Denis Sallin

Hybrid MOS-PN photodiode with positive feedback for pulse-modulation imaging

A new type of CMOS compatible photodetector, exhibiting intrinsic light-to-time conversion, is proposed. Its main objective is to start the time-to-digital conversion directly at its output, thereby avoiding the cumbersome analog processing. The operation starts with an internal charge integration, followed by a positive feedback, and a sharp switching-current. The device, consisting of a deeply depleted MOS structure controlling the conduction of a forward-based PN diode, is presented and its operation explained. TCAD simulations are used to show the effects of semiconductor parameters and bias conditions. The photodetector and its detection circuit are designed and fabricated in a 0.18µm CMOS process. Measurements of this new device under different biasing and illumination conditions show highly promising properties in terms of linearity, internal gain, and noise performances.

An Ultra-High Speed Emulator Dedicated to Power System Dynamics Computation Based on a Mixed-Signal Hardware Platform

This paper presents an ultra-high speed hardware platform dedicated to power system dynamic (small signal) and transient (large signal) stability. It is based on an intrinsic parallel architecture which contains hybrid mixed-signal (analog and digital) circuits. For a given model, this architecture overcomes the speed of the numerical simulators by means of the so-called emulation approach. Indeed, the emulation speed does not depend on the power system size. This approach is nevertheless not competing against high-performance numerical simulators in term of accuracy and model complexity. It targets to complement the numerical simulators with the advantage of speed, portability, low cost and autonomous functioning. The proof of concept is a flexible and modular 96-node hardware platform. It is based on a reconfigurable array of power system buses called Field Programmable Power Network System (FPPNS). Details on this hardware are given. Two benchmark topologies with, respectively, 17 nodes and 57 nodes are provided. Comparisons with a digital simulator are done in terms of speed and accuracy. The calibration of the system is explained and different applications are proposed and discussed. The promising results of this hardware platform show that the design of a fully integrated solution containing hundreds of power system buses can be achieved in order to provide a low cost solution.

Design of a direct light to time converter and its noise analysis

This paper presents a fully Digital Pixel Sensor (DPS) front-end with a focus on its noise modelling and analysis. The design relies on a new type of photodetector displaying an intrinsic light-to-time conversion. Avoiding the pixel level analog processing improves significantly the overall performances of the image sensor. The photodetector as well as its front-end circuit are described. The noise performances and their variations with the physical and bias conditions are theoretically and experimentally studied.

Toward direct light-to-digital conversion using a pulse-driven hybrid MOS-PN photodetector

In this Letter, a direct light-to-digital converter based on an MOS-PN photodetector driven by pulsed voltage is presented. The objective is to avoid any analog-to-digital or time-to-digital conversion and, thereby, to pave the way for a new generation of fully digital imaging sensors with reduced complexity, area, and power consumption. Moreover, the pulsed voltage operation allows for a significant reduction of the dark level. The concept is validated by a theoretical study and TCAD simulations. A first prototype fabricated in 0.18 μm CMOS technology is presented. The experimental results under various light conditions show that the pulsed voltage improves the light sensitivity by several orders of magnitude.

A mixed-platform framework for Dynamic Stability Assessment

This paper describes a mixed-platform framework dedicated to Dynamic Stability Assessment of power systems. DSA refers to tools capable of characterizing the dynamic stability of the system. Time domain simulation is critical for DSA analysis and is done by algorithms known as TD engines. In this work, operations are shared between a software platform and a hardware one. TD simulation is handled by a dedicated mixed-signal electronics implementation. Data flow control, user interfacing, configuration, result post-processing and other auxiliary operations are realized in software. This architecture combines the flexibility of the software with the high-performance of dedicated hardware. Results of a multi-contingency analysis and a critical clearing time determination analysis for sample test cases are presented. It is demonstrated that an increase in speed of almost three orders of magnitude can be achieved, compared to single-platform solutions.

Silicon-on-insulator technology for bioluminescence imaging and application to a switching photodetector

This paper analyzes some advantages of Silicon-on-Insulator (SOI) based photodetectors for bioluminescence imaging. It shows that SOI based sensors not only solve the bulk carriers problem, it can also act as a very selective spectral filter by acting as a resonant cavity, which is useful in application with a very narrow spectrum of interest, such as bioluminescence imaging. Then, the authors discuss the application of those findings and the electrical advantages of SOI for a new kind of switching photodetector, the Hybrid MOS-PN device and their advantages in terms of dark current minimization.

Optimized operation and temperature dependence of a direct light-to-time converter

This paper presents a fully Digital Pixel Sensor (DPS) front-end with a focus on the optimization of its operation and temperature dependence. The system relies on a new type of photodetector based on a hybrid MOS-PN structure displaying intrinsic light-to-time conversion. The photodetector as well as its front-end circuit are described as well as pulsed operation techniques that increase the Signal to Noise Ratio (SNR). The presented pulsed operation of the photodetector behaves as a direct light-to-digital conversion. Temperature dependence and its variation with bias conditions are theoretically and experimentally studied.

Optical effect considerations for bulk to SOI retargeting of hybrid MOS-PN dynamic photo-sensor

SOI & CMOS technologies have been compared many times in term of efficiencies and performances with regards to different types of applications. Nowadays, the ASIC combining optical sensor with its readout and signal processing electronics on the same chip becomes more and more a target for applications mainly in the bio and the automotive domain. Many publications have addressed the design issues. This paper aims to highlight the main parameters to be analyzed for a fast retargeting approach regarding the optics aspect of optoelectronics sensors; it will be focusing on the light to time sensors.

A 3D architecture platform dedicated to high-speed computation for power system

This paper presents an innovative 3D hardware architecture for power system dynamic and transient stability. Based on an intrinsic parallel architecture by means of mixed-signal circuits (analog and digital) it overcomes the speed of numerical simulators for given models. This approach does not competing the accuracy and model complexity of the high performance numerical simulators. It intends to complement them with the advantage of speed, low-cost, portability and autonomous functions. The presented architecture provides an ultra-high speed platform by means of emulation principle. The proof of concept is an array of 4×24 nodes reconfigurable platform. Hardware details and comparisons with a reference digital simulator are given.