Amplifier Bias Circuit for Adaptive Linearity and Supply Current Control
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Solution Overview
Problem
Amplifier devices face limitations in power usage due to non-linear power-gain and power-phase curves, leading to increased complexity and cost when using pre-distortion circuits, which also vary with input signal, voltage source, and temperature, necessitating a simpler circuit with self-adjusting linearity.
Innovation Solution
An amplifier device comprising an amplifying unit and a bias module that adjusts supply current using counter-gradients correlated with the voltage signal, maintaining linearity within a predetermined range by employing a variable current source, transistors, and diodes to dynamically adjust impedance and bias current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
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 automatically adjusts its operating point by detecting supply voltage variations and modulating bias current accordingly, eliminating the need for external pre-distortion circuits. The system serves itself by using internal components (detecting unit, bias module) to compensate for voltage-induced linearity deviations without external intervention.
Solution Approach 2:
The detecting unit continuously monitors supply voltage and feeds this information to the bias module, which adjusts bias current in real-time. This closed-loop feedback mechanism automatically compensates for voltage variations that would otherwise cause linearity degradation, replacing complex pre-distortion circuitry with a simple feedback-controlled bias adjustment system.
2Manufacturing precision
If pre-distortion circuit is introduced to improve linearity, then linearity is improved, but cost increases
Solution Approach 1:
The amplifier uses its own internal resources (power supply, existing components) to perform linearity compensation. The detecting unit and bias module are integrated within the amplifier itself, eliminating the need for separate pre-distortion circuit components and reducing overall manufacturing cost.
Solution Approach 2:
The invention changes the operating parameters (bias current) dynamically based on supply voltage conditions to maintain linearity. By adjusting the bias current parameter in response to voltage variations, the system achieves linearity improvement without adding costly fixed pre-distortion circuitry.
3Power
If supply current is increased to improve power gain, then power gain is improved, but power consumption increases
Solution Approach 1:
The bias module dynamically adjusts supply current based on detected voltage conditions rather than maintaining a fixed high current. When supply voltage is adequate, current is reduced to save power; when voltage drops, current is increased to maintain gain, creating an adaptive power management system.
Solution Approach 2:
The system changes the supply current parameter dynamically in response to supply voltage variations. By modulating current based on actual voltage conditions, the amplifier maintains acceptable power gain while minimizing power consumption during normal operating conditions.
Data Source
AI summary
An amplifier device includes 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 generate a bias current according to a first counter-gradient and a second counter-gradient, and provide the 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.