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Results for “VOLTAGE AMPLIFIER”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Cascaded transformerless DC-DC voltage amplifier with optically isolated switching devices

A very high voltage amplifier is provided in which plural cascaded banks of capacitors are switched by optically isolated control switches so as to be charged in parallel from the preceding stage or capacitor bank and to discharge in series to the succeeding stage or capacitor bank in alternating control cycles. The optically isolated control switches are controlled by a logic controller whose power supply is virtually immune to interference from the very high voltage output of the amplifier by the optical isolation provided by the switches, so that a very high voltage amplification ratio may be attained using many capacitor banks in cascade.

Sridharan, Govind↗
DOE OSTI2019

Demonstration of waferscale voltage amplifier and electrostatic quadrupole focusing array for compact linear accelerators

Compact linear accelerators, with beam energies in the kiloelectron volt to megaelectron volt range, have applications in medicine, neutron/X-ray generation, surface modifications, etc. The size, weight, and power of existing accelerators preclude them from mass availability in portable formats. This paper presents a specific implementation of an ion accelerator architecture based on planar wafers with accelerating and focusing sections. Our low cost approach allows the control of the final ion beam energy with potential applications, for example, for accelerator-based ion implantation. In this paper, we demonstrate two important waferscale modules required to build a linear particle accelerator; these include (1) on-wafer voltage amplification for beam acceleration using Inductor-Capacitor (LC) resonators and (2) waferscale electrostatic quadrupole arrays (ESQA) to refocus the ion beams during transport. On-board LC resonators were developed using Printed Circuit Board fabrication processes to implement an LC element resonant at ~ 16.6 MHz with a quality factor of 25. An energy gain of ~ 250 eV was observed using a two wafer acceleration unit with an argon ion beam with 6.5 keV initial energy. A 3 × 3 ESQA was fabricated on a glass wafer with metal electrodes formed by depositing copper metal around the beam apertures. The ESQA was used to focus and defocus an argon ion beam, demonstrating a field gradient of ~ 500 V over a gap of ~ 250 μm.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

PHIL Interface Design for Use With a Voltage-Regulated Amplifier

Power hardware-in-the-loop (PHIL) has emerged as a leading strategy to thoroughly assess the impact of proprietary inverter controls on a specific power system. The development of a PHIL test bed typically involves an inverter under test, a power amplifier, controllable DC supply, and a digital real-time simulator (DRTS) to simulate the power system under study. As a result of PHIL nonidealities, a form of digital compensation within the DRTS is used, which is commonly referred to as a PHIL interface. Many existing methods use legacy power amplifiers that do not contain internal voltage regulation. These existing interface methods are based around a voltage regulator within the DRTS and do not consider the interaction with the controls in newer amplifiers. In this study, a three-step approach of PHIL interface development for modern power amplifiers with built-in voltage regulation is introduced and is validated in hardware with a 30-kW grid-following inverter.

DRTS↗
DOE OSTI2015

High temperature charge amplifier for geothermal applications

An amplifier circuit in a multi-chip module includes a charge to voltage converter circuit, a voltage amplifier a low pass filter and a voltage to current converter. The charge to voltage converter receives a signal representing an electrical charge and generates a voltage signal proportional to the input signal. The voltage amplifier receives the voltage signal from the charge to voltage converter, then amplifies the voltage signal by the gain factor to output an amplified voltage signal. The lowpass filter passes low frequency components of the amplified voltage signal and attenuates frequency components greater than a cutoff frequency. The voltage to current converter receives the output signal of the lowpass filter and converts the output signal to a current output signal; wherein an amplifier circuit output is selectable between the output signal of the lowpass filter and the current output signal.

15 GEOTHERMAL ENERGY↗
DOE OSTI2023

PHIL Interface Design for Use With a Voltage-Regulated Amplifier: Preprint

As inverter controls have become increasingly complex, power hardware-in-the-loop (PHIL) has emerged as a leading strategy to thoroughly assess the impact of proprietary inverter controls on a specific power system. The development of a PHIL test bed typically involves the desired inverter, a power amplifier, and a digital real-time simulator (DRTS) to control the simulated power system. As a result of PHIL nonidealities, a form of digital compensation within the DRTS is used, which is commonly referred to as a PHIL interface. The interface design for PHIL test beds has been previously examined in the literature, but many existing methods use older power amplifiers that do not contain internal voltage regulation. These existing interface methods are based around a voltage regulator within the DRTS rather than one preexisting in hardware. In this study, a three-step approach of PHIL interface development for modern power amplifiers with built-in voltage regulation is introduced and validated in hardware with a single 30-kW grid-following inverter.

DRTS↗
NASA NTRS2020

AD8065 Voltage Feedback Amplifier’s Total Ionizing Dose Characterization Report

The purpose of this testing was to characterize Analog Devices’ AD8065 FastFET amplifier for low-dose rate (LDR) total ionizing dose (TID) response based on the Lucy project requirements and will be used on the L’ORRI instrument being built by Johns Hopkins University Applied Physics Lab. The AD8065 is a voltage feedback amplifier with FET inputs developed with the proprietary eXtra Fast Complementary Bipolar (XFCB) process. The amplifier boasts low noise operation and very high input impedance with a wide supply voltage range.

Megan Casey↗
NASA NTRS1996

An Acoustic Charge Transport Imager for High Definition Television Applications: Low-Voltage SAW Amplifiers on Multilayer GaAs/ZnO Substrates

This thesis addresses the acoustoelectric issues concerning the amplification of surface acoustic waves (SAWs) and the reflection of SAWs from slanted reflector gratings on GaAs, with application to a novel acoustic charge transport (ACT) device architecture. First a simple model of the SAWAMP was developed, which was subsequently used to define the epitaxially grown material structure necessary to provide simultaneously high resistance and high electron mobility. In addition, a segmented SAWAMP structure was explored with line widths on the order of an acoustic wavelength. This resulted in the demonstration of SAWAMPS with an order of magnitude less voltage and power requirements than previously reported devices. A two-dimensional model was developed to explain the performance of devices with charge confinement layers less then 0.5 mm, which was experimentally verified. This model was extended to predict a greatly increased gain from the addition of a ZnO overlay. These overlays were experimentally attempted, but no working devices were reported due to process incompatibilities. In addition to the SAWAMP research, the reflection of SAWs from slanted gratings on GaAs was also studied and experimentally determined reflection coefficients for both 45 deg grooves and Al stripes on GaAs have been reported for the first time. The SAWAMp and reflector gratings were combined to investigate the integrated ring oscillator for application to the proposed ACT device and design parameters for this device have been provided.

Hunt, W. D.↗
DOE OSTI2015

The CARIBU EBIS control and synchronization system

The Californium Rare Isotope Breeder Upgrade (CARIBU) Electron Beam Ion Source (EBIS) charge breeder has been built and tested. The bases of the CARIBU EBIS electrical system are four voltage platforms on which both DC and pulsed high voltage outputs are controlled. The high voltage output pulses are created with either a combination of a function generator and a high voltage amplifier, or two high voltage DC power supplies and a high voltage solid state switch. Proper synchronization of the pulsed voltages, fundamental to optimizing the charge breeding performance, is achieved with triggering from a digital delay pulse generator. The control system is based on National Instruments realtime controllers and LabVIEW software implementing Functional Global Variables (FGV) to store and access instrument parameters. Fiber optic converters enable network communication and triggering across the platforms.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS2012

Feedback Augmented Sub-Ranging (FASR) Quantizer

This innovation is intended to reduce the size, power, and complexity of pipeline analog-to-digital converters (ADCs) that require high resolution and speed along with low power. Digitizers are important components in any application where analog signals (such as light, sound, temperature, etc.) need to be digitally processed. The innovation implements amplification of a sampled residual voltage in a switched capacitor amplifier stage that does not depend on charge redistribution. The result is less sensitive to capacitor mismatches that cause gain errors, which are the main limitation of such amplifiers in pipeline ADCs. The residual errors due to mismatch are reduced by at least a factor of 16, which is equivalent to at least 4 bits of improvement. The settling time is also faster because of a higher feedback factor. In traditional switched capacitor residue amplifiers, closed-loop amplification of a sampled and held residue signal is achieved by redistributing sampled charge onto a feedback capacitor around a high-gain transconductance amplifier. The residual charge that was sampled during the acquisition or sampling phase is stored on two or more capacitors, often equal in value or integral multiples of each other. During the hold or amplification phase, all of the charge is redistributed onto one capacitor in the feedback loop of the amplifier to produce an amplified voltage. The key error source is the non-ideal ratios of feedback and input capacitors caused by manufacturing tolerances, called mismatches. The mismatches cause non-ideal closed-loop gain, leading to higher differential non-linearity. Traditional solutions to the mismatch errors are to use larger capacitor values (than dictated by thermal noise requirements) and/or complex calibration schemes, both of which increase the die size and power dissipation. The key features of this innovation are (1) the elimination of the need for charge redistribution to achieve an accurate closed-loop gain of two, (2) a higher feedback factor in the amplifier stage giving a higher closed-loop bandwidth compared to the prior art, and (3) reduced requirement for calibration. The accuracy of the new amplifier is mainly limited by the sampling networks parasitic capacitances, which should be minimized in relation to the sampling capacitors.

Guilligan, Gerard↗
DOE OSTI2015

On filament structure and propagation within a commercial plasma globe

The filamentary discharge seen within commercial plasma globes is commonly enjoyed yet not well understood. Here, we investigate the discharge properties of a plasma globe using a variable high voltage amplifier. We find that increasing voltage magnitude increases the number of filaments while leaving their individual structure basically unchanged, a result typical of dielectric barrier discharges. The frequency of the voltage also affects filament population but more significantly changes filament structure, with more diffuse filaments seen at lower frequencies. Voltage polarity is observed to be important, especially at lower frequencies, where for negative-gradient voltages the discharge is more diffuse, not filamentary. At late stages of the discharge circular structures appear and expand on the glass boundaries. We find no trend of discharge speed with respect to voltage variables, though this may be due to manufacturer sample-to-sample variation. Each voltage cycle the discharge expands outward at ∼10–15 km/s, a speed significantly higher than the estimated electron drift yet considerably lower than that observed for most streamers. We discuss the physics of these observations and their relation to similar discharges that can be found within nature and industry.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1966

Applications of models to circuits

Active device models for linear circuit application and their application to design of operational amplifier and emitter-peaked voltage amplifier stage

SOLID STATE DEVICE↗