Toroidal Inductor Segmented Parallel Conductors Reduce DCR
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Solution Overview
Problem
Conventional embedded toroidal inductors have high direct current resistance (DCR) due to small cross-sectional area of conductive traces, leading to a low quality factor (Q), which is undesirable in many applications, and existing designs cannot reduce DCR without increasing the inductor's footprint or requiring additional machining steps.
Innovation Solution
The toroidal inductor design incorporates a coil formed from elongated conductors with alternating segments of parallel conductors and conductive vias, where the parallel conductors are spaced apart and connected by conductive links, reducing DCR by increasing the effective cross-sectional area and using conductive vias to minimize capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional embedded toroidal inductor design with single conductive trace is used, then manufacturing is simple, but direct current resistance is high and quality factor is low
Solution Approach 1:
The coil is divided into multiple segments where each segment contains multiple parallel conductive traces instead of a single trace. These parallel traces are connected through conductive vias at their ends, creating a segmented parallel structure that reduces DCR while maintaining a manageable design complexity through modular repetition.
Solution Approach 2:
The design transitions from a two-dimensional planar trace to a three-dimensional structure by utilizing vertical vias that connect traces across different layers. This adds the vertical dimension to the conductor path, allowing parallel traces to be stacked in multiple layers and connected through vias, thereby reducing resistance without increasing footprint area.
2Reliability
If parallel conductors are used to reduce DCR, then quality factor improves, but capacitance between parallel conductors increases
Solution Approach 1:
The continuous parallel conductor structure is segmented into discrete sections by spacing the conductors apart at regular intervals. This segmentation breaks up the continuous capacitive coupling between parallel traces, reducing the total parasitic capacitance while still maintaining low resistance through the parallel configuration and via connections.
Solution Approach 2:
Conductive vias serve as intermediary connection points that join parallel traces at discrete locations rather than maintaining continuous contact. These via intermediaries allow the parallel traces to be electrically connected for current flow while physically separating them to minimize capacitive coupling between adjacent traces.
3Reliability
If conductor cross-sectional area is increased to reduce DCR, then quality factor improves, but inductor footprint area increases
Solution Approach 1:
Instead of increasing the cross-sectional area of a single conductor in the planar dimension, the design stacks multiple conductors in vertical layers and connects them through vias. This utilizes the vertical dimension to effectively increase the total conductive cross-section without expanding the horizontal footprint area of the inductor.
Solution Approach 2:
Multiple parallel conductors across different layers are merged into a single effective conductor path through the use of conductive vias. This combining of multiple thin traces into a parallel bundle achieves the equivalent of a thicker conductor for reducing resistance, while the individual traces remain thin enough to maintain a compact 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
This design significantly reduces the direct current resistance, thereby enhancing the quality factor (Q) of the inductor, with a nearly half reduction in DCR compared to conventional designs without increasing the inductor's footprint or requiring additional processing steps.
Implementation Method 1
The elongated conductor includes one or more coil segments of a first type. Each coil segment of the first type is comprised of a plurality of elongated parallel conductors spaced apart and electrically connected by conductive links
Implementation Method 2
reduces DCR by increasing the effective cross-sectional area and using conductive vias to minimize capacitance
Data Source
AI summary
A toroidal inductor (100) and method of forming same. The invention is intended to decrease the direct current resistance (DCR) of the toroidal inductor circuit. Thus, an increase in the quality factor (Q) of the circuit is produced. The toroidal inductor includes a coil formed from an elongated conductor extending around a core material and defining a plurality of turns. The elongated conductor is comprised of one or more coil segments. The coil segments are arranged in an alternating pattern of a first type segment (101) and a second type segment (102). Each of the coil segments of the first type includes a plurality of elongated parallel conductors (104, 105) spaced apart and electrically connected by conductive links (108) at predetermined intervals along their respective lengths. The coil segments of the second type are formed of a single conductor defined by a conductive via (302, 304) formed in the substrate.