PCB Holding Structure for Reduced Bending and Thermal Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing printed circuit board assemblies face challenges in reducing bending and deformation, which increases thermal resistance and limits the layout possibilities due to the need for increased thermal interface material thickness.
Innovation Solution
A printed circuit board assembly with a holding down construction that applies pressure at specific points on the upper surface of the PCB, using screwing posts and contact structures like pushing pins, while mechanically reinforcing dedicated support points to guide pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a holding down clamp is used to prevent PCB bending, then PCB deformation is reduced and reliability is improved, but the number of screw connections increases which restricts PCB layout flexibility
Solution Approach 1:
The holding down clamp is divided into multiple independent contact structures (pushing pins) distributed at different locations on the PCB. Each pushing pin independently applies localized pressure to prevent bending in its specific area, replacing a single complex clamping mechanism with multiple simple, distributed elements.
Solution Approach 2:
The pressure application function is extracted from the screw connections and assigned to separate contact structures (pushing pins). The screw connections are retained only for securing the heat sink, while the pushing pins handle the PCB flattening function, separating the two functions into distinct structural elements.
2Loss of energy
If the thickness of thermal interface material is reduced to improve heat transfer, then thermal resistance is decreased, but the tolerance range for gap between heat sink and power electronics device must be reduced
Solution Approach 1:
The holding down clamp with pushing pins applies preliminary pressure to flatten the PCB and compensate for height tolerances of power electronics devices before the final assembly is completed. This pre-compensation action reduces the gap variations, allowing thinner thermal interface material to be used effectively.
3Reliability
If contact structures are placed close to screwing posts to maximize pressure application, then PCB bending is better controlled, but the area available for PCB layout is further reduced
Solution Approach 1:
The pressure application is segmented into multiple distributed pushing pins rather than concentrated near screw posts. This distribution allows pressure to be applied effectively across the PCB surface while maintaining adequate spacing between contact structures and screw connections, preserving layout area.
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
This solution effectively reduces PCB bending, minimizes the thickness of the thermal interface material, and improves heat transfer by limiting the gap between the heat sink and the electrical modules, thereby enhancing the reliability of the thermal coupling.
Implementation Method 1
a holding down construction for the printed circuit board, the holding down construction comprising screwing posts configured to be screwed against the printed circuit board... contact structures which are configured to rest or press on the printed circuit board at specific contact points only
Implementation Method 2
the printed circuit board comprises dedicated support points that correspond to the specific contact points of the holding down construction and are contacted by the specific contact points, wherein the dedicated support points are mechanically reinforced
Implementation Method 3
an increased thickness of the gap and of the thermal interface material is associated with an increased thermal resistance... improve heat transfer by limiting the gap between the heat sink and the electrical modules
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention regards a printed circuit board assembly which comprises a printed circuit board (1) having an upper side (11) and a lower side (12), at least one electrical module (2) having an upper side (21) and a lower side (22), the electrical module (2) being arranged with its upper side (21) on the lower side (12) of the printed circuit board (1), and a holding down construction (9) for the printed circuit board (1), the holding down construction comprising screwing posts (92) which are configured to be screwed against the printed circuit board (1). It is provided that the holding down construction (9) is arranged on the upper side (11) of the printed circuit board (1) and comprises contact structures which are at a distance from the screwing posts (92) and configured to rest or press on the printed circuit board (1) at specific contact points (95) only, wherein the printed circuit board (1) comprises dedicated support points (15) that correspond to the specific contact points (95) of the holding down construction (9) and are contacted by the specific contact points (95), wherein the dedicated support points (15) are mechanically reinforced.