Farhan Quaiyum

A Low-Power 1-V Potentiostat for Glucose Sensors

In this brief, a 1-V potentiostat circuit for a glucose sensor has been proposed. Test results of this 1-V potentiostat demonstrate high linearity with respect to glucose concentration, which is comparable with conventional potentiostat designs. This high linearity is achieved with the help of a transconductance enhanced bulk-driven operational amplifier. The overall current consumption of the circuit is around 22 μA. The potentiostat is tested as a glucose biosensor for glucose concentration ranging from 0 to 30 mM. The design is realized in a 0.35-μm bulk-CMOS process, and the area for the core layout is 0.13 mm2. The proposed low-power potentiostat can be incorporated in an implantable glucose sensor system due to its low-power operation and small footprint.

Optimization of perimeter gated SPADs in a standard CMOS process

Perimeter gated single photon avalanche diodes (PGSPADs) in standard CMOS processes have increased breakdown voltages and improved dark count rates. These devices use a polysilicon gate to reduce the premature breakdown of the device. This work characterizes the variation in PGSPAD noise (dark count rate) and breakdown voltage as a function of applied gate voltages for varying device shape, size, and junction type. Eight different PGSPADs were designed and fabricated in standard 0.5μm 2 poly, 3 metal CMOS process. Our study showed the size of the device has negligible effect on the breakdown voltage of the device. The dark count rate for a circular shaped device is higher than a square shaped device but the effect of excess bias on the noise of the circular shaped device is less. Using a psub/n-well junction instead of an n-well/p+ junction increased the breakdown voltage. The effects of five factors: the size, the shape, the type of junction, the excess bias voltage and the gate voltage were investigated in this work.

A low power wireless apnea detection system based on pyroelectric sensor

The paper presents a fully integrated system for apnea detection. Apnea has been one of the leading causes of death in the USA and it is even more critical for premature neonatal infants. A prototype device with the pyroelectric sensor and a wireless telemetry designed in 0.5 μm CMOS process is presented which overcomes the complexity of the point of care diagnosis of sleeping disorders.

Development of a reconfigurable low cost multi-mode radar system for contactless vital signs detection

In this work, we propose a Multi-Mode Radar (MMR) with reconfigurable center frequency incorporating the functions of both CW and SFCW Doppler radars rather than using separate platforms for each radar type. This MMR is controlled by a micro-controller and it can be used in an indoor environment for tracking more than one subject, human gait analysis and for long-range vital signs detection. The radar was built and experimentally utilized for both close range and long range heart rates monitoring.

Simulation and Modeling of Single Photon Avalanche Diodes

A comprehensive SPICE model is developed for single photon avalanche diodes (SPADs). The model simulates both the static and dynamic behaviors of SPADs. Parameters of the model were extracted form experimental data obtained from SPADs designed and fabricated in a standard 0.5μm CMOS process. In this model, the resistive behavior of the device was modeled with an exponential function. Moreover, the device simulated response to incident optical power stimulation is modeled. Experimentally extracted parameters were incorporated into the model, and simulation results agreed with the experimental data.