A low-power low-data-rate neural recording system with adaptive spike detection

A design of small, low-power, low-data rate, wireless 32-channel neural recording system for small animal head-stage is presented. A neural pre-amplifier has low-input-referred-noise of 1.95μV_rms and consumes 53.6μW. To enable digital telemetry with optimized bandwidth under size and power constraint for small-animal headstage, we propose to separately record spikes and local-field potentials. An adaptive spike detector using absolute value algorithm accompanied with 7th-order all-pass delay filter provides accurate on-chip acquisition of spike waveform in duration of 2ms. A low-power 10-bit and 5-bit resolution A/D converters running at 22Ksamples/s for active spikes and 200samples/s for local field potential, respectively, can be integrated with the proposed system. Using adaptive bandwidth control, we achieve reduction of data-rate up to seven times which provides compatibility to 1Mbps Ultra Low Power Bluetooth technology. Total power consumption of single channel excluding ADCs is 109.58μW in 3.3V power supply.