Deep-Well Tunable Resonant Circuit for Wider Frequency Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tunable resonant circuits face limitations in their tuning range due to parasitic circuit elements, which restrict the adjustment of resonance frequency in response to manufacturing variations, temperature changes, and voltage fluctuations.
Innovation Solution
The implementation of a tunable resonant circuit design that includes matched capacitors and transistors with gate electrodes responsive to tuning signals, coupled with an inductor, and a biasing circuit with current mirrors to adjust capacitance and inductance, reducing parasitic capacitance and extending the tuning range by differential operation and binary-weighted capacitance layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional resonant circuit design is used, then the circuit can function as a filter or oscillator, but the tuning range is limited due to parasitic circuit elements
Solution Approach 1:
The resonant circuit is divided into multiple parallel resonant circuits, each with its own inductor and capacitor. This segmentation allows each unit to be optimized independently and enables broader overall tuning range by combining multiple segments with different resonant frequencies.
Solution Approach 2:
The patent implements nested deep-well structures where a first well is disposed within a second well that is disposed within a substrate. This nesting arrangement minimizes parasitic capacitance by creating isolated regions that reduce unwanted electrical coupling to the substrate, thereby extending the tuning range.
2Reliability
If the tuning range is increased to compensate for manufacturing variations and operating conditions, then frequency stability improves, but parasitic elements limit the achievable tuning range
Solution Approach 1:
The nested deep-well structure with a first well within a second well within a substrate creates isolated regions that minimize parasitic capacitance. This enables the resonant frequency to be tuned over a wider range to compensate for manufacturing variations, temperature changes, and voltage fluctuations while maintaining frequency stability.
Solution Approach 2:
The patent uses variable capacitors and variable inductors to dynamically change the resonant frequency parameter. By adjusting the capacitance and inductance values, the circuit can track application requirements and compensate for operating condition variations, achieving frequency stability across different conditions.
3Adaptability or versatility
If deep-well arrangements are implemented to reduce parasitic capacitance, then tuning range increases, but device complexity increases
Solution Approach 1:
The resonant circuit is divided into multiple parallel branches, each containing an inductor and capacitor. This segmentation allows the use of deep-well arrangements in each branch independently, reducing parasitic capacitance without requiring a single complex deep structure. The modular approach simplifies fabrication while achieving extended tuning range.
4Reliability
If matched capacitors are used in parallel resonant circuits, then quality factor improves, but circuit complexity increases
Solution Approach 1:
The circuit is divided into multiple parallel resonant circuits with matched capacitors. Each segment contributes to the overall quality factor, and the segmentation allows for modular design and fabrication. The matched capacitors in each parallel branch work together to enhance the total quality factor while maintaining a manageable circuit structure.
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 enhances the tuning range and frequency stability of resonant circuits, reducing parasitic capacitance and increasing inductance, thereby extending the frequency range of oscillators and improving quality factor, leading to reduced frequency jitter.
Implementation Method 1
resonant circuits are useful for various applications, such as filters and oscillators. The frequency of resonance can be adjusted in tunable resonant circuits
Implementation Method 2
Two varactor diodes can be coupled in series combination, and the inductor can be coupled across the series combination, wherein the varactor diodes can be responsive to a tuning signal
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A tunable resonant circuit (102) includes first capacitors (104, 108, 216, 228, 232) and second capacitors (106, 1 10, 218, 230, 234) that provide a matched capacitance between first and second electrodes of the first and second capacitors. A deep-well arrangement includes a first well (320, 326) disposed within a second well (322, 328) in a substrate (324). The first and second capacitors are each disposed on the first well. Two channel electrodes of a first transistor (120, 130) are respectively coupled to the second electrode (1 14, 304) of the first capacitor and the second electrode (1 18, 308) of the second capacitor. Two channel electrodes of a second transistor (122, 132) are respectively coupled to the second electrode of the first capacitor and to ground. Two channel electrodes of the third transistor (124, 134) are respectively coupled to the second electrode of the second capacitor and to ground. The gate electrodes (226, 314) of the first, second, and third transistors are responsive to a tuning signal (126, 136), and an inductor (144, 202) is coupled between the first electrodes (1 12, 1 16, 302, 306) of the first and second capacitors.