Bottom Entry Interconnection Element for Circuit Board Assembly
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Solution Overview
Problem
The existing methods for mounting power converter modules to printed circuit boards, particularly on the bottom side, face challenges such as manual soldering difficulties due to large leads and extensive power planes, high capital costs for automated solutions, and risks of damage during soldering and rework, especially with lead-free solders. Additionally, commercially available sockets require special assembly processes and have stringent positional tolerance requirements, making automated insertion infeasible and increasing assembly costs.
Innovation Solution
A top-side interconnection element with a planar portion and opposing spring fingers that grip leads from the bottom side, providing a robust mechanical and electrical connection, adaptable to various pin arrangements, and enabling automated surface-mount technology placement, eliminating the need for hand soldering and allowing easy rework or replacement of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual soldering is used to connect bottom side power converter module leads to circuit board, then connection is achieved, but the process is extremely difficult due to large lead mass and extensive power planes, requiring special skills and time
Solution Approach 1:
The invention divides the connection process into two separate stages: first, automated placement of the power converter module onto the circuit board using standard surface-mount equipment; second, automated reflow soldering. This segmentation eliminates the need for difficult manual soldering of large leads while achieving reliable connections through the modular assembly approach.
Solution Approach 2:
The invention introduces an intermediary carrier or socket structure that facilitates the connection between the power converter module and the circuit board. This intermediary element enables automated placement and soldering processes by providing a standardized interface, thereby eliminating the difficulties of direct manual soldering of large leads to the board.
2Reliability
If lead-free solder is used for soldering, then RoHS compliance is achieved, but the solder has much higher melting temperature and does not wet easily, making manual soldering even more difficult
Solution Approach 1:
The invention replaces the manual mechanical soldering process with an automated reflow soldering system. The lead-free solder paste is applied to the board, the assembly is placed in a reflow oven that automatically controls temperature profiles, and the solder joints are formed without manual intervention. This substitution eliminates the difficulties of manual soldering while maintaining RoHS compliance.
3Ease of operation
If power converter module is mounted on bottom side of circuit board, then heat sink mating is easier, but the through-hole leads protrude from bottom to top requiring manual soldering and increasing fabrication complexity
Solution Approach 1:
The invention segments the assembly process into distinct stages: bottom-side mounting of the power converter module with its leads protruding through the board, followed by automated top-side soldering operations. This segmentation allows the heat sink to be easily mated to the bottom side while the through-hole leads are subsequently connected using automated surface-mount technology and reflow soldering, reducing overall assembly complexity.
Solution Approach 2:
The invention inverts the traditional mounting approach by mounting the power converter module on the bottom side of the board rather than the top side. This inversion enables easier heat sink mating while the subsequent automated soldering process connects the protruding leads without requiring manual intervention, thereby reducing assembly complexity.
4Reliability
If existing bottom side socket arrangements are used, then connection is achieved, but they require special assembly processes and have stringent positional tolerance requirements making automated insertion infeasible
Solution Approach 1:
The invention employs a universal socket or carrier design that can accommodate various power converter module configurations and lead arrangements. This universal interface enables automated placement equipment to position modules accurately without requiring stringent positional tolerances, while still achieving reliable connections. The socket serves multiple functions: mechanical support, electrical connection, and alignment reference.
Solution Approach 2:
The invention changes the positional tolerance parameters by using a socket or carrier with built-in compliance features such as spring-loaded contacts or adjustable positioning elements. These parameter changes allow automated insertion equipment to place modules within broader tolerance ranges while maintaining reliable electrical and mechanical connections, thereby enabling automated manufacturing.
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 solution provides a cost-effective, reliable, and efficient method for attaching power converter modules to circuit boards, reducing damage risks and assembly costs, while enabling automated placement and easy rework, and maintaining a robust connection without the need for precise pin alignment or manual soldering.
Implementation Method 1
Opposing spring fingers are coupled to the planar portion and each spring finger has a support leg extending upwardly from the planar portion and a gripping leg extending downwardly toward the planar portion
Data Source
AI summary
An interconnection element for coupling a component with a circuit board having a top side and a bottom side has a planar portion configured to be surface mounted on the top side of the circuit board to overlie an opening in the circuit board. An opening is formed in the planar portion to coincide with the circuit board opening. Opposing spring fingers are coupled to the planar portion, and each spring finger has a gripping leg extending downwardly toward the planar portion. The gripping legs are positioned on opposite sides of the opening in the planar portion and extend through the opening in the planar portion to extend into the board opening and capture a component lead that extends in the board opening from the bottom side of the circuit board.