Backplane Feed Bus Bar Cooling and Strength
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Solution Overview
Problem
The backplane structure in electronic devices faces issues with power loss and heat generation due to high current flow, particularly with the implementation of the anteroposterior intake and exhaust cooling system, which also compromises mechanical strength and increases costs.
Innovation Solution
A backplane structure featuring a planar feed bus bar with pinnate projections that is closely connected to the backplane, providing multiple electrical and mechanical points of contact, and forming ventilation openings to reduce power loss and heat generation while enhancing mechanical strength and cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large current is allowed to flow through the feed bus bar to supply power to circuit board units, then the power supply capability is improved, but the feed bus bar is heated due to resistive losses
Solution Approach 1:
The invention transitions from planar power feeding to three-dimensional power feeding by arranging multiple feed bus bars in the vertical direction (upward and downward from the backplane surface). This spatial arrangement increases the effective cross-sectional area for current flow without increasing the planar footprint, thereby reducing current density and resistive heating while maintaining power supply capability.
Solution Approach 2:
The single feed bus bar is segmented into multiple feed bus bars (first and second feed bus bars positioned above and below the backplane). This segmentation distributes the total current across multiple parallel paths, reducing the current load on each individual bus bar and consequently reducing heat generation in each segment.
2Temperature
If ventilation openings are formed in the backplane to enable cooling air flow, then the cooling performance is improved, but the mechanical strength of the backplane is reduced
Solution Approach 1:
The invention uses a laminated structure combining resin layers and reinforcement ribs to create a composite backplane. The reinforcement ribs (protruding portions) provide mechanical strength while the resin layers allow for ventilation openings. This composite approach maintains structural integrity despite the presence of cooling vents.
Solution Approach 2:
The backplane is segmented into multiple layers (first resin layer, first reinforcement layer, second resin layer, second reinforcement layer) with ventilation openings strategically positioned. This layered segmentation allows ventilation channels to be formed without compromising the overall mechanical strength, as the reinforcement layers provide structural support between the openings.
3Power
If the number of power supply connector pins is increased to supply large current through usual connectors, then the power supply capability is improved, but the connector complexity and cost increase
Solution Approach 1:
The invention extracts the power feeding function from the signal connectors and implements it through a dedicated feed bus bar structure that makes direct contact with the backplane. This separates the high-current power transmission path from the low-current signal transmission path, allowing power supply capability to be improved without increasing connector pin complexity.
Solution Approach 2:
The feed bus bar acts as an intermediary component between the power supply source and the circuit board units. It provides a low-resistance path for large current flow and distributes power through multiple contact points with the backplane, eliminating the need for numerous connector pins while maintaining high power supply capability.
4Temperature
If the feed bus bar cross-sectional area is increased to reduce resistive heating, then the heat generation is reduced, but the device size and weight increase
Solution Approach 1:
The invention utilizes the vertical dimension by positioning feed bus bars both above and below the backplane surface. This three-dimensional arrangement effectively increases the total cross-sectional area for current flow without increasing the planar dimensions of the device, thereby reducing heat generation while maintaining compact size.
Solution Approach 2:
The current path is segmented into multiple parallel paths through the use of multiple feed bus bars. Each bus bar carries a portion of the total current, which reduces the current density and resistive heating in each individual bus bar. This allows the use of thinner, lighter bus bars that collectively provide the same heat dissipation performance as a single large bus bar.
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 configuration effectively suppresses power loss and heat generation, reinforces mechanical strength, and ensures adequate ventilation, thereby improving cooling performance and reducing costs by minimizing the number of power and ground layers on the backplane.
Implementation Method 1
signal transfer and power feeding between the circuit board units are executed through the backplane
Implementation Method 2
a radiation projection is further formed on the bus bar
Implementation Method 3
a cooling fin is disposed in the feed bus bar to forcedly cool the feed bus bar
Implementation Method 4
a cooling structure of an anteroposterior intake and exhaust system complying with an NEBS
Data Source
Figure 1(a)~1(b)
Figure 1(c)~2(a)
Figure 2(b)~2(c)
AI summary
In an electronic device, when a 48 V feed system is shifted to a 12 V feed system, in order to supply the same electric power, a current of fourth times needs to flow into a backplane. Also, in an anteroposterior intake and exhaust system, there is a need to form a ventilator through which a cooling air passes in the backplane. Further, there arises a problem that a mechanical strength is deteriorated by provision of the ventilator in the backplane. There is provided a structure in which a pinnate projection is provided on a feed bus bar, and a cooling air is applied to the feed bus bar. Also, the feed bus bar is brought into close contact with an overall surface of the backplane, and electrically and mechanically connected thereto at multiple points, to thereby perform both of cooling and the suppression of stiffness deterioration.