Amplifier Bias Module With Dynamic Impedance for Stable Linearity
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Solution Overview
Problem
Amplifier devices face limitations in power usage due to non-linear power-gain and power-phase curves, and introducing pre-distortion circuits complicates circuit design and increases costs, while linearity varies with input signal, voltage source, and temperature.
Innovation Solution
An amplifier device comprising an amplifying unit and a bias module with a variable voltage source, where the bias module adjusts linearity based on input signal frequency, voltage source, and temperature, using impedance units and adjusting modules to dynamically adjust impedance and bias voltage, thereby maintaining linearity across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-distortion circuit is introduced to improve linearity, then linearity is improved, but circuit complexity and cost increase
Solution Approach 1:
The amplifier device uses its own output signal to control the bias module, creating a self-adjusting system that maintains linearity without external pre-distortion circuits. The output signal directly modulates the bias current to compensate for non-linearities in real-time.
Solution Approach 2:
The system implements feedback by using the output signal to control the bias module, which adjusts the bias current based on the actual output conditions. This closed-loop feedback mechanism automatically compensates for non-linear distortions without requiring separate pre-distortion circuitry.
2Reliability
If pre-distortion circuit is introduced to improve linearity, then linearity is improved, but cost increases
Solution Approach 1:
The bias module serves multiple functions: it provides the necessary bias current for amplifier operation and simultaneously acts as a linearity compensation mechanism by adjusting its output based on the output signal. This multi-functionality eliminates the need for separate pre-distortion circuit components.
Solution Approach 2:
The invention merges the biasing function and linearity compensation function into a single integrated bias module. Instead of having separate circuits for biasing and pre-distortion, the system combines these functions, reducing component count and manufacturing cost.
3Reliability
If bias current is increased to maintain linearity under varying conditions, then linearity is improved, but power consumption increases
Solution Approach 1:
The bias current is made dynamic rather than static, allowing it to adjust in real-time based on operating conditions such as temperature, input signal frequency, and output signal level. This dynamic adjustment enables the system to maintain optimal linearity while consuming only the necessary power for each specific condition.
Solution Approach 2:
The system changes the bias current parameter dynamically in response to varying operating conditions. By adjusting this key parameter based on temperature, frequency, and signal level, the amplifier maintains linearity across different conditions without unnecessarily increasing power consumption.
Data Source
AI summary
An amplifier device comprises an amplifying unit and a bias module. The amplifying unit has a first end coupled to a voltage source configured to receive a source voltage, a second end configured to receive an input signal, and a third end coupled to a first reference potential terminal configured to receive a first reference potential. The first end of the amplifying unit is configured to output an output signal amplified by the amplifying unit. The bias module is coupled to the second end of the amplifying unit, and configured to receive a voltage signal to provide a bias current to the amplifying unit. The voltage signal is a variable voltage. A supply current flowing into the amplifying unit and is adjusted in accordance with the voltage signal to stay within a predetermined range.