Power Supply Fluctuations Research Articles

Reliable Eye-Diagram Analysis of Data Links via Device Macromodels

This paper addresses the impact of device macromodels on the accuracy of signal integrity and performance predictions for critical digital interconnecting systems. It exploits nonlinear parametric models for both single-ended and differential devices, including the effects of power supply fluctuations and receiver bit detection. The analysis demonstrates that the use of well-designed macromodels dramatically speeds up the simulation as well it preserves timing accuracy even for long bit sequences.

Introduction of a new Energy Recovery System—optimized for the combination with renewable energy

The ENERCON Desalination Department has developed a new energy recovery system for RO desalination plants, optimized for the combination with wind energy converters. The main problem for the combination of desalination processes and wind energy is the fluctuation of power supply generated through renewable energies. Conventional desalination plants (and the belonging energy recovery systems) work at a fixed operation point or in a very small range. ENERCON developed a system that can adjust the operation in a range of 12,5 - 100% energy availability - in a very energy efficient way! The energy recovery system consists of a low pressure pump (20bar) and three combined pistons (there is no need for a second/booster pump). This “piston type accumulator” is able to transfer the pressure up to 70 bar, needed for the desalination process. As a side effect we can also avoid the use of chemicals for the antiscaling and antifouling problem. We managed to avoid additives by a low recovery rate. In the combination with the very efficient energy recovery system we experienced an energy consumption within the RO unit between 2-2,8 kWh / m 3 for sea water and between 0,8-1,3 for brackish water with our prototype plants in the Mediterranean sea. The ENERCON design enables a reduction of operation costs through low energy consumption and the avoidance of chemicals. Furthermore it is also a benefit for the environment. Our goal: A reliable, sustainable drinking water production of finest water quality!

Design Techniques of Delay-Locked Loop for Jitter Minimization in DRAM Applications

High performance delay-locked loop (DLL) is key to the high data rate chip-to-chip communication, suggesting the output jitter, due to power noise, bang-bang noise, temperature-voltage drift, etc, should be properly controlled. In this paper, high speed DRAM operation can be achieved by a dual loop DLL with various novel techniques; a new counting code with hysteretic bit-transitions can remove the large DAC glitches by preventing the binary bit-transitions in the locking states. A delay buffer, which is insensitive to the power supply fluctuations, is proposed. The voltage-temperature (VT) dependencies of the feedback path and the open clock path are balanced, minimizing the VT shift of the clock. As a result, the high-speed DRAM interface with the maximized setup/hold window can be accomplished.

Behavioural macromodels of digital IC receivers for analogue-mixed signal simulations

A behavioural multiport macromodel for the input buffers of digital integrated circuits is presented, including the bit detection and the effects of power-supply fluctuations. The model is given in terms of mathematical expressions, thus preserving proprietary information of designers, and offers comparable accuracy and improved efficiency compared with transistor-level models. It is also completely compatible with SPICE, VHDL-AMS and IBIS implementations.

Techniques for Localization of IC Interconnection Defects

AbstractThe advances in integrated circuit technology has made failure site localization extremely challenging. Charge-Induced Voltage Alteration (CIVA), Low Energy CIVA (LECIVA), Light-Induced Voltage Alteration (LIVA), Seebeck Effect Imaging (SEI) and Thermally-Induced Voltage Alteration (TIVA) are five recently developed failure analysis techniques which meet the challenge by rapidly and non-destructively localizing interconnection defects on ICs. The techniques take advantage of voltage fluctuations in a constant current power supply as an electron or photon beam is scanned across an IC. CIVA and LECIVA are scanning electron microscopy (SEM) techniques that yield rapid localization of open interconnections. LIVA is a scanning optical microscopy (SOM) method that yields quick identification of damaged semiconductor junctions and determines transistor logic states. SEI and TIVA are SOM techniques that rapidly localize open interconnections and shorts respectively. LIVA, SEI, and TIVA can be performed from the backside of ICs by using the proper photon wavelength. CIVA, LECIVA, LIVA, TIVA, and SEI techniques in terms of the physics of signal generation, data acquisition system required, and imaging results displaying the utility of each technique for localizing interconnection defects. In addition to the techniques listed above, the Resistive Contrast Imaging (RCI) for localizing opens on metal test patterns will be described as a starting point for the “IVA” technologies.

Global fault localization using induced voltage alteration

Advances in integrated circuit technology have made failure site localization extremely challenging. Charge-induced voltage alteration (CIVA), low energy CIVA (LECIVA), light-induced voltage alteration (LIVA), Seebeck effect imaging (SEI) and thermally-induced voltage alteration (TIVA) are five recently developed failure analysis techniques which meet the challenge by rapidly and non-destructively localizing interconnection defects on ICs. The techniques take advantage of voltage fluctuations in a constant current power supply as an electron or photon beam is scanned across an IC. CIVA and LECIVA are scanning electron microscopy techniques that yield rapid localization of open interconnections. LIVA is a scanning optical microscopy (SOM) method that yields quick identification of damaged semiconductor junctions and determines transistor logic states. SEI and TIVA are SOM techniques that rapidly localize open interconnections and shorts respectively. LIVA, SEI, and TIVA can be performed from the backside of ICs by using the proper photon wavelength. This paper describes the CIVA, LECIVA, LIVA, TIVA, and SEI techniques in terms of the physics of signal generation, general data acquisition system required, and imaging results displaying the utility of each technique for localizing interconnection defects.

Experience in the design, sizing, economics, and implementation of autonomous wind-powered hydrogen production systems

While much research effort has concentrated on utilising solar photovoltaics to generate hydrogen via electrolysis, the possibility of using wind power has received little attention. This paper summarises results from a recent EC-funded project to demonstrate the practicality of such a system and to identify possible drawbacks or areas requiring further development. Specifically, the project examined the effects of fluctuating power supplies on electrolyser operation and the modification of wind turbine operation to smooth power output, assessed the sizing and economics of a wind-hydrogen production plant, and resulted in the construction of a demonstration plant at ENEA’s Casaccia Research Centre in Italy.

Low-noise CMOS preamplifier-shaper for silicon drift detectors

We have designed a 16-channel preamplifier-shaper for particle tracking using silicon drift detectors (SDD). The preamplifier, which is optimized for a detector capacitance of 0.2-0.8 pF, uses two new circuit techniques to achieve a low noise (ENC 120 e/sup -/+62 e/sup -//pF), high linearity (<0.5% to 50 fC), and good tolerance to process variations and temperature and power supply fluctuations. The circuit is continuously sensitive, has no digital signals on chip, and requires no external components or critical adjustments. The peaking time of the shaper is 50 nsec and the power dissipation, including an off-chip driver, is 6.5 mW/channel. The circuit is fabricated in 1.2 /spl mu/m CMOS and can accommodate detector leakage currents of up to 1.5 uA. Although the circuit was developed for use with particle tracking detectors, these techniques are also well-suited for the design of lower-noise preamplifiers for high-resolution X-ray spectroscopy systems.

CMOS preamplifier with high linearity and ultra low noise for X-ray spectroscopy

We report here an ultra low noise charge sensitive monolithic CMOS amplifier (CSA) suitable for small anode capacitance (200 fF), low leakage current solid state detectors. The CSA is continuously sensitive, the charge from the input node being drained by a feedback transistor Mf biased as a resistor with effective values in the G/spl Omega/ range. This very high value was achieved by a novel scheme which tracks threshold variations, and power supply and temperature fluctuations. A good linearity of the CSA conversion gain is achieved (<0.1% up to 1.8 fC input charge) by inserting a voltage divider between the output of the CSA and the source of Mf. The equivalent noise charge (ENC) of the CSA is equal to the theoretical lower limit imposed by the flicker noise. The circuit has been fabricated in two different CMOS technologies. With no detector connected, we measure a room-temperature ENC of 9 e/sup -/ rms at 12 /spl mu/sec shaping time. When coupled to a cooled detector a FWHM of 111 eV is obtained at 2.4 /spl mu/sec shaping, corresponding to an ENC of 13 e/sup -/ rms. This is the best reported energy resolution ever obtained with a CMOS preamplifier.

Multi-gigahertz operation of 3-junction-interferometer-based Josephson latching logic circuits

Josephson latching logic gates require an ac power supply for correct operation. Owing to the difficulty in fabricating Josephson regulators for large power currents, multi-phase sinusoidal power supply is the preferred method for multi-gigahertz operation. However, the inherently variable ac power reduces device margin for covering process variations. As a result, there exists a strong relationship between circuit size, maximum operating frequency and circuit throughput for a given available margin. The trade-offs between these performance criteria are analyzed for 3-junction-interferometer-based logic gates. Experimental evaluation of the multi-gigahertz operation of small circuits showed that careful design of power supply networks that reduce power supply fluctuations will be needed to maximize performance. Simulation and experimental results are discussed.

Flatcoil systems for measurements of Fermilab magnets

A flux measurement system has been developed for measuring the integrated strength and relative shape of the magnetic field of Fermilab Main Injector dipoles. Improved field shape measurements have been obtained by constructing coil geometries which reduce the flux contribution from unwanted field derivatives. A bucking coil scheme employing reference coils in both the test magnet and a reference magnet reduce the sensitivity to power supply fluctuations. Design strategies for various measurement requirements are described, along with the details of implementing an assembly to measure curved 6 m and 4 m dipoles. Some representative results and comparison with redundant measurement systems are presented.

FAULT FEATURES OF LARGE ROTATING MACHINERY AND DIAGNOSIS USING SENSOR FUSION

Large rotating machinery such as turbines and compressors are the key equipment in oil refineries, power plants, and chemical engineering plants. To minimize the economic loss incurred because of the defects of malfunctions of these machines, diagnosis is very important. Currently, diagnosis is carried out mainly using spectral analysis. In spite of being effective in detecting the faults (monitoring), spectral analysis is often ineffective in pin-pointing what the fault is (diagnosis). This is due to the fact that it cannot clarify the spatial and temporal features in the sensor signals that are correlated to different types of faults. In this paper, phase spectra, holospectra, purified orbit diagrams, and filtered orbit diagrams are used in searching for fault features. From the data obtained from more than 50 practical machines, distinct fault features and diagnostic induces are found for 11 different types of faults including unbalance, cracks, misalignment, rub, loose bearing caps, oil whirl, surge, fluid excitation, rotating stall, electric power supply fluctuation, and pipe excitation. Accordingly, a diagnostic procedure is proposed.

95/00885 IAPCS: A computer model that evaluates pollution control systems for utility boilers

Natural gas combined cycle (NGCC) power plants with pre-combustion CO2 capture called, integrated reforming combined cycle (IRCC) power plants could be operated in a flexible and environment friendly manner by incorporating hydrogen storage. The current article presents a thermodynamic model evaluation of such a flexible large scale power plant system with co-production of hydrogen and subsequent hydrogen storage with metal hydrides (MH). A comparative analysis has been presented using steady state ASPEN Plus models for a Reference NGCC system, an IRCC system and a Flexible IRCC system with MH (MgH2) based hydrogen storage. In addition, a detailed exergy analysis indicating irreversibilities in the system has been presented. The system study indicates that such Flexible IRCC systems could be operated with a time based average (considering charging and discharging) electrical efficiency above 45% depending on the amount of hydrogen stored, appropriate heat integration and choice of the metal hydride. Exergy analysis indicates that such flexible systems could still be operated at a relatively high average net exergy efficiency (considering charging and discharging). Addition of MH based H2 storage in an IRCC system does not lead to significant electrical/exergy efficiency penalty. Carbon capture and storage is a larger source of efficiency penalty than the MH based H2 storage unit. The largest exergy destruction is observed in the gas turbine combustor and reformer units, providing additional scope for efficiency enhancement. With a larger share of renewable power in the total electrical power production expected in future, Flexible IRCC systems as presented in this article could be used as an efficient solution to address the large fluctuations in power supply and demand. Additional investigations are however encouraged further toward optimizing the choice of the metal hydride, detailed design of a single heat integrated system (including part load behavior) and economic assessments based on the heat and mass balances developed in this study.

95/00867 Extraction behavior of polycyclic aromatic hydrocarbons adsorbed on waste incinerator fly ash

Natural gas combined cycle (NGCC) power plants with pre-combustion CO2 capture called, integrated reforming combined cycle (IRCC) power plants could be operated in a flexible and environment friendly manner by incorporating hydrogen storage. The current article presents a thermodynamic model evaluation of such a flexible large scale power plant system with co-production of hydrogen and subsequent hydrogen storage with metal hydrides (MH). A comparative analysis has been presented using steady state ASPEN Plus models for a Reference NGCC system, an IRCC system and a Flexible IRCC system with MH (MgH2) based hydrogen storage. In addition, a detailed exergy analysis indicating irreversibilities in the system has been presented. The system study indicates that such Flexible IRCC systems could be operated with a time based average (considering charging and discharging) electrical efficiency above 45% depending on the amount of hydrogen stored, appropriate heat integration and choice of the metal hydride. Exergy analysis indicates that such flexible systems could still be operated at a relatively high average net exergy efficiency (considering charging and discharging). Addition of MH based H2 storage in an IRCC system does not lead to significant electrical/exergy efficiency penalty. Carbon capture and storage is a larger source of efficiency penalty than the MH based H2 storage unit. The largest exergy destruction is observed in the gas turbine combustor and reformer units, providing additional scope for efficiency enhancement. With a larger share of renewable power in the total electrical power production expected in future, Flexible IRCC systems as presented in this article could be used as an efficient solution to address the large fluctuations in power supply and demand. Additional investigations are however encouraged further toward optimizing the choice of the metal hydride, detailed design of a single heat integrated system (including part load behavior) and economic assessments based on the heat and mass balances developed in this study.

Design of a ternary D/A converter

The design is presented of a ternary D/A converter using current mirror sources. The design goal has been to obtain a system with a higher tolerance to both power supply and physical parameter fluctuations compared to existing systems. Furthermore, comparison with previously reported 3R-4R resistive network D/A converters reveals a better area saving in the present design.

Symmetric self-electro-optic effect device: Optical set-reset latch

We demonstrate an integrated symmetric self-electro-optic effect device consisting of two quantum well p-i-n diodes electrically connected in series. The device acts as a bistable optical memory element with individual set (S) and reset (R) inputs and complementary outputs (optical S-R latch). The switching point is determined by the ratio of the two inputs, making the device insensitive to optical power supply fluctuations when both power beams are derived from the same source. The device also shows time-sequential gain, in that the state can be set using low-power beams and read out with subsequent high-power beams. The device showed bistability for voltages greater than 3 V, incident optical switching energy densities of ∼16 fJ/μm2, and was tested to a switching time of 40 ns.

Optical transmission measurements using computer response correction

A low-cost double beam spectrophotometer using separate detectors is described. This device, capable of transmission measurements as low as 0.001%, incorporates computer response correction for both beam differences and fluctuations in detector power supply and light source. This type of measurement is achieved without the use of high-quality optical components or hardware-based response correction.

A Pulsed Setpum Magnet for Extraction from the Fermilab Booster

A pulsed, water-cooled, single-turn septum magnet presently used for extraction from the Fermilab Booster synchrotron is described. The most novel feature of the magnet is the empirically determined shape of the septum coil which compensates for the current distribution and the distortions caused by leads and crossovers. The magnet operates in vacuum at ~20,000 A or ~9 kG, has a half-sine-wave pulse 180 ?s long, and operates as a dogleg with an identical magnet to minimize effects of power supply fluctuations.

A Heavy-Ion Energy Loss Spectrometer

A high resolution system for the measurement of the energy loss spectra of 20–250 keV heavy ions incident on gas targets is described. The high resolution is obtained by decelerating the ion beam to a low, well defined energy before performing the energy analysis. The energy loss spectrum is determined by changing the accelerator energy to compensate for energy lost in collisions with the gas atoms. The system is arranged so that normal fluctuations in the accelerator's power supply do not affect the energy resolution. The resolving power of the system is 2.5×104. The primary proton beam has a detected WHM of 2 V at 50 kV. An energy loss spectrum is shown for which the collision-excited 11S-21P transition in helium is clearly resolved.

The NRL Cyclotron Ion Optics System

A 9 foot radius, 135 degree, double focusing magnet, having a second order energy resolution less than 2 × 10-4 for 1 mm slits, is the principal element in the NRL Cyclotron Ion Optics System. A 21.5 inch wide pole face and 4.75 inch gap provide radial and axial acceptance angles of 3.0 degrees and 1.3 degrees respectively. This 80 ton magnet can be remotely traversed on a tracking system making it possible to bring the energy-analyzed beam into either of two experimental vaults for use along 8 different beam paths. Also described is the coupling of quadrupoles with the analyzing magnet in a manner that provides a minimum dispersion system when the full cyclotron beam intensity is desired on the experimental target. Ray-tracing calculations have been performed to determine the properties of the composite ion optics system, and the influence on image quality of power supply fluctuations and quadrupole misalignment. The design criteria for the system, the calculational methods used in the ray-tracing programs, and the results of ray-tracing along typical paths is discussed.