By Topic

Devices, Circuits and Systems, 2008. ICCDCS 2008. 7th International Caribbean Conference on

Date 28-30 April 2008

Filter Results

Displaying Results 1 - 25 of 72
  • Technical program

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | PDF file iconPDF (187 KB)  
    Freely Available from IEEE
  • A novel piecewise curvature-corrected CMOS bandgap reference

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1377 KB) |  | HTML iconHTML  

    A novel and simple piecewise curvature-corrected bandgap voltage reference (BGR) is proposed. It features in employing temperature-dependent resistor ratio to get a piecewise corrected current, which corrects the nonlinear temperature dependence of the first-order BGR. The piecewise corrected current generator forms a negative feedback to improve the line regulation and power supply rejection (PSR) of the proposed BGR. Simulation result shows the temperature coefficient (TC) of 5ppm/K in the industry temperature range (223-398K) and PSR of -82dB are achieved at 2.6-V supply voltage. The simulated line regulation is 0.6mV/V in the supply range of 2.6V-5.6V. It is designed in SMIC 0.35-mum 5-V n-well digital CMOS process. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new cognitive-based massive alarm management system in electrical power administration

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB) |  | HTML iconHTML  

    This paper presents a methodology that integrates several available techniques to manage the massive amount of alarm signals in electrical power dispatch control centres, as well as the contribution of each entity involved in the system. Artificial intelligence techniques that can be used in this problem are reviewed here based on the available information. The final objective is to find the root cause of avalanches of alarms (failure tree) and to reduce their number through grouping or clustering techniques so that the EEMUA 191 standards are followed. Even though other contributions in this topic have been made before, the alarm management problem continues to be practically unsolved for many applications in industry. Here, the integration is developed using the ontology of each system domains, i.e., the ontology corresponding to the alarms, controls, events, energy flow and trigger sequence. Additionally, in this methodology, a rule based expert system is used to treat the alarms with a neural net based approach to treat the historical database of alarms and failures. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Package to board interconnect design for minimum return loss

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1374 KB) |  | HTML iconHTML  

    Return loss from impedance discontinuities severely limits the bandwidth and power efficiency of chip-to-chip copper interconnects. Among the more frequently found discontinuities are vertical transitions connecting signals in different layers in the system. In this work, we present a general condition to improve return loss in vertical package to board transitions in high speed links. The relationship involves the impedance of on-package and on-board transmission lines as well as the via model. Experimental results that apply the proposed method show a 10-dB improvement in return loss. The proposed method can be applied in the design of copper interconnects with minimum reflection, which is a requirement of high-speed and low-power signaling systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The isolated multilevel inverter using common-arm scheme for 3-phase system

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB) |  | HTML iconHTML  

    For 3-phase applications, an isolated multilevel inverter employing 3-phase transformers can reduce the number of transformers compared with that of using single- phase transformers. However it needs a large number of switches. To solve this problem, we propose a modified 3-phase isolated multilevel inverter adopting common-arm scheme. Phase angle control based on equal-area method is presented to obtain optimal switching functions identified with fundamental frequency of output voltage. Thanks to this control strategy, harmonic components of output voltage and switching losses can be diminished considerably. To verify performance of the proposed multilevel inverter, we implemented computer-aided simulations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Implementation of error decoders for A-VSB systems with additional use of transport stream information as forward error correction

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1138 KB) |  | HTML iconHTML  

    In the last years several standards had been discussed in order to provide an opportunity for a robust reception of video streams in portable, handheld products. With regard to a backward compatible system, the advanced VSB (A-VSB) standard is presented. One feature of A-VSB is the increasing performance of forward error correction. The additional redundancy information is placed in the adaptation field of the transport stream, which is being ignored by a legacy receiver. Due to this complex transmission technology, the receiver should optimize the performance of its error decoders. The use of optimum decoding with soft-output Viterbi algorithm is essential and offers the possibility of exchanging the belief information between serial concatenated convolutional decoders. Furthermore, this implementation provides a way to adapt Viterbi distances of periodically appearing information in the transport stream which are predictable and can be used as additional forward error correction. This is what will also be described in this paper. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A simplified rectifier voltage vector selection for Direct Power Control

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (707 KB) |  | HTML iconHTML  

    This work presents a simple scheme for vector selection in Direct Power Control (DPC) in a three-phase rectifier without the use of switch selection tables, by using a rectifier voltage computed with a closed expression. The method is simulated using a C language description of the system and its results are later verified on an experimental test rig. The use of an optimum rectifier voltage and the use of Space Vector Modulation (SVM) provides an operation with lower ripple in the current and in the calculated active and reactive power. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An approach for an effectively implemented transmission adapter enableing the adaption field by reorganizing a common MPEG-2 Transport Stream

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1128 KB) |  | HTML iconHTML  

    This paper proposes an implementation method to build a simplified transmission adapter to process a common MPEG-2 Transport Stream. The reorganization of the Transport Stream enables the option to use the additively introduced adaptation field for new services or for the improvement of system performance. If there are new extensions available for existing transmission systems the downwards compatibility to the original system is always an essential requirement. Using the adaptation field the advantage of the downwards compatibility to legacy receivers is guaranteed, because the adaptation field will be ignored by conventional decoders. One application field for the use of this auxiliary MPEG-2 field is the ATSC-M/H proposal standard published by Samsung Electronics and Rhode & Schwarz called Advanced-VSB (A-VSB). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Current and capacitance modeling of short-channel DG MOSFETs

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (938 KB) |  | HTML iconHTML  

    We present a precise two-dimensional current and capacitance modeling for nanoscale double-gate MOSFETs covering a wide range of operating regions, geometries and material combinations. The modeling in the sub-threshold regime is based on conformal mapping techniques. In moderate to strong inversion, we obtain self-consistent results based on the 2D Poisson's equation. The results are in excellent agreement with numerical simulations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Asynchronous circuits design using quantum-dot cellular automata for molecular computing

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1253 KB) |  | HTML iconHTML  

    Quantum-dot cellular automata (QCA) implementation of digital logic circuits families has received popular attention. A QCA circuit because of its unique characteristics in terms of power consumption, speed and size of the circuit could be a great potential alternative for classical circuits. However, control over the timing and fault-tolerance are significant issues in design and manufacturing. This paper describes the design of an asynchronous circuit as an example to discuss the rules for translating a classical circuit to its QCA counterpart. Besides the points should be taken into account for partitioning the circuit as well as a comprehensive defect tolerance analysis will be presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Active energy recovering snubber for the asymmetric inverter

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1590 KB) |  | HTML iconHTML  

    This paper presents a single capacitor active snubber circuit for the asymmetric inverters used to drive switched reluctance motors. The proposed configuration uses the motor coil inductance as an integral component in the snubber process, acting in sequence to ensure the low-loss commutation of each inverter main power device. The two auxiliary snubber switches naturally commutate in ZCS mode. Only one minor change in the inverter firing sequence is required to include the snubber. Initial simulations in AIMSPICE show that the snubber produces significant reduction in commutation losses without affecting the asymmetric inverter operation. A laboratory prototype is undergoing tests to study the complete operating envelope of the modified inverter driving a switched reluctance motor under DTC control. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compatibility of co-tunneling and power-law models of soft breakdown current in MOS structures

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1563 KB) |  | HTML iconHTML  

    The connection between two of the most frequently used mathematical models to fit the soft breakdown I-V characteristic in MOS devices was investigated. First, we show that our experimental data is well represented by the monomial power-law model and we extract its parameters by means of an auxiliary operator that involves numerical integration of the I-V curve. Next, we consider the co-tunneling conduction model, which represents the current by a polynomial expression with only odd-order terms and positive coefficients. The best fit of our experimental data to odd-order polynomials yields some negative coefficients, which is contrary to its physical foundations. Finally, in an attempt to conciliate both representations, we have approximated the power-law model to a polynomial with only odd-order terms and arbitrary coefficients and again we have found that is not possible to obtain all positive coefficients. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • PLATAFORMA: A useful tool for high level education, research and development

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1087 KB) |  | HTML iconHTML  

    This work presents the PLATAFORMA system impact over the teaching and research activities of the lecturers and the post graduate students at Master and Doctorate levels working in the Power Electronics Industrial Systems group (Grupo de Sistemas Industriales de Electronica de Potencia, SIEP) of the Universidad Simon Bolivar. PLATAFORMA is an integrated test system intended for experiments requiring validation of different types of new strategies and control schemes, based on vector control theories, parametric estimation, neural networks and fuzzy logic control systems, applied to machine drives, and it can be also used for analyzing the effect of these control strategies over the mains quality. The equipment includes driver power stages, an instrumentation stage and a signal processing and control stage. PLATAFORMA has eliminated most of the tedious work that every single researcher or post graduate student in the GSIEP group had to do in order to obtain experimental results, enhancing the quality of the thesis and papers produced by the group members. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A fingertip detection and tracking system as a virtual mouse, a signature input device and an application selector

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (333 KB) |  | HTML iconHTML  

    The paper presents a vision-based fingertip detection and tracking system on a 2D plane using a camera as an input interface to the computer. An intensity based approach is used to detect the arbitrary shaped, uniform colored 2D area on which the hand operates, and then the fingertip is effectively detected and tracked using the sampled hand contour. Grid sampling approach is used for a fast implementation. The system achieves speeds of up to 30 fps. Tip pointers such as a stylus or a pen can be used in place of the fingertip, making the device user-friendly. The system is used to implement a virtual mouse, a signature input device and an application selector. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Authentication and digital signature USB device for telemedicine applications

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (371 KB) |  | HTML iconHTML  

    The main objective of this project was to design, develop and validate a digital signature in a security device for telemedicine applications. Medical domain requires high security conditions for archiving since the information to be protected contains images, diagnosis, personal information of the patients and physicians involved in the telemedicine process. The developed strategy consists in a USB device which allows proper authentication in the information system using a conventional public-private key scheme, through a zero knowledge proof algorithm that guarantees the privacy of the personal password. Once the user is accepted, the device also makes possible the generation of the digital signature required for generated documents. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of a programmable platform for the control of mobile robots based on a multi-FPGA architecture

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (374 KB) |  | HTML iconHTML  

    This work presents the design of a programmable platform for mobile robots control, based on a multi-FPGA architecture. The designed platform presents four FPGAs distributed in three processing levels. In the presented platform the user will be able to program systems with two closed-loop controls, which contain the navigation system of the mobile robot, and the control of its actuators. The upper processing level has a Xilinxreg XC4VSX35-FF668, in which the platform user can program the navigation control of the robot. Three Xilinxreg XC3S2000-FG676 are the programmable units for the other two processing levels, one in the middle level and two in the lower level, and between these FPGAs the user can program a distributed control of actuators. The programmable control platform designed in this project will allow the user to test, independently, the real performance of different navigation systems and controls of actuators, while keeping a low money investment. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bending effect of Si MOSFETs on flexible plastic substrate

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1614 KB) |  | HTML iconHTML  

    By applying ~0.27% tensile strain to the flexible die of a 0.16 mum thin-body (100 mum) Si MOSFET mounted on plastic, the DC characteristics have been improved. The small DC performance degradation of the Si MOSFET transferred to plastic shows the potential of integrating electronics onto plastic. The device performance was improved by flexing the substrate to create stress, which produced a 10.7% enhancement of the saturation drain current and only 0.003 V Vth is lower. The approach has the advantages of flexible electronics on the insulating plastic substrate and low cost. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Characterization and modeling of electronic packages using S-parameters

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (780 KB) |  | HTML iconHTML  

    In this paper, we demonstrate the feasibility to characterize and model singled-ended electronic packages using experimental S-parameters up to 30 GHz. TRL calibration and transmission line theory techniques were applied to obtain the two-port network parameters of the packages from measurements performed to package-to-transmission line test structures. With this information, an assessment of the performance of the package was carried out, as well as the development of equivalent circuit models to represent this structure up to 30 GHz. The methodology is explained step-by-step including the description of the required prototypes. Excellent agreement of the resulting models with experimental data validates the proposed methodology. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time-Domain analysis of carbon nanotubes

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1416 KB) |  | HTML iconHTML  

    Time-domain behavior of carbon nanotubes as the future candidates for interconnects is of great importance. In order to analyze an entire circuit containing carbon nanotube interconnects, we need to have an electrical circuit model for carbon nanotubes as well as the rest of the system. Several studies have demonstrated the extracted electrical elements of carbon nanotubes. At this paper, we're going to perform a comprehensive transient analysis on carbon nanotubes to achieve time-domain parameters like delay, rise time and overshoot. An overall transfer function of carbon nanotubes is obtained analytically. Besides, the time-domain quality metrics as well as relative stability based on the variation of the geometry of carbon nanotubes would be analyzed through simulation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low-voltage and low-power adjustable differential delay line using the FGMOS transistor

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (515 KB) |  | HTML iconHTML  

    This paper proposes a novel low-voltage and low-power analog differential delay line CMOS circuit design in the audio frequency range. The circuit is based on the Gm-C linear integrator used as the main block in a low-pass filter which can be tuned varying a bias voltage. To overcome the dynamic range problems by the supply voltage reduction, the design is implemented using the FGMOS transistor. The simulated results in a 1.2 μm CMOS technology show that delay time can be adjustable through 6 tap with a dissipation power of 140 μW and a supply voltage of 1.5V. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Identification of high speed jittered digital interconnects using bicoherence spectra

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2238 KB) |  | HTML iconHTML  

    Interference due to narrowband and broadband sources in mobile computing platforms have the capability to degrade overall wireless performance. Identification of these radio frequency interference (RFI) sources allows for mitigation and improved wireless performance. While shielding gives some immunity, interference sources operating within the same platform as sensitive radio receivers presents challenges far and above traditional electromagnetic compatibility (EMC) of device integration. In this paper, bicoherence, a signal processing analysis algorithm, is used to identify the presence of high-speed interconnects in radiated platform emissions. This paper uses a practical example of RFI found in current wireless platforms and shows that detection is feasible in Gaussian and non-Gaussian additive noise environments. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analytic evaluation of the uplink Erlang capacity of CDMA macrocells with hotspot microcells

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1361 KB) |  | HTML iconHTML  

    In this paper we evaluate the uplink user capacity of a macrocell/microcell CDMA system under non-uniform traffic loading conditions. The "hot spots" microcells are embedded within a large macrocell and operate over the same bandwidth as the large cell. The analytic method to compute Erlang user capacity takes into account propagation and shadowing losses, arrival process, multiple access interference and power control of user terminals. The necessary desensitivity in the microcell so that it covers only the region of the hot spot is determined. Also, to calculate the interference in the macrocell and microcells we take into account the soft handoff process and the coverage regions of the microcells. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simulation of Chua’s chaotic oscillator using unity-gain cells

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (695 KB) |  | HTML iconHTML  

    A novel topology to design a chaotic oscillator which is based on Chua's circuit, is proposed. The chaotic oscillator is realized with unity-gain cells, that is, the use of voltage followers (VF) and current followers (CF) to emulate the behavior of the two most important elements of the Chua's circuit: the active three-segment voltage controlled nonlinear resistor and the grounded inductor. Furthermore, it is shown that a negative current follower (CF-) can be implemented by using the IC AD844AN type current feedback operational amplifier (CFOA). The approach shows that the proposed topology can generate chaotic oscillations, where the HSPICE simulations have been obtained by using the macromodel of the IC AD844AN in configuration of unity-gain cell. Therefore, chaotic behavior in the time domain and the state space are presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A reconfigurable battery pack for improving power conversion efficiency in portable devices

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2338 KB) |  | HTML iconHTML  

    Extending battery life for portable computing systems not only requires new power management techniques and high efficiency power delivery systems but also must address low power consumption modes. Mobile systems spend most of their operating time in very low power modes, in which the voltage regulators (VRs) that feed the different components typically exhibit low efficiencies. Variable frequency control is one of the most commonly used methods to minimize both driving and switching losses by scaling the switching frequency at light loads. However, further benefit can be achieved if the input voltage scales as well. This paper proposes a novel reconfigurable battery pack (RBP) concept to improve power conversion efficiency of VRs under light load conditions. It describes a methodology to change the input voltage of VRs based on load conditions by changing the internal connection of battery cells to provide a variable input bus voltage to the system and extend battery life as a result of power loss reduction. Experimental results show ~15 min battery life improvement for a typical Thin & Light Laptop. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • FPGA based radar image enhanced: A robust evolutionary controlled filter approach

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1685 KB) |  | HTML iconHTML  

    In this work, we implemented the robust evolutionary controlled (REC) filter in a FPGA platform. Due unknown a priori statistical information, we replace the Optimal Wiener Filter by its rough approximation referred to as REC filter. The evolution of the filter is controlled by changing/choosing the vector of the controlled parameters gamma. Such a control provides additional degrees of freedom of the filter. We report and discuss some implementation results in the Xilinx Virtex-II Pro XC2VP30 FPGA related to enhancement of the uncertain real-world RS imagery, these are indicative of the significantly increased performance efficiency gained with the developed approach. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.