Differential Amplifier Circuit With Non-Linearity Cancellation
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Solution Overview
Problem
Amplifiers with multiple stages exhibit increased overall non-linearity, which degrades signal quality and increases bit error rates in digital communications systems due to non-uniform voltage level separation in amplified signals.
Innovation Solution
The implementation of a primary differential amplifier circuit and a secondary differential amplifier circuit, where the secondary circuit generates an output with opposing polarity to cancel out the non-linearity of the primary circuit, reducing overall non-linearity and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple amplifier stages are connected in series to achieve higher amplification, then the amplification capability is improved, but the overall non-linearity increases and signal quality deteriorates
Solution Approach 1:
The amplifier is divided into multiple independent amplifier stages connected in series, where each stage contributes to the overall amplification. By segmenting the amplification function across multiple stages, the system achieves higher total amplification while managing non-linearity through individual stage optimization.
Solution Approach 2:
The invention adjusts operating parameters of individual amplifier stages, particularly bias currents and voltage levels, to optimize the transfer characteristics. By changing parameters such as tail currents and resistor values in each stage, the system achieves linear transfer characteristics across multiple stages, preventing cumulative non-linearity.
2Reliability
If amplifier stages operate with high current to maintain linearity, then signal quality is improved, but power consumption increases
Solution Approach 1:
The system optimizes power consumption by carefully selecting and adjusting operating parameters such as tail currents, resistor values, and voltage levels in each amplifier stage. By changing these parameters, the invention achieves acceptable linearity and signal quality at reduced current levels compared to conventional single-stage high-current amplifiers.
Solution Approach 2:
The amplification function is segmented across multiple stages, allowing each stage to operate at lower current levels while contributing to the overall amplification. This segmentation enables the system to achieve the required signal quality without requiring high current through a single stage, thereby reducing total power consumption.
Data Source
AI summary
An amplifier circuit includes a primary differential amplifier circuit connected to receive a differential input and provide a primary differential output with a first non-linearity. A secondary differential amplifier circuit is connected to receive the differential input. The secondary differential amplifier circuit is configured to generate a secondary differential output with a second non-linearity. The secondary differential output and the primary differential output are coupled together with opposing polarities such that the second non-linearity cancels out at least the first non-linearity.