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A novel fully differential biopotential amplifier with dc suppression.
Enrique Mario Spinelli1, Nolberto Martínez, Miguel Angel Mayosky
1Laboratorio de Electrónica Industrial Control e Instrumentación, Facultad de Ingeniería, Universidad Nacional de La Plata and Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina. spinelli@ieee.org
IEEE Transactions on Bio-Medical Engineering
|August 18, 2004
Summary
This study introduces a novel fully differential biopotential amplifier with a unique DC-suppression circuit. It achieves high common mode rejection ratio (CMRR) and fast recovery without matched components, ideal for low-voltage systems.
Area of Science:
- Biomedical Engineering
- Analog Circuit Design
Background:
- Fully differential amplifiers offer high gain and common mode rejection ratio (CMRR) but are limited in biopotential measurements by electrode offset voltage.
- Conventional solutions for DC offset in biopotential amplifiers often compromise CMRR and increase input noise.
- Existing methods typically convert differential signals to single-ended, limiting performance.
Purpose of the Study:
- To present a novel fully differential biopotential amplifier.
- To introduce a fully differential DC-suppression circuit that avoids matched passive components.
- To enhance CMRR and enable fast recovery from DC transients in low-voltage systems.
Main Methods:
- Development of a fully differential DC-suppression circuit.
- Integration of the circuit into a fully differential biopotential amplifier architecture.
- Implementation using standard low-power operational amplifiers (op amps) and a 5-V power supply.
Main Results:
- The amplifier accepts input offset voltages up to +/-500 mV.
- Achieved a high CMRR of 102 dB at 50 Hz.
- Demonstrated fast recovery from DC level transients and overload conditions, adhering to the AAMI EC38 standard.
Conclusions:
- The proposed fully differential amplifier with integrated DC suppression offers superior performance without requiring matched passive components.
- This design is particularly suitable for low supply voltage applications in biopotential measurements.
- The amplifier meets stringent standards for offset voltage handling and transient recovery.