Surface Mount Power Module with Inverted Circuit Boards
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Solution Overview
Problem
Existing power module designs for surface mounting applications face challenges with heat accumulation and size constraints due to increased soldering temperatures from lead-free soldering, which can cause reliability issues and require larger devices to accommodate heat dissipation, while maintaining a small footprint is desirable.
Innovation Solution
The design features first and second circuit boards mounted on opposite sides of a central body portion, with conductive pins providing mechanical and electrical connections, allowing the reverse side of the circuit boards to act as the external housing, eliminating the need for a separate housing and enhancing heat dissipation through air circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the housing is made larger to allow heat escape during soldering, then heat dissipation is improved, but device size increases
Solution Approach 1:
The circuit boards are mounted vertically on opposite sides of the body portion, utilizing the vertical dimension for heat dissipation. The reverse sides of the vertically mounted circuit boards form the exterior housing, creating air circulation paths along the sides of the device rather than requiring increased horizontal footprint.
2Ease of manufacture
If lead-free solder is used with increased soldering temperature, then manufacturing compliance is improved, but reliability deteriorates due to moisture sensitivity and solder reflow
Solution Approach 1:
The circuit boards are mounted on opposite sides of the body portion before final housing formation, allowing heat to escape during the soldering process. This preliminary structural arrangement prevents heat accumulation that would otherwise cause solder reflow and reliability issues during lead-free soldering.
3Temperature
If an open frame or semi-open frame device is used to improve heat dissipation, then heat escape is improved, but device complexity and size increase
Solution Approach 1:
The reverse sides of the circuit boards serve dual functions: they form the exterior housing of the device and simultaneously provide heat dissipation surfaces. This eliminates the need for a separate complex housing structure while achieving effective heat escape.
4Object-affected harmful factors
If circuit boards are mounted with circuit elements facing outward, then component protection is improved, but heat dissipation deteriorates
Solution Approach 1:
Instead of mounting circuit boards with circuit elements facing outward for protection, the invention inverts the arrangement by mounting boards with circuit elements facing inward toward the body portion. The reverse sides of the boards then form the protective exterior housing while the circuit elements remain protected inside, simultaneously achieving both protection and heat dissipation.
Data Source
AI summary
An electrical component for surface mounting, such as a DC-DC power converter includes a body portion including one or more surface mounting pins to connect the body portion to a circuit board, and first and second circuit boards including respective circuit elements mounted thereon. The first and second circuit boards are mounted on the body portion, such that sides of the first and second circuit board on which the circuits are mounted face the interior of the device and the reverse sides of the first and second circuit boards define an exterior surface of the component. In this way, no separate housing for the component is required. The size of the electrical component can therefore be kept small, and protection provided to the circuit elements by the reverse side of the circuit board.