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Published on: June 1, 2012
Wide dynamic range CMOS potentiostat for amperometric chemical sensor
Wei-Song Wang1, Wei-Ting Kuo, Hong-Yi Huang
1Department of Electrical Engineering, National Cheng Kung University, Tainan, Taiwan. n2895145@ccmail.ncku.edu.tw
Sensors (Basel, Switzerland)
|February 2, 2012
Summary
A new fully-differential potentiostat improves linearity and dynamic range for detecting low sensor currents. This design enhances biomedical applications by overcoming limitations of traditional single-ended potentiostats.
Area of Science:
- Electrical Engineering
- Biomedical Engineering
- Analog Integrated Circuit Design
Background:
- Single-ended potentiostats face linearity limitations and restricted dynamic range, especially when measuring low sensor currents.
- Harmonic distortion in single-ended designs degrades performance, limiting the detectable current and overall dynamic range.
Purpose of the Study:
- To design and implement a fully-differential potentiostat topology.
- To enhance linearity and expand the dynamic range for precise low-current measurements in biomedical applications.
Main Methods:
- A novel interface connection was developed to prevent cell voltage deviation and ensure linear current-to-voltage conversion.
- Two potentiostat circuits, including a fully-differential design, were implemented using a TSMC 0.18-μm CMOS process.
Main Results:
- The fully-differential potentiostat demonstrated superior linearity compared to the single-ended version for currents ranging from 500 pA to 10 µA.
- The implemented fully-differential design achieved a significant dynamic range of 86 dB.
Conclusions:
- The fully-differential potentiostat topology effectively addresses the linearity and dynamic range limitations of single-ended designs.
- This improved performance makes the fully-differential potentiostat suitable for sensitive biomedical sensing applications requiring accurate low-current detection.
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