Multistage control initiating explosive device ignition circuit

Abstract

The utility model belongs to the field of circuits, and relates to a multi-stage control initiating explosive device ignition circuit, which comprises a first-stage control circuit, a second-stage control circuit, a third-stage control circuit and a fourth-stage control circuit. The first-stage control circuit, the second-stage control circuit and the third-stage control circuit form a three-stage control circuit through combination of a photoelectric coupler, a voltage comparator, a field-effect tube and part of resistance-capacitance devices, and ignition control is achieved by controlling on-off of the photoelectric coupler through a processor. According to the utility model, by using a combined control mode of the photoelectric coupler and the field-effect tube, the multi-stage control of the ignition circuit of the initiating explosive device is realized, so that the characteristics of high reliability, high safety, synchronous compatibility and miniaturization of the ignition circuit are realized, and the safety and reliability of the initiating explosive device are ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of circuits and specifically discloses a multi-stage controlled ignition circuit for explosives. Background Art

[0002] The characteristics of pyrotechnics themselves determine that their safety is very important. Because various pyrotechnics are installed inside weapons during assembly, delivery and use, the gathering of various pyrotechnics after equipment is bound to pose a great danger. Once an accident occurs, it may cause injuries or even casualties, and the consequences are disastrous. Since pyrotechnics are widely used in weapons and occupy a very important position, whether pyrotechnics can work safely and reliably has a decisive impact on the success or failure of the use of weapons. Therefore, the use characteristics of pyrotechnics determine that the requirements for the reliability, safety, and electromagnetic compatibility of their ignition circuits are increasingly valued. Utility Model Content

[0003] In order to solve the above technical problems, the utility model proposes a multi-stage control ignition circuit for explosives, comprising a first-stage control circuit, a second-stage control circuit and a third-stage control circuit, wherein one side of the first-stage control circuit is connected to the system control end, and the other side is connected to the second-stage control circuit, the first-stage control circuit comprises a photoelectric coupler B1, a photoelectric coupler B2, a comparator U1 and a field effect tube U2, pin 1 of the photoelectric coupler B1 is connected to a separation signal, pin 2 of the photoelectric coupler B1 is connected to a separation signal ground, pin 3 of the photoelectric coupler B1 is grounded, pin 4 of the photoelectric coupler B1 is connected to pin 8 of the comparator U1, pin 6 of the comparator U1 is grounded, pin 1 of the comparator U1 is connected to pin 2 of the photoelectric coupler B2, pin 3 of the photoelectric coupler B2 is connected to an ignition voltage ground, the drain of the field effect tube U2 is the output of the first-stage control circuit, the gate of the field effect tube U2 is connected to pin 4 of the photoelectric coupler B2 through a resistor, and the source of the field effect tube U2 is connected to the ignition voltage; the second-stage control circuit comprises a photoelectric coupler B3, a field effect tube U 3, pin 1 of the photocoupler B3 is connected to the positive electrode of the secondary control signal, pin 2 of the photocoupler B3 is connected to the negative electrode of the secondary control signal, pin 3 of the photocoupler B3 is connected to the ignition voltage ground, pin 4 of the photocoupler B3 is connected to the output of the first-stage control circuit through a resistor, the source of the field effect tube U3 is connected to the output of the first-stage control circuit, the drain of the field effect tube U3 is the output of the second-stage control circuit, and the gate of the field effect tube U3 is connected to pin 4 of the photocoupler B3 through a resistor; the third-stage control circuit includes a photocoupler B4 and a field effect tube U4, pin 1 of the photocoupler B4 is connected to the positive electrode of the third-stage control signal, pin 2 of the photocoupler B4 is connected to the negative electrode of the third-stage control signal, pin 3 of the photocoupler B4 is connected to the ignition voltage ground, pin 4 of the photocoupler B4 is connected to the output of the second-stage control circuit through a resistor, the source of the field effect tube U4 is connected to the output of the second-stage control circuit, the drain of the field effect tube U4 is the output of the third-stage control circuit, and the gate of the field effect tube U4 is connected to pin 4 of the photocoupler B4 through a resistor.

[0004] Furthermore, after the first-stage control circuit is turned on, the field effect transistor U2 outputs the ignition voltage to the next stage, and generates a secondary ignition control signal and a tertiary ignition control signal through the digital circuit to control the working state of the optocoupler and the field effect transistor in the second-stage control circuit and the third-stage control circuit, thereby controlling the generation of the ignition command.

[0005] Furthermore, when the voltage difference between the "secondary control signal +" signal and the "secondary control signal -" signal at the input end of the photocoupler B3 is greater than 1.5V, the photocoupler B3 is turned on, and the rear-stage output pins 3 and 4 of the photocoupler B3 are internally connected, and the field effect transistor U3 outputs a signal.

[0006] Furthermore, the drain of the field effect transistor U4 is connected to the ignition resistor.

[0007] Furthermore, filter capacitors are added to the front ends of the control ends of the photocouplers B1 , B3 and B4 .

[0008] The utility model realizes multi-level control of the ignition circuit of the initiator by using the combined control mode of the photoelectric coupler and the field effect tube, so as to realize the characteristics of high reliability and high safety of the ignition circuit and synchronous compatibility with miniaturization, thereby ensuring the safety and reliability of the initiator. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a multi-stage controlled ignition circuit diagram of an explosive device of the utility model;

[0010] Figure 2 This is the circuit diagram of optical isolation + high-power MOS tube;

[0011] Figure 3 This is the schematic diagram of the first-level control circuit;

[0012] Figure 4 This is the schematic diagram of the second and third level control circuits. DETAILED DESCRIPTION

[0013] In order to better understand the purpose, technical solution and function of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings, but the utility model can be implemented in a variety of different ways defined and covered by the claims. The accompanying drawings that constitute a part of the utility model are used to provide a further understanding of the utility model, and the schematic embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an improper limitation of the utility model.

[0014] The utility model circuit realizes three-level control of the ignition of explosives by selecting appropriate photoelectric couplers, field effect tubes and different combinations of resistors and capacitors. Figure 1 As shown in the figure, a three-level control circuit is formed by a combination of a photocoupler, a voltage comparator, a field effect tube and some resistors and capacitors. The ignition control is realized by controlling the on and off of the photocoupler through the processor.

[0015] This ignition circuit is controlled by a three-level control signal, and then outputs the ignition command to the next stage to be emitted, which improves the reliability and safety of the pyrotechnics. The circuit design adopts a combination of optocoupler isolation and high-power PMOS circuit to replace the magnetic isolation in the traditional integrated solid-state relay. While ensuring the performance indicators of the circuit design, it also reduces the electromagnetic compatibility problems that may be caused by traditional magnetic isolation relays. The selection reduces the size of the device, reduces the PCB layout area, realizes miniaturization design, and takes economic factors into consideration.

[0016] Its single-channel control circuit is as follows Figure 2A filter capacitor is added to the front end of the photocoupler control end to prevent the power MOS tube circuit from being falsely triggered due to glitch pulses.

[0017] The circuit contains three levels of control, of which the first level is controlled by an external separation signal; the second and third levels are controlled by digital circuits. The three-level control circuit is a cascade design, and the next level circuit does not work when the previous level is not turned on. Therefore, the entire ignition circuit can only successfully complete the ignition operation after all three levels of control signals are valid.

[0018] First stage control circuit:

[0019] The design principle of the first-level control circuit is as follows Figure 3 As shown, the left side of the circuit is an external separation signal, which is connected to the system control end; the right side is connected to the second-level control circuit. The first-level control circuit includes a photocoupler B1, a photocoupler B2, a comparator U1 and a field effect tube U2. Pin 1 of the photocoupler B1 is connected to the separation signal, pin 2 of the photocoupler B1 is connected to the separation signal ground, pin 3 of the photocoupler B1 is grounded, pin 4 of the photocoupler B1 is connected to pin 8 of the comparator U1, pin 6 of the comparator U1 is grounded, pin 1 of the comparator U1 is connected to pin 2 of the photocoupler B2, pin 3 of the photocoupler B2 is connected to the ignition voltage ground, the drain of the field effect tube U2 is the output of the first-level control circuit, the gate of the field effect tube U2 is connected to pin 4 of the photocoupler B2 through a resistor, and the source of the field effect tube U2 is connected to the ignition voltage.

[0020] Here’s how it works:

[0021] The separation signal is initially at a high level, then the photocoupler (B1) is turned on, and the 3rd and 4th pins of the subsequent output are in a short-circuit state. At this time, the level of the REF pin of the subsequent voltage comparator U1 is 0V, which is less than 2.5V, and V+ and V- are cut off, that is, the 2nd pin of the subsequent photocoupler (B2) is in a floating state. At this time, the front stage of B2 is not turned on, and the 3rd and 4th pins of the output end are in an open circuit state. The R3 resistor is floating to the ground, and the gate (G) of the field effect tube U2 is connected to the 4th pin of the output end of the photocoupler through the R2 and R3 resistors. Because R3 is floating to the ground, the gate (G) and the source (S) are equal in level, the field effect tube works in a cut-off state, and the drain (D) has no output to the outside;

[0022] When the explosive device needs to be ignited, the system outputs a low-level separation signal, and the photocoupler (B1) is cut off, and pins 3 and 4 of the photocoupler are in an open-circuit state. At this time, the level of the REF pin of the subsequent comparator U1 is 5V, which is greater than 2.5V, V+ and V- are turned on, the photocoupler (B2) is turned on, and pins 3 and 4 of the photocoupler are short-circuited. The resistor R3 is grounded. At this time, the gate (G) voltage of the field effect tube U2 is obtained by dividing the resistors R1 and R3. This voltage is less than the source (S) voltage, Vgs>Vth, and the field effect tube works in the on state. At this time, the subsequent stage generates an output voltage.

[0023] The function of the resistor in series with the gate (G) of the field effect transistor is to limit the current at the G pole and suppress oscillation.

[0024] 1) Limit the G-pole current

[0025] The field effect tube is driven by voltage, so the gate (G) current is very small. However, due to the existence of parasitic capacitance, when the field effect tube is working in the on or off state, the capacitance needs to be charged, resulting in a large instantaneous current. Therefore, a small resistance should be added to limit the current to protect the field effect tube.

[0026] 2) Suppress oscillation

[0027] After the field effect tube is connected to the circuit, the parasitic inductance generated by the lead wires, together with the parasitic capacitance, forms an LC oscillation circuit. For the switching square wave waveform, there will be many frequency components. When there is a frequency that is the same as or close to the resonant frequency, a series resonant circuit will be formed. Therefore, connecting a resistor in series can effectively reduce the Q value of the oscillation circuit, making the oscillation decay quickly, thereby avoiding failure of the subsequent circuit due to oscillation.

[0028] Second and third level control circuit:

[0029] The design principles of the second and third level control circuits are the same. Figure 4 As shown, the second-stage control circuit includes a photocoupler B3 and a field effect transistor U3. Pin 1 of the photocoupler B3 is connected to the positive electrode of the secondary control signal, pin 2 of the photocoupler B3 is connected to the negative electrode of the secondary control signal, pin 3 of the photocoupler B3 is connected to the ignition voltage ground, pin 4 of the photocoupler B3 is connected to the output of the first-stage control circuit through a resistor, the source of the field effect transistor U3 is connected to the output of the first-stage control circuit, the drain of the field effect transistor U3 is the output of the second-stage control circuit, and the gate of the field effect transistor U3 is connected to pin 4 of the photocoupler B3 through a resistor.

[0030] The third-stage control circuit includes a photocoupler B4 and a field effect transistor U4. Pin 1 of the photocoupler B4 is connected to the positive electrode of the third-stage control signal, pin 2 of the photocoupler B4 is connected to the negative electrode of the third-stage control signal, pin 3 of the photocoupler B4 is connected to the ignition voltage ground, pin 4 of the photocoupler B4 is connected to the output of the second-stage control circuit through a resistor, the source of the field effect transistor U4 is connected to the output of the second-stage control circuit, the drain of the field effect transistor U4 is the output of the third-stage control circuit, and the gate of the field effect transistor U4 is connected to pin 4 of the photocoupler B4 through a resistor.

[0031] After the first-stage control circuit is turned on, the field effect tube outputs the ignition voltage to the next stage. At this time, the secondary and tertiary ignition control signals are generated through the digital circuit part to control the working status of the secondary and tertiary photocouplers and field effect tubes, and then control the generation of ignition commands to control the operation of the pyrotechnics.

[0032] Here’s how it works:

[0033] When the voltage difference between the "secondary control signal +" signal and the "secondary control signal -" signal at the input end of the photocoupler is greater than 1.5V, the photocoupler (B3) is turned on, and the 3rd and 4th pins of the photocoupler's rear output are internally connected, and the resistor R13 is connected to the ground wire through the photocoupler. At this time, the gate (G) voltage of the field effect tube U3 is obtained by dividing the resistors R10 and R13, and this voltage is less than the source (S) voltage, Vgs>Vth, and the field effect tube works in the on state. At this time, the field effect tube U3 outputs the "secondary control output" signal.

[0034] The third-level control signal has the same principle as the second-level control signal.

[0035] Device selection requirements:

[0036] B1, B2, B3, B4: Use a photocoupler with a power supply voltage ≥ 5V and an input current of 5 to 20mA;

[0037] U1: It is a voltage comparator. The FW431 device is recommended here.

[0038] U2, U3, U4: Use high-power PMOS circuits.

[0039] V1, V2, V3: Clamping diodes. When selecting, it should be ensured that the back-end field effect transistor will not be broken down when conducting.

[0040] V4: Zener diode. When selecting, just consider the previous stage input voltage.

[0041] The ignition control circuit of the initiator of the utility model is realized by using a circuit of a photoelectric coupler and a high-power field effect tube, and generates an ignition control command through a three-level control signal to control the operation of the initiator, which can effectively improve the safety, reliability and stability of the ignition control circuit, reduce the size of components, and reduce the PCB layout area, thereby ensuring the safety and reliability of the initiator in the weapon system.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art may make various changes or modifications within the scope of the claims, which should all be included in the protection scope of the present invention.

Claims

1. A multi-stage controlled ignition circuit for explosives, characterized in that: The invention comprises a first-stage control circuit, a second-stage control circuit and a third-stage control circuit, wherein one side of the first-stage control circuit is connected to the system control end, and the other side is connected to the second-stage control circuit. The first-stage control circuit comprises a photoelectric coupler B1, a photoelectric coupler B2, a comparator U1 and a field effect tube U2. Pin 1 of the photoelectric coupler B1 is connected to the separation signal, pin 2 of the photoelectric coupler B1 is connected to the separation signal ground, pin 3 of the photoelectric coupler B1 is grounded, pin 4 of the photoelectric coupler B1 is connected to pin 8 of the comparator U1, pin 6 of the comparator U1 is grounded, pin 1 of the comparator U1 is connected to pin 2 of the photoelectric coupler B2, pin 3 of the photoelectric coupler B2 is connected to the ignition voltage ground, the drain of the field effect tube U2 is the output of the first-stage control circuit, the gate of the field effect tube U2 is connected to pin 4 of the photoelectric coupler B2 through a resistor, and the source of the field effect tube U2 is connected to the ignition voltage. The second-stage control circuit comprises a photoelectric coupler B3 and a field effect tube U3. Pin 1 of the photoelectric coupler B3 is connected to the second-stage control circuit. The third-stage control circuit includes a photocoupler B4 and a field effect tube U4. Pin 1 of the photocoupler B4 is connected to the positive electrode of the third-stage control signal, pin 2 of the photocoupler B3 is connected to the negative electrode of the second-stage control signal, pin 3 of the photocoupler B3 is connected to the ignition voltage ground, pin 4 of the photocoupler B3 is connected to the output of the first-stage control circuit through a resistor, the source of the field effect tube U3 is connected to the output of the first-stage control circuit, the drain of the field effect tube U3 is the output of the second-stage control circuit, and the gate of the field effect tube U3 is connected to pin 4 of the photocoupler B3 through a resistor; the third-stage control circuit includes a photocoupler B4 and a field effect tube U4. Pin 1 of the photocoupler B4 is connected to the positive electrode of the third-stage control signal, pin 2 of the photocoupler B4 is connected to the negative electrode of the third-stage control signal, pin 3 of the photocoupler B4 is connected to the ignition voltage ground, pin 4 of the photocoupler B4 is connected to the output of the second-stage control circuit through a resistor, the source of the field effect tube U4 is connected to the output of the second-stage control circuit, the drain of the field effect tube U4 is the output of the third-stage control circuit, and the gate of the field effect tube U4 is connected to pin 4 of the photocoupler B4 through a resistor.

2. A multi-stage controlled explosive device ignition circuit according to claim 1, characterized in that: After the first-stage control circuit is turned on, the field effect transistor U2 outputs the ignition voltage to the next stage, and generates a secondary ignition control signal and a tertiary ignition control signal through the digital circuit to control the working state of the optocoupler and the field effect transistor in the second-stage control circuit and the third-stage control circuit, thereby controlling the generation of the ignition command.

3. A multi-stage controlled ignition circuit for explosives according to claim 1, characterized in that: When the voltage difference between the "secondary control signal +" and the "secondary control signal -" at the input end of the photocoupler B3 is greater than 1.5V, the photocoupler B3 is turned on, and the post-stage output pins 3 and 4 of the photocoupler B3 are internally connected, and the field effect transistor U3 outputs a signal.

4. A multi-stage controlled explosive device ignition circuit according to claim 1, characterized in that: The drain of the field effect transistor U4 is connected to the ignition resistor.

5. A multi-stage controlled explosive device ignition circuit according to claim 1, characterized in that: A filter capacitor is added to the front end of the control end of the photocoupler B1, the photocoupler B3 and the photocoupler B4.

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