Open-Loop Transconductance Amplifier with Parallel Calibration
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Solution Overview
Problem
Conventional transconductance amplifiers struggle to support high-bandwidth and rapid transient responses without significantly increasing circuit board area.
Innovation Solution
A dual amplifier architecture is employed, where one amplifier performs transconductance operations while the other performs calibration phases, including auto-zeroing and gain offset correction, in an open loop configuration, allowing for parallel operation and reduced input offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional transconductance amplifier designs are used to support high-bandwidth and rapid transient responses, then performance requirements are met, but circuit board area footprint increases unreasonably
Solution Approach 1:
The amplifier is divided into two separate amplifiers: a first amplifier dedicated to transconductance operations and a second amplifier dedicated to calibration operations. This segmentation allows each amplifier to be optimized for its specific function, enabling high-bandwidth operation while reducing the total circuit board area compared to a single large amplifier attempting to perform both functions simultaneously.
Solution Approach 2:
The system employs periodic switching between transconductance phase and calibration phase. During the transconductance phase, the first amplifier converts voltage to current while the second amplifier performs calibration operations. This periodic alternation allows calibration to occur without interfering with high-bandwidth signal processing, maintaining both performance and area efficiency.
2Measurement precision
If calibration operations are performed during transconductance operation, then accuracy is improved, but bandwidth and transient response deteriorate
Solution Approach 1:
The system implements periodic calibration during which the first amplifier is decoupled from the input and output nodes and dedicated to calibration operations, while the second amplifier handles transconductance. This periodic separation ensures that calibration activities do not interfere with the high-bandwidth signal path, maintaining both precision and speed.
Solution Approach 2:
Switching circuitry acts as an intermediary to decouple the amplifiers from the input and output nodes during calibration phases. This switching mechanism allows seamless transition between calibration and transconductance operations, ensuring that calibration does not degrade bandwidth while still achieving accurate offset correction.
3Device complexity
If a single amplifier performs both transconductance and calibration operations, then device complexity is reduced, but performance requirements for high-bandwidth and rapid transient response cannot be met
Solution Approach 1:
The system uses two amplifiers with clearly defined roles: the first amplifier for transconductance and the second for calibration. This segmentation, while increasing the number of amplifiers, enables each to be optimized for its specific function, achieving high transient response that would be impossible for a single amplifier attempting to perform both functions.
Solution Approach 2:
By periodically alternating the operational phases of the two amplifiers, the system achieves high transient response during transconductance phases while performing calibration during dedicated calibration phases. This periodic operation allows the system to meet stringent performance requirements without requiring a single overly complex amplifier.
Data Source
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AI summary
Some examples of the disclosure are directed to systems and methods for calibrating and operating transconductance amplifiers for high-bandwidth applications configured in open loop configurations. Some examples of the disclosure are directed to setting a gain of the transconductance amplifiers based upon a value of an output load. Some examples of the disclosure are directed to using auto-zeroing circuitry and gain correction circuitry to modify a biasing of a transconductance amplifier.