M. Kayal

École Polytechnique Fédérale de Lausanne, Lausanne, Vaud, Switzerland

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Publications (201)94.93 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    No preview · Article · Aug 2015
  • F. Gaugaz · F. Krummenacher · M. Kayal
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    ABSTRACT: This paper explores the potential and limitations of analog integrated circuit techniques for the simulation of low-loss or lossless 1D or 2D transmission mediums. In this approach, a transmission line is mapped into a ladder consisting of N identical LC elements, each modeling a finite length increment of the line. Inductors are then emulated by a gyrator-capacitor combination, yielding a classical transconductor-capacitor (gm-C) circuit, suitable for integration. The validity of this approximation is discussed in the context of fault location in power networks, an application based on the electromagnetic time-reversal method. Design constraints on gm-C circuits are derived and non-ideal effects such as finite open-loop gain and component mismatches are evaluated. It is shown that a simple analog implementation can locate the fault within 1% accuracy with a significant speed advantage over classical computational methods, reducing the processing time to less than 100ms.
    No preview · Article · Aug 2015
  • D. Sallin · A. Koukab · M. Kayal
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    ABSTRACT: 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.
    No preview · Article · Aug 2015
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    ABSTRACT: An Application Specific Integrated Circuit (ASIC) has been designed in order to demonstrate the limitations and the challenges in ultralow current sensing. The Utopia (Ultralow Picoammeter) ASIC is foreseen to be the front-end in the new radiation measurement system for personnel safety at CERN. It is based on the topology of a Current to Frequency Converter (CFC) and has a wide dynamic range of 7 decades without range changing. Four different channels have been implemented in order to evaluate the limits regarding sub-picoampere current measurements. Test currents starting from -50 fA have been measured.
    No preview · Article · Aug 2015
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    ABSTRACT: In smart power IC technology, low and high voltage circuits are integrated on the same substrate. The commutation of the high voltage circuits can induce substrate parasitic currents which can severely disturb the operation of the low voltage circuits. The parasitic currents due to minority carriers in the high voltage technology can be significantly high. However, the minority carrier propagation into the substrate is not considered in most of existing circuit simulators. In this paper, a novel computer-aided design tool for substrate parasitic extraction is proposed. A simple circuit with an injecting and a collecting Nwells over a P-substrate is studied. With the distance between the wells varying, the lateral bipolar effect is illustrated. The spectre simulation results of extracted substrate equivalent circuit are compared to a TCAD simulation results. The comparison shows an acceptable relevant error. However, the simulation time was reduced by approximately 1400 times with respect to the TCAD.
    No preview · Conference Paper · May 2015
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    ABSTRACT: This paper presents an extended model for transient and ac circuit-level simulation of minority carriers propagation through the substrate of smart power integrated circuits (ICs). A p-n junction and a diffusion resistor with capacitive components are proposed to efficiently simulate transient parasitic coupled currents in high-power stages. From a general chip layout, an equivalent substrate network including capacitive effects (junction and diffusion capacitances) can be extracted and parasitic bipolar transistor can be simulated for the first time in transient operation by circuit simulators once the minority carriers continuity conditions are satisfied. This paper shows simulation results of the implemented models in good agreement with those obtained from technology computer-aided design. This implies that transient layout dependent mechanisms between high-voltage aggressor wells and low-voltage victims can be verified in early stages of IC design flow.
    No preview · Article · Apr 2015 · IEEE Transactions on Electron Devices
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    ABSTRACT: Classical substrate noise analysis considers the silicon resistivity of an integrated circuit only as doping dependent besides neglecting diffusion currents as well. In power circuits minority carriers are injected into the substrate and propagate by drift–diffusion. In this case the conductivity of the substrate is spatially modulated and this effect is particularly important in high injection regime. In this work a description of the coupling between majority and minority drift–diffusion currents is presented. A distributed model of the substrate is then proposed to take into account the conductivity modulation and its feedback on diffusion processes. The model is expressed in terms of equivalent circuits in order to be fully compatible with circuit simulators. The simulation results are then discussed for diodes and bipolar transistors and compared to the ones obtained from physical device simulations and measurements.
    No preview · Article · Mar 2015 · Solid-State Electronics
  • Denis Sallin · Adil Koukab · Maher Kayal
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    ABSTRACT: 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 μmCMOS technology is presented. The experimental results under various light conditions show that the pulsed voltage improves the light sensitivity by several orders of magnitude.
    No preview · Article · Feb 2015 · Optics Letters
  • G. Lanz · T. Kyriakidis · R. Cherkaoui · M. Kayal
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    ABSTRACT: This paper presents the extension of a platform originally devoted to symmetrical transient stability analysis, into the domain of unbalanced faults. The aim of this solver is to increase the speed of dynamic stability assessment for power systems. It is based on an analog representation of the grid alongside dedicated digital resources for the simulation of the models of power network components. Using the symmetrical components theory, this platform can be adapted to handle unsymmetrical disturbances, such as single-phase-to-ground faults, and the tripping of single-phase circuit breakers.
    No preview · Article · Feb 2015
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    ABSTRACT: Traditionally, photodiodes operate at static reverse bias, and incident light intensity is obtained from the relatively week photocurrent. In this paper, we introduce a different concept of photodiode function: the photodiode is used in a dynamic regime where it is switched from the reverse to forward state. Thus, the light intensity is defined not by the measured photocurrent but by the delay time of appearance of the strong forward current with the amplitude independent of the light intensity. Our experimental results as well as finite element modeling show that the dynamic mode of photodiode operation can potentially provide an improvement of the device performance.
    No preview · Article · Jan 2015 · Applied Physics Letters

  • No preview · Article · Jan 2015 · IEEE Transactions on Power Electronics

  • No preview · Article · Jan 2015 · IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
  • N.A. Zanjani · G. Lilis · G. Conus · M. Kayal
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    ABSTRACT: This paper addresses a bottom-up approach for energy management in buildings. Future smart cities will need smart citizens, thus developing an interface to connect humans to their energy usage becomes a necessity. The goal is to give a touch of energy to occupants' daily behaviours and activities and making them aware of their decisions' consequences in terms of energy consumption, its cost and carbon footprint. Second, to allow people directly interacting and controling their living spaces, that means individual contributions to their feeling of comfort. Finally, a software solution to keep track of all personal energy related events is suggested and its possible features are explained.
    No preview · Article · Jan 2015
  • G. Lilis · G. Conus · N. Asadi · M. Kayal
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    ABSTRACT: 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.
    No preview · Article · Jan 2015
  • Denis Sallin · Adil Koukab · Maher Kayal
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    ABSTRACT: This paper 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.
    No preview · Article · Oct 2014 · IEEE Photonics Technology Letters
  • Denis Sallin · Adil Koukab · Maher Kayal
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    ABSTRACT: 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 experimentally studied.
    No preview · Conference Paper · Sep 2014
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    ABSTRACT: The current work focuses on presenting specific Hall cells with high performance, and their corresponding parameters. The design, integration, measurements and model development for their performance assessment are necessary stages considered in the generation of the Hall cells. Experimental results regarding the Hall cells absolute sensitivity, offset and offset temperature drift are provided for two particular structures exhibiting the best behavior in terms of maximum sensitivity and lowest offset. Three-dimensional physical simulations were performed for the structures and the Hall mobility was extracted. Representation of the inverse of the geometrical correction factor for the Greek-cross Hall cell is also provided.
    No preview · Article · Sep 2014 · Microelectronics Journal
  • C. Kauth · M. Pastre · M. Kayal
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    ABSTRACT: The state-of-the-art mass sensing so far has been rather developed along the resolution axis, reaching atomic-scale detection, than into the direction of high-speed. This paper reports a novel self-calibrating technique, making high-speed inertial mass sensors capable of instant high-resolution particle detection and weighing. The sensing nanoelectromechanical resonator is embedded into a phase-locked loop and the sensor-inherent nonlinear phase–frequency relation is exploited for auto-calibration. A tunable on-chip carbon nanotube based mass balance serves as a case study of small-size and low-cost environmental and healthcare applications. Tunability and a phase-locked loop topology make the system widely universal and invariant to nanotube characteristics. Operational for tube eigenfrequencies up to 385 MHz, the circuit integration in a 180 nm technology achieves instantaneous zeptogram resolution, while yoctogram precision is obtained within the tenth of a second. These figures of merit range at the physical limits of carbon nanotube resonators, in both mass- and time-resolution.
    No preview · Article · Aug 2014 · Microelectronics Journal
  • Christian Kauth · Marc Pastre · Maher Kayal
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    ABSTRACT: Mass sensing has so far rather developed along the resolution axis, reaching atomic-scale detection, than into the direction of high-speed. This letter reports on a novel self-calibrating technique that makes high-speed inertial mass sensors capable of instant high-resolution detection and weighing. The sensing nanoelectromechanical resonator is embedded into a phase-locked loop and the sensor-inherent nonlinear phasefrequency relation is exploited for auto-calibration.
    No preview · Article · Aug 2014 · IEEE Sensors Journal
  • Source
    Denis Sallin · Adil Koukab · Maher Kayal
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    ABSTRACT: 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.
    Full-text · Article · Jun 2014 · Optics Express

Publication Stats

848 Citations
94.93 Total Impact Points


  • 2002-2015
    • École Polytechnique Fédérale de Lausanne
      • • Industrial Electronics Laboratory
      • • Institute of Electrical Engineering
      Lausanne, Vaud, Switzerland
  • 1990-2013
    • Eawag: Das Wasserforschungs-Institut des ETH-Bereichs
      Duebendorf, Zurich, Switzerland
  • 2010
    • École Polytechnique
      Paliseau, Île-de-France, France
  • 2008
    • CERN
      Genève, Geneva, Switzerland
  • 2004
    • Politecnico di Bari
      Bari, Apulia, Italy