title: A low-power configurable neural recording system for epileptic seizure detection.
abstract: This paper describes a low-power configurable neural recording system capable of capturing and digitizing both neural action-potential (AP) and fast-ripple (FR) signals. It demonstrates the functionality of epileptic seizure detection through FR recording. This system features a fixed-gain, variable-bandwidth (BW) front-end circuit and a sigma-delta ADC with scalable bandwidth and power consumption. The ADC employs a 2nd-order single-bit sigma-delta modulator (SDM) followed by a low-power decimation filter. Direct impulse-response implementation of a sinc(3) filter and 8-cycle data pipelining in an IIR filter are proposed for the decimation filter design to improve the power and area efficiency. In measurements, the front end exhibits 39.6-dB DC gain, 0.8 Hz to 5.2 kHz of BW, 5.86- μVrms input-referred noise, and 2.4- μW power consumption in AP mode, while showing 38.5-dB DC gain, 250 to 486 Hz of BW, 2.48- μVrms noise, and 4.5- μW power consumption in FR mode. The noise efficiency factor (NEF) is 2.93 and 7.6 for the AP and FR modes, respectively. At 77-dB dynamic range (DR), the ADC has a peak SNR and SNDR of 75.9 dB and 67 dB, respectively, while consuming 2.75-mW power in AP mode. It achieves 78-dB DR, 76.2-dB peak SNR, 73.2-dB peak SNDR, and 588- μW power consumption in FR mode. Both analog and digital power supply voltages are 2.8 V. The chip is fabricated in a standard 0.6- μm CMOS process. The die size is 11.25 mm(2).
authors.affiliation: Department of Electrical and Computer Engineering, Analog and Mixed Signal Center, Texas A&M University, College Station, TX 77843-3128 USA.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Qian
authors.forename: Jess
authors.initials: J
authors.lastname: Shi
authors.forename: Jordi
authors.initials: J
authors.lastname: Parramon
authors.forename: Edgar
authors.initials: E
authors.lastname: Sánchez-Sinencio
mesh_terms: D000200:Action Potentials; D000703:Analog-Digital Conversion; D004560:Electricity; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology; D004867:Equipment Design; D006801:Humans; D009474:Neurons / Q000473:pathology*; D009482:Neurophysiology / Q000295:instrumentation* / Q000379:methods*; D059629:Signal-To-Noise Ratio