Driven right leg circuit compensation for improved common mode interference rejection.

FEDERICO NICOLÁS GUERRERO; ENRIQUE MARIO SPINELLI

San Nicolas de los Arroyos

Congreso; XX Congreso Argentino de Bioingeniería y IX jornadas de Ingeniería Clínica SABI 2015; 2015

Sociedad Argentina de BioIngeniería

The dominant pole compensation commonly used in driven right leg circuits is a proven design that allows a trade-off between the desired interference rejection and the common mode feedback loop stability. However, the use of small area dry electrodes imposes a strain on the interference rejection capabilities of biopotential amplifiers, because their high impedance magnitude and variability produces significant interference through the potential divider effect. This paper presents a driven right leg circuit compensation scheme that allows to increase the common mode voltage attenuation without compromising the stability of the system. The interference model is analyzed and a design rationale for the proposed compensator is presented. A conservative circuit design and implementation is shown, and biopotential measurements are conducted with both the proposed and the dominant pole compensated DRLs. The proposed compensator allowed to obtain an increased gain in the frequency band of the electromyogram, with a 20 dB improvement at 50 Hz.