PoDL Board Layout With Ground Plane Cutout for Impedance Matching
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Solution Overview
Problem
Existing Power over Data Lines (PoDL) systems face challenges in efficiently transmitting high-speed bi-directional data while minimizing electromagnetic interference and maintaining impedance matching across different current types, which affects data channel specifications and wiring complexity, especially in applications like autonomous vehicles and high-resolution image transmission.
Innovation Solution
A PoDL system design featuring a coaxial cable with strategically positioned pads and circuitry elements, including inductors and ferrite beads, that provide low impedance for DC power and high impedance for alternating currents, along with a cutout in the ground plane to adjust impedance, reducing electromagnetic interference and meeting electrical specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If inductors and ferrite beads are added to provide low impedance for DC power and high impedance for alternating currents, then electromagnetic interference is reduced and data channel specifications are met, but device complexity and wiring complexity increase
Solution Approach 1:
The patent combines multiple circuit elements (inductors, ferrite beads, and ground plane modifications) into an integrated solution where the ground plane cutout works in conjunction with the inductors and ferrite beads to achieve impedance matching and EMI reduction. This merging approach consolidates what would otherwise be separate complexity elements into a coordinated system that meets data channel specifications while managing electromagnetic interference.
Solution Approach 2:
The patent applies local quality by creating a cutout in the ground plane at specific locations to adjust impedance characteristics locally. This localized modification allows the ground plane to provide different impedance characteristics in different regions, enabling high impedance for alternating currents in data channels while maintaining low impedance for DC power in power channels, thereby reducing EMI without requiring complex wiring throughout the entire system.
2Manufacturing precision
If a cutout is created in the ground plane to adjust impedance, then impedance matching for different current types is improved, but manufacturing complexity increases
Solution Approach 1:
The ground plane cutout is a localized modification that creates specific impedance characteristics only where needed. By removing ground plane material in specific areas, the patent achieves different impedance values in different regions of the PCB, allowing precise impedance matching for both DC power and AC data signals without requiring complex manufacturing processes across the entire board.
Solution Approach 2:
The cutout modifies the physical parameters of the ground plane (area, shape, position) to change the electrical impedance characteristics. By adjusting the cutout's dimensions and location, the patent can precisely control the impedance values to match requirements for different current types, transforming a manufacturing feature into a precise electrical parameter control mechanism.
3Device complexity
If PoDL is used to minimize wiring and reduce costs, then wiring complexity is reduced, but maintaining impedance matching and reducing EMI becomes more challenging
Solution Approach 1:
The patent merges power transmission and data transmission functions into a single PoDL interface, allowing both DC power and high-speed data to travel over the same cable. By integrating ground plane modifications and EMI reduction features directly into the PoDL implementation, the patent maintains the wiring simplification benefits while addressing EMI challenges through coordinated design of the connection interface.
Solution Approach 2:
The inductors and ferrite beads act as intermediary elements that separate and manage different current types on the PoDL interface. These components mediate between the DC power channel and AC data channel, allowing both to coexist on the same line while preventing electromagnetic interference between them, thus enabling PoDL to maintain both wiring simplicity and EMI performance.
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
The solution enables efficient high-speed bi-directional data transmission with reduced wiring complexity, simplifying systems and allowing greater freedom of movement in sensor systems, while maintaining electrical specifications such as return loss, insertion loss, and crosstalk.
Implementation Method 1
circuitry elements (110) connected to the first pad (106). The circuitry elements (110) may include one or more inductors, one or more ferrite beads, or both.
Implementation Method 2
the second physical layer (114) may include a cutout (116). The first pad (106) and/or the second pad (112) may be positioned over the cutout (116) such that an impedance at the first pad (106) and/or the second pad (112) matches an impedance before and after the first pad (106) and/or the second pad (112).
Data Source
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AI summary
Aspects of the disclosure provide for a system for a power over data line (PoDL) system. The system includes a ground plane (104) that has a cutout (116). In addition, the system includes an alternating current (AC) capacitor pad (112) configured to establish a bidirectional data channel. The AC capacitor pad is positioned in the cutout of the ground plane. Similarly, a PoDL pad (106) connected to one or more inductors and a direct current (DC) power source is positioned in the cutout of the ground plane and is in series with the AC capacitor pad.