Leaf Spring Heat Sink Mounting With Reduced PCB Keep-Out Area
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Solution Overview
Problem
Existing leaf spring designs for coupling heat sinks to integrated circuits on printed circuit boards require a large 'keep-out' area, which restricts the placement of other electronic components and can degrade performance due to increased transmission latencies.
Innovation Solution
A leaf spring design with a central portion having an aperture, first and second spring arms with through-holes for fasteners, and bending axes perpendicular to the longitudinal axis of the leaf spring, allowing for a smaller keep-out area and increased force application with fewer screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional leaf spring design is used to couple a heat sink to an integrated circuit, then the heat sink can be securely attached with uniform pressure, but a large keep-out area is required on the back side of the PCB that prevents other electronic components from being mounted nearby
Solution Approach 1:
The leaf spring is divided into multiple spring arms (first spring arm, second spring arm, etc.) that can be independently configured. Each spring arm can be positioned and dimensioned differently, allowing the keep-out area to be segmented and reduced while maintaining effective heat sink attachment at the integrated circuit location.
Solution Approach 2:
The spring arms are configured to concentrate elastic deformation and applied force specifically at the integrated circuit location rather than distributing it uniformly across the entire PCB back side. This localized approach reduces the keep-out area to only what is necessary near the IC, allowing other components to be mounted in previously restricted areas.
2Force
If traditional leaf spring designs are used, then adequate pressure can be applied to the integrated circuit, but more fasteners are required which increases device complexity
Solution Approach 1:
The leaf spring utilizes elastic deformation of thin spring arms to generate and distribute pressure across the integrated circuit. This flexible mechanism replaces the need for multiple rigid fasteners, reducing device complexity while maintaining adequate and uniform pressure application through the heat sink.
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 design enables efficient coupling of heat sinks to integrated circuits with a reduced keep-out area, allowing for more flexible component placement and improved performance by applying greater force with fewer fasteners.
Implementation Method 1
By tightening the threaded fasteners against the elastic spring arms of a leaf spring, the heat sink can be pulled towards the leaf spring and pressed against one or more chips mounted on the front side of the PCB.
Data Source
AI summary
A leaf spring for coupling a heat sink to an integrated circuit includes a central portion that has an aperture; a first spring arm that is formed on a first side of the central portion and includes a first through-hole for a first fastener; a second spring arm that is formed on a second side of the central portion and includes a second through-hole for a second fastener; a first bending axis that passes through the first side and is substantially perpendicular to a longitudinal axis of the leaf spring that passes through the first through-hole and the second through-hole; and a second bending axis that passes through the second side and is substantially perpendicular to the longitudinal axis of the leaf spring.