Multi-Input Amplifier Gain Paths Without Degeneration Switches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication devices face performance issues in achieving desired characteristics across multiple gain modes due to reduced linearity and noise figure in signal amplifiers, which are often addressed by using a single amplifier core for all gain modes.
Innovation Solution
The implementation of a variable-gain signal amplifier with multiple active cores and a degeneration matrix that provides tailored impedances without switches, allowing for selective direction of signals to dedicated amplifier architectures for specific gain modes, enhancing linearity and noise figure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single amplifier core is used for all gain modes, then device complexity is reduced, but linearity and noise figure performance deteriorate across different gain modes
Solution Approach 1:
The amplifier is divided into multiple independent active cores (first active core, second active core), each optimized for specific gain modes. The gain mode selector segments the signal path to direct input signals to appropriate cores based on the required gain mode, allowing each core to be specialized for particular performance characteristics.
Solution Approach 2:
Each active core is designed with tailored characteristics optimized for specific operating conditions. The first active core may be optimized for low noise figure in high gain modes, while the second active core may be optimized for linearity in other gain modes. This local optimization ensures best performance for each specific gain mode requirement.
2Reliability
If multiple active cores with dedicated architectures are used for different gain modes, then linearity and noise figure are improved, but device complexity increases
Solution Approach 1:
Multiple active cores are merged into a single amplifier device with a common input node and output node. The gain mode selector and degeneration matrix are shared resources that manage the multiple cores, reducing overall complexity compared to separate amplifier devices. This merging allows coordinated operation of multiple cores under unified control.
Solution Approach 2:
The degeneration matrix is designed to provide tailored inductances for multiple different signal paths simultaneously. The same degeneration matrix structure serves multiple active cores and multiple gain modes, making it a universal component that adapts to different configurations without requiring separate degeneration networks for each core.
3Adaptability or versatility
If switches are used in the degeneration matrix for switching between gain modes, then gain mode switching is enabled, but device complexity and package size increase
Solution Approach 1:
The mechanical switch system in the degeneration matrix is replaced with an electronic control system. The gain mode selector, which is already present for directing signals to appropriate active cores, electronically controls the degeneration matrix to provide the appropriate inductance values for each gain mode. This substitution eliminates mechanical switches and associated control logic while maintaining gain mode switching capability.
Solution Approach 2:
The degeneration matrix is designed to automatically provide the correct inductance values based on the active signal path determined by the gain mode selector. The matrix self-adjusts its effective inductance for each gain mode without requiring external switch control, as the same control signals that select the active core also determine the appropriate degeneration inductance.
Data Source
AI summary
Disclosed herein are signal amplifiers that include a plurality of switchable amplifier architectures so that particular gain modes can use dedicated amplifier architectures to provide desired characteristics for those gain modes, such as low noise figure or high linearity. The disclosed signal amplifier architectures provide tailored impedances using a degeneration block or matrix without using switches in the degeneration switching block. The disclosed signal amplifier architectures provide a plurality of gain modes where different gain modes use different paths through the amplifier architecture. Switches that are used to select the path through the amplifier architecture also provide targeted impedances in a degeneration block or matrix. The switches that select the gain path are provided in the amplifier architecture and are thus not needed or used in the degeneration block, thereby reducing the size of the package for the amplifier architecture.