PCB Packaging in Aluminum Case for DC-DC Converter
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Solution Overview
Problem
Current military-grade DC-DC converters and electronic circuits face issues such as substrate fracture, limited component mounting, high production costs, inferior electrical conductivity, and vulnerability to shock and vibration due to the use of ceramic substrates and specific metal alloys, which hinder efficient and cost-effective high-volume manufacturing.
Innovation Solution
The use of printed circuit boards (PCBs) with fiberglass and copper layers for mechanical packaging, allowing for multiple layers, improved conductivity, and side-mounted components, along with a plastic/insulating header and extruded aluminum case for enhanced protection and assembly efficiency, reduces production costs and improves reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic substrates are used for mounting electronic components, then hermetic sealing and thermal stability are achieved, but substrate fracture and manufacturing complexity increase
Solution Approach 1:
The patent extracts the hermetic sealing function from the ceramic substrate and relocates it to a separate metal enclosure (can). This allows the substrate to be replaced with a more fracture-resistant material while maintaining the hermetic protection through the metal can assembly with sealing mechanisms.
Solution Approach 2:
The invention employs composite construction by combining metal enclosure materials with sealing materials to create a hermetic assembly. The metal can provides structural strength and fracture resistance, while separate sealing components provide the hermetic barrier, creating a composite solution that addresses both requirements.
2Ease of manufacture
If thick film conductors are used on ceramic substrates, then electrical connections are established, but electrical conductivity and production cost worsen
Solution Approach 1:
The patent extracts the conductor function from thick film ceramic technology and relocates it to traditional printed circuit board (PCB) technology. The PCB provides superior electrical conductivity through copper traces while maintaining ease of manufacture through standard PCB fabrication processes, eliminating the need for expensive thick film deposition.
Solution Approach 2:
The invention changes the material parameters from thick film ceramic conductors to thin film copper conductors on PCB. This parameter change results in significantly improved electrical conductivity while maintaining manufacturing feasibility through standard PCB industry processes.
3Device complexity
If ceramic substrates with limited layers are used, then component mounting is simplified, but interconnection capability and device complexity worsen
Solution Approach 1:
The patent transitions from the limited two-dimensional surface mounting of ceramic substrates to the multi-layer three-dimensional architecture of PCBs. The PCB's multiple conductive layers stacked in the third dimension provide extensive interconnection capability while maintaining manageable device complexity through standardized layer configurations.
4Reliability
If bare silicon microcircuits are soldered and wire bonded, then electrical connections are achieved, but assembly cost and clean room requirements increase
Solution Approach 1:
The patent merges the separate processes of component mounting and wire bonding into a single surface mount technology (SMT) process. Electronic components are directly soldered to the PCB without requiring separate wire bonding steps, eliminating the need for clean room environments and significantly reducing assembly costs while maintaining reliable electrical connections.
5Reliability
If wire bonds are used to connect microcircuits, then electrical connectivity is achieved, but vibration and shock resistance worsen
Solution Approach 1:
The patent extracts the wire bonding process and replaces it with direct solder joint connections between components and the PCB. This eliminates the fragile wire bonds that are susceptible to vibration and shock, while maintaining electrical connectivity through robust solder joints that are integral to the PCB assembly.
6Stability of the object's composition
If Molybdenum and Kovar are used for base plate and ring frame, then thermal expansion matching is achieved, but package weight increases
Solution Approach 1:
The patent changes the material parameters from dense heavy metals (Molybdenum, Kovar) to lighter metal alloys that can achieve comparable thermal expansion matching. The metal can enclosure uses aluminum or other lightweight alloys with appropriate thermal expansion properties, significantly reducing package weight while maintaining dimensional stability under thermal conditions.
Data Source
AI summary
Electronics mounted on a printed circuit board are housed within a high conductivity case with connecting pins extending therethrough. The case is filled with thermally conductive potting material to provide thermal conduction from the printed circuit board to the case. The case may be a conduit having open ends through which the printed circuit board is inserted or it may comprise a cover mounted to a base plate.