Abstract-A 8 12 array of integrated potentiostats for on-CMOS neurotransmitter imaging is presented. Each potentiostat channel measures bidirectional redox currents proportional to the concentration of a neurochemical. By combining the current-to-frequency and the single-slope analog-to-digital converter (ADC) architectures a total linear dynamic range of 95 dB is achieved. A 3.8 mm 3.1 mm prototype fabricated in a 0.35 standard CMOS technology was integrated with flat and 3D on-die gold microelectrodes and an on-chip microfluidic network. It is experimentally validated in in-situ recording of neurotransmitter dopamine.
This paper presents a fully intraocular self-calibrating epiretinal prosthesis with 512 independent channels in 65 nm CMOS. A novel digital calibration technique matches the biphasic currents of each channel independently while the calibration circuitry is shared among every 4 channels. Dual-band telemetry for power and data with on-chip rectifier and clock recovery reduces the number of off-chip components. The rectifier utilizes unidirectional switches to prevent reverse conduction loss in the power transistors and achieves an efficiency > 80%. The data telemetry implements a phase-shift keying (PSK) modulation scheme and supports data rates up to 20 Mb/s. The system occupies an area of 4.5 ×3.1 mm². It features a pixel size of 0.0169 mm² and arbitrary waveform generation per channel. In vitro measurements performed on a Pt/Ir concentric bipolar electrode in phosphate buffered saline (PBS) are presented. A statistical measurement over 40 channels from 5 different chips shows a current mismatch with μ = 1.12 μA and σ = 0.53 μA. The chip is integrated with flexible MEMS origami coils and parylene substrate to provide a fully intraocular implant.
We present a fully implantable subcutaneous continuous glucose monitoring (CGM) microsystem on CMOS platform.The proposed design incorporates electrochemical sensing technique using an ultra-low-power potentiostatic system. It is wirelessly powered through an inductive coupling link at 900MHz and supports bidirectional data communication with an external reader. A low-power potentiostat and a dual-slope ADC record the on-chip sensor signal. Pt and Ag/ AgCI on-chip electrodes are post-fabricated and functionalized in situ by glucose oxidase enzyme to enable glucose measurement. The 1.4x l.4xO.25mm 3 prototype fabricated in a 0.18f.1m CMOS technology was validated in glucose measurements. Total power consumption of the system is 6f.1W.
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