Shielded Multilayer Power Transmission Board EMI Reduction
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Solution Overview
Problem
Conventional power supplies face challenges in effectively shielding against electromagnetic interference (EMI) due to the lack of adequate shielding mechanisms in their multilayer power transmission boards, leading to increased noise interference and potential compliance issues with EMI standards.
Innovation Solution
The implementation of a multilayer power transmission board design featuring conductive outer layers and a dielectric medium, with conductive plating material connecting these layers to form a shielded structure that electrically couples the outer layers and reduces EMI, thereby enhancing shielding performance and reducing the need for additional filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional multilayer power transmission boards without shielding structures are used, then the device complexity is reduced and manufacturing is easier, but electromagnetic interference increases and EMI compliance becomes difficult to achieve
Solution Approach 1:
The outer conductive layers serve multiple functions: they provide EMI shielding for the inner power transmission layers while also functioning as ground layers for signal reference and noise dissipation. This multi-functionality reduces the need for separate shielding structures, thereby limiting the increase in device complexity despite the shielding capability.
Solution Approach 2:
The shielding structure is nested within the multilayer board architecture itself, with inner conductive layers (carrying power signals) surrounded by outer conductive ground layers. This nesting integrates the shielding function into the existing board structure rather than adding external shielding components, thus containing the complexity increase within the board's inherent multi-layer design.
2Object-affected harmful factors
If outer conductive ground layers are added to the multilayer board, then EMI shielding performance improves, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The shielding function is merged with the ground layer function in the outer conductive layers. By combining these two functions into a single structural element, the manufacturing process does not require separate shielding layers and ground layers, thereby limiting the increase in manufacturing complexity despite improved EMI shielding performance.
Solution Approach 2:
The multilayer board employs a composite structure combining conductive layers (for power transmission) and conductive ground layers (for shielding) separated by dielectric materials. This composite approach integrates shielding functionality into the existing material stack-up, allowing standard PCB manufacturing processes to produce the shielding structure without requiring additional specialized manufacturing steps.
3Object-affected harmful factors
If a shielded multilayer structure is implemented, then EMI compliance is improved and noise reduction is achieved, but the board area and space requirements increase
Solution Approach 1:
The shielding capability is achieved by transitioning to a multi-layer vertical architecture rather than expanding horizontally. Inner power transmission layers are surrounded by outer ground layers in the vertical dimension, providing EMI shielding without increasing the board's footprint area, thus limiting the space penalty despite improved noise reduction 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
This design effectively reduces conducted and radiated EMI, ensuring compliance with EMI standards and freeing up space on the main circuit board by efficiently transmitting power while minimizing noise interference.
Implementation Method 1
a conductive plating material positioned within a slot formed in the multilayer power transmission board and covering an interior portion of the multilayer power transmission board facing the slot. The conductive plating material electrically couples the first and second conductive outer layers
Implementation Method 2
a dielectric medium positioned between the conductive neutral layer and the conductive line layer
Data Source
AI summary
A power supply comprises a main circuit board and a multilayer power transmission board electrically coupled to the main circuit board. The multilayer board includes a conductive neutral layer having an inner side, a conductive line layer having an inner side facing the inner side of the conductive neutral layer, and a dielectric medium positioned between the conductive neutral layer and the conductive line layer. The power supply also comprises a first conductive outer layer positioned adjacently to an outer side of the conductive neutral layer, a second conductive outer layer positioned adjacently to an outer side of the conductive line layer, and a conductive plating material positioned within a slot formed in the multilayer power transmission board and covering an interior portion of the multilayer power transmission board facing the slot. The conductive plating material electrically couples the first and second conductive outer layers.