, and power is supplied to electronic equipment, so that the working reliability of the power supply and distribution system in the electronic equipment for aerospace is improved, and the on-orbit life of the electronic equipment is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies and power supply and distribution systems, and in particular to an automatic isolation control circuit for main and standby power supply failures for aerospace use and a control method thereof. Background Art

[0002] The power supply and distribution system of electronic equipment is usually composed of a multi-output switching power supply and a control function circuit. Its main function is to realize the isolation and conversion of the primary power supply into various voltages required for the power supply of electronic equipment, while meeting the requirements of the power supply of electronic equipment, such as the on / off pulse command control and the input bus voltage power-off locking.

[0003] The power supply and distribution system of electronic equipment is usually composed of a multi-output switching power supply and a switching power supply control functional circuit, which realizes the isolation and conversion of the primary power supply into various voltages required for powering the electronic equipment, while meeting the needs of power distribution of electronic equipment such as power on and off command control, timing power-on control, and output voltage telemetry.

[0004] The power supply and distribution system for aerospace electronic equipment is usually designed with two identical sets of multi-output switching power supplies and switching power supply control function circuits, namely the main and backup sets, to improve the on-orbit service life and long-term working reliability. The main and backup sets of power supply and distribution systems for aerospace electronic equipment usually realize autonomous switching between the main and backup sets, and isolate the faulty switching power supply voltage output at the same time. The main and backup sets of two completely independent switching power supplies, and the output power supply is only for the same load system. When one of them fails, it does not affect the normal power supply of the other. It is necessary to design an isolation circuit for the output of the two completely independent switching power supplies. It is often designed as a MOS tube and Schottky diode isolation circuit. When the output current of the switching power supply is large, a MOS tube isolation circuit is often used. If an N-channel MOS tube is used to control the output bus, a MOS tube driver auxiliary power supply needs to be designed. If a P-channel MOS tube is used to control the output bus, a MOS tube drive circuit needs to be designed.

[0005] Therefore, it is necessary to realize an aerospace main and backup power supply fault automatic isolation control circuit for improving the power supply reliability of the power supply and distribution system in aerospace electronic equipment, which is suitable for the main and backup and fault automatic isolation occasions of the power supply and distribution system in aerospace electronic equipment. Summary of the invention

[0006] In order to address the deficiencies in the prior art, the purpose of the present invention is to provide an automatic isolation control circuit for main and backup power supply faults for aerospace use and a control method thereof. The circuit and its control method design the switching power supply and its control circuit in the power supply and distribution system as a main and backup. When the main power supply system fails, the fault can be effectively and automatically isolated, and the backup power supply system can be started to power the electronic equipment, thereby improving the working reliability of the power supply and distribution system in aerospace electronic equipment and extending the on-orbit life of the electronic equipment.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] An automatic isolation control circuit for main and standby power supply faults for aerospace use comprises a main control unit and a backup control unit; the main control unit comprises a main DC / DC converter, a main fault detection and latching circuit and a main output isolation circuit; the backup control unit comprises a backup DC / DC converter, a backup fault detection and latching circuit and a backup output isolation circuit; the main fault detection and latching circuit comprises a main fault detection circuit and a main fault latching circuit; the backup fault detection and latching circuit comprises a backup fault detection circuit and a backup fault latching circuit.

[0009] Preferably according to the present invention, the main fault latch circuit and the backup fault latch circuit both include a transistor V1, an operational amplifier N2, a diode V2, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a voltage regulator V3; the collector of the transistor V1 is connected to the INH terminal of the DC / DC converter, the emitter of the transistor V1 is grounded, and the base of the transistor V1 is respectively connected to the positive electrode of the diode V2 and the output terminal of the operational amplifier N2; the negative electrode of the diode V2 is connected to the same-direction input terminal of the operational amplifier N2 via the resistor R1; the power supply terminal of the operational amplifier N2 is connected to the VCC power supply, and the ground terminal is grounded; the reverse input terminal of the operational amplifier N2 is connected to the input terminal of the fault detection circuit; the first terminal of the resistor R2 is connected to the power supply VCC, and the second terminal is respectively connected to the same-direction input terminal of the operational amplifier N2 and the first terminal of the resistor R3; the second terminal of the resistor R3 is grounded; the first terminal of the resistor R4 is connected to the power supply VCC, and the second terminal is connected to the negative electrode of the voltage regulator V3, and the positive electrode of the voltage regulator V3 is grounded.

[0010] Preferably according to the present invention, the transistor V1 is an NPN transistor.

[0011] Preferably, according to the present invention, the main fault detection circuit and the backup fault detection circuit both include an optocoupler N3, a resistor R5 and a voltage regulator V4; the optocoupler N3 includes a light emitting diode and a phototransistor; the collector of the phototransistor is connected to the reverse input terminal of the operational amplifier N2, and the emitter of the phototransistor is grounded; the positive electrode of the light emitting diode is connected to the positive output terminal of the DC / DC converter via the resistor R5; the negative electrode of the light emitting diode is connected to the negative electrode of the voltage regulator V4, and the positive electrode of the voltage regulator V4 is grounded.

[0012] Preferably according to the present invention, the main output isolation circuit and the backup output isolation circuit both include a resistor R6, a voltage regulator V5, a resistor R7, a transistor V7, a resistor R8, a resistor R9, a resistor R10, a MOS tube V6, a capacitor C1 and a voltage regulator V8.

[0013] The first end of the resistor R6 is connected to the positive output end of the DC / DC converter, and the second end is connected to the negative electrode of the voltage regulator tube V5, and the positive electrode of the voltage regulator tube V5 is grounded; the negative electrode of the voltage regulator tube V5 is also connected to the first end of the resistor R7 and the base of the transistor V7 respectively; the second end of the resistor R7 and the emitter of the transistor V7 are both grounded; the collector of the transistor V7 is connected to the first end of the resistor R10, and the second end of the resistor R10 is respectively connected to the first end of the resistor R8, the first end of the resistor R9, the positive electrode of the voltage regulator tube V8, and the first end of the capacitor C1; the second end of the resistor R8 is connected to the gate of the MOS tube V6, and the drain of the MOS tube V6 is connected to the positive output end of the DC / DC converter; the source of the MOS tube V6 is connected to the second end of the resistor R9, the negative electrode of the voltage regulator tube V8, and the second end of the capacitor C1, and serves as the positive output end of the fault detection circuit.

[0014] Preferably according to the present invention, the transistor V7 is an NPN transistor.

[0015] Preferably according to the present invention, the MOS tube V6 is a PMOS tube.

[0016] The present invention also includes a control method for the above-mentioned aerospace main and standby power supply fault isolation control circuit, the method comprising the following steps:

[0017] When the output voltage of the main DC / DC converter is normal, the light-emitting diode in the optocoupler N3 does not emit light, the phototransistor is cut off, the reverse input terminal of the operational amplifier N2 is high, the non-inverting input terminal is low, and the output of the operational amplifier N2 is low; the transistor V1 is cut off, the INH terminal of the main DC / DC converter output is not pulled low, and the main DC / DC converter output is powered normally; the PMOS tube V6 is turned on, and the output voltage of the main DC / DC converter is passed to the load; at this time, the backup control unit output is in standby state, and the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter.

[0018] When the output of the main DC / DC converter is abnormal, if the output voltage of the main DC / DC converter is lower than the set threshold, the transistor V7 is cut off; the PMOS tube V6 is turned off, cutting off the connection between the output of the main DC / DC converter and the load; since the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter, the PMOS tube V6 is turned on, and the output of the backup DC / DC converter starts to supply power to the load; if the output voltage of the main DC / DC converter exceeds the set threshold, the light-emitting diode in the optocoupler N3 lights up, the phototransistor is turned on, and after the phototransistor is turned on, the reverse input terminal of the operational amplifier N2 becomes low level, the output of operational amplifier N2 becomes high level, transistor V1 is turned on, the INH terminal of the main DC / DC converter output is pulled low, and the output of the main DC / DC converter is turned off; the high level output of operational amplifier N2 is fed back to the same-direction input terminal of operational amplifier N2 through diode V2 and resistor R1, so that operational amplifier N2 maintains a high level output, realizing fault latching; PMOS tube V6 is turned off, cutting off the connection between the output of the main DC / DC converter and the load; because the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter, PMOS tube V6 is turned on, and the output of the backup DC / DC converter starts to supply power to the load.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] (1) The present invention controls the output of the main and backup switching power supply circuits respectively through power MOS tubes, and at the same time performs fault detection and fault state locking on the output voltages of the main and backup switching power supply circuits, and controls the control ports of the main and backup switching power supplies; when the output voltage of the main switching power supply fails, the main switching power supply output is effectively and automatically shut down through the fault detection circuit and the fault state latching circuit; at this time, the backup switching power supply output voltage supplies power for electronic equipment. The present invention uses output isolation, fault detection and fault latching to realize automatic switching and isolation of main and backup power supplies for aerospace use, and has the characteristics of simple circuit, improved reliability of power supply system and long life, and can be widely used in circuits in the field of switching power supplies and power supply and distribution systems.

[0021] (2) The present invention can effectively suppress the malfunction problem caused by system interference by designing the N2 circuit controlled by the optocoupler N3 as a comparison circuit of the hysteresis window. By designing the power MOS tube V6 as a soft start circuit, a smooth and stable output voltage can be provided for the subsequent circuit. The fault detection unit has the function of monitoring the low output voltage or high output voltage of the DC / DC converter, and can effectively shut down the faulty DC / DC converter. When designing the circuit, the present invention gives priority to the circuit failure problems caused by single particles and total doses in the aerospace environment, and selects devices that are sensitive to single particles and total doses, which are more reliable in aerospace applications. The circuit described in the present invention has the characteristics of fast response speed, automatic fast switching of the main and standby circuits, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an application schematic diagram of the aerospace main and standby power supply failure automatic isolation control circuit of the present invention;

[0023] Figure 2 It is a principle block diagram of the automatic isolation control circuit for the main and standby power supply failure for aerospace use in the present invention;

[0024] Figure 3 The invention discloses a circuit schematic diagram of an automatic isolation control circuit for aerospace main and standby power supply failures.

[0025] in:

[0026] 1. Main short-circuit protection circuit, 2. Main surge suppression circuit, 3. Main EMI filter circuit, 4. Main control circuit, 5. Main DC / DC converter, 6. Main output isolation circuit, 7. Main fault detection and latch circuit, 8. Output filter circuit, 9. Output voltage state detection circuit, 10. Backup short-circuit protection circuit, 11. Backup surge suppression circuit, 12. Backup EMI filter circuit, 13. Backup control circuit, 14. Backup DC / DC converter, 15. Backup output isolation circuit, 16. Backup fault detection and latch circuit, 17. Main fault latch circuit, 18. Main fault detection circuit, 19. Backup fault latch circuit, 20. Backup fault detection circuit. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings:

[0028] like Figure 1As shown, when the aerospace main and backup power supply fault automatic isolation control circuit described in the present invention is applied to the power supply and distribution system, the main control unit and the backup control unit both include a short-circuit protection circuit (main short-circuit protection circuit 1 and backup short-circuit protection circuit 10), a surge suppression circuit (main surge suppression circuit 2 and backup surge suppression circuit 11), an EMI filter circuit (main EMI filter circuit 3 and backup EMI filter circuit 12), a control circuit (main control circuit 4 and backup control circuit 13), an output isolation circuit (main output isolation circuit 6 and backup output isolation circuit 15) and a fault detection and latch circuit (main fault detection and latch circuit 7 and backup fault detection and latch circuit 16); the output end of the main control unit and the output end of the backup control unit are commonly connected to an output filter circuit 8 and an output voltage state detection circuit 9.

[0029] Specifically, the short-circuit protection circuit 1 is used to prevent damage to the primary power supply due to a short circuit in the load. When a short circuit is detected, the circuit will quickly cut off the power supply to protect the entire power supply system. The input DC voltage passes through the short-circuit protection circuit to protect the safety of the primary power supply. The surge suppression circuit is used to suppress the surge current generated when the subsequent capacitor is charged and the transient large current that may come from the load to avoid impact on the previous power supply. The surge suppression circuit is used to suppress the surge current generated by the subsequent capacitor and the load. The EMI filter circuit is used to reduce the electromagnetic interference (EMI) generated by the DC / DC converter, and can also filter the noise in the input power supply to ensure the quality of the power input to the DC / DC converter. After the EMI filter circuit, the reflected ripple voltage of the DC / DC converter is suppressed, and the conducted interference is suppressed, providing input power for the DC / DC converter. The DC / DC converter outputs the power supply requirements of different voltage and power of the load. The output voltage of the DC / DC converter is isolated by the output isolation circuit to provide working voltage for the load; by setting the output voltage fault detection and fault latch circuit, the fault can be effectively isolated when the DC / DC converter fails, and the backup control unit can effectively and reliably supply power to the load. The control circuit is responsible for managing the entire power supply process, including startup, shutdown, fault handling and other operations. It can adjust the output voltage and current as needed and monitor the system status. The DC / DC converter is used to convert the input DC voltage into the output voltage required by different loads. It is the core component of the entire system and can provide stable voltage output. The output isolation circuit is used to achieve electrical isolation between the main unit and the backup unit to ensure that even if one unit fails, it will not affect the normal operation of the other unit, which helps to improve the stability and safety of the system. The fault detection and latching circuit is used to continuously monitor the working status of the DC / DC converter. Once an abnormal situation is found, it will be recorded immediately and the corresponding protection measures will be triggered; the latching mechanism can maintain the fault state until it is manually reset or the system is restarted. The output filter circuit is used to purify the output voltage of the DC / DC converter, remove any residual ripple or other undesirable signals, and provide a purer power supply to the load. The output voltage status detection circuit is used to detect the status of the output voltage in real time to ensure that it is within the predetermined range; if the voltage exceeds the set range, the control system is notified to take corresponding measures.

[0030] When the aerospace main and standby power supply fault automatic isolation control circuit described in the present invention is applied to the power supply and distribution system, first, the input DC voltage passes through the short-circuit protection circuit and the surge suppression circuit to ensure safety and reduce the impact of surge current. Then, the EMI filter circuit removes the interference signal in the power supply, and the cleaned power supply is supplied to the DC / DC converter for voltage conversion. The converted voltage passes through the output isolation circuit to provide electrical isolation between the main and standby systems. During the whole process, the fault detection and latch circuit continuously monitors the system status to ensure that any problems can be identified and handled in time. Finally, the output filter circuit and the output voltage status detection circuit ensure that the quality of the power supply finally provided meets the requirements. Such a design not only improves the stability of the system, but also enhances the ability to cope with emergencies, and is very suitable for application scenarios with extremely high requirements for power supply.

[0031] like Figure 2 As shown, the aerospace main and standby power supply fault automatic isolation control circuit described in the present invention includes a main control unit and a backup control unit. The main control unit includes a main DC / DC converter 5, a main fault detection and latching circuit 7 and a main output isolation circuit 6. The backup control unit includes a backup DC / DC converter 14, a backup fault detection and latching circuit 16 and a backup output isolation circuit 15. The main fault detection and latching circuit 7 includes a main fault detection circuit 18 and a main fault latching circuit 17. The backup fault detection and latching circuit 16 includes a backup fault detection circuit 20 and a backup fault latching circuit 19.

[0032] The present invention improves the overall reliability and safety of the system through the redundant configuration of the main control unit and the backup control unit. Among them, the main control unit serves as the main control unit. The main DC / DC converter is used to convert the input power into a stable voltage suitable for use by the equipment. The fault latch circuit is used to latch the fault state when a fault is detected. Even if the fault disappears, it will not be automatically cleared and requires manual reset or specific signal to clear. The fault detection circuit is used to continuously monitor the working status of the system and take immediate measures once an abnormal situation is found. The main output isolation circuit is used to quickly cut off the connection with the load in the event of a fault to protect the entire system from being affected. The backup control unit exists as a backup system and takes over the work when the main system fails to ensure uninterrupted power supply. The functions of each circuit in the backup control unit are the same as those of each circuit in the main control unit.

[0033] like Figure 3As shown, the main fault latch circuit 17 and the backup fault latch circuit 19 both include a transistor V1, an operational amplifier N2, a diode V2, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a voltage regulator V3. The collector of the transistor V1 is connected to the INH terminal of the DC / DC converter, the emitter of the transistor V1 is grounded, and the base of the transistor V1 is respectively connected to the positive electrode of the diode V2 and the output terminal of the operational amplifier N2; the negative electrode of the diode V2 is connected to the same-direction input terminal of the operational amplifier N2 via the resistor R1; the power supply terminal of the operational amplifier N2 is connected to the VCC power supply, and the ground terminal is grounded; the reverse input terminal of the operational amplifier N2 is connected to the input terminal of the fault detection circuit. The first terminal of the resistor R2 is connected to the power supply VCC, and the second terminal is respectively connected to the same-direction input terminal of the operational amplifier N2 and the first terminal of the resistor R3. The second terminal of the resistor R3 is grounded. The first end of the resistor R4 is connected to the power supply VCC, and the second end is connected to the negative electrode of the voltage regulator tube V3, and the positive electrode of the voltage regulator tube V3 is grounded. Preferably, the transistor V1 is an NPN transistor. The transistor V1 is used as a switch. The diode V2 is used to protect the output end of the operational amplifier N2 to prevent reverse current.

[0034] When no fault occurs, the output of the fault detection circuit is low (assumed to be 0V). The inverting input of op amp N2 is at a low level, while the non-inverting input is at a higher potential due to the voltage divider network formed by resistors R2 and R3, depending on the resistance ratio of R2 and R3. Therefore, the output of op amp N2 is high, making the base of transistor V1 high, and transistor V1 is turned on. After transistor V1 is turned on, its collector (i.e., the INH terminal of the DC / DC converter) is pulled low, and the DC / DC converter works normally.

[0035] When the fault detection circuit detects a fault, the output of the fault detection circuit becomes high (e.g., 5V). Because the stable voltage provided by the voltage regulator V3 is low, the inverting input terminal of the op amp N2 becomes high, which is higher than the potential of the non-inverting input terminal. This causes the output terminal of the op amp N2 to become low, making the base of the transistor V1 low, and the transistor V1 is cut off. After the transistor V1 is cut off, its collector (i.e., the INH terminal of the DC / DC converter) is no longer pulled down, but remains in a high impedance state or floating state, thereby triggering the disable function of the DC / DC converter and stopping the output. Once a fault occurs and triggers the output of the op amp N2 to become low, even if the output of the fault detection circuit returns to a low level, the output of the op amp N2 will not automatically return to a high level. This is because when the output of the op amp N2 becomes low, the diode V2 connects the output of the op amp N2 to the non-inverting input terminal, forming a feedback path. This feedback path keeps the non-inverting input terminal of the op amp N2 at a lower potential, thereby maintaining the output of the op amp N2 at a low level. This state will continue until the system is reset or manually intervened, causing the output of op amp N2 to return to a high level, thereby releasing the fault latch state.

[0036] Therefore, the design of the fault latch circuit ensures that the power output can be cut off in time when a fault occurs, and prevents erroneous operation after the fault signal disappears through the latch mechanism, thereby improving the reliability and safety of the system. If a more detailed analysis or specific circuit diagram is required, please provide more details or specific requirements.

[0037] like Figure 3 As shown, the main fault detection circuit 18 and the backup fault detection circuit 20 both include an optocoupler N3, a resistor R5 and a voltage regulator V4; the optocoupler N3 includes a light emitting diode and a phototransistor. The collector of the phototransistor is connected to the reverse input terminal of the operational amplifier N2, and the emitter of the phototransistor is grounded; the positive electrode of the light emitting diode is connected to the positive output terminal of the DC / DC converter through the resistor R5; the negative electrode of the light emitting diode is connected to the negative electrode of the voltage regulator V4, and the positive electrode of the voltage regulator V4 is grounded. The phototransistor is turned on after being illuminated, and the reverse input terminal of the operational amplifier N2 is pulled down to nearly 0V. The resistor R5 is used to limit the current flowing through the light emitting diode and protect the light emitting diode from excessive current shock. The voltage regulator V4 is used to provide a stable reference voltage to ensure that the light emitting diode will only be turned on when the output voltage exceeds a certain specific value.

[0038] When the output voltage of the DC / DC converter is within the normal range, the voltage across the LED is insufficient to make it emit light. Therefore, the phototransistor is not turned on, and its collector (i.e., the reverse input terminal of the op amp N2) is kept at a higher potential. The non-inverting input terminal of the op amp N2 is at a lower potential (determined by the stable voltage provided by the voltage regulator tube V3) due to the voltage divider network formed by resistors R2 and R3. Therefore, the output of the op amp N2 is high, which makes the transistor V1 turn on, the INH terminal of the DC / DC converter is pulled down, and the converter works normally. When the output voltage of the DC / DC converter becomes higher, the voltage across the LED is sufficient to make it emit light. The light emitted by the LED shines on the phototransistor, turning it on. After the phototransistor is turned on, its collector (i.e., the reverse input terminal of the op amp N2) is pulled down to nearly 0V. This causes the reverse input terminal of the op amp N2 to have a lower potential than the non-inverting input terminal, and the output of the op amp N2 becomes low. The base of the transistor V1 is at a low level, the transistor V1 is cut off, the INH terminal of the DC / DC converter is released, the disable function of the DC / DC converter is triggered, and the output is stopped.

[0039] The design of the fault detection circuit ensures that the power output can be cut off in time when the output voltage of the DC / DC converter is abnormal, and prevents erroneous operation after the fault signal disappears through the latch mechanism, thereby improving the reliability and safety of the system.

[0040] like Figure 3 As shown, the main output isolation circuit 6 and the backup output isolation circuit 15 both include a resistor R6, a voltage regulator tube V5, a resistor R7, a transistor V7, a resistor R8, a resistor R9, a resistor R10, a MOS tube V6, a capacitor C1 and a voltage regulator tube V8. The MOS tube V6 is a PMOS tube. The transistor V7 is an NPN transistor.

[0041] The first end of the resistor R6 is connected to the positive output end of the DC / DC converter, and the second end is connected to the negative electrode of the voltage regulator tube V5, and the positive electrode of the voltage regulator tube V5 is grounded; the negative electrode of the voltage regulator tube V5 is also connected to the first end of the resistor R7 and the base of the transistor V7. The second end of the resistor R7 and the emitter of the transistor V7 are both grounded. The collector of the transistor V7 is connected to the first end of the resistor R10, and the second end of the resistor R10 is connected to the first end of the resistor R8, the first end of the resistor R9, the positive electrode of the voltage regulator tube V8, and the first end of the capacitor C1. The second end of the resistor R8 is connected to the gate of the MOS tube V6, and the drain of the MOS tube V6 is connected to the positive output end of the DC / DC converter. After the source of the MOS tube V6 is connected to the second end of the resistor R9, the negative electrode of the voltage regulator tube V8, and the second end of the capacitor C1, it serves as the positive output end of the fault detection circuit. The voltage regulator tube V5 is used to detect whether the output voltage exceeds the set threshold. When the output voltage exceeds the breakdown voltage of the voltage regulator tube V5, the voltage regulator tube V5 is turned on, triggering the subsequent isolation action. Transistor V7 is used as a switch. When the voltage regulator tube V5 is turned on, the transistor V7 is turned on, pulling down the gate of the MOS tube V6, so that the MOS tube V6 is cut off. MOS tube V6 is the main isolation switch to control whether the output voltage is transmitted to the load. Resistors R8, R9, and R10 form a voltage divider network to ensure that the gate voltage of the MOS tube V6 is correct. The voltage regulator tube V8 is used to provide a stable reference voltage to ensure the stability of the source voltage of the MOS tube V6. Capacitor C1 is used for filtering to reduce noise on the power line.

[0042] When the output voltage of the main DC / DC converter is normal, the voltage is divided by resistors R6 and R7, and the voltage is stabilized by the voltage regulator tube V5, so that the NPN transistor V7 is turned on. Resistors R9 and R10 divide the output voltage, and after the voltage regulator tube V8 stabilizes, the gate and source voltages of the PMOS tube V6 are negative, the PMOS tube V6 is turned on, and the output voltage supplies power to the load. When the output voltage of the main DC / DC converter fails to be low, the voltage is divided by resistors R6 and R7, and the voltage is stabilized by the voltage regulator tube V5, so that the NPN transistor V7 is turned off, and the gate and source voltages of the PMOS tube V6 are close to 0, the PMOS tube V6 is turned off, and the backup DC / DC converter outputs at the same time, the diode in the PMOS tube V6 is biased, and the output voltage of the backup DC / DC converter supplies power to the load. This design ensures that the power output can be cut off in time when the output voltage of the DC / DC converter is abnormal, and a reliable output isolation function is achieved through a simple circuit structure. If further details or specific circuit diagrams are required, please provide more specific requirements. The deep search acts as the main isolation switch, controlling whether the output voltage is delivered to the load.

[0043] like Figure 3 As shown, the working principle of the present invention is:

[0044] The aerospace main and standby power supply fault automatic isolation control circuit described in the present invention, when the output voltage of the main DC / DC converter is normal, the light-emitting diode in the optocoupler N3 does not emit light, and the photosensitive transistor is cut off. The reverse input terminal of the operational amplifier N2 is high level, and the same direction input terminal is low level (provided by the voltage regulator tube V3), so the output of the operational amplifier N2 is low level. The transistor V1 is cut off, the INH terminal of the main DC / DC converter output is not pulled down, and the main DC / DC converter output is normally powered. The PMOS tube V6 is turned on to pass the output voltage of the main DC / DC converter to the load. The standby output is in standby state, and the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter. Since the PMOS tube V6 is turned on, the standby output will not affect the output of the main DC / DC converter.

[0045] When the output of the main DC / DC converter is abnormal, if the output voltage of the main DC / DC converter is lower than the set threshold, the transistor V7 is cut off; the PMOS tube V6 is turned off, cutting off the connection between the output of the main DC / DC converter and the load. Since the standby output voltage is higher than the output voltage, the PMOS tube V6 is turned on, and the standby output starts to supply power to the load. If the output voltage of the main DC / DC converter exceeds the set threshold, the light-emitting diode in the optocoupler N3 emits light, and the phototransistor is turned on. After the phototransistor is turned on, the reverse input terminal of the operational amplifier N2 becomes a low level. The output of the operational amplifier N2 becomes a high level, the transistor V1 is turned on, the INH terminal of the DC / DC output is pulled low, and the output of the main DC / DC converter is turned off. The high level is fed back to the same-direction input terminal of the operational amplifier N2 through the diode V2 and the resistor R1, so that the operational amplifier N2 maintains a high level output, realizing fault latching. The PMOS tube V6 is turned off, cutting off the connection between the output of the main DC / DC converter and the load. Since the standby output voltage is higher than the output voltage of the main DC / DC converter, the PMOS tube V6 is turned on, and the standby output starts to supply power to the load.

[0046] In addition, even if the output voltage of the main DC / DC converter returns to normal, due to the fault latch mechanism, the operational amplifier N2 still maintains a high level output, the transistor V1 is still turned on, and the output of the main DC / DC converter is still turned off. The system requires manual reset or a specific signal to clear the fault latch state and re-enable the output of the main DC / DC converter. During this period, the load continues to be powered by the backup output.

[0047] The automatic isolation control circuit for main and backup power supply faults for aerospace use described in the present invention can quickly detect and respond to abnormal output voltages, and once a fault is detected, it can be reliably latched, and the fault state will be maintained even if the fault disappears until it is manually reset. The output voltage is isolated by a PMOS tube to prevent the influence of the faulty output on the load. When the output of the main DC / DC converter fails, it automatically switches to the backup output to ensure the continuous operation of the system. Specifically, the present invention isolates the output of the main DC / DC converter and the output of the backup DC / DC converter through a PMOS tube, and the output voltage provides a working voltage for the load; when the output of the main DC / DC converter fails, when the output voltage is low, the NPN transistor V7 is mainly cut off, the PMOS tube V6 is turned off, and the backup DC / DC converter outputs, the output voltage is higher than the output of the main DC / DC converter, and the load is powered by the backup DC / DC converter; when the output voltage is high, the optocoupler N3 is connected through the resistor R5 and the voltage regulator tube V4, the optocoupler N3 has photocurrent, the voltage at the reverse input terminal of operational amplifier N2 is low, operational amplifier N2 outputs a high level, and NPN transistor V1 is turned on, turning off the output of the main DC / DC converter. At the same time, the high level is fed back to the same-direction input terminal of operational amplifier N2 through V2 and resistor R1. Operational amplifier N2 maintains a high level output, so that the main DC / DC converter is always in a closed output state. At this time, PMOS tube V6 is suppressed in the off state, and the backup DC / DC converter outputs. The output voltage is higher than the output of the main DC / DC converter, and the load is powered by the backup DC / DC converter.

[0048] In summary, the present invention realizes the automatic switching and fault latching functions of the output of the main DC / DC converter and the backup output through components such as voltage regulator tubes, optical couplers, operational amplifiers, transistors and PMOS tubes. When the output voltage of the main DC / DC converter is abnormal, the system can quickly cut off the output of the main DC / DC converter and switch to the backup output. At the same time, the fault latching mechanism ensures that the output of the main DC / DC converter will not automatically recover after the fault disappears, thereby improving the reliability and safety of the system.

[0049] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An automatic isolation control circuit for main and standby power supply failures for aerospace use, characterized in that: It includes a main control unit and a backup control unit; the main control unit includes a main DC / DC converter, a main fault detection and latching circuit and a main output isolation circuit; The backup control unit includes a backup DC / DC converter, a backup fault detection and latching circuit, and a backup output isolation circuit; The master fault detection and latching circuit comprises a master fault detection circuit and a master fault latching circuit; The backup fault detection and latching circuit includes a backup fault detection circuit and a backup fault latching circuit.

2. The aerospace main and standby power supply fault automatic isolation control circuit according to claim 1 is characterized in that: The main fault latch circuit and the backup fault latch circuit both include a transistor V1, an operational amplifier N2, a diode V2, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a voltage regulator V3; the collector of the transistor V1 is connected to the INH terminal of the DC / DC converter, the emitter of the transistor V1 is grounded, and the base of the transistor V1 is respectively connected to the positive electrode of the diode V2 and the output terminal of the operational amplifier N2; the negative electrode of the diode V2 is connected to the same-direction input terminal of the operational amplifier N2 via the resistor R1; the power supply terminal of the operational amplifier N2 is connected to the VCC power supply, and the ground terminal is grounded; the reverse input terminal of the operational amplifier N2 is connected to the input terminal of the fault detection circuit; the first terminal of the resistor R2 is connected to the power supply VCC, and the second terminal is respectively connected to the same-direction input terminal of the operational amplifier N2 and the first terminal of the resistor R3; the second terminal of the resistor R3 is grounded; the first terminal of the resistor R4 is connected to the power supply VCC, and the second terminal is connected to the negative electrode of the voltage regulator V3, and the positive electrode of the voltage regulator V3 is grounded.

3. The aerospace main and standby power supply fault automatic isolation control circuit according to claim 2 is characterized in that: The transistor V1 is an NPN transistor.

4. The aerospace main and standby power supply fault automatic isolation control circuit according to claim 1 is characterized in that: The main fault detection circuit and the backup fault detection circuit both include an optocoupler N3, a resistor R5 and a voltage regulator V4; the optocoupler N3 includes a light emitting diode and a phototransistor; the collector of the phototransistor is connected to the reverse input terminal of the operational amplifier N2, and the emitter of the phototransistor is grounded; the positive electrode of the light emitting diode is connected to the positive output terminal of the DC / DC converter via the resistor R5; the negative electrode of the light emitting diode is connected to the negative electrode of the voltage regulator V4, and the positive electrode of the voltage regulator V4 is grounded.

5. The aerospace main and standby power supply fault automatic isolation control circuit according to claim 1 is characterized in that: The main output isolation circuit and the backup output isolation circuit both include a resistor R6, a voltage regulator tube V5, a resistor R7, a transistor V7, a resistor R8, a resistor R9, a resistor R10, a MOS tube V6, a capacitor C1 and a voltage regulator tube V8; The first end of the resistor R6 is connected to the positive output end of the DC / DC converter, and the second end is connected to the negative electrode of the voltage regulator tube V5, and the positive electrode of the voltage regulator tube V5 is grounded; the negative electrode of the voltage regulator tube V5 is also connected to the first end of the resistor R7 and the base of the transistor V7 respectively; the second end of the resistor R7 and the emitter of the transistor V7 are both grounded; the collector of the transistor V7 is connected to the first end of the resistor R10, and the second end of the resistor R10 is respectively connected to the first end of the resistor R8, the first end of the resistor R9, the positive electrode of the voltage regulator tube V8, and the first end of the capacitor C1; the second end of the resistor R8 is connected to the gate of the MOS tube V6, and the drain of the MOS tube V6 is connected to the positive output end of the DC / DC converter; the source of the MOS tube V6 is connected to the second end of the resistor R9, the negative electrode of the voltage regulator tube V8, and the second end of the capacitor C1, and serves as the positive output end of the fault detection circuit.

6. The aerospace main and standby power supply fault automatic isolation control circuit according to claim 5 is characterized in that: The transistor V7 is an NPN transistor.

7. The automatic isolation control circuit for main and standby power supply failure for aerospace use according to claim 5 is characterized in that: The MOS tube V6 is a PMOS tube.

8. The control method of the aerospace main and standby power supply fault isolation control circuit according to claim 5, characterized in that: The method comprises the following steps: When the output voltage of the main DC / DC converter is normal, the light-emitting diode in the optocoupler N3 does not emit light, the phototransistor is cut off, the reverse input terminal of the operational amplifier N2 is high level, the non-inverting input terminal is low level, and the output of the operational amplifier N2 is low level; the transistor V1 is cut off, the INH terminal of the main DC / DC converter output is not pulled down, and the main DC / DC converter output is normally powered; the PMOS tube V6 is turned on, and the output voltage of the main DC / DC converter is passed to the load; at this time, the output of the backup control unit is in standby state, and the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter; When the output of the main DC / DC converter is abnormal, if the output voltage of the main DC / DC converter is lower than the set threshold, the transistor V7 is cut off; the PMOS tube V6 is turned off, cutting off the connection between the output of the main DC / DC converter and the load; since the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter, the PMOS tube V6 is turned on, and the output of the backup DC / DC converter starts to supply power to the load; if the output voltage of the main DC / DC converter exceeds the set threshold, the light-emitting diode in the optocoupler N3 lights up, the phototransistor is turned on, and after the phototransistor is turned on, the reverse input terminal of the operational amplifier N2 becomes low level, the output of operational amplifier N2 becomes high level, transistor V1 is turned on, the INH terminal of the main DC / DC converter output is pulled low, and the output of the main DC / DC converter is turned off; the high level output of operational amplifier N2 is fed back to the same-direction input terminal of operational amplifier N2 through diode V2 and resistor R1, so that operational amplifier N2 maintains a high level output, realizing fault latching; PMOS tube V6 is turned off, cutting off the connection between the output of the main DC / DC converter and the load; because the output voltage of the backup DC / DC converter is higher than the output voltage of the main DC / DC converter, PMOS tube V6 is turned on, and the output of the backup DC / DC converter starts to supply power to the load.

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