Switched-Capacitor LNA for Uniform Gain and High Linearity
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Solution Overview
Problem
Conventional low-noise amplifiers face challenges in achieving uniform gain spacings and high linearity, particularly at low-gain levels, with passive structures causing signal phase changes and active structures increasing power consumption without satisfactory results.
Innovation Solution
A high-linearity low-noise amplifier design incorporating a primary-stage and secondary-stage amplification unit, a switched capacitor branch, and configurable load units, utilizing bias voltage control and impedance matching to achieve uniform gain spacings and improved linearity through cancellation of third-order intermodulation terms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive structure signal path is used to improve linearity at low-gain level, then linearity is improved, but signal phase changes and non-uniform gain spacings occur
Solution Approach 1:
The patent employs dynamic switching between different signal paths (passive and active) based on operating conditions. A switching mechanism selectively connects the passive structure path for linearity improvement while maintaining the ability to switch to active paths when phase stability or gain uniformity is required, making the system adaptable to different operational requirements
Solution Approach 2:
The signal path is divided into multiple segments including passive structure paths for linearity enhancement and active paths for phase stability. Each segment can be independently controlled and switched, allowing the system to combine benefits of both approaches while avoiding their respective drawbacks
2Reliability
If the bias voltage of amplifying tube is raised to improve linearity in active structure, then linearity is improved to some extent, but power consumption increases and system requirements are not satisfied
Solution Approach 1:
Instead of continuously raising bias voltage to improve linearity, the patent changes the operating parameter by switching between different signal paths with different characteristics. The passive structure path provides linearity improvement without requiring increased bias voltage, thus avoiding additional power consumption while maintaining linearity performance
Solution Approach 2:
The passive structure signal path acts as an intermediary element that provides linearity improvement without requiring direct manipulation of amplifying tube bias voltage. This intermediary path enables linearity enhancement while avoiding the power consumption penalty associated with raising bias voltage in active structures
Data Source
AI summary
Disclosed are a high-linearity low-noise amplifier, a chip, and an electronic device. The low-noise amplifier comprises a primary-stage amplification unit, at least one secondary-stage amplification unit, a drive unit, a configurable load unit, an input impedance matching unit and an output impedance matching unit, and further comprises a switched capacitor branch; wherein the input end of the at least one secondary-stage amplification unit is connected via the switched capacitor branch to the input end of the primary-stage amplification unit, and the input end of the secondary-stage amplification unit is provided with an independent bias voltage; in a low-gain operating mode, the switched capacitor branch is closed, and at the same time, a secondary amplification unit path connected to the switched capacitor branch is opened.