An Implantable Neural Recording IC with In-Situ Spike Detection and Preservation

We present an implantable neural recording IC with a unique scheme for detecting spike signals and preserving their waveform in real-time. Each channel in the proposed device has a delta modulator that stores a series of consecutive subtracted signal values. The delta modulation doesn't only allow low-voltage operation by reducing the signal dynamic range, but also detects only the spike signal by extracting its two key features, frequency and amplitude, in analog domain. The full waveform of the detected spike signal is accurately conserved and transmitted to outside. A prototype recording IC with 16 channels has been fabricated using 1P6M 0.18-mu m CMOS and demonstrates to record the spike signal successfully. It only consumes 0.88 mu W/channel at 0.5 V supply and its spike detection technique can save much more power in the overall system by compressing the neural signal to be transferred.