Initiating explosive device insurance state detection circuit

Abstract

The invention relates to the technical field of flight electronic control, in particular to an initiating explosive device insurance state detection circuit. The initiating explosive device safety state detection circuit comprises an initiating explosive device and a safety switch which are connected in parallel, and further comprises a detection control circuit and a voltage acquisition circuit, and the detection control circuit comprises an optical MOS relay U1 connected with the safety switch; the voltage acquisition circuit comprises an operational amplifier circuit, an analog-to-digital converter U3 and a microprocessor U4 which are connected in sequence, and the operational amplifier circuit is connected with the safety switch and can realize high-precision and high-reliability detection on the state of the MOS tube safety circuit.

Description

Technical Field

[0001] This invention relates to the field of flight electronic control technology, and more specifically to a pyrotechnic safety status detection circuit. Background Technology

[0002] Pyrotechnic devices are used to receive ignition and detonation commands to perform predetermined actions. If a pyrotechnic device is accidentally triggered, the aircraft may miss its designated time window, affecting the success or failure of flight tests and potentially causing injury or death. Therefore, safety measures must be added to pyrotechnic devices to ensure that even if a false trigger signal is sent to either end of the device, it can be released through a safety circuit.

[0003] Therefore, the flight and launch sequence of an aircraft is strongly correlated with the detection of its safety status. Only when the safety status is in the preset position can the flight and launch sequence continue smoothly. Thus, the accurate detection of the status of the safety circuit on the aircraft is particularly important for the overall safety status of the aircraft. The success or failure of the safety circuit detection will directly determine the success or failure of the aircraft's flight and launch.

[0004] Traditional pyrotechnic protection circuits use relays. Relays are mechanical switches, and the fuse status can be determined simply by monitoring the relay contacts using a simple optocoupler circuit. However, relays, being mechanically sensitive devices, have poor shock and vibration resistance. Therefore, MOSFETs, which offer superior shock and vibration resistance, can replace relays to perform the fuse switch function, improving the overall environmental adaptability of the product. However, MOSFET fuse circuits cannot monitor the MOSFET's state using a simple optocoupler circuit. Summary of the Invention

[0005] The present invention aims to provide a pyrotechnic fuse status detection circuit, which can achieve high-precision and high-reliability detection of the status of MOSFET fuse circuits.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: The present invention provides a pyrotechnic safety status detection circuit, including a pyrotechnic device and a safety switch connected in parallel, and further including: a detection control circuit and a voltage acquisition circuit, wherein the detection control circuit includes an optical MOS relay U1 connected to the safety switch; the voltage acquisition circuit includes an operational amplifier circuit, an analog-to-digital converter U3, and a microprocessor U4 connected in sequence, wherein the operational amplifier circuit is connected to the safety switch.

[0007] By adopting the above technical solution, when detecting the safety status of pyrotechnics, the external power supply (which can be one or more) supplies power to the optical MOS relay U1, the operational amplifier circuit, the analog-to-digital converter U3, and the microprocessor U4, respectively. The detection control signal is input to the optical MOS relay U1. After the detection control current passes through the fuse switch, the operational amplifier circuit collects the voltage across the fuse switch and converts it into a digital quantity through the analog-to-digital converter U3. Then, it is compared with the preset threshold voltage in the microprocessor U4 to determine the unlocking status of the fuse circuit.

[0008] Optionally, the IN+ pin of the optical MOS relay U1 is connected to a +5V power supply, the IN- pin is used to detect the control signal input, the Out+ pin is connected to the operational amplifier circuit and the analog-to-digital converter U3 for power supply, and the Out- pin is connected to the fuse switch.

[0009] Optionally, the detection control circuit further includes a resistor R2, which is connected in series with the Out+ pin.

[0010] Optionally, the detection control circuit further includes a resistor R1, which is connected in series between the IN+ pin and the +5V power supply.

[0011] Optionally, the operational amplifier circuit includes operational amplifier U2, resistors R3, R4, R5, R6, R7, and R8, and capacitors C1, C2, C3, and C4. Capacitor C1 is connected in parallel with a fuse switch. Resistors R4 and R7 are connected across capacitor C1, with the other end of resistor R4 connected to the non-inverting input of operational amplifier U2 and the other end of resistor R7 connected to the inverting input of operational amplifier U2. The positive power supply terminal of operational amplifier U2 is connected to the Out+ pin of MOS relay U1, the negative power supply terminal is grounded, and the output terminal is connected to digital-to-analog converter U3. Connections are as follows: one end of resistor R3 is connected to the non-inverting input of operational amplifier U2, and the other end is grounded; the two ends of resistor R8 are connected to the inverting input and output of operational amplifier U2, respectively; resistor R5 is connected between operational amplifier U2 and digital-to-analog converter U3; one end of capacitor C2 is connected between resistor R5 and analog-to-digital converter U3, and the other end is grounded; one end of capacitor C3 is connected to the positive power supply terminal of operational amplifier U2, and the other end is grounded and connected to the end of capacitor C1 near resistor R7; one end of capacitor C4 is connected to the Out+ pin of MOS relay U1, and the other end is grounded.

[0012] Optionally, the safety switch consists of two MOSFETs connected in series.

[0013] In summary, the present invention has at least the following beneficial technical effects: This circuit can accurately acquire and judge the weak voltage of the fuse circuit.

[0014] The detection control current will not trigger pyrotechnic devices, ensuring high reliability and non-damaging detection. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of a pyrotechnic safety status detection circuit. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] This invention provides a circuit for detecting the safety status of pyrotechnic devices.

[0018] refer to Figure 1 A circuit for detecting the safety status of a pyrotechnic device includes: a pyrotechnic device, a fuse switch, a detection control circuit, and a voltage acquisition circuit. The pyrotechnic device and the fuse switch are connected in parallel, and the fuse switch is used to deactivate the fuse on the pyrotechnic device. The detection control circuit and the voltage acquisition circuit are respectively connected to the fuse switch, and the detection control circuit is also connected to the voltage acquisition circuit. The detection control circuit applies a weak detection control current to the fuse switch, and the voltage acquisition circuit acquires the voltage across the fuse switch under different safety states through an operational amplifier and compares it with a preset threshold voltage in a microprocessor to determine the status of the fuse switch.

[0019] The internal resistance of the pyrotechnic device is represented by resistor R6. The fuse switch uses two MOSFETs connected in series, represented by switches S1 and S2 respectively.

[0020] The detection and control circuit includes a photoelectric MOS relay U1. The voltage acquisition circuit includes an operational amplifier circuit, an analog-to-digital converter (ADC) U3, and a microprocessor U4 connected in sequence. The operational amplifier circuit is connected to a fuse switch.

[0021] The opto-MOS relay U1 has 8 pins, which are divided into two sets of inputs and outputs. Only one set is used in this application. The IN+ pin (pin 1) of the opto-MOS relay U1 is connected to the +5V power supply, the IN- pin (pin 2) is used to detect the control signal input, the Out+ pin (pin 8) is connected to the operational amplifier circuit and the analog-to-digital converter U3 for power supply, and the Out- pin (pin 7) is connected to the fuse switch.

[0022] To protect the device, a resistor R1 is connected in series between the IN+ pin and the +5V power supply for current limiting. To ensure the safety of the pyrotechnic device during testing, a resistor R2 is connected in series with the Out+ pin for current limiting. Resistor R2 is a high-precision 1kΩ resistor to control the detection control current at 5mA. 5mA is far below the safety specification of "1A 1W 5min" for insensitive pyrotechnic devices, preventing false triggering and ensuring high reliability and non-damaging testing.

[0023] The operational amplifier circuit includes operational amplifier U2, resistors R3, R4, R5, R6, R7, and R8, and capacitors C1, C2, C3, and C4. Capacitor C1 is connected in parallel with the fuse switch. Resistors R4 and R7 are connected across capacitor C1. The other end of resistor R4 is connected to the non-inverting input (pin 3) of operational amplifier U2, and the other end of resistor R7 is connected to the inverting input (pin 2) of operational amplifier U2. The positive power supply terminal (pin 4) of operational amplifier U2 is connected to the Out+ pin of MOS relay U1, the negative power supply terminal (pin 5) is grounded, and the output terminal (pin 1) is connected to digital-to-analog converter U3. One end of resistor R3 is connected to the non-inverting input of operational amplifier U2, and the other end is grounded. The two ends of resistor R8 are connected to the inverting input and output of operational amplifier U2, respectively. Resistor R5 is connected between operational amplifier U2 and digital-to-analog converter U3. One end of capacitor C2 is connected between resistor R5 and analog-to-digital converter U3, and the other end is grounded. One end of capacitor C3 is connected to the positive power supply terminal of operational amplifier U2, and the other end is grounded and connected to the end of capacitor C1 closest to resistor R7. One end of capacitor C4 is connected to the Out+ pin of MOS relay U1, and the other end is grounded.

[0024] Because the resistance R6 of the pyrotechnic device is greater than the on-resistance of the two MOSFETs in the fuse switch, the voltage at the "+" terminal and the voltage at the "-" terminal of the pyrotechnic device will differ depending on whether the fuse is on or off. 火工品 The inconsistency is addressed by differential amplification of V by the subsequent operational amplifier. 火工品 The test is performed, and then the analog-to-digital converter U3 converts V... 火工品 The analog signal is converted into a digital signal, which is then compared with a pre-set detection threshold by the microprocessor U4 to determine the safety status.

[0025] Depending on the actual situation, the resistance of the pyrotechnic components on the aircraft can be adjusted. Here, we use the inherent resistance R of the pyrotechnic component as an example. 火工品 Taking 1Ω as an example, the calculation formula is as follows: , The on-resistance of a single MOSFET in the fuse circuit is 0.075Ω. When the fuse circuit is in the active state, the R value of the two MOSFETs connected in series is... 保险开关 The Ω is 0.15Ω, and V can be calculated. 火工品 =0.65mV.

[0026] When the circuit is in the unlocked state, both MOSFETs are in the off state, R 保险开关 =∞, and V can be calculated. 火工品 =5mV.

[0027] Table 1 shows the voltage comparison between the two ends of the pyrotechnic device in the unlocked and unlocked states.

[0028] Table 1. Comparison of voltages across pyrotechnic devices under unlocked and unlocked states. Serial Number Voltage of pyrotechnic device in unlocked state Explosives on-state voltage 1 5mV 0.65mV A detection threshold is set for each of the two states. The collected voltage is compared with the threshold. If it is less than the threshold, it is determined to be in the protection state; if it is greater than the threshold, it is determined to be in the protection state. This completes the detection of the protection state.

[0029] After the test is completed, disconnect the photoelectric MOS relay U1 to cut off the detection control current. That is, the 0.65mV and 5mV voltages only exist during the fuse-state test and are absent at other times, ensuring the safety of pyrotechnic devices.

[0030] In practical applications, different resistance values ​​of the selected pyrotechnic components will affect the V values ​​in the unlocked and locked states. 火工品 With different voltages, the circuit can be adapted to pyrotechnic devices with different resistance values ​​simply by adjusting the preset threshold voltage in the microprocessor U4 after calculation or prototype verification, demonstrating the excellent compatibility of the circuit solution.

[0031] The above description of the embodiments is only used to provide a detailed introduction to the technical solution of the present invention. However, the description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention, and should not be construed as a limitation of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A circuit for detecting the safety status of pyrotechnic devices, comprising pyrotechnic devices and a safety switch connected in parallel, characterized in that, Also includes: The detection control circuit and voltage acquisition circuit include a photoelectric MOS relay U1 connected to a fuse switch. The voltage acquisition circuit includes an operational amplifier circuit, an analog-to-digital converter U3, and a microprocessor U4 connected in sequence. The operational amplifier circuit is connected to a fuse switch.

2. The pyrotechnic safety status detection circuit as described in claim 1, characterized in that, The IN+ pin of the optical MOS relay U1 is connected to the +5V power supply, the IN- pin is used to detect the control signal input, the Out+ pin is connected to the operational amplifier circuit and the analog-to-digital converter U3 for power supply, and the Out- pin is connected to the fuse switch.

3. The pyrotechnic safety status detection circuit as described in claim 2, characterized in that, The detection and control circuit also includes a resistor R2, which is connected in series with the Out+ pin.

4. The pyrotechnic safety status detection circuit as described in claim 2, characterized in that, The detection and control circuit also includes a resistor R1, which is connected in series between the IN+ pin and the +5V power supply.

5. A pyrotechnic safety status detection circuit as described in any one of claims 2-4, characterized in that, The operational amplifier circuit includes operational amplifier U2, resistors R3, R4, R5, R6, R7, and R8, and capacitors C1, C2, C3, and C4. Capacitor C1 is connected in parallel with a fuse switch. Resistors R4 and R7 are connected across capacitor C1, with the other end of resistor R4 connected to the non-inverting input of operational amplifier U2 and the other end of resistor R7 connected to the inverting input of operational amplifier U2. The positive power supply terminal of operational amplifier U2 is connected to the Out+ pin of MOS relay U1, the negative power supply terminal is grounded, and the output terminal is connected to digital-to-analog converter U3. One end of resistor R3 is connected to the non-inverting input of operational amplifier U2, and the other end is grounded; the two ends of resistor R8 are connected to the inverting input and output of operational amplifier U2, respectively; resistor R5 is connected between operational amplifier U2 and digital-to-analog converter U3; one end of capacitor C2 is connected between resistor R5 and analog-to-digital converter U3, and the other end is grounded; one end of capacitor C3 is connected to the positive power supply terminal of operational amplifier U2, and the other end is grounded and connected to the end of capacitor C1 near resistor R7; one end of capacitor C4 is connected to the Out+ pin of MOS relay U1, and the other end is grounded.

6. The pyrotechnic safety status detection circuit as described in claim 5, characterized in that, The fuse switch consists of two MOSFETs connected in series.

Images