High gain driven right leg circuit for dry electrode systems

- A DRL compensation is presented allowing higher common mode voltage attenuation.
- Dry electrode and single-ended systems can benefit from the proposed high gain DRL.
- The stability margin and simplicity of the established alternative are preserved.
- A design procedure and sample implementation for a dry electrode system are shown.
- Better rejection of power line harmonics is experimentally demonstrated.

This paper presents an improved driven right leg (DRL) circuit compensation together with a practical implementation. The proposed design allows to increase common mode voltage attenuation compared with the widely used dominant pole compensation while maintaining the same proven stability margin and design criteria, and requiring only a modification of its passive feedback network. A sample implementation of the proposed DRL was obtained estimating the values of interference model parameters for a dry electrode measurement system. A dominant pole compensated DRL with the same stability margin was also implemented in order to experimentally validate the proposed design against this established alternative. Measurements were conducted under both controlled and uncontrolled interference conditions. The proposed compensation experimentally demonstrated achieving a better reduction of power line harmonics, with a peak comparative improvement of around 18  dB at 50  Hz.