MOS Amplifier Bias Control for Constant Phase Gain Adjustment
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Solution Overview
Problem
Conventional variable gain amplifiers in 5G communications systems face challenges in maintaining a constant phase during gain adjustments, leading to increased bit error rates and antenna receiving angle changes, as they require separate phase compensation solutions that are inflexible and costly due to the use of hardware components.
Innovation Solution
The proposed amplifier design uses a configuration of MOS transistors with controlled gate and bias voltage inputs to adjust the phase difference between input and output signals, allowing for flexible phase adjustment and constant phase maintenance during gain changes by modifying the transconductance of the MOS transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a digital switched attenuator with phase compensation component is used, then constant phase is achieved, but layout area and cost increase
Solution Approach 1:
The patent extracts the phase compensation function from a separate hardware component and integrates it into the bias voltage control mechanism of the MOS transistor amplifier. By removing the need for external phase compensation components (inductors, capacitors), the layout area is reduced while maintaining constant phase through electronic bias control.
Solution Approach 2:
The bias voltage input end serves multiple functions: it controls the gain of the amplifier by adjusting the transconductance of the MOS transistor, and simultaneously compensates for phase variations. This multi-functional approach eliminates the need for separate phase compensation hardware, reducing overall circuit complexity and area.
2Stability of the object's composition
If hardware phase compensation components are used, then constant phase is maintained, but device complexity and cost increase
Solution Approach 1:
The patent merges the gain control function and phase compensation function into a single integrated circuit block. The bias voltage control mechanism simultaneously adjusts both the amplitude (through transconductance modulation) and phase (through bias point adjustment) of the amplifier, eliminating the need for separate phase compensation hardware and reducing overall device complexity.
Solution Approach 2:
The patent replaces mechanical/hardware phase compensation components (inductors, capacitors, switches) with an electronic control mechanism. By using voltage-controlled transconductance modulation, the system achieves phase compensation through electrical signals rather than physical component adjustments, reducing complexity and improving integration.
3Stability of the object's composition
If active current injection is used for phase compensation, then constant phase is achieved, but additional components and complexity are required
Solution Approach 1:
The amplifier circuit performs self-phase-compensation through its intrinsic bias control mechanism. By adjusting the bias voltage at the gate of the MOS transistor, the circuit automatically compensates for phase variations that occur during gain changes, without requiring external phase compensation circuits or additional active current injection mechanisms.
4Device complexity
If fixed gain amplifier is used, then simple structure is maintained, but dynamic range and adaptability are limited
Solution Approach 1:
The patent implements a variable gain amplifier by dynamically controlling the bias voltage at the gate of the MOS transistor. This allows the transconductance and gain of the amplifier to be adjusted in real-time according to signal conditions, providing adaptability while maintaining a relatively simple transistor-based structure without requiring complex switching networks or multiple amplifier stages.
Data Source
AI summary
Amplifiers, amplification circuits, and phase shifters, for example, for flexibly adjusting an output phase to thereby meet a requirement of a constant phase on a link in a communications field, are provided. In one aspect, an amplifier includes first, second, and third MOS transistors. The first MOS transistor includes a gate separately coupled to a signal input end and a bias voltage input end, a source coupled to a power supply, and a drain separately coupled to sources of the second and third MOS transistors. A drain of the third MOS transistor is coupled to a ground, and a drain of the second MOS transistor is coupled to a signal output end. The bias voltage input end is configured to receive a bias voltage to adjust a phase difference between an input signal at the signal input end and an output signal at the signal output end.