Maher Kayal

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Papers by Maher Kayal

Procedural analog design (pad) tool

This paper presents a new Procedural Analog Design tool called PAD. It is a chart-based design en... more This paper presents a new Procedural Analog Design tool called PAD. It is a chart-based design environment dedicated to the design of analog circuits aiming to optimise design and quality by finding good tradeoffs. This interactive tool allows step-by-step design of analog cells by using guidelines for each analog topology. At each step, the user modifies interactively one subset of design parameters and observes the effect on other circuit parameters. At the end, an optimised design is ready for simulation (verification and fine-tuning). Furthermore, PAD provides a layout generator for matched substructures such as current mirror, cascode stage, differential pair, etc. The analog basic structures calculator embedded in PAD uses the complete set of equations of the EKV MOS model, which links the equations for weak and strong inversion in a continuous way[1,2]. The present version of PAD covers the procedural design of transconductance amplifiers (OTAs) and different operational ampl...

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Event-driven human based evolutionary knowledge base for smart buildings

This paper presents an approach to automatically create a knowledge base for smart buildings and ... more This paper presents an approach to automatically create a knowledge base for smart buildings and let it dynamically evolve based on the behaviors of the occupants inside. Such a knowledge base compromises all life-style experiences and intelligent buildings. Accordingly, management decisions and control can be performed. To achieve the goal, an online learning algorithm is used which is designed to catch knowledge and generate rules from environmental sensing data and actuators states. Rules are fed to the system as fuzzified events. Applying such a learning approach to maintain the knowledge base, abstracts the complicated coordination between human, infrastructure components and static structures such as building floorplan and architecture.

Methodology for 3-D Substrate Network Extraction for Spice Simulation of Parasitic Currents in Smart Power ICs

IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 2015

A 3-D simulation of substrate currents is crucial to analyze parasitic coupling effects due to mi... more A 3-D simulation of substrate currents is crucial to analyze parasitic coupling effects due to minority carrier injection in smart power ICs. In this paper, a substrate parasitic extraction methodology is introduced by dividing the IC layout into elementary elements to solve the continuity equation for minority carriers in the volume based on the finite-difference method. A substrate parasitic network is derived from the mesh generated through the existing mixed-signal design flow. The induced substrate model is included in circuit simulators such as SPICE to predict the effects of substrate couplings during the design phase. Furthermore, this analysis enables optimization of layout with minimal parasitic effects. By linking the substrate model to the active components, the couplings between the integrated circuit with the substrate parasitic currents can be analyzed during circuit simulations. Simulations and measurements on an high voltage driver reveal consistent results and therefore confirm the validity of the method. Therefore, the approach developed herein is effective to predict parasitic couplings due the injection of minority carriers.

Continuosly Calibrated Magnetic Field Sensor

Transient stability analysis of series unbalanced conditions using dedicated mixed-signal hardware

2015 IEEE Eindhoven PowerTech, 2015

This paper examines the use of the symmetrical components theory for the representation of unbala... more This paper examines the use of the symmetrical components theory for the representation of unbalanced conditions, when using the concept of analog emulation for highspeed power system analysis. This concept has been proven and validated through the realization of a mixed-signal hardware platform dedicated to power system studies. Computations related to the grid are handled by analog electronics, while the models of the network components are implemented on a digital processing core. Balanced operation is natively supported, while unbalanced operation is handled with the symmetrical component theory. Particular focus is given on series unbalanced operations, such as the opening of a single-phase circuit breaker. A hardware architecture solution for the complete unbalanced conditions representation is described. The proposed approach has shown significant computational speed benefits compared to traditional digital solutions.

Power flow method using a dedicated mixed-signal hardware platform

2015 IEEE Eindhoven PowerTech, 2015

Recent work in the field of analog computing has shown that electronic emulation circuits are of ... more Recent work in the field of analog computing has shown that electronic emulation circuits are of large interest when targeting the speed of routines dedicated to power systems. In this paper, a power flow implementation is presented that is tailored to such a mixed-signal computing platform. A computation time of a few microseconds per algorithm iteration is reported. This time is also almost independent of the network size. Convergence in the modified algorithm is usually achieved in less than ten iterations for systems of small and moderate size. This yields an average solution speed of the power flow problem that is in the order of a hundred of microseconds.

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

2015 22nd International Conference Mixed Design of Integrated Circuits & Systems (MIXDES), 2015

This paper analyzes some advantages of Silicon-on-Insulator (SOI) based photodetectors for biolum... more 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.

ANTIGONE: A Programmable Energy-Efficient Current Digitizer for an ISFET Wearable Sweat Sensing System

Sensors

This article describes the design and the characterization of the ANTIGONE (ANalog To dIGital cON... more This article describes the design and the characterization of the ANTIGONE (ANalog To dIGital cONvErter) ASIC (Application Specific Integrated Circuit) built in AMS 0.35 m technology for low dc-current sensing. This energy-efficient ASIC was specifically designed to interface with multiple Ion-Sensitive Field-Effect Transistors (ISFETs) and detect biomarkers like pH, Na+, K+ and Ca2+ in human sweat. The ISFET-ASIC system can allow real-time noninvasive and continuous health monitoring. The ANTIGONE ASIC architecture is based on the current-to-frequency converter through the charge balancing principle. The same front-end can digitize multiple currents produced by four sweat ISFET sensors in time multiplexing. The front-end demonstrates good linearity over a dynamic range that spans from 1 pA up to 500 nA. The consumed energy per conversion is less than 1 J. The chip is programmable and works in eight different modes of operation. The system uses a standard Serial Peripheral Interface...

format_quoteANTIGONE ASIC offers innovative power management and interfaces for better performance in low-power applications compared to conventional ADCs.format_quote

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JouleSense: A Simulation based Platform for Proactive Feedback on Building Occupants’ Energy Use

Proceedings of the 5th International Conference on Smart Cities and Green ICT Systems, 2016

A significant amount of energy in the buildings can be saved by inducing efficient occupant behav... more A significant amount of energy in the buildings can be saved by inducing efficient occupant behavior. The occupant's awareness tools that have been shown to be effective in achieving energy efficiency gains depend on various computational and estimation algorithms. This paper proposes an energy feedback scheme that relies on a model based, building thermal simulation in order to identify the areas for efficiency improvement. By leveraging the specific mathematical formulation of those models and a dedicated open-source solver, improved computational speed, reduced cost and enhanced interoperability is obtained. This combined with the integration into a building management system (BMS), permits real-time sensing and feedback. Unlike similar studies, this work's outcome allows the creation of the energy awareness tools that rely solely on validated thermal model simulation, thus increasing their accuracy and potential in the future smart buildings.

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Integrating Building Automation Technologies with Smart Cities - An Assessment Study of past, Current and Future Interroperable Technologies

Proceedings of the 4th International Conference on Smart Cities and Green ICT Systems, 2015

Future smart cities would integrate a wide range of mostly heterogeneous systems and ICT is an es... more Future smart cities would integrate a wide range of mostly heterogeneous systems and ICT is an essential asset in the coordination of those. The smart buildings, a major smart cities research and development domain, should advance beyond the complex automation tools and the anticipated energy and comfort envelope. The universal convergence to technologies that would enable the seamless integration with the anticipated smart cities urban environment should be highlighted. Although it is a concept widely accepted for current and future developing standards, it is much less communicated across scientific fields as for example the urban development and building automation. Even worse its necessity, in the latter, is frequently challenged. This paper firstly will try to address the market and scientific criticism towards a fully web-services enabled building in a fair and transparent approach. Secondly it proposes a system as an interoperability layer able to build advanced managements schemes by integrating the assets of current automation and monitoring systems to the Internet backbone. This research has been funded by Nano-Tera.ch, a program of the Swiss Confederation, evaluated by SNSF. Integrating Building Automation Technologies with Smart Cities-An Assessment Study of past, Current and Future Interroperable Technologies.

format_quoteUtilizing Internet infrastructure for building management ensures efficient integration of multiple stakeholders in smart city development.format_quote

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Substrate Current Modeling for high Temperature Smart Power BCD Technology

Keywords: Smart power IC ; integrated circuit ; methodology modeling ; noise ; parasitic coupling... more Keywords: Smart power IC ; integrated circuit ; methodology modeling ; noise ; parasitic coupling ; power semiconductor devices ; power parasitic modeling ; substrate modeling ; lumped modeling These Ecole polytechnique federale de Lausanne EPFL, n° 5473 (2012)Programme doctoral Microsystemes et MicroelectroniqueFaculte des sciences et techniques de l'ingenieurInstitut de genie electrique et electroniqueLaboratoire d'electronique generale 1Jury: P.-A. Farine (president), H. Ballan, C. Dehollain, R. Iskander Public defense: 2012-10-26 Reference doi:10.5075/epfl-thesis-5473Print copy in library catalog Record created on 2012-12-05, modified on 2017-05-10

Fully intergrated calibration for high-performance Hall Sensor Microsystems

Keywords: Hall sensor Microsystem ; sensitivity calibration ; AC field rejection ; Differential D... more Keywords: Hall sensor Microsystem ; sensitivity calibration ; AC field rejection ; Differential Differences Amplifier ; current-mode output ; current transducer ; Voltage-to-current converter ; full system integration These Ecole polytechnique federale de Lausanne EPFL, n° 5659 (2013)Programme doctoral Microsystemes et MicroelectroniqueFaculte des sciences et techniques de l'ingenieurInstitut de genie electrique et electroniqueGroupe KayalJury: C. Dehollain (presidente), E. Favre, L. Hebrard, J.-M. Sallese Public defense: 2013-3-15 Reference doi:10.5075/epfl-thesis-5659Print copy in library catalog Record created on 2013-03-07, modified on 2016-08-09

Ultra high-speed electronics for power system dynamic emulation

Keywords: emulation ; high-speed simulation ; mixed analog digital integrated circuits ; applicat... more Keywords: emulation ; high-speed simulation ; mixed analog digital integrated circuits ; application specific integrated circuit (ASIC) ; power system simulation ; power system stability ; VLSI technology These Ecole polytechnique federale de Lausanne EPFL, n° 5842 (2013)Programme doctoral Microsystemes et MicroelectroniqueFaculte des sciences et techniques de l'ingenieurInstitut de genie electrique et electroniqueLaboratoire d'electronique generale 1Jury: J.-M. Sallese (president), X. Feng, T.B. Melly, M. Paolone Public defense: 2013-9-20 Reference doi:10.5075/epfl-thesis-5842Print copy in library catalog Record created on 2013-09-19, modified on 2016-08-09

A transient stability assessment method using post-fault trajectories

Transient Stability Assessment (TSA) is the process in which the stability of a system is charact... more Transient Stability Assessment (TSA) is the process in which the stability of a system is characterized qualitatively or quantitatively. The TSA algorithm presented in this paper is derived from the well-established Single Machine Equivalent (SIME) method and can thus be categorized as a hybrid directtemporal method. The novelty of the proposed algorithm is that it derives a Transient Stability Index (TSI) with a single Time-Domain (TD) simulation for both stable and unstable cases. The resulting TSI is uniform in units and linear around the instability point. Results are reported for two sample power systems of 9 and 36 buses. The proposed algorithm has also been successfully employed to speed-up a Critical Clearing Time (CCT) determination algorithm.

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Hall cells offset analysis and modeling approaches

Keywords: Hall cells ; offset ; offset temperature drift ; current-related sensitivity ; three-di... more Keywords: Hall cells ; offset ; offset temperature drift ; current-related sensitivity ; three-dimensional physical simulations ; lumped circuit model ; temperature effects These Ecole polytechnique federale de Lausanne EPFL, n° 5741 (2013)Programme doctoral Microsystemes et MicroelectroniqueFaculte des sciences et techniques de l'ingenieurInstitut de genie electrique et electroniqueGroupe KayalJury: C. Dehollain (presidente), H. Blanchard, S. Carrara, D. De Venuto Public defense: 2013-6-17 Reference doi:10.5075/epfl-thesis-5741Print copy in library catalog Record created on 2013-06-12, modified on 2017-05-10

Calibration of a Mixed-Signal Power NetworN Transient Stability Analysis Emulator

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

2013 IEEE Grenoble Conference, 2013

This paper presents an innovative 3D hardware architecture for power system dynamic and transient... more This paper presents an innovative 3D hardware architecture for power system dynamic and transient stability. Based on an intrinsic parallel architecture by means of mixedsignal 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 4x24 nodes reconfigurable platform. Hardware details and comparisons with a reference digital simulator are given.

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

Optics Express, 2014

A new type of CMOS compatible photodetector, exhibiting intrinsic light-to-time conversion, is pr... more 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.

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MOS-PN Hybrid Device With Minimum Dark Current for Sensitive Digital Photodetection

IEEE Photonics Technology Letters, 2014

This letter presents a CMOS-compatible photodetector displaying direct light-to-time conversion a... more This letter presents a CMOS-compatible photodetector displaying direct light-to-time conversion and intrinsic charge integration with a very low dark current. This device is particularly adapted for applications requiring high sensitivity such as bioluminescence detection. The effects of the physical structure, the process parameters, and the bias conditions on the device are discussed with the support of TCAD simulations and experimental measurements. The photodetector and its readout circuit are designed and implemented in standard 0.18-μm CMOS process. The experimental study shows promising tunability and sensitivity characteristics.

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

Optics Letters, 2015

In this Letter, a direct light-to-digital converter based on an MOS-PN photodetector driven by pu... more 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.

Maher Kayal

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