An ultra low-power CMOS action potential detector

We present a low-power CMOS analog circuit for automatic detection of action potentials (APs) in extracellular recordings. The detector emphasizes neural APs by means of an energy-based preprocessor and locates them with a precision comparator. A linear-phase delay filter allows signal buffering to avoid truncated waveforms. The proposed detector isolates the identified waveforms in their entirety and completely preserves their features in order to improve shapes discrimination. The proposed circuit, implemented in a CMOS 0.18-mu m process, achieves ultra low-power consumption as the whole detector dissipates only 781.5 nW. The detector has been validated in simulations with real neural signals and successfully detects APs from the underlying background activity.