Galvanic Isolation Transformer LC Resonant Network
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Solution Overview
Problem
Current galvanic isolation systems face challenges in achieving high isolation ratings, especially for power transfer applications, due to technological limitations, which result in high losses and inefficiencies, particularly when trying to maintain reinforced isolation beyond 5 kV.
Innovation Solution
A fully integrated two-chip system utilizing a combination of isolation transformers and capacitors in a resonant network, allowing for efficient data and power transfer with reinforced isolation up to 10 kV, by leveraging LC resonance and series coupling of inductors and capacitors to reduce silicon area and losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick isolating layers are used to achieve higher isolation ratings, then galvanic isolation performance is improved, but area and cost increase due to lower capacitance density
Solution Approach 1:
The patent divides the isolation barrier into multiple thin oxide layers (first oxide layer and second oxide layer) separated by a semiconductor substrate, replacing a single thick isolating layer. This segmentation allows achieving high isolation ratings without proportionally increasing the device area, as each layer can be optimized independently for thickness and capacitance density.
Solution Approach 2:
The patent transitions from a planar capacitor structure to a vertically stacked multi-layer structure with the semiconductor substrate in between. This three-dimensional arrangement allows the isolation barrier to extend through the substrate thickness, effectively increasing the isolation path length without increasing the lateral footprint of the device.
2Reliability
If series-coupled isolation devices are used to improve isolation rating, then isolation rating is improved, but power transfer efficiency deteriorates due to high losses
Solution Approach 1:
The patent merges the isolation function with the power transfer function by integrating the oxide isolation layers directly into the power transfer path between primary and secondary windings. This combined structure eliminates the need for separate series-coupled isolation devices, reducing the number of interfaces and associated losses while maintaining high isolation ratings.
Solution Approach 2:
The oxide layers serve dual functions: providing galvanic isolation and enabling power transfer. The same structural elements that block DC isolation also facilitate AC power coupling, eliminating the need for separate isolation components that would introduce additional losses.
3Ease of manufacture
If conventional 5-kV platforms are used, then manufacturing compatibility is maintained, but reinforced isolation beyond 5 kV cannot be achieved
Solution Approach 1:
The patent segments the isolation barrier into multiple oxide layers that can be formed using standard CMOS oxidation processes, allowing conventional 5-kV manufacturing platforms to be used. Each oxide layer can be grown independently with controlled thickness, and the cumulative isolation rating exceeds 5 kV while remaining compatible with existing fabrication capabilities.
Solution Approach 2:
The patent changes the parameter of oxide layer thickness to achieve higher isolation ratings. By increasing the total oxide thickness through multiple layers rather than using a single thick layer, the isolation rating exceeds 5 kV while maintaining compatibility with standard oxidation processes used in conventional manufacturing.
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 high-efficiency data and power transfer with reinforced isolation, reducing losses and silicon area requirements, and allows for the use of conventional 5-kV platforms in more demanding applications, while maintaining robustness against voltage transients.
Implementation Method 1
an isolation transformer with a primary winding and a secondary winding
Implementation Method 2
utilizing a combination of isolation transformers and capacitors in a resonant network, allowing for efficient data and power transfer
Data Source
AI summary
A galvanic isolation system includes a first isolation barrier and a second isolation barrier. The first isolation barrier includes a transformer. The second isolation barrier includes an inductive circuit connected to a secondary winding of the transformer. The first and the second isolation barriers are coupled to form an LC resonant network.