Isolation Transformer PCB Layout for Higher Creepage Distance
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Solution Overview
Problem
Existing galvanic isolation apparatuses in substation automation fail to withstand high voltage transients, leading to flash-overs and interference with electronics, and require costly space and components to mitigate these issues.
Innovation Solution
A galvanic separating apparatus with a printed circuit board featuring a recess between soldering pads, incorporating an insulating layer that increases clearance and creepage distances, and insulated winding layers connected via a THT bobbin, ensuring effective insulation and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clearance and creepage distances are increased to withstand high voltage transients, then reliability is improved, but device area increases
Solution Approach 1:
The insulating layer extends vertically from the upper side through the recess and protrudes on the lower side, utilizing the third dimension (height) to increase clearance distance without proportionally increasing the PCB footprint. This vertical extension allows the insulating layer to provide enhanced isolation while maintaining a compact planar area.
Solution Approach 2:
The insulating layer is nested within the recess structure, where the recess provides a cavity that accommodates the insulating layer. This nesting approach allows the insulating layer to be integrated into the existing PCB structure without requiring additional external space, effectively utilizing the recess volume to house the insulation mechanism.
2Reliability
If protection circuits are added to limit over voltage and current, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The insulating layer acts as an intermediary element between the primary and secondary winding layers, providing electrical isolation and preventing direct coupling of high voltage transients. This passive insulating structure mediates the voltage stress without requiring active protection circuits, thereby reducing component count while maintaining protection functionality.
Solution Approach 2:
The invention extracts the protection function from active electronic components (protection circuits) and implements it through a passive structural solution (insulating layer with increased clearance and creepage distances). This extraction eliminates the need for additional protection components while maintaining the essential safety function.
3Strength
If clearance and creepage distances are increased according to IEC 60255-27, then insulation strength is improved, but ESD protection capability deteriorates
Solution Approach 1:
The insulating layer extends vertically through the recess and protrudes on both sides of the PCB, utilizing the vertical dimension to simultaneously increase both clearance distance (for insulation strength) and creepage distance (for ESD protection). This three-dimensional configuration allows both parameters to be enhanced without proportionally increasing the planar footprint.
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 effectively prevents flash-overs and reduces interference, enhances reliability and availability, allows for higher integration of I/O channels, and decreases manufacturing costs by eliminating the need for additional protection measures.
Implementation Method 1
an insulating layer (13), wherein the insulating layer extends from the upper side through the recess and protrudes on the lower side beyond the printed circuit board thereby increasing the clearance and/or creepage distance, wherein the insulating layer is arranged in between and thereby insulates the winding layers from each other
Implementation Method 2
a THT, through hole technology, bobbin and a primary insulated winding layer connected to the first soldering pad and a second insulated winding layer connected to the second soldering part, wherein the winding layers are arranged on the THT bobbin
Data Source
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AI summary
The invention relates to a galvanic separating apparatus, comprising a printed circuit board (3), the printed circuit board (3) comprising a first soldering pad (7), a second soldering pad (8) and a recess (12), whereby the pads (7, 8) are arranged on a lower side (9) of the printed circuit board (3) thereby defining a clearance and/or creepage distance (10, 11) between the pads (7, 8), and the recess (12) is arranged between the pads (7, 8), a primary insulated winding layer (5) connected to the first soldering pad (7) and a second insulated winding layer (6) connected to the second soldering part (8), whereby the winding layers (5, 6) are arranged on an upper side (2) of the printed circuit board (3), and an insulating layer (13), whereby the insulating layer (13) extends from the upper side (2) through the recess (12) and protrudes on the lower side (9) beyond the printed circuit board (3) thereby increasing the clearance and/or creepage distance (10, 11).