Insulating Magnetic Components on Silicon Using PN Junctions
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Solution Overview
Problem
The miniaturization of magnetic components is limited by the difficulty in maintaining adequate dielectric strength and minimum creepage and clearance distances between windings, especially in high-frequency applications, where conventional insulating materials fail to provide sufficient isolation.
Innovation Solution
The use of reverse-biased PN or NP junctions as insulation between current conductors in magnetic components, which offers higher dielectric strength and isolation properties, allowing for closer conductor spacing and compliance with regulatory standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulating materials (oxidized silicon, FRP) are used between windings, then manufacturing is easier and structure is simpler, but dielectric strength and isolation properties are insufficient, limiting miniaturization
Solution Approach 1:
The patent changes the electrical parameters of the semiconductor substrate by creating doped regions with specific conductivity types (N-type and P-type). By controlling the doping concentration and distribution, the substrate itself provides high dielectric strength when reverse-biased, eliminating the need for separate insulating materials and enabling compact magnetic component design with adequate isolation.
Solution Approach 2:
The patent replaces mechanical/physical insulating structures (FRP layers, oxidized silicon interfaces) with an electrical field-based insulation mechanism. The reverse-biased PN junction creates a depletion region that provides electrical isolation through the semiconductor substrate itself, substituting physical insulation with field-based insulation that achieves superior dielectric strength.
2Volume of moving object
If conductors are placed closer together to achieve miniaturization, then component size decreases, but maintaining minimum creepage and clearance distances becomes difficult, compromising safety and isolation
Solution Approach 1:
The patent changes the electrical characteristics of the substrate between conductors by forming reverse-biased PN junctions. This creates a high-impedance depletion region that provides effective electrical isolation even when physical distances are reduced, enabling miniaturization while maintaining adequate isolation and meeting safety requirements for creepage and clearance distances.
3Speed
If operating frequency is increased to reduce component size, then magnetic components become smaller, but maintaining dielectric strength between turns and windings becomes more difficult
Solution Approach 1:
The patent modifies the electrical parameters of the substrate by creating doped regions that form reverse-biased junctions. This provides frequency-independent dielectric strength through the depletion region, allowing high-frequency operation while maintaining adequate isolation between turns and windings, thus enabling miniaturization without compromising reliability at elevated frequencies.
4Reliability
If reverse-biased PN junctions are used for insulation between conductors, then dielectric strength and isolation properties improve significantly, but device structure and fabrication become more complex
Solution Approach 1:
The patent makes the semiconductor substrate serve multiple functions: it acts as both the structural foundation for mounting windings and as the insulating medium between conductors. The doped regions within the substrate provide electrical isolation when reverse-biased, eliminating the need for separate insulating layers and simplifying the overall device architecture despite the added doping steps.
Solution Approach 2:
The patent merges the substrate structure with the insulation function by integrating doped regions directly into the semiconductor substrate. This combines what would traditionally be separate elements (substrate and insulating layers) into a unified structure where the substrate itself provides both mechanical support and electrical isolation through its doped regions.
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 approach enables the creation of more compact and reliable magnetic components that meet safety and regulatory standards by significantly reducing leakage current and allowing for closer conductor placement while maintaining reliable dielectric strength.
Implementation Method 1
the reverse saturation current of commercially produced PN junctions is in the range of a few tens of nA for a reversed biased voltage in the range of about 100 V
Implementation Method 2
the reverse-biased PN junction acts as an insulator, the minimum creepage distance is a distance through insulation (DTI)
Data Source
AI summary
A magnetic component includes a semiconductor substrate, a first winding that is located in the semiconductor substrate and that includes at least two turns, and intra-winding insulation located between two adjacent turns of the at least two turns and including doped regions in the semiconductor substrate that define either an NPN-junction or a PNP junction.