Hamed Mazhab Jafari

64-Channel UWB Wireless Neural Vector Analyzer SOC With a Closed-Loop Phase Synchrony-Triggered Neurostimulator

An ultra wideband (UWB) 64-channel responsive neural stimulator system-on-chip (SoC) is presented. It demonstrates the first on-chip neural vector analyzer capable of wirelessly monitoring magnitude, phase and phase synchronization of neural signals. In a closed-loop, abnormal phase synchrony triggers the programmable-waveform biphasic current-mode neural stimulator. To implement these functionalities, the SoC integrates 64 neural recording amplifiers with tunable switched-capacitor (SC) bandpass filters, 64 multiplying 8-bit SAR ADCs, 64 programmable 16-tap FIR filters, a tri-core CORDIC processor, 64 biphasic current stimulation channels, and a 3.1-10.6 GHz UWB wireless transmitter onto a 4 mm × 3 mm 0.13 μm CMOS die. To minimize both the area and power dissipation of the SoC, the SAR ADC is re-used as a multiplier for FIR filtering and as a DAC and duty cycle controller for the biphasic neural stimulator. The SoC has been validated in the early detection and abortion of seizures in freely moving rodents on-line and in early seizure detection in humans off-line.

16-Channel CMOS Impedance Spectroscopy DNA Analyzer With Dual-Slope Multiplying ADCs

We present a 16-channel, mixed-signal CMOS DNA analyzer that utilizes frequency response analysis (FRA) to extract the real and imaginary impedance components of the biosensor. Two computationally intensive operations, the multiplication and integration required by the FRA algorithm, are performed by an in-channel dual-slope multiplying ADC in the mixed-signal domain resulting in minimal area and power consumption. Multiplication of the input current by a digital coefficient is implemented by modulating the counter-controlled duration of the charging phase of the ADC. Integration is implemented by accumulating output digital bits in the ADC counter over multiple input samples. The 1.05 × 1.6 mm prototype fabricated in a 0.13 μm standard CMOS technology has been validated in prostate cancer DNA detection. Each channel occupies an area of only 0.06 mm2 and consumes 42 μW of power from a 1.2 V supply.

Nanostructured CMOS Wireless Ultra-Wideband Label-Free PCR-Free DNA Analysis SoC

A fully integrated 54-channel wireless fast-scan cyclic voltammetry DNA analysis SoC is presented. The microsystem includes 546 3D nanostructured and 54 2D gold DNA sensing microelectrodes as well as 54 pH sensors. Each channel consists of a chopper-stabilized current conveyer with dynamic element matching. It is utilized as the amperometric readout circuit with a linear resolution from 8.6 pA to 350 nA. The on-chip programmable waveform generator provides a wide range of user-controlled rate and amplitude parameters with a maximum scan range of 1.2 V, and scan rate ranging between 0.1 mV/sec to 300 V/sec. A digital ultra-wideband transmitter based on a delay line architecture provides wireless data communication with data rates of up to 50 Mb/sec while consuming 400 μW. The 3 mm × 3 mm prototype fabricated in a 0.13 μm standard CMOS technology has been validated in prostate cancer synthetic DNA detection with 10 aM label-free PCR-free detection limit. Each channel occupies an area of only 0.06 mm2 and consumes 42 μW of power from a 1.2 V supply.

Chopper-Stabilized Bidirectional Current Acquisition Circuits for Electrochemical Amperometric Biosensors

Two low-noise bidirectional current acquisition circuits for interfacing with electrochemical amperometric biosensor arrays are presented. The first design is a switched-capacitor transimpedance amplifier (TIA). The second design is a current conveyer (CC) with regulated-cascode current mirrors. Both circuits employ chopper stabilization to reduce flicker noise. The TIA and the CC were prototyped in 0.13 μm CMOS and consume 3 μW and 4 μW from a 1.2 V supply, respectively. The electrical and electrochemical recording properties of both circuits have been characterized. The current conveyer exhibits superior performance in low-concentration electrochemical catalytic reporter sensing, as less switching noise is injected into the biosensor.

Inductively-powered direct-coupled 64-channel chopper-stabilized epilepsy-responsive neurostimulator with digital offset cancellation and tri-band radio

An inductively powered 0.13μm CMOS neurostimulator SoC for intractable epilepsy treatment is presented. Digital offset cancellation yields a compact 0.018mm2 DC-coupled neural recording front-end. Input chopper stabilization is performed on all 64 channels resulting in a 4.2μVrms input-referred noise. A tri-band FSK/UWB radio provides a versatile transcutaneous interface. The inductive powering system includes a 20mm × 20mm 8-layer flexible receiver coil with 40% power transfer efficiency. In-vivo chronic epilepsy treatment experimental results show an average sensitivity and specificity of seizure detection of 87% and 95%, respectively, with over 76% of all seizures aborted.

Battery-less Tri-band-Radio Neuro-monitor and Responsive Neurostimulator for Diagnostics and Treatment of Neurological Disorders

A 0.13 μm CMOS system on a chip (SoC) for 64 channel neuroelectrical monitoring and responsive neurostimulation is presented. The direct-coupled chopper-stabilized neural recording front end rejects up to ±50 mV input dc offset using an in-channel digitally assisted feedback loop. It yields a compact 0.018 mm2 integration area and 4.2 μVrms integrated input-referred noise over 1 Hz to 1 kHz frequency range. A multiplying specific absorption rate (SAR) ADC in each channel calibrates channel-to-channel gain mismatch. A multicore low-power DSP performs synchrony-based neurological event detection and triggers a subset of 64 programmable current-mode stimulators for subsequent neuromodulation. Triple-band FSK/ultra-wideband (UWB) wireless transmitters communicate to receivers located at 10 cm to 10 m distance from the SoC with data rates from 1.2 to 45 Mbps. An inductive link that operates at 1.5 MHz, provides power and is also used to communicate commands to an on-chip ASK receiver. The chip occupies 16 mm2 while consuming 2.17 and 5.8 mW with UWB and FSK transmitters, respectively. Efficacy of the SoC is assessed using a rat model of temporal lobe epilepsy characterized by spontaneous seizures. It exhibits an average seizure detection sensitivity and specificity of 87% and 95%, respectively, with over 78% of all seizures aborted.

64-Channel UWB wireless neural vector analyzer and phase synchrony-triggered stimulator SoC

A UWB 64-channel responsive neural stimulator is presented. It wirelessly monitors magnitude, phase and phase synchronization of neural signals. Abnormal phase synchrony triggers programmable-waveform biphasic current-mode stimulation in a closed loop. To implement these functionalities, the SoC integrates 64 neural recording amplifiers with tunable switched-capacitor (SC) bandpass filters, 64 multiplying 8-bit SAR ADCs, 64 programmable 16-tap FIR filters, a tri-core CORDIC processor, 64 biphasic current stimulation channels, and a 3.1-10.4GHz UWB wireless transmitter onto a 4mm × 3mm 0.13μm CMOS die. The SoC dissipates 1.4mW/1.5mW when recording/stimulating and has been validated in early detection and abortion of epileptic seizures in freely moving rodents on-line and in early seizure detection in humans off-line.

Nanostructured CMOS wireless ultra-wideband label-free DNA analysis SoC

A 0.13-micron CMOS fully integrated 48-channel UWB label-free DNA analysis SoC is demonstrated in prostate cancer screening. The 3mm×3mm die includes 578 nanostructured DNA sensors, 48 pH sensors, and 48 temperature sensors and reuses key circuits for cyclic voltammetry, amperometry and temperature regulation.

Neural synchrony-monitoring wireless brain implant for intractable epilepsy neuromodulation

A validation of a closed-loop system-on-chip (SoC) for epilepsy treatment is presented. A 12mm2 0.13μm CMOS SoC provides the functionality of neural recording, neural stimulation and early seizure detection based on the bivariate phase synchrony estimation algorithm. The SoC can operate in a closed loop, has 64 neural recording and 64 neural stimulation channels, and dissipates 1.4mW and 1.5mW across 64 channels for neural recording and stimulation, respectively. Two in vivo experiments with freely moving rats based on a non-convulsive and convulsive seizure model are presented. The first in vivo experiment validates the results by comparing the output of the SoC with a SIMULINK model of the implant. The second in vivo experiment validates the SoC in early seizure detection and as a closed-loop intractable epilepsy treatment with 80 percent efficacy. Long Evans rats are used for all experiments. All data are cross-validated by a conventional benchtop amplifier.

0.13μm CMOS 230Mbps 21pJ/b UWB-IR transmitter with 21.3% efficiency

An ultra-wide-band impulse-radio (UWB-IR) transmitter for low-energy implantable and wearable biomedical microsystems is presented. The transmitter provides a power-efficient high-data-rate wireless link within the 3-5 GHz band. It yields an overall power efficiency of 21.3% at data-rate of 230Mbps while consuming 21pJ per bit. The transmitted UWB pulse train is recovered at the receiver with less than 10-6 bit-error-rate (BER) measured at a distance of 1m without any pulse averaging. The chip is implemented in a 130nm CMOS technology and has an average power consumption of 3.7mW.