Programmable Inductor LC Tank for Wide-Range Frequency Tuning
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Solution Overview
Problem
Conventional LC tank circuits face design tradeoffs when aiming to cover wide frequency ranges, leading to limitations in size, performance, power consumption, and cost, due to fixed inductance and capacitance values that result in excessive impedance variation across frequencies.
Innovation Solution
A resonant tank circuit with a programmable inductor and capacitor, where different amounts of inductance are switched in depending on the desired frequency, allowing operation in multiple sub-bands within a total frequency range, reducing impedance variation and enhancing quality factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fixed-value inductor is used with a variable capacitor to tune operating frequency, then the circuit can operate at high frequency, but the impedance varies excessively across wide frequency ranges
Solution Approach 1:
The patent applies dynamics by making the inductor value adjustable rather than fixed. The inductor array allows switching between different inductance values (L1, L2, L3) depending on the desired frequency range, enabling the circuit to maintain stable impedance across wide frequency variations while still achieving high-frequency operation.
Solution Approach 2:
The patent changes the inductance parameter dynamically by providing multiple inductor options in an array. The controller selects appropriate inductors based on the target frequency, thereby adjusting the L value to compensate for frequency changes and maintain impedance stability across the operating range.
2Adaptability or versatility
If a variable capacitor array is used to cover wide frequency range, then the frequency tuning range increases, but the circuit complexity and design tradeoffs increase
Solution Approach 1:
The patent segments the frequency tuning function by providing multiple fixed inductors with different values rather than using a continuously variable capacitor. This segmentation allows the circuit to cover wide frequency ranges by switching between discrete inductor values, reducing the complexity of the tuning mechanism while maintaining adaptability.
Solution Approach 2:
The inductor array serves multiple functions: it provides frequency tuning, maintains impedance stability, and reduces circuit complexity compared to alternative approaches. Each inductor in the array is designed with specific characteristics (different Q factors, different inductance values) to handle different frequency sub-ranges, making the overall system universally applicable across wide frequency ranges.
3Stability of the object's composition
If different inductors with different Q factors are used for different frequency sub-ranges, then impedance stability improves, but the number of components increases
Solution Approach 1:
The patent uses dynamic switching between different inductor configurations. The controller selectively connects appropriate inductors based on the desired frequency sub-range, enabling impedance stability without permanently having all inductors connected. This dynamic approach reduces the effective component count needed at any given time.
Solution Approach 2:
Each inductor in the array is optimized with specific local qualities (different inductance values, different Q factors) suited for particular frequency sub-ranges. This local optimization allows each component to perform its specific function efficiently, reducing the need for oversized components that would be required if a single inductor had to cover the entire frequency range.
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 efficient operation over a wide frequency range with reduced chip area and power consumption, while maintaining stable impedance across frequencies, thus improving performance and relaxing design constraints.
Implementation Method 1
a first inductor L1 having a first terminal coupled to the fourth switch and a second terminal coupled to at least the second switch; and a second inductor L2 having a first terminal coupled to the second terminal of the first inductor L1 and a second terminal coupled to the controllable capacitance
Implementation Method 2
a controllable capacitance
Implementation Method 3
A resonant tank circuit with a programmable inductor and capacitor, where different amounts of inductance are switched in depending on the desired frequency, allowing operation in multiple sub-bands within a total frequency range
Data Source
AI summary
In one embodiment, a tuning network includes: a controllable capacitance; a first switch coupled between the controllable capacitance and a reference voltage node; a second switch coupled between the controllable capacitance and a third switch; the third switch coupled between the second switch and a second voltage node; a fourth switch coupled between the second voltage node and a first inductor; the first inductor having a first terminal coupled to the fourth switch and a second terminal coupled to at least the second switch; and a second inductor having a first terminal coupled to the second terminal of the first inductor and a second terminal coupled to the controllable capacitance.