Compressible Polymer Bus Bar for PCB Power Distribution
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Solution Overview
Problem
The challenge in distributing power to electronic components on printed circuit boards (PCBs) is the high cost and increased electrical resistance due to the need for multiple copper layers or thicker pathways, which also leads to heat generation and thermal stress issues when interfacing bus bars, and conventional current sense elements consume space and introduce additional resistance.
Innovation Solution
A rigid, electronically conductive bus bar with compressible polymer contact pads secured along its length, which is securely fastened to the PCB using rivets, allowing for accurate current sensing and reduced thermal expansion issues, replacing discrete current sense elements and minimizing space and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bus bar is soldered to PCB, then electrical connection is achieved, but thermal damage to electronic components occurs due to high heat requirement and dissipation
Solution Approach 1:
The patent introduces a solderless connection mechanism as an intermediary between the bus bar and PCB. This mechanism uses compression force applied through a compression element (such as a rivet or clamp) to create electrical contact without requiring soldering heat, thereby eliminating thermal damage to electronic components while maintaining reliable electrical connection.
2Reliability
If screw terminal is used to interface bus bar, then connection is achieved, but vibrations and cyclic thermal stresses cause screw to back out and contact to fail
Solution Approach 1:
The patent extracts the problematic screw threadable connection from the system and replaces it with a solderless compression connection mechanism. This eliminates the issues of screws backing out under vibration and thermal stress, providing a more stable and reliable connection that maintains electrical contact integrity under cyclic loading conditions.
3Measurement precision
If conventional current sense elements are installed on discrete conductive pathways, then current measurement is achieved, but valuable PCB space is consumed and additional resistance is introduced
Solution Approach 1:
The patent merges the current measurement function with the existing bus bar structure by incorporating measurement circuitry directly into the bus bar or its connection mechanism. This integration eliminates the need for separate discrete current sense elements on the PCB, thereby conserving valuable PCB space while maintaining accurate current measurement capability through voltage drop sensing across the bus bar connection points.
4Measurement precision
If conventional current sense elements are installed on discrete conductive pathways, then current measurement is achieved, but resistance to current flow increases causing heat and increased resistance of adjacent components
Solution Approach 1:
The patent merges the current measurement function with the existing bus bar structure, utilizing the bus bar's own low-resistance pathway for current flow. By measuring voltage drop across the bus bar connection points rather than inserting discrete sense elements into current-carrying pathways, the system achieves accurate current measurement without introducing additional resistance that would generate heat or increase resistance of adjacent components.
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 provides a reliable, low-profile power distribution with accurate current measurement and reduced heat dissipation, achieving less than 1% error in current measurement and maintaining connection integrity under thermal stress, while reducing the need for costly low-resistance current sense elements.
Implementation Method 1
A first set of holes in the bus bar are positioned to receive a first set of fasteners, each of the first set of fasteners compressing a respective one of the first set of contact pads
Implementation Method 2
A first set of holes in the bus bar are positioned to receive a first set of fasteners
Data Source
AI summary
A bus bar distributes power to a plurality of electronic components supported on a printed circuit board. One embodiment of the bus bar comprises a plurality of compressible contact pads made from an electronically conductive polymer, spaced along the bus bar for contacting conductive contacts that are coupled to a power domain or individual electronic component. The pads may be secured to the bus bar and the conductive traces using an electronically conductive epoxy adhesive. Rivets may then be used to secure the bus bar to the printed circuit board and compress the pads, which conform to the printed circuit board to make a reliable electrical connection with the conductive traces. The bus bar further comprises a plurality of current sense points disposed adjacent to the pads for measuring the amount of current provided to each power domain.