Multi-Input Variable-Gain Amplifier With Switched Degeneration Bypass
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Solution Overview
Problem
Wireless communication devices face challenges in providing variable gain amplification for radio-frequency signals with improved linearity and reduced noise, especially in multi-input scenarios where different frequency bands require distinct gain modes and impedance settings.
Innovation Solution
A variable-gain signal amplifier with a degeneration switching block that provides tailored impedances and a bypass path, allowing for selective gain modes and impedance adjustments to enhance linearity and reduce noise, while also incorporating a medium gain mode feedback block for further performance improvement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable-gain stage is used to provide multiple gain levels, then gain versatility is improved, but linearity and noise performance deteriorate
Solution Approach 1:
The patent applies dynamics by making the impedance of the degeneration block variable rather than fixed. Switches selectively connect different impedance values (Z1, Z2, Z3) to the degeneration block based on the desired gain level, allowing the system to dynamically adjust impedance to maintain optimal linearity across different gain settings. This resolves the contradiction by enabling both gain versatility and sustained linearity through adaptive impedance matching.
Solution Approach 2:
The patent changes the impedance parameter of the degeneration block to optimize performance at different gain levels. By providing multiple impedance values and selectively connecting them via switches, the system adjusts the impedance parameter to maintain improved linearity while achieving various gain levels, thus resolving the contradiction between gain versatility and linearity maintenance.
2Adaptability or versatility
If a variable-gain stage is used to provide multiple gain levels, then gain versatility is improved, but noise performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the impedance of the degeneration block variable rather than fixed. Switches selectively connect different impedance values (Z1, Z2, Z3) to the degeneration block based on the desired gain level, allowing the system to dynamically adjust impedance to maintain optimal noise performance across different gain settings. This resolves the contradiction by enabling both gain versatility and sustained noise performance through adaptive impedance matching.
Solution Approach 2:
The patent changes the impedance parameter of the degeneration block to optimize noise performance at different gain levels. By providing multiple impedance values and selectively connecting them via switches, the system adjusts the impedance parameter to maintain improved noise performance while achieving various gain levels, thus resolving the contradiction between gain versatility and noise performance.
3Adaptability or versatility
If a bypass path is added to provide low-gain mode, then gain range is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the bypass block to serve multiple functions: it provides the low-gain bypass path while also being integrated with the feedback block and impedance adjustment mechanism. The bypass block can operate in conjunction with the feedback path and impedance switches, allowing a single structural element to fulfill multiple roles in different operating modes, thus reducing overall device complexity while expanding gain range.
Solution Approach 2:
The patent merges the bypass function with the feedback and impedance control mechanisms. The bypass block is integrated with the feedback block such that the same structural elements serve both bypass and feedback functions depending on the operating mode. This consolidation reduces the number of separate components needed, thereby reducing device complexity while providing extended gain range including low-gain mode.
4Reliability
If tailored impedances are provided for different gain levels, then linearity is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the impedance control into discrete, manageable segments. Instead of using a continuous or complex variable impedance mechanism, the system segments the impedance into distinct values (Z1, Z2, Z3) that can be selectively connected via simple switches. This segmentation simplifies the impedance control circuit while still providing the tailored impedances needed to improve linearity at different gain levels.
Solution Approach 2:
The patent applies local quality by providing specific impedance values at specific locations in the circuit based on the operating mode. Each impedance value (Z1, Z2, Z3) is tailored for specific gain levels, and the local impedance characteristic is optimized for that particular operating condition. This localized optimization improves linearity without requiring complex global impedance control, as each segment of the circuit receives the appropriate impedance for its specific function.
Data Source
AI summary
Described herein are variable gain amplifiers that selectively provide variable or tailored impedances at a degeneration block and/or feedback block depending at least in part on a gain mode of the variable gain amplifier. This advantageously reduces or eliminates performance penalties in one or more gain modes. The variable impedances can be configured to improve linearity of the amplification process in targeted gain modes. The variable gain amplifier can be configured to provide a low-loss bypass mode in a low gain mode to improve signal quality.