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  • Conference paper
    Woods VM, Triantis IF, Toumazou C, 2011,

    Offset prediction for charge-balanced stimulus waveforms

    , Publisher: IOP PUBLISHING LTD, ISSN: 1741-2560
  • Journal article
    Grossman N, Nikolic K, Toumazou C, Degenaar Pet al., 2011,

    Modeling Study of the Light Stimulation of a Neuron Cell With Channelrhodopsin-2 Mutants

    , IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, Vol: 58, Pages: 1742-1751, ISSN: 0018-9294
  • Conference paper
    Saremi-Yarahmadi S, Fobelets K, Toumazou C, 2011,

    Coupled RF inductive sensors for monitoring the conductivity of electrolyte solutions

    , International symposium on medical information & communication technology
  • Journal article
    Goh ZDC, Georgiou P, Constandinou TG, Prodromakis T, Toumazou Cet al., 2011,

    A CMOS-based ISFET Chemical Imager with Auto-Calibration Capability

    , IEEE Sensors Journal, Vol: 11, Pages: 3253-3260, ISSN: 1530-437X

    This paper presents a novel auto-calibration technique for eliminating sensor mismatch in CMOS-based chemical imagers. Designed using an 8x8 array comprising of pH sensitive Ion Sensitive Field Effect Transistors (ISFETs), the chemical imager is capable of implementing a gradient based calibration algorithm by biasing programmable-gate (PG) ISFETs at a common operating point when exposed to a solution of homogenous pH. The system was fabricated in a typical 0.35um CMOS technology and demonstrated a fast rate of convergence (500ms per iteration) while a convergence accuracy of 45mV on a gain of 10 (0.5% relative standard error and 2% pixel-to-pixel variation) was achieved. A maximum pH sensitivity of 57mV/pH is also reported.
  • Patent
    Toumazou C, Premanode B, Shepherd L, 2011,

    Signal Processing Circuit Containing Ion-Sensitive Field-Effect Transistor and Method for Monitoring Property of Fluid

    , JP2011099877 (A); GB2416210 (A) GB2416210 (A8) GB2416210 (B) US2008265985 (A1) US7649358 (B2

    PROBLEM TO BE SOLVED: To provide a processing system and a control using an ion-sensitive field-effect transistor. ; SOLUTION: A signal processing circuit contains one or more ion-sensitive field-effect transistors, namely, ISFET, and a bias circuit for biasing them or each ion-sensitive field-effect transistor so as to operate in a weak inversion region. The method for using the ion-sensitive field-effect transistor to monitor properties of a medium includes the step of biasing the ion-sensitive field-effect transistor in a weak inversion region, exposing the ion-sensitive field-effect transistor to the medium, and analyzing the output of different ion-sensitive field-effect which depends on the properties.
  • Journal article
    Lui KW, Vilches A, Toumazou C, 2011,

    Ultra-efficient microwave harvesting system for battery-less micropower microcontroller platform

    , IET MICROWAVES ANTENNAS & PROPAGATION, Vol: 5, Pages: 811-817, ISSN: 1751-8725
  • Journal article
    Thanapitak S, Pookaiyaudom P, Seelanan P, Lidgey FJ, Hayatleh K, Toumazou Cet al., 2011,

    Verification of ISFET response time for millisecond range ion stimulus using electronic technique

    , ELECTRONICS LETTERS, Vol: 47, Pages: 586-588, ISSN: 0013-5194
  • Journal article
    Sharma S, Radomska-Botelho Moniz A, Triantis I, Michelakis K, Trzebinski T, Azarbadegan A, Field B, Toumazou C, Eames I, Cass Aet al., 2011,

    An integrated silicon sensor with microfluidic chip for monitoring potassium and pH

    , Microfluidics and Nanofluidics, Vol: 10, Pages: 1119-1125

    We present ion-sensitive field effect transistor-based sensors, integrated with a microfluidic chip, for monitoring pH and potassium cations. The sensor is strategically located at the base of a well so that the response time of the device depends both on the mean flow through the device and the diffusion coefficient of the analyte being monitored. This would enable monitoring of ions in the presence of larger molecules. The dependence of the device response time on diffusive transport of analytes was examined through a numerical study of the flow field and the passive diffusion of a chemical species. The predicted device response time was compared with the experimental measurements and reasonable agreement found. The general dependence of device response time on geometry, flow rate, and analyte diffusion coefficient was derived. These devices can be used with biological fluids where monitoring of pH and cations provide vital information about the well-being of patients.
  • Conference paper
    Goh ZDC, Georgiou P, Constandinou TG, Prodromakis T, Toumazou Cet al., 2011,

    Live demonstration: A CMOS-based lab-on-chip array for combined magnetic manipulation and opto-chemical sensing

    , IEEE International Symposium on Circuits and Systems (ISCAS), Pages: 1997-2001, ISSN: 0271-4302
  • Journal article
    Pookaiyaudom P, Seelanan P, Lidgey FJ, Hayatleh K, Toumazou Cet al., 2011,

    Measurement of urea, creatinine and urea to creatinine ratio using enzyme based chemical current conveyor (CCCII plus )

    , SENSORS AND ACTUATORS B-CHEMICAL, Vol: 153, Pages: 453-459, ISSN: 0925-4005
  • Journal article
    Prodromakis T, Liu Y, Toumazou C, 2011,

    A Low-Cost Disposable Chemical Sensing Platform Based on Discrete Components

    , IEEE Electron Device Letters, Vol: 32, Pages: 417-419

    A method of fabricating low-cost chemical sens- ing platforms is presented. The device utilizes a discrete metal–oxide–semiconductor field-effect transistor to detect ionic concentrations in electrolytes, with particular emphasis to pH. Measured results indicate a chemical sensitivity of 36.5 mV/pH, while the device exhibits low-leakage currents (in picoamperes) and a drift of 9 mV/h. The proposed technique has a great potential for disposable implementations, while the sensing selectivity of the device can be easily altered, resulting into a versatile platform.
  • Conference paper
    Serb A, Nikolic K, Constandinou TG, 2011,

    A CMOS-based light modulator for contactless data transfer: theory and concept

    , Silicon Photonics VI, Publisher: SPIE, Pages: 794317-794325

    A new technique pertaining to the optical contactless chip-to-board communication using a commercially available CMOS technology is under development. The main concept is to use mid-IR light from a small LED which will enter an IC from the underside, impinge upon one or more pn-junctions and be reflected by a metallic sheet so that it falls on an external, discrete photodetector. After propagation through the doped semiconductor, the light undergoes attenuation due to free carrier absorption. By varying the reverse bias across the pn-junction(s), the depletion region widths are changed and therefore modulation of light intensity can be achieved. Through this scheme, data readout can be realized optically, thus alleviating the need for galvanic contacts (most notably wirebonds).
  • Conference paper
    Goh ZDC, Georgiou P, Constandinou TG, Prodromakis T, Toumazou Cet al., 2011,

    A CMOS-based Lab-on-Chip Array for Combined Magnetic Manipulation and Opto-Chemical Sensing

    , IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 1998-2001, ISSN: 0271-4302
  • Conference paper
    Paraskevopoulou S, Constandinou TG, 2011,

    A sub-1μW Neural Spike-Peak Detection and Spike-Count Rate Encoding Circuit

    , IEEE Biomedical Circuits and Systems (BioCAS) conference, Publisher: IEEE, Pages: 29-32

    In this paper we present a circuit for determining neural spike features such as peak occurrence, peak amplitude and spike count rate in continuous-time. The system achieves these functions concurrently and in real-time achieving an accuracy higher than a typical digital solution (constrained by a the sampling time and/or resolution). For an average spike rate of 50$spikes/s$ the system consumes 815nW designed in a commercially-available 0.18μm CMOS technology. The complete circuit core (excluding bondpads) occupies a total area of approximately 0.022mm²
  • Conference paper
    Serb A, Nikolic K, Constandinou TG, 2011,

    Feasibility of an Electro-Optic Link for Bondpad-less CMOS Lab-on-Chips

    , IEEE Biomedical Circuits and Systems (BioCAS) conference, Publisher: IEEE, Pages: 353-356

    This paper explores the feasibility of developing CMOS-based lab-on-chips to analyse the properties of a fluid, without the need for bond wires. Both inductive and electro-optical schemes are suggested as possible solutions. Specifically, this paper details a novel approach in achieving electro-optical modulation in unmodified, commercially-available CMOS technology. By exploiting the plasma dispersion effect, it is shown how mid-infrared light can be modulated using parasitic structures designed in a CMOS integrated circuit. Both the fundamental theory and practical realisation are supported with measured data from an experimental setup.
  • Journal article
    Woods VM, Triantis IF, Agathos C, Toumazou Cet al., 2011,

    "Capacitive" Pulse Shapes for Platinum Cuff Electrodes

    , 2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), Pages: 5408-5411, ISSN: 1557-170X
  • Conference paper
    Abshire P, Andreou A, Bermak A, Cauwenberghs G, Chen S, Christen JB, Constandinou TG, Culurciello E, Dandin M, Datta T, Delbruck T, Dudek P, Eftekhar A, Etienne-Cummings R, Indiveri G, Law MK, Linares-Barranco B, Tapson J, Tang W, Zhai Yet al., 2011,

    Confession Session: Learning from Others Mistakes

    , IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 1149-1162

    People rarely put in their papers the things that didn’t work, the mistakes they made, and how they found out what went wrong. Such confessions can help others learn how to avoid similar mistakes. Twenty-six confessions were collected to form the bulk of this paper. Themes that arise are errors that result from not understanding the limitations of simulation tools in modeling physical reality, chip verification errors that result from lack of clear communication between designers, and projects that are considered in their own isolated environment of technical challenges rather than the broader context of their environment or application.
  • Conference paper
    Deep H, Georgiou P, Toumazou C, 2011,

    A Silicon Pancreatic Beta Cell based on the Phantom Bursting Model

    , Annual IEEE Biomedical Circuits and Systems Conference (BioCAS) - Engineering Tomorrow's Healthcare, Publisher: IEEE, Pages: 273-276, ISSN: 2163-4025
  • Conference paper
    Sole M, Sanni A, Vilches A, Toumazou C, Constandinou TGet al., 2011,

    A Bio-Implantable Platform for Inductive Data and Power Transfer with Integrated Battery Charging

    , IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2605-2608

    This paper describes a mixed signal subsystem for the inductive transfer of power and data to a fully-implantable medical device. The design includes circuits for the inductive power recovery and energy storage (charging), in addition to data recovery and demodulation. The data link is used to upload (at a data rate of up to 180Kbps) calibration and configuration data to the implanted device and integrates both error detection and correction on the recovered bitstream. The system incorporates an implanted Li-Ion micro-battery with supporting charging hardware to provide an uninterrupted power supply for autonomous deployment. This is to provide continuous operation without the requirement for an externally worn unit and additionally ensures registry (i.e. patient calibration) settings are maintained. The circuit has been implemented in a commercially available 0.35um CMOS technology without requiring high-voltage device options.
  • Conference paper
    Luan S, Eftekhar A, Murphy O, Constandinou TGet al., 2011,

    Towards an Inductively Coupled Power/Data Link for Bondpad-Less Silicon Chips

    , IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 7-10

    This paper explores the concept of developing a bondpad-less fullyintegrated inductive link for power/data transfer between a silicon chip and a PCB. A key feature of the implemented system is that it requires no off-chip components. The proposed chip uses a standard 0.35um process and occupies an area of 2.5 x 2.5 mm^2. 9mW power was designed to be obtained on-chip through 900MHz carrier wave. Binary Phase Shift Keying (BPSK) and Load shift keying (LSK) are used for the the PCB-to-chip and chip-to-PCB link respectively for half-duplex communication.

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