Integrated Circuit Inductor With Non-Uniform Turns Density
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Solution Overview
Problem
Ferromagnetic transformer cores in integrated circuits suffer from early saturation due to uneven magnetic flux density distribution, leading to non-ideal behavior and limited saturation current, which restricts power transfer and efficiency.
Innovation Solution
The magnetic core is designed with varying turns density along the coil axis and a laminated structure with alternating layers of magnetically active and insulating materials, along with shape modifications to achieve uniform magnetic flux distribution, reducing the tendency for central core saturation and enhancing power handling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a ferromagnetic core is used in an integrated circuit transformer, then power transfer capability is improved, but early saturation occurs due to uneven magnetic flux density distribution
Solution Approach 1:
The patent applies local quality by varying the turns density along the coil axis, with higher turns density at the ends and lower turns density in the central region. This non-uniform distribution compensates for the naturally higher magnetic flux density at the ends, achieving more uniform flux distribution throughout the core and preventing early saturation.
Solution Approach 2:
The patent changes the parameter of turns density from uniform to non-uniform along the coil axis. By modifying this geometric parameter, the magnetic flux density distribution is optimized to prevent saturation, thereby increasing the saturation current and improving reliability.
2Ease of manufacture
If uniform turns density is used in the coil, then manufacturing is simplified, but non-linear behavior occurs due to uneven magnetic flux density
Solution Approach 1:
The patent implements local quality by creating different turns density regions along the coil axis. The varying turns density (higher at ends, lower in center) is designed to compensate for non-uniform magnetic flux distribution, achieving linear power transfer characteristics while maintaining compatibility with standard integrated circuit fabrication processes.
3Power
If the core size is increased to handle higher power, then power transfer capability is improved, but the integrated circuit footprint increases
Solution Approach 1:
The patent changes the turns density parameter along the coil axis to optimize magnetic flux distribution. This allows the transformer to handle higher power levels without increasing core size, thereby maintaining a compact footprint suitable for integrated circuit applications.
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 design increases the saturation current by about 20% and maintains linearity in power transfer, allowing for more efficient operation before core saturation occurs, while minimizing resistance and maintaining compact footprint.
Implementation Method 1
uniform magnetic flux distribution, reducing the tendency for central core saturation
Implementation Method 2
magnetic core is designed with varying turns density along the coil axis and a laminated structure with alternating layers of magnetically active and insulating materials
Implementation Method 3
spaced apart conductors generally forming a spiral or an approximation of a spiral can be formed on or within a semiconductor substrate to form a coil as part of an inductor or a transformer
Data Source
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AI summary
Inductive components, such as transformers, can be improved by the inclusion of a magnetic core. However the benefit of having a core is lost if the core enters magnetic saturation. One way to avoid saturation is to provide a bigger core, but this is costly in the context of integrated electronic circuits. The inventor realized that the flux magnetic flux density varies with position in a magnetic core within an integrated circuit, causing parts of the magnetic core to saturate earlier than other parts. This reduces the ultimate performance of the magnetic core. This disclosure provides structures that delay the onset of early saturation, enabling a transformer to handle more power.