Fully Differential Parallel Amplifier for Low-Noise Bioelectric Detection
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Solution Overview
Problem
Traditional biology electrical signal amplifiers face issues with high cost, complex circuits, low common mode rejection ratio, and noise immunity, making them unsuitable for efficient and cost-effective biology signal detection.
Innovation Solution
A fully differential non-inverting parallel amplifier is designed, comprising input buffer circuits, differential filter circuits, a data selector, non-inverting parallel amplifying circuits, and analog-digital circuits, which simplifies the design and enhances common mode rejection ratio while reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional AC magnitude amplifier is used, then biology electrical signal can be amplified, but the circuit becomes complex and baseline recovery becomes slow
Solution Approach 1:
The amplifier is divided into two independent parallel channels (inverting and non-inverting) that process signals simultaneously. Each channel has its own amplifier and feedback path, allowing independent optimization and simplifying the overall circuit design while maintaining high performance
Solution Approach 2:
The patent employs periodic sampling and resetting of capacitors in the feedback paths to achieve rapid baseline recovery. The capacitors are periodically discharged to remove accumulated DC offsets, enabling the system to quickly return to baseline after signal acquisition
2Measurement precision
If instrumentation amplifier is used, then common mode rejection ratio can be improved, but the cost increases significantly
Solution Approach 1:
The patent combines the functions of multiple amplifiers into a unified fully differential parallel amplifier architecture. By merging the inverting and non-inverting paths with a shared feedback mechanism, it achieves instrumentation amplifier-level common mode rejection using standard operational amplifiers rather than expensive dedicated instrumentation amplifier chips
Solution Approach 2:
The patent achieves high common mode rejection ratio by carefully controlling circuit parameters such as feedback resistance ratios and capacitor values. By optimizing these parameters in the parallel amplifier configuration, it attains CMRR performance comparable to instrumentation amplifiers but with lower cost components
3Power
If multiple amplifying steps are used, then signal can be amplified sufficiently, but system noise increases and common mode interference is hard to restrain
Solution Approach 1:
The patent introduces differential signaling as an intermediary mechanism between the input stage and output stage. By converting single-ended signals to differential signals early in the amplification process and maintaining differential operation throughout, it provides inherent immunity to common mode interference and reduces noise accumulation
Solution Approach 2:
The patent extracts and rejects common mode signals through the fully differential architecture. The parallel inverting and non-inverting paths naturally cancel common mode components, separating them from the differential signal of interest and eliminating them before they can affect the output
Data Source
AI summary
This invention relates to a fully differential non-inverting parallel amplifier for detecting biology electrical signal, including input buffer circuits, differential filter circuits, data selector, non-inverting parallel amplifying circuits and analog-digital circuits. The biology electrical signal, first impeded and converted by the input buffer circuits, and then low-pass filtered by the differential filter circuits, shall be amplified with its common mode signal rejected by passing through the data selector and non-inverting parallel amplifier circuits. At last, the amplified biology electrical signal is output by analog to digital conversion in the analog-digital circuits after its noises beyond signal high frequency band are filtered by anti-aliasing filter net. This invention, with low noise and high common mode rejection ratio, stable baseline, large signal input dynamic range, is reliable and not easy to be saturated. Furthermore, it can support mature PACE Detecting with a low cost. It is notable in social and economical benefits for its simple electrical circuits and easy use in any biology electrical testing equipments and controlling system.