A wearable EEG amplifier using a novel teraohm low-distortion tunable hybrid pseudo-resistor

This paper presents a comparison report on various pseudoresistor topologies used in biosignal processing. Two novel hybrid pseudoresistor (PR) designs are being proposed. An ultra-low-power, low-noise chopped EEG amplifier is then implemented using a hybrid PR, and measurement results reported. The EEG amplifier is designed to handle an electrode offset of value, 50mVpp while preserving the low-frequency EEG signal. A dc servo loop (DSL) is used to reject the dc offset, and the chopping ripple is reduced through a dc offset calibration loop. The amplifier is implemented in 0.18 mu m CMOS technology and can operate with a total current of 1.6 mu A, achieving NEF of 2.92. The amplifier achieved a PSRR and CMRR of 85dB. The current consumption of 1.6 mu A affirms suitability of this implementation for coin cell battery operated wearable EEG recording headset. The achieved input-referred noise of 0.61 mu V in the frequency band of 0.5-100Hz is desirable for EEG system.

Automated summary

This paper presents a comparison report on various pseudoresistor topologies used in biosignal processing, proposes two novel hybrid pseudoresistor designs, and implements an ultra-low-power, low-noise chopped EEG amplifier suitable for wearable EEG recording devices.