LC Tank Circuit with Distributed Capacitive Coupling for Frequency Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LC tank circuits face a significant downward shift in resonant frequency due to the interconnect metal used to connect the inductor and capacitor, which increases the inductance, particularly when the capacitor is large and requires a long interconnect metal.
Innovation Solution
A loop topology coil with inward and outward extension legs and strategically placed capacitors forms a distributed inductor and capacitor, minimizing the impact of these legs on effective inductance and maintaining resonant frequency stability, using a distributed inductor and capacitor configuration where the capacitors provide capacitive coupling between the ends of the coil and its legs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a long interconnect metal is used to connect the inductor to the capacitor, then the capacitor can be physically larger, but the inductance increases significantly causing resonant frequency to shift downward
Solution Approach 1:
The patent divides the inductor structure into multiple segments by adding extension legs at different locations (first, second, and third ends) of the coil. These segmented extension legs distribute the capacitive coupling points along the inductor length, reducing the inductive effect of any single connection point and minimizing resonant frequency shift while accommodating larger capacitor dimensions.
Solution Approach 2:
The extension legs act as intermediary elements between the coil and the capacitor. By introducing these intermediate connection points, the patent reduces the direct impact of long interconnect metals on the inductor's effective inductance, thereby maintaining resonant frequency stability while allowing larger capacitor physical size.
2Adaptability or versatility
If the interconnect metal is made longer to accommodate larger capacitors, then more design flexibility is achieved, but the inductance increase causes harmful downward frequency shift
Solution Approach 1:
The patent applies different structural qualities to different parts of the inductor by adding extension legs at specific locations (first, second, and third ends) rather than uniformly modifying the entire structure. This localized modification provides design flexibility for accommodating various capacitor sizes while minimizing the overall inductance increase through strategic placement of capacitive coupling points.
3Reliability
If extension legs are added to the coil, then capacitive coupling can be distributed to reduce inductive effects, but the device structure becomes more complex
Solution Approach 1:
The patent merges the extension legs with the existing coil structure to form an integrated inductor component. The extension legs are directly connected to the coil ends, combining multiple functions (inductance, capacitive coupling, and frequency stabilization) into a single unified structure, thereby reducing overall device complexity while maintaining resonant frequency stability.
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 configuration effectively offsets the inductive effects of the extension legs, maintaining the resonant frequency stability and preventing the downward shift typically seen in prior art integrated LC tank circuits, while allowing for tunability by using variable capacitors.
Implementation Method 1
a first capacitor configured to provide a capacitive coupling between the first end and the second end; a second capacitor configured to provide a capacitive coupling between the third end and the fourth end; and a third capacitor configured to provide a capacitive coupling between the fifth end and the sixth end
Data Source
AI summary
A device includes a coil configured in a loop topology starting from a first end and extending to a second end, a pair of inward extension legs configured to extend from the first end and the second end toward an interior side of the coil to a third end and a fourth end, respectively, a pair of outward extension legs configured to extend from the first end and the second end toward an exterior side of the coil to a fifth end and a sixth end, respectively, a first capacitor configured to provide a capacitive coupling between the first end and the second end, a second capacitor configured to provide a capacitive coupling between the third end and the fourth end, and a third capacitor configured to provide a capacitive coupling between the fifth end and the sixth end.