LC Tank Circuit Tuning via Inductor-Capacitor Eddy Current Coupling
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Solution Overview
Problem
Existing LC tank circuits have limited tunability due to independently working inductors and capacitors, making it difficult to change inductance values once fabricated, which restricts the resonant frequency range to the range of available capacitance values.
Innovation Solution
The implementation of vertically natural capacitors (VNCAPs) that utilize lateral and vertical capacitive couplings, allowing for simultaneous variation of capacitance and inductance values through inductor-induced eddy currents, thereby expanding the resonant frequency range of LC circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If independently working inductors and capacitors are used in LC tank circuits, then the circuit structure is simple and easy to manufacture, but the tunability is limited and the resonant frequency range is restricted
Solution Approach 1:
The patent merges the inductor and capacitor into a coupled structure where the capacitor is positioned beneath the inductor, creating magnetic coupling between them. This allows the capacitor to influence the inductor's effective inductance through eddy currents, enabling continuous tuning of the resonant frequency beyond what independent components could achieve.
Solution Approach 2:
The patent introduces dynamic tuning capability by allowing the capacitor voltage to modulate the effective inductance of the inductor through eddy current effects. This creates a dynamically adjustable resonant frequency that can be continuously varied, transforming the static LC circuit into a tunable oscillator.
2Adaptability or versatility
If capacitance values are varied to tune LC tank circuits, then the resonant frequency can be adjusted, but the inductance values remain fixed and cannot be changed once fabricated
Solution Approach 1:
The patent makes the inductance dynamic by using the capacitor's electric field to induce eddy currents in the inductor's magnetic path. By varying the capacitor voltage, the effective inductance can be continuously adjusted, allowing independent control of both capacitance and inductance parameters to achieve wide frequency tuning.
Solution Approach 2:
The patent introduces eddy currents as an intermediary mechanism that couples the capacitor's electrical field to the inductor's magnetic field. This intermediary effect allows the capacitor to indirectly control the inductor's effective inductance, enabling frequency tuning through a single control voltage while maintaining the physical separation of L and C components.
3Adaptability or versatility
If inductor-induced eddy currents are used to simultaneously vary capacitance and inductance, then the resonant frequency range is expanded, but the device complexity increases
Solution Approach 1:
The patent nests the capacitor structure beneath the inductor, with the capacitor occupying the space under the inductor's magnetic path. This nested arrangement allows the capacitor to be positioned optimally for maximum coupling while minimizing the overall device footprint and reducing the complexity of interconnections.
Solution Approach 2:
The coupled inductor-capacitor structure serves multiple functions simultaneously: the capacitor provides its primary capacitance function while also controlling the effective inductance through eddy currents, and the inductor provides its primary inductance function while being modulated by the capacitor's electric field. This multi-functionality reduces the need for separate tuning components.
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 reconfigurable LC circuits with increased oscillating or resonant frequency, maintaining compatibility with standard CMOS fabrication processes and providing high capacitance density with low equivalent series resistance.
Implementation Method 1
Eddy currents are formed when sending an operating current through the terminals of the oscillator circuit. The eddy current influences, by inductive coupling, the inductance value, the current through the inductor and the capacitor
Implementation Method 2
The inductor and the capacitor are inductively coupled to one another. The eddy current influences, by inductive coupling, the inductance value
Implementation Method 3
The capacitor includes a capacitance value and together, the inductor and capacitor creates an oscillator circuit
Data Source
AI summary
A method for controlling a semiconductor circuit, including forming an inductor and a capacitor on a substrate, which are inductively coupled to one another. The inductor has an inductance value while the capacitor has a capacitance value. The inductor and capacitor make up an oscillator circuit with two terminals. Eddy currents are generated through the capacitor when an operating current flows along the inductor. These eddy currents influence, by inductive coupling, the inductance value and performance of the oscillator circuit, thus simultaneously tuning the inductance and capacitance of the oscillator circuit.