Amplifier Offset Compensation Using Dual Current Injection
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Solution Overview
Problem
Amplifier circuits amplify both the signal-of-interest and input offset components, leading to limited gain and dynamic range, often requiring higher resolution analog-to-digital converters and potentially exceeding power supply rails.
Innovation Solution
The amplifier circuit employs a dual-stage configuration with negative feedback resistances and current sources to selectively amplify or nullify the input signal offset, using current digital-to-analog converters to adjust currents across a gain resistance, allowing for unity or zero offset gain, thereby isolating the signal-of-interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the amplifier circuit amplifies the full input signal including offset, then the signal-of-interest is amplified, but the gain is limited and the output may exceed power supply rails
Solution Approach 1:
The patent segments the input signal into two components: signal-of-interest and offset component. It then processes these components separately through different signal paths, allowing the signal-of-interest to be amplified while the offset component is handled independently to prevent output saturation.
Solution Approach 2:
The patent extracts the offset component from the full input signal using a dedicated offset detection path. By separating and measuring the offset component independently, the system can compensate for it without limiting the amplification of the signal-of-interest.
2Power
If the amplifier circuit amplifies the full input signal including offset, then the signal-of-interest is amplified, but the dynamic range suffers and higher resolution ADC is required
Solution Approach 1:
The patent segments the signal processing into separate paths: one for amplifying the signal-of-interest and another for detecting and compensating the offset component. This segmentation allows the system to maintain high gain for the signal-of-interest while using lower-resolution ADCs for offset measurement and compensation.
Solution Approach 2:
The patent introduces an intermediary offset compensation mechanism that measures the offset component separately and subtracts it from the amplified signal. This intermediary process allows the use of lower-resolution ADCs while maintaining the overall dynamic range and measurement precision.
3Power
If higher gain is used to amplify the signal-of-interest, then the signal amplification is improved, but the input offset amplification causes the output to exceed power supply rails
Solution Approach 1:
The patent extracts the offset component from the input signal and processes it through a separate detection and compensation path. This allows high gain amplification of the signal-of-interest while the offset component is independently managed to prevent output saturation.
Solution Approach 2:
The patent applies preliminary anti-action by detecting and compensating for the offset component before it can be amplified along with the signal-of-interest. The offset compensation is applied in advance to prevent the harmful effect of offset amplification that would otherwise cause the output to exceed power supply rails.
Data Source
AI summary
Various examples are directed to amplifier circuits and methods for operating amplifier circuits. The amplifier circuit may comprise a first amplifier stage. The first amplifier stage comprises a first amplifier, a first feedback resistance, a second amplifier, a second feedback resistance, and a gain resistance. A first current source may be electrically coupled to provide a first current across the gain resistance in a first direction. A second current source may be electrically coupled to provide a second current across the gain resistance in a second direction opposite to the first direction.