Variable Inductance Gain Control in Cascoded HF Amplifiers
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Solution Overview
Problem
Existing high-frequency amplifier circuits face challenges in controlling gain without negatively impacting low-frequency operation, and fixed inductances are sensitive to process, voltage, and temperature variations.
Innovation Solution
Implementing a variable inductance system in cascoded differential amplifier topologies, allowing post-fabrication gain control by switching between transistors with different inductance values, maintaining optimal current density and reducing capacitive load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed inductance is used in high-frequency amplifier circuits, then gain control is simplified, but the circuit becomes sensitive to process, voltage, and temperature variations
Solution Approach 1:
The patent implements variable inductance through switching between multiple inductor configurations (series, parallel, single) based on operating conditions. This dynamic adjustment allows the circuit to adapt to process, voltage, and temperature variations, resolving the contradiction between simplified gain control and reliability under PVT variations.
2Adaptability or versatility
If variable inductance system is implemented for high-frequency gain control, then flexible gain control is achieved, but device complexity increases
Solution Approach 1:
The patent divides the inductance control into discrete segments or configurations (first inductor configuration, second inductor configuration, third inductor configuration). Each configuration provides a specific inductance value suitable for different gain requirements. This segmentation enables flexible gain control while managing device complexity through modular design.
3Reliability
If traditional amplifier topologies are used, then low-frequency operation is maintained, but high-frequency gain control is limited
Solution Approach 1:
The patent designs the amplifier circuit to serve multiple frequency ranges and gain requirements using a unified topology with switchable inductor configurations. The same amplifier structure maintains low-frequency performance while enabling high-frequency gain control through the variable inductance mechanism, achieving multi-functionality without requiring separate circuits for different frequency ranges.
Data Source
AI summary
Various embodiments of the invention provide amplifier control systems and methods for adjusting a high frequency gain of an amplifier circuit. In certain embodiments, this is accomplished by varying an effective inductance of an amplifier circuit that comprises a first path, which comprises a first cascoded transistor in series with a first inductor and a second cascoded transistor in parallel with the first cascoded transistor. A second path to carry a second current in parallel with the first path comprises a third cascoded transistor that is coupled in series with a second inductor, wherein adjusting comprises maintaining the sum of the first and second currents to be substantively constant when alternating current between the second and third transistors.