Planar Air-Core Transformer for High Voltage Isolation
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Solution Overview
Problem
Traditional transformers, such as those used in MRI systems and high-frequency switching power electronic converters, face limitations in isolation capabilities and are bulky, making them unsuitable for integration in printed circuits and high-frequency applications.
Innovation Solution
A planar air-core transformer design integrated with a flex or printed circuit board, featuring planar spiral windings and tuned parasitic elements, provides enhanced isolation at specific frequencies, reducing common mode currents and EMI, and is suitable for replacing traditional baluns and transformers in MRI systems and power electronic converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional parallel resonant balun with co-axial inductor and capacitor is used, then isolation capability is provided, but device size becomes bulky and integration in printed circuits becomes difficult
Solution Approach 1:
The patent replaces the traditional mechanical co-axial inductor and capacitor structure with a planar air-core transformer design that can be directly integrated into printed circuit boards. This substitution eliminates the need for discrete cylindrical components and their associated mounting hardware, achieving compact integration while maintaining isolation functionality through planar spiral windings and tuned parasitic elements
Solution Approach 2:
The patent transforms the transformer parameters by tuning the parasitic elements (inductance and capacitance) to achieve parallel resonance at a desired frequency. By adjusting these electrical parameters in the planar structure, the design achieves enhanced isolation at specific frequencies without requiring the bulky traditional resonant circuit components
2Reliability
If traditional transformer design is used, then power isolation is provided, but device complexity increases and manufacturability decreases
Solution Approach 1:
The patent merges the primary and secondary windings into a single planar structure where both windings are fabricated on the same circuit board layer or adjacent layers. This integration eliminates the need for separate component assemblies and complex interconnections, reducing structural complexity while maintaining power isolation through magnetic coupling between the planar windings
Solution Approach 2:
The planar air-core transformer design serves multiple functions: it provides power isolation, signal transmission, and frequency-selective filtering through its tuned parasitic elements. This multi-functionality eliminates the need for separate isolation components and filters, reducing overall device complexity
3Productivity
If Ethernet transformer with differential mode matching is used, then data signal transmission is optimized, but isolation voltage capability is limited
Solution Approach 1:
The patent changes the electrical parameters by tuning the parasitic inductance and capacitance to achieve parallel resonance at the data transmission frequency. This resonance condition provides both differential mode matching for optimal signal transmission and enhanced common mode isolation, simultaneously achieving high data transmission efficiency and high isolation voltage capability
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 planar air-core transformer design offers improved isolation, reduced size, and increased manufacturability, enabling effective signal and power isolation in high-frequency applications while being immune to external magnetic fields and suitable for integration in printed circuit boards.
Implementation Method 1
one or more respective transformer parasitic elements and the substrate permittivity between the primary and secondary windings together are tuned to a desired parallel resonant frequency
Implementation Method 2
at least one primary winding and at least one secondary winding, each winding integrated with a corresponding flex or printed circuit board layer
Data Source
AI summary
A transformer includes a flex or printed circuit board consisting of a substrate material having a desired permittivity, and at least one primary winding and at least one secondary winding. Each winding is integrated with the flex or printed circuit board such that one or more respective transformer parasitic elements and the substrate permittivity between the primary and secondary windings together are tuned to a desired parallel resonant frequency.