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 1.95 muVrms and consumes 53.6 muW. 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 2 ms. A low-power 10-bit and 5-bit resolution A/D converters running at 22 Ksamples/s for active spikes and 200 samples/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 1 Mbps ultra low power Bluetooth technology. Total power consumption of single channel excluding ADCs is 109.58 muW in 3.3 V power supply