Compact CDU Firing Switch Layout for High-G Survivability
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Solution Overview
Problem
Existing capacitive discharge units (CDUs) for military munitions are large and prone to damage under significant G-forces, limiting their reliability and efficiency in detonating explosive materials.
Innovation Solution
A compact CDU design featuring an insulated gate bipolar transistor (IGBT) firing switch with reduced pin lengths and an offset trigger circuit, allowing for a smaller footprint and improved survivability, while maintaining efficient high-speed detonation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional firing switch designs are used in CDUs, then the CDU can achieve reliable detonation, but the CDU size becomes large and prone to damage under G-forces
Solution Approach 1:
The patent repositions the trigger circuit from a linear arrangement along the CDU axis to an offset position, utilizing two-dimensional space on the circuit board. This allows the trigger circuit to overlap with other components in the axial direction, reducing the overall axial length of the CDU while maintaining all necessary electrical connections and functional reliability
Solution Approach 2:
The patent integrates the trigger circuit components within the existing CDU structure by positioning them to overlap with other components in the axial dimension. The trigger circuit is effectively 'nested' within the spatial envelope defined by other CDU components, allowing multiple functional elements to occupy the same projection area without interfering with each other's operation
2Reliability
If traditional firing switch designs are used in CDUs, then the CDU can achieve reliable detonation, but the CDU axial length increases
Solution Approach 1:
The trigger circuit is repositioned from a linear axial arrangement to an offset two-dimensional layout on the circuit board. This allows the trigger circuit to utilize the lateral dimensions of the board rather than extending the axial length, enabling all components to be accommodated within a compact axial footprint while maintaining proper electrical connectivity for reliable detonation
3Reliability
If larger CDU size is used, then reliable detonation can be achieved, but additional space is wasted that could be used for explosive ordnance
Solution Approach 1:
By repositioning the trigger circuit to an offset location that utilizes lateral space on the circuit board rather than axial space, the patent reduces the overall axial length of the CDU. This compacted design frees up volume within the munition that can be allocated to additional explosive ordnance or other functional components, thereby increasing the quantity of useful substance without compromising detonation reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The compact CDU design enhances reliability and survivability by reducing size, allowing for additional explosive ordnance or components within munitions, and enabling use in smaller projectiles without the need for redesign, while maintaining efficient detonation performance.
Implementation Method 1
Activating an EFI requires a high current pulse with a very short rise time. In some CDUs, the pulse is generated by discharging a large voltage capacitor through a spark gap switch or a Metal Oxide Semiconductor Controlled Thyristor (MCT) switch.
Implementation Method 2
Electrical ignition may occur in at least two distinct ways, including by way of ignition of a priming material (e.g., electrically ignited blasting cap or priming material) or by way of direct energization of an explosive mass by electrical power.
Implementation Method 3
a capacitive discharge unit (CDU) that includes an exploding foil initiator (EFI) used to detonate munitions
Data Source
AI summary
A capacitive discharge unit (CDU) for detonating an explosive in response to a control signal comprises a set of CDU components, including an exploding foil initiator (EFI), a trigger circuit, a firing capacitor, and an insulated-gate bipolar transistor (IGBT) firing switch. In various embodiments the components are arranged on a board for mechanically and electrically supporting the components in an ordered arrangement along a CDU axis where the CDU having an axial length defined by the ordered arrangement of two or more of the EFI, the firing capacitor, and the IBGT firing switch, wherein the trigger circuit is offset from the CDU axis such that the trigger circuit does not contribute to the axial length.