Dual Riser Slot Motherboard Layout for Shorter PCIe Gen5 Traces
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Solution Overview
Problem
The perpendicular placement of expansion cards in electronic devices with height constraints, such as 1U and 2U devices, is problematic, especially for Full Height Full Length (FHFL) cards, due to height limitations and the need to route metal traces around memory slots, exceeding the length requirements of PCIe Generation 5 specifications.
Innovation Solution
The implementation of a mother board with two spaced-apart riser slots and a riser card with spaced-apart edge connectors, allowing for shorter metal traces and flexible routing, accommodating two FHFL expansion cards within a 1U form factor while adhering to PCIe Generation 5 specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single riser slot is used to connect expansion cards to the motherboard, then the device structure is simple, but the metal trace length becomes too long when routing around memory slots, exceeding PCIe Generation 5 specifications
Solution Approach 1:
The single riser slot is divided into two separate riser slots positioned at different locations on the motherboard. This segmentation allows metal traces to be routed independently through shorter paths, avoiding the need to route around memory slots and reducing overall trace length to comply with PCIe Generation 5 specifications.
Solution Approach 2:
The invention utilizes spatial distribution by positioning two riser slots at different locations on the motherboard, effectively using the two-dimensional layout to create shorter routing paths. This dimensional arrangement allows traces to connect expansion cards to the processor through more direct routes rather than following a single long peripheral path.
2Area of stationary object
If memory slots are positioned near the riser slot on the motherboard, then the device layout is compact, but the metal traces must be routed along the periphery of memory slots, increasing trace length
Solution Approach 1:
By separating the riser slot configuration into two distinct slots positioned at different locations, the invention creates independent routing paths that can avoid memory slots. This segmentation allows the metal traces to take shorter, more direct routes rather than routing around memory modules, thus reducing trace length while maintaining compact layout.
3Ease of operation
If expansion cards are placed perpendicular to the motherboard in 1U and 2U devices, then the cards are easily installed, but the height constraints prevent proper placement especially for Full Height Full Length cards
Solution Approach 1:
The invention uses a riser card that extends vertically from the motherboard, utilizing the vertical dimension to accommodate Full Height Full Length expansion cards in compact 1U and 2U devices. This vertical extension allows the expansion cards to be positioned perpendicular to the motherboard while maintaining proper clearance and accessibility for installation, effectively solving the height constraint problem.
Data Source
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AI summary
A mother board (2) for an electronic device, the mother board comprising at least one central processing unit (21) and a first riser slot (24) and a second riser slot (25), said slots (24, 25) being configured to cooperate with one riser card (5) for connecting two expansion cards to the mother board (21), the first riser slot (24) and the second riser slot (25) being connected by metal traces (L4, L5) to the central processing unit (21), the first riser slot (24) and the second riser slot (25) being spaced apart by a distance (D1) greater than 8 cm.