Multi-Terminal Condenser Structure for PCB Voltage Stress Mitigation
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Solution Overview
Problem
High voltage switching power supplies face challenges in mitigating voltage stresses on printed circuit boards (PCBs) due to high voltage fields, especially in densely integrated and space-constrained devices, where traditional insulation methods are impractical.
Innovation Solution
A multi-terminal condenser structure is implemented on a multi-layered PCB, comprising overlapping conductive traces with dielectric layers, connecting specific terminals to ground and AC voltage, forming a voltage dividing capacitor circuit that bypasses high voltage electric fields to the ground plane, thereby reducing voltage stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional insulation methods (long insulators, liquid insulators, or potting material) are used to mitigate voltage stresses, then safety is improved, but device space is excessively occupied and weight increases
Solution Approach 1:
The insulation function is segmented into multiple PCB layers, with conductive traces on different layers forming capacitive structures that provide electrical insulation through dielectric layers. This distributes the insulation function across the PCB structure rather than requiring a single bulky insulator.
Solution Approach 2:
The capacitive insulation structure is nested within the multi-layer PCB itself, utilizing the existing PCB layers and dielectric materials. The conductive traces are embedded within the PCB structure, nesting the insulation function inside the circuit board rather than adding external insulation components.
2Reliability
If traditional insulation methods are used, then voltage stress mitigation is achieved, but device weight increases
Solution Approach 1:
The PCB structure itself provides the insulation function through its multi-layer construction with dielectric layers between conductive traces. The PCB serves both as the circuit carrier and as the insulation medium, eliminating the need for separate heavy insulation materials like liquid insulators or potting compound.
3Productivity
If high density components are mounted on limited board space, then integration is improved, but voltage stress on PCB increases
Solution Approach 1:
The solution moves from two-dimensional PCB surface mounting to three-dimensional multi-layer PCB construction. By utilizing multiple layers stacked vertically, the design achieves high integration density while the dielectric layers between conductive traces provide voltage stress mitigation through capacitive coupling.
4Volume of moving object
If multiple PCBs are mounted in close proximity with little clearance, then space utilization is improved, but safety clearance for high voltage is compromised
Solution Approach 1:
The dielectric layers between PCB layers act as thin film insulation barriers that provide electrical isolation without requiring large physical clearances. This enables multiple PCBs to be mounted in close proximity while maintaining adequate electrical insulation through the multi-layer capacitive structure.
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 multi-terminal condenser structure effectively suppresses voltage stresses, allowing high voltage sources like 15 kV RMS AC to be integrated in limited spaces while ensuring safety and enabling air cooling, thus preventing arcing or flashover.
Implementation Method 1
a multi-terminal condenser structure is implemented on a multi-layered PCB, comprising overlapping conductive traces with dielectric layers
Implementation Method 2
the first terminal and the second terminal are connected to a ground point, and the third terminal and the fourth terminal are connected to the AC voltage
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A method for mitigating voltage stress on a PCB includes applying AC voltage to a multi-terminal condenser structure of a multi-layered PCB. The terminal condenser structure is formed by overlapping a plurality of conductive traces between board layers of the multi-layered PCB. A corresponding dielectric layer is disposed between the overlapping conductive traces of the board layers. The overlapping conductive traces include a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal and the third terminal are disposed on a first layer of the multi-layered PCB, and the second terminal and the fourth terminal are disposed on a bottom layer of the multi-layered PCB. The first terminal and the second terminal are connected to a ground point, and the third terminal and the fourth terminal are connected to the AC voltage. Voltage stresses on the PCB are mitigated utilizing the multi-terminal condenser structure.