84% High efficiency dynamic voltage scaler with nano-second settling time based on charge-pump and BWC-DAC

Ragheb, A.N.,Kim, HyungWon,Lee, Jae-Jin Elsevier 2018 Microelectronics Journal Vol.79 No.-

<P>This paper introduces an energy-efficient dynamic voltage scaler (DVS) based on charge- pump and binary-weighted capacitor digital to analog converter (BWC-DAC). Conventional DVS architectures suffer from long settling-time beside the limitation of coarse voltage resolution, so we propose DVS architecture based on BWC-DAC architecture. It takes advantage of DAC's reconfigurable structure to provide an output voltage scaled with high resolution of V-IN/2(N) for input voltage VIN and N configuration bits; and Nano-second transition time. However, DAC inherently suffers from low power efficiency because it requires frequent reset to maintain the output voltage. To overcome this issue, a high efficiency charge-pump is employed to restore the charges in DAC's capacitors without the need to reset which results in improved power efficiency. The proposed DVS with a 6-bit DAC and a feedback controlled circuit have been implemented using a 130 nm CMOS process. The measurement results show an accurate 64 voltage levels of the 6-bit DAC from 0 V to 1.476 V, when supplied by an input voltage of 1.5 V. We achieved a peak efficiency of 84% for load current ranging from 1 mu A-14.76 mu A. Furthermore, it provides an extremely short settling time that is as short as 83.6 Nano second.</P>

Ultra low power wide-band mixer circuit based on subthreshold operation for MB-OFDM UWB

Ragheb, A.N.,Kim, H. Mackintosh Publications] 2016 Microelectronics Journal Vol.50 No.-

<P>This paper presents an extremely low power down-conversion mixer based on subthreshold operation for MB-OFDM UWB receiver, for the first band of operation 3.1-3.628 GHz. The proposed down conversion mixer uses a double balanced Gilbert cell to provide the required performance in the conversion gain (CG) and the isolation among ports. It includes an input matching network (IMN) to enhance the input matching of the mixer. The proposed mixer is designed such that all transistors work in subthreshold regime under a supply voltage of 0.5 V, thus resulting in extremely low power consumption. We implemented the proposed mixer using a 0.18 mu m CMOS process. Simulation experiments show that the conversion gain of the mixer is 2.17-3.25 dB over the frequency range of 3.1-3.628 GHz when IF port is terminated with 50 Omega. The noise figure of the mixer is 5.12-5.93 dB, while the LO-IF isolation is lower than 111 dB. The 1-dB compression point is -16.68 dBm, third-order input intercept point IIP3 is -5.7 dBm. The experiments show that the proposed design consumes only 6.6 uW at 0.5 V, which is extremely low power compared with existing work. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Statistical Phantoms and Determining the Uncertainty of the Thyroid Mathematical Phantom in Internal Dosimetry Using the Monte Carlo Method

Ragheb Vahid,Sajjadi Zahra,Mohammadi Saeed 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.12

The purpose of this study was to investigate the effect of changes in the thyroid mass on its absorbed dose rate. To this end, 100 similar mathematical phantoms, which only differed in their thyroid mass, were created. Then, the thyroid was selected as the source of photon, electron and 131I, respectively, the absorbed doses to the thyroid and other organs were estimated using the MCNPX code. The results show when the mass increases, the amount of absorbed dose in the thyroid decreased. The power of this reduction for the energies between 0.01 and 4 MeV was in the ranges of (1/3 ≤ x ≤ 1) for photons and (2/3 ≤ x ≤ 1) for electrons. Finally, analyzing the statistical distribution of the doses, the coefficient of changes in the thyroid absorption dose for photon energies ranging from 0.01 to 4 MeV was 12-30%, for electrons in the same energy range, it was between 12-23%, and per decay of 131I, the figure turned out to be 19%. Moreover, the risk of a secondary cancer related to the non-consideration of the special body thyroid mass per 100 mCi (3.7 GBq) of the 131I radiopharmaceutical, was estimated to be 1.2%.

Readout Circuit Based on Differential Offset Cancellation Technique for Projected Mutual-Capacitance Large Touch Screens

A. N. Ragheb,강호진,박경한,원동민,김형원 한국과학기술원 반도체설계교육센터 2016 IDEC Journal of Integrated Circuits and Systems Vol.2 No.1

This paper proposes an efficient method to improve the performance of the projected mutual capacitance large touch screen panels (TSPs) based on differential offset cancellation technique. To achieve high scan rate the proposed architecture uses concurrent and continuous sine waves as driving technique. In contrast to the conventional offset compensation topologies cannot handle such a concurrent or continuous signals properly, however, the proposed architecture overcomes such switching noise. In addition to, it provides an effective noise cancellation for such signals. The proposed architecture has been implemented using a Magnachip/SK Hynix 0.18 µm CMOS process. However, the measured results show a 14 dB improvement I SNR compared to conventional architectures. Also, the proposed readout circuit shows a good performance after mismatch condition applied to input stage of the differential amplifier to show the effectiveness of the proposed cancellation technique.

Low-Power Voltage Converter Using Energy Recycling Capacitor Array

Shah, Syed Asmat Ali,Ragheb, A.N.,Kim, HyungWon The Korea Institute of Information and Commucation 2017 Journal of information and communication convergen Vol.15 No.1

This paper presents a low-power voltage converter based on a reconfigurable capacitor array. Its energy recycling capacitor array stores the energy during a charge stage and supplies the voltage during an energy recycle stage even after the power source is disconnected. The converter reconfigures the capacitor array step-wise to boost the lost voltage level during the energy recycle stage. Its energy saving is particularly effective when most of the energy remaining in the charge capacitors is wasted by the leakage current during a longer sleep period. Simulations have been conducted using a voltage source of 500 mV to supply a $V_{DD}$ of around 800 mV to a load circuit consisting of four 32-bit adders in a 65-nm CMOS process. Results demonstrate energy recycling efficiency of 85.86% and overall energy saving of 40.14% compared to a conventional converter, when the load circuit is shortly active followed by a long sleep period.

연성 FRP 보강시스템

Grace Nabil F.,Ragheb Wael F.,Sayed George Abdel 한국콘크리트학회 2005 콘크리트학회지 Vol.17 No.2

Dynamic Voltage Scaler Based on Binary-Weighted Charge Redistribution Digital-to-Analog Converter

Kyeong-Han Park(박경한),A. N. Ragheb,Hyung-Won Kim(김형원) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6

This paper presents a dynamic voltage scaler architecture based on binary-weighted charge redistributed digital-to-analog (DAC) converter. The proposed architecture uses a DAC as a reconfigurable voltage scaler based on digital control circuit to select the required voltage level. Whereas it is difficult for the conventional voltage converters to scale the output voltage, the output voltage of the proposed architecture can be accurately scaled by the resolution of DAC. The proposed voltage scaler using a 3-bit DAC has been implemented using a 65nm CMOS process. The simulation results with the 3-bit DAC showed accurate 8 output voltage levels of 0 V to 1.05 V from an input voltage of 1.2V. When the proposed voltage scaler was configured to supply 600mV to a 32-bit adder, it showed a small ripple voltage of 10 mV and consumed energy of 4.425 pJ for 6 addition operations during the simulation of 780 nsec.

Energy Recycling Voltage Scaler Based on Reconfigurable Capacitive Array

Syed Asmat Ali Shah,A.N. Ragheb,HyungWon Kim(김형원) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6

This paper introduces a novel architecture of voltage scaler based on a reconfigurable capacitive array. While its reconfigurable structure allows it to scale the output voltage to any target level, its energy recycling process permits the voltage scaler to supply the voltage even after the input voltage is turned off. This architecture stores the energy in the capacitor array during the voltage scaling stage, then it reconfigures these charges step-wise to boost the lost voltage level during the energy recycling stage. Using the proposed architecture, an example voltage scaler was implemented using 65 nm CMOS process, which generates an output voltage of a range 500 mV to 1.16 V from an input voltage of 500 mV. Simulations were conducted with a 32-bit adder circuit as a load, which showed a reduction in energy consumption by 45.8% compared to a conventional converter.

Innovation of Radically New Colorant Hybrid Nanocomposite for Printing Various Textile Fabrics

A. A. Hebeish,A. A. Shahin,A. A. Ragheb,I. Abd El-Thalouth,E. E. Allam,H. A. Shaban 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1

New benign colorant nanoparticles were innovated. The innovation is based on reacting the Indigo Blue Vat Dye with a natural clay named montmorillonite (K10) under sonication. A mixture of the dye and clay (1:1) at a ratio was used. The obtained new colorant nanoparticles in the form of hybrid nanocomposites were applied as a nano pigment in printing on various fabrics. The new colorant succeeded in printing silk, wool, cotton, polyester, and nylon as well as their different blends in the presence and absence of binder. Prints of the new colorant were compared with those obtained usingcommercial pigment. The effect of adding different amounts of binder to the printing paste on major technical properties of the prints was also investigated. Evaluation of the various printed fabrics was performed through monitoring color strength (K/S), TEM images, SEM micrographs, and overall fastness properties.

Effects of increasing concentrations of corn distillers dried grains with solubles on the egg production and internal quality of eggs.

Sun, H,Lee, E J,Samaraweera, H,Persia, M,Ragheb, H S,Ahn, Dong U Poultry Science Association, etc 2012 Poultry science Vol.91 No.12

<P>A study was conducted to determine the effect of feeding high concentrations of corn distillers dried grains with solubles (DDGS) on egg production and the internal quality of eggs from laying hens. Four diets were formulated to contain 0, 17, 35, or 50% corn DDGS. A total of two hundred forty 54-wk-old Single-Comb White Leghorn laying hens were randomly allotted to 2 birds per cage with 3 consecutive cages representing an experimental unit (EU). Each EU was assigned to 1 of 4 dietary treatments according to a completely randomized design. Hens were fed for a 24-wk experimental period after transition feeding to gradually increase corn DDGS inclusion over a 4-wk period. Two sets of experimental diets were formulated, and each diet was fed for 12 wk. Egg production, feed consumption, egg component, yolk color, Haugh unit during storage times, and shell breaking strength were measured. Egg production, egg weight, egg mass, feed intake, and feed efficiency were adversely affected by the highest level of DDGS in the diet (50%) during the first 12-wk period. Once diets were reformulated to include an increased concentration of both lysine and methionine, differences among the dietary treatments were reduced, as the performance of the 50% DDGS diets was greatly improved. Over the last 6 wk of study, no differences in egg production, egg weight, and feed intake among DDGS treatments were found. The DDGS diets positively affected the internal quality of eggs during storage. Improved yolk color and Haugh unit were observed as the dietary DDGS levels increased, but the increase for Haugh unit was significant only when the DDGS level was 50%. Shell weight percentage was increased in the 50% DDGS diet, but no differences in yolk and albumen percentage were observed. It was concluded that up to 50% of DDGS could be included in the layer's diet without affecting egg weight, feed intake, egg mass, feed efficiency, and egg production as long as digestible amino acids were sufficient in DDGS-added diets.</P>