Fast and effective method of CMRR enhancement for multichannel integrated circuits dedicated to biomedical measurements

Abstract

The common mode rejection ratio (CMRR) strongly depends on matching and this effect is clearly visible in multichannel recording systems. Therefore, a method for improving the CMRR in multichannel recording integrated circuits (ICs) dedicated to biomedical experiments is reported. The method is based on balancing the amplifier's inputs using leakage currents. The proposed technique was verified in the 64 channel IC processed in CMOS 180 nm. The measurement results show that with use of the proposed balancing technique the CMRR is increased by more than 30 dB. Additionally, in comparison to conventional CMRR measurement methods, the proposed solution is attractive in three ways: its on-chip implementation simplicity, fast operation, and it is especially suitable for modern nanometre processes.

Highly Configurable 100 Channel Recording and Stimulating Integrated Circuit for Biomedical Experiments

“…The Neural Recording and Stimulating 100-channel Integrated Circuit (NRS100 IC) is composed of 10 × 10 pixels (each built of recording and stimulation blocks, and 36 × 9bit memory), Successive Approximation Register (SAR)-based analog to digital converter (ADC), Random-Access Memory (RAM) controller, current/voltage user-controlled refer- This paper aims to provide a possible solution that can be implemented whenever the abovementioned requirements need to be satisfied in the multichannel systems dedicated to different types of biomedical experiments. The proposed solution is a result of the author's former works [21][22][23][24][25][26]. The paper is organized as follows.…”

A CMRR enhancement circuit by employing auxiliary buffer of capacitively coupled instrumentation amplifier for neural signal recording

“…To acquire such low amplitude and low frequency, a high common‐mode rejection ratio (CMRR), a high input impedance, a low power, and a low noise are becoming the most important performance indicators for biopotential FEAs [5]. Especially as multi‐channel acquisition becomes increasingly widespread and demanded to improve the robustness in therapeutic or prosthetic devices, it imposes the challenge of high CMRR to suppress the undesired common‐mode interference (CMI) while amplifying the differential biopotential signal [4, 6].…”