On the Stability of Shield-Driver Circuits

ENRIQUE M. SPINELLI; FERRAN REVERTER

IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT

IEEE

Año: 2010 vol. 59 p. 458 - 462

0018-9456

This paper analyses the stability of shield-driver circuits (SDC) applied to the measurement of remote signal sources (such as bioelectric signals) and then proposes design ideas to guarantee it. According to the analysis performed, there are at least two factors that explain the potential instability of the SDC: (a) a high order of the SDC transfer function, and (b) the parasitic inductance of the interconnecting cable. The former makes the circuit unstable for intermediate values of the output resistance RS of the signal source, whereas the latter makes the circuit unstable for low values of These theoretical predictions are validated experimentally using several commercial operational amplifiers.