A power adaptive variable gain instrumentation amplifier for electrical impedance tomography

Wide-Bandwidth Electronically Programmable CMOS Instrumentation Amplifier for Bioimpedance Spectroscopy

“…As observed in Table 2, the proposed solution leads to the widest programmability range of the IA gain, featuring a BW suitable for bioimpedance spectroscopy applications and presenting a current consumption similar to that of the other proposals. In general, current mode techniques [21], [22], [24], [25], [28] provide a wider operating frequency range, even though the CMRR in these cases is, also in general, much lower as compared to that of the voltagemode approaches proposed in [17], [19], [20], and in the present work. The noise of the proposed IA was measured in a frequency range between 100 Hz and 2.1 MHz, due to BW reduction suffered by the IA in this particular test configuration.…”

“…Thus, to set the gain to a different value, the external component must be replaced. A straightforward solution to obtain a programmable IA is to incorporate a digitally configurable bank of components, thus achieving a discrete adjustment [4], [11], [17], [20]. Besides, different circuit techniques have been proposed to continuously tune the response of an analog section, some of which have been applied to program the voltage gain of an instrumentation amplifier [15], [19], [21]- [25], [28].…”