Stability Analysis of Bootstrapped Buffers With Application to Two-Wired Biopotential Electrode

SPINELLI, ENRIQUE MARIO; HABERMAN, MARCELO ALEJANDRO; GUERRERO, FEDERICO NICOLÁS

Houston

Conferencia; 2018 IEEE International Instrumentation and Measurements Technology Conference (IEEE I2MTC); 2018

IEEE Instrumentation & Measurement Society

In this work, the stability of voltage followersimplemented with operational amplifiers featuring power supplybootstrapping is analyzed. Power supply bootstrapping allowsincreasing the input impedance of an amplifier. However, becauseit constitutes a positive feedback loop, the circuit can becomeunstable. The model of the bootstrapped amplifier is determinedand a compensation strategy is proposed based on the relationbetween the common mode and power supply rejection ratiosof the operational amplifier, which can be consulted for mostcommercial devices. Finally, the proposed compensation is experimentallytested implementing it for a two-wired active electrodefor biopotential measurement applications.