Kofi Odame

Characterization of Quanta Image Sensor Pump-Gate Jots With Deep Sub-Electron Read Noise

Characterization of quanta image sensor pixels with deep sub-electron read noise is reported. Pixels with conversion gain of

Analysis and Optimization of Maximum Power Point Tracking Algorithms in the Presence of Noise

423\mu \text{V}

A Bandpass Filter With Inherent Gain Adaptation for Hearing Applications

/e- and read noise as low as 0.22e- r.m.s. were measured. Dark current is 0.1e-/s at room temperature, and lag less than 0.1e-. This is one of the first works reporting detailed characterization of image sensor pixels with mean signals from sub-electron (0.25e-) to a few electrons level. Such pixels in a nearly-conventional CMOS image sensor process will allow realization of photon-counting image sensors for a variety of applications.

Theory and Design of OTA-C Oscillators with Native Amplitude Limiting

This paper analyzes the effect of noise on several maximum power point tracking (MPPT) algorithms for photovoltaic systems. Noise is an essential consideration for optimization of MPPT algorithms. For example, for a perturb and observe algorithm, the perturbation size must be big enough to produce a signal larger than the measurement noise; however, the larger the perturbation, the farther the system will deviate from the maximum power point in steady state. There is also a tradeoff with respect to tracking speed, as slower tracking allows for more averaging of the signals, mitigating the noise. The effect of noise and other parameters on tracking performance is quantified, leading to an optimization of the system parameters to provide the best tracking accuracy for a specified tracking speed. The performance of the various algorithms is compared, and the analysis is verified by both simulations and experiments.

A 2.5 pJ/b Binary Image Sensor as a Pathfinder for Quanta Image Sensors

In this paper, we propose a novel bandpass filter design that incorporates automatic gain control (AGC). The gain control in the filter reduces the performance requirements of a wide-band AGC, and allows for low-power multichannel compression. The filter achieves up to 15 dB of compression on a 55-dB input dynamic range and is tunable over the audio frequency range, with microwatt power consumption and <5% harmonic distortion.

Performance of photovoltaic maximum power point tracking algorithms in the presence of noise

An analog sinusoidal oscillator usually involves some form of amplitude-limiting mechanism. We examine operational-transconductance-amplifier (OTA) nonlinearity as a choice for amplitude limiting and develop a general theory for its use in OTA-capacitor (OTA-C) oscillators. We facilitate our theoretical discussion with an illustrative design example that we fabricated and tested.

An Efficient Oscillator Design Based on OTA Nonlinearity

This paper presents a pathfinder binary image sensor for exploring low-power dissipation needed for future implementation of gigajot single-bit quanta image sensor (QIS) devices. Using a charge-transfer amplifier design in the readout signal chain and pseudostatic clock gating units for row and column addressing, the 1-Mpixel binary image sensor operating at 1000 frames/s dissipates only 20-mW total power consumption, including I/O pads. The gain and analog-to-digital converter stages together dissipate 2.5 pJ/b, successfully paving the way for future gigajot QIS sensor designs.

A Bandwidth-Adaptive Preamplifier

This paper introduces a probabilistic analysis of the effects of noise on various maximum power point tracking (MPPT) algorithms for photovoltaic systems, including how noise affects both tracking speed and overall efficiency. The results of this analysis are verified by simulations. This analysis provides a better understanding of how noise affects performance and it can be used to optimize an MPPT system.

Real-Time Embedded Implementation of the Binary Mask Algorithm for Hearing Prosthetics

An analog sinusoidal oscillator usually involves some form of amplitude-limiting mechanism. We examine OTA nonlinearity as a choice for amplitude limiting, and introduce a general method for its use in OTA-C oscillators. We illustrate our discussion with an example design that we fabricated and tested. Our results show that OTA nonlinearity yields low-distortion oscillators at practically no power- or area cost

Quanta Image Sensor (QIS): Early Research Progress

We propose an adaptive microphone preamplifier that adjusts its power consumption according to the input signals bandwidth. A chip prototype of the adaptive preamplifier for speech processing was fabricated in a 0.5-μm CMOS process. The adaptive preamplifiers measured input referred noise is 3 μV rms and its total harmonic distortion is -40 dBc for an 80-mV rms input amplitude. These noise and distortion specifications remain virtually constant over the preamplifiers range of bandwidth adaptation. The adaptive preamplifier consumes 65 μW of power. This is achieved with no degradation in speech quality, when compared to a conventional preamplifier of fixed bandwidth, and as measured by the perceptual evaluation of speech quality (PESQ) score.