Multi-Input Cascode Amplifier Tree Structure
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Solution Overview
Problem
The increasing complexity of RF devices to support multiple frequency bands and modes of operation leads to a costly and physically large solution with traditional mode-specific amplifiers, causing performance degradation.
Innovation Solution
A multi-input cascode amplifier configuration is introduced, featuring a tree structure where at least one cascode transistor of a first stage is coupled to two transistors of a second stage, allowing for shared transistors across different modes of operation, reducing the physical layout size and eliminating the need for selection switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional mode-specific amplifiers are used to support multiple frequency bands and modes of operation, then the RF device can operate in different modes, but the physical layout size and cost increase significantly
Solution Approach 1:
The amplifier circuit is designed with a universal structure that can operate in multiple modes (full-duplex, half-duplex, full-duplex with simultaneous RX/TX) using the same transistors and circuit components. The cascode configuration with stacked transistors enables the circuit to adapt to different operational modes without requiring separate amplifiers for each mode, thereby reducing physical layout size while maintaining versatility.
2Reliability
If multiple mode-specific amplifiers are implemented to support different frequency bands, then each mode can be optimized, but the physical size and cost become prohibitive
Solution Approach 1:
The amplifier circuit employs dynamic biasing control where the bias voltage applied to the cascode transistor can be adjusted based on the operational mode. This dynamic adjustment allows the same physical circuit to be optimized for different modes of operation (full-duplex, half-duplex, etc.) without requiring multiple dedicated amplifiers, thus maintaining performance optimization while reducing physical size.
3Adaptability or versatility
If selection switches are added to switch between different amplifiers for different modes, then mode switching is enabled, but the circuit complexity and physical size increase
Solution Approach 1:
The invention extracts and eliminates the need for selection switches by designing a single amplifier circuit that can directly support multiple operational modes. The cascode configuration with controllable transistors allows mode switching to be achieved through bias control rather than physical switch insertion, thereby reducing circuit complexity while maintaining mode switching capability.
Data Source
AI summary
Methods and devices for amplifying a plurality of input RF signals based on a multi-input cascode configuration is described. Transistors of stages of the multi-input cascode configuration are connected according to a tree, where there is at least one cascode transistor that is connected to at least two transistors of a stage below. In one case the stage below is an input stage, and in another case the stage below is a cascode stage. Activation and deactivation of transistors of the stages provide different conduction paths between the input stage and an output stage.