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Ashraf Lotfi

Also published under: Ashraf W. Lotfi, A. Lotfi, A. W. Lotfi

Publications
17
Citations
196
Publications by Year
20012018
Co-Authors:
Show All Co-Authors (28)
Image of author Ashraf Lotfi

Ashraf Lotfi

Also published under: Ashraf W. Lotfi, A. Lotfi, A. W. Lotfi

Affiliation

Intel Corporation
Hampton
NJ, USA

Publication Topics

Biography

Ashraf Lotfi (SM’00) received the B.Sc. degree in electrical engineering from Cairo University, Giza, Egypt, in 1984, the M.S. and Ph.D. degrees in electrical engineering from Virginia Tech, Blacksburg, VA, USA, in 1993, and the Executive MBA degree from Northeastern University, Boston, MA, USA, in 2001.,He is currently the VP/Fellow in Intel serving as CTO of the power products business organization. Prior to Intel, he was with Altera as a Power CTO, serving its Enpirion power business as well as the broader FPGA R&D community. Prior to Altera, he was the President and the CEO of Enpirion, which he founded in 2002. In 2013, he drove Enpirion's merger into Altera to realize his vision of highly integrated power management closely coupled to...
Publications
17
Citations
196
Publications by Year
20012018
Co-Authors:
Show All Co-Authors (28)
Author's Published Works

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Frequency-Domain Power Delivery Network Self-Characterization in FPGAs for Improved System Reliability

Shuze Zhao;Ibrahim Ahmed;Vaughn Betz;Ashraf Lotfi;Olivier Trescases

IEEE Transactions on Industrial Electronics
Year: 2018 | Volume: 65, Issue: 11 | Journal Article |
Cited by: Papers (10)
Modern field-programmable gate arrays (FPGAs) operate at a core voltage around 1 V and therefore even small voltage fluctuations lead to timing violations and logic errors. The power delivery network (PDN) between the voltage regulator and the FPGA core must be carefully designed to achieve a low output impedance over a broad range of frequencies. Simulation tools are commonly used to estimate the...Show More

Frequency-Domain Power Delivery Network Self-Characterization in FPGAs for Improved System Reliability

Shuze Zhao;Ibrahim Ahmed;Vaughn Betz;Ashraf Lotfi;Olivier Trescases

Year: 2018 | Volume: 65, Issue: 11 | Journal Article |

Robust Self-Calibrated Dynamic Voltage Scaling in FPGAs With Thermal and IR-Drop Compensation

Shuze Zhao;Ibrahim Ahmed;Carl Lamoureux;Ashraf Lotfi;Vaughn Betz;Olivier Trescases

IEEE Transactions on Power Electronics
Year: 2018 | Volume: 33, Issue: 10 | Journal Article |
Cited by: Papers (10)
Field programmable gate arrays (FPGAs) are widely used in telecom, medical, military, cloud computing, and other high-performance computing applications, thanks to their unique combination of parallel hardware execution and reprogrammability. During compilation, the computer-aided design (CAD) tool estimates the maximum operating frequency of the user application based on the worst case timing ana...Show More

Robust Self-Calibrated Dynamic Voltage Scaling in FPGAs With Thermal and IR-Drop Compensation

Shuze Zhao;Ibrahim Ahmed;Carl Lamoureux;Ashraf Lotfi;Vaughn Betz;Olivier Trescases

Year: 2018 | Volume: 33, Issue: 10 | Journal Article |

A universal self-calibrating Dynamic Voltage and Frequency Scaling (DVFS) scheme with thermal compensation for energy savings in FPGAs

Shuze Zhao;Ibrahim Ahmed;Carl Lamoureux;Ashraf Lotfi;Vaughn Betz;Olivier Trescases

2016 IEEE Applied Power Electronics Conference and Exposition (APEC)
Year: 2016 | Conference Paper |
Cited by: Papers (17)
Field Programmable Gate Arrays (FPGAs) are widely used in telecom, medical, military and cloud computing applications. Unlike in microprocessors, the routing and critical path delay of FPGAs is user dependent. The design tool suggests a maximum operating frequency based on the worst-case timing analysis of the critical paths at a fixed nominal voltage, which usually means there is significant volt...Show More

A universal self-calibrating Dynamic Voltage and Frequency Scaling (DVFS) scheme with thermal compensation for energy savings in FPGAs

Shuze Zhao;Ibrahim Ahmed;Carl Lamoureux;Ashraf Lotfi;Vaughn Betz;Olivier Trescases

Year: 2016 | Conference Paper |

Introducing FCA, a new alloy for Power Systems on a chip and Wafer Level Magnetic applications

Trifon Liakopoulos;Amrit Panda;Matt Wilkowski;Ashraf Lotfi;KH Tan;Li Zhang;Chiming Lai;Dong Chen

2012 13th International Conference on Electronic Packaging Technology & High Density Packaging
Year: 2012 | Conference Paper |
Cited by: Papers (4)
On chip integrated inductors and transformers require novel and improved materials and CMOS-compatible Wafer Level Magnetics (WLM) deposition techniques. In this work we are presenting an Fe-Co based amorphous magnetic alloy, called FCA that was specifically designed and developed by Enpirion to be used for the first time in volume production for highly integrated and miniaturized power management...Show More

Introducing FCA, a new alloy for Power Systems on a chip and Wafer Level Magnetic applications

Trifon Liakopoulos;Amrit Panda;Matt Wilkowski;Ashraf Lotfi;KH Tan;Li Zhang;Chiming Lai;Dong Chen

Year: 2012 | Conference Paper |

A 20MHz monolithic DC-DC converter manufactured with the first commercially viable silicon magnetics technology

Wei Zhang;Matthew A. Wilkowski;John Weld;Ashraf Lotfi

Proceedings of The 7th International Power Electronics and Motion Control Conference
Year: 2012 | Conference Paper |
Cited by: Papers (2)
This paper presents a Power System on Chip (Power-SoC), switch-mode DC-DC synchronous buck converter with switching frequency of 20 MHz, which monolithically integrates high-speed power MOSFET switches, controller and drive circuits, the compensation network, and more importantly, a silicon-based inductor. The new device implements a type III voltage mode control scheme with wide loop bandwidth, w...Show More

A 20MHz monolithic DC-DC converter manufactured with the first commercially viable silicon magnetics technology

Wei Zhang;Matthew A. Wilkowski;John Weld;Ashraf Lotfi

Year: 2012 | Volume: 1 | Conference Paper |

Integrated, High-Frequency DC-DC Converter Technologies Leading to Monolithic Power Conversion

Ashraf W. Lotfi;Qiang Li;Fred C. Lee

2012 7th International Conference on Integrated Power Electronics Systems (CIPS)
Year: 2012 | Conference Paper |
Cited by: Papers (1)
Increasing demands in end-user applications such as greater speed and bandwidth, computing power, storage density with demands on energy efficiency have driven power management solutions towards higher conversion efficiencies, higher power densities, greater noise immunity, and extreme integration. We present advances and choices in the fundamental technologies as well as their manufacturing count...Show More

Integrated, High-Frequency DC-DC Converter Technologies Leading to Monolithic Power Conversion

Ashraf W. Lotfi;Qiang Li;Fred C. Lee

Year: 2012 | Conference Paper |

High frequency QSW-ZVS integrated buck converter utilizing an air-core inductor

Yasser Nour;Mohamed Orabi;Ashraf Lotfi

2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC)
Year: 2012 | Conference Paper |
Cited by: Papers (6) | Patents (2)
In order to achieve tiny point of load converters, higher switching frequencies should be used to minimize the magnetic component sizes and enable the integration process. High frequency hard switching buck converters dissipate a lot of power due to the high switching losses. This paper discusses the utilization of Quasi-Square Wave Zero Voltage Switching (QSW-ZVS) integrated buck converter with a...Show More

High frequency QSW-ZVS integrated buck converter utilizing an air-core inductor

Yasser Nour;Mohamed Orabi;Ashraf Lotfi

Year: 2012 | Conference Paper |

Advances towards fully integrated, single chip power management

Ashraf W. Lotfi

2011 IEEE 33rd International Telecommunications Energy Conference (INTELEC)
Year: 2011 | Conference Paper |
Cited by: Papers (2)
Many advances in end-user applications such as greater speed and bandwidth, computing power, storage density with demands on energy efficiency have driven power management solutions towards higher conversion efficiencies, higher power densities, greater noise immunity, and extreme integration. We present advances in the key fundamental technologies which lead to the simultaneous increase in switch...Show More

Advances towards fully integrated, single chip power management

Ashraf W. Lotfi

Year: 2011 | Conference Paper |

A novel linear-nonlinear technique for fast transient buck converter

Mohamed Saad;Mohamed Orabi;El-Sayed Hasaneen;Ashraf Lotfi

2011 IEEE 33rd International Telecommunications Energy Conference (INTELEC)
Year: 2011 | Conference Paper |
Modern Portable devices require high performance Power Management Integrated Circuits (PMICs) for powering it. Old requirements for PMICs were high efficiency and small footprint area. However there are some applications that are also sensitive for the output voltage deviations due to sudden step-up and step-down load change. A novel nonlinear control technique that can be used side-by-side with t...Show More

A novel linear-nonlinear technique for fast transient buck converter

Mohamed Saad;Mohamed Orabi;El-Sayed Hasaneen;Ashraf Lotfi

Year: 2011 | Conference Paper |

Integrated ZVS POL synchronous buck converter for portable applications

Yasser Nour;Mohamed Orabi;Ashraf Lotfi

Intelec 2010
Year: 2010 | Conference Paper |
Cited by: Papers (9)
This paper proposes an integrated, high switching frequency, zero-voltage-switching quasi-square-wave (ZVS-QSW) point of load (POL) buck converter for portable applications. The design and analysis of a fully integrated synchronous buck dc-dc converter with integrated inductor is presented. The converter has been optimized to convert 5V input voltage to 1.2V at 3A maximum load current at a 5MHz sw...Show More

Integrated ZVS POL synchronous buck converter for portable applications

Yasser Nour;Mohamed Orabi;Ashraf Lotfi

Year: 2010 | Conference Paper |

A novel integrated 50 MHz POL solution utilizing internal OTA compensation

Yasser Nour;Shimaa Nagar;Mohamed Orabi;Ashraf Lotfi

Intelec 2010
Year: 2010 | Conference Paper |
Cited by: Papers (1)
In this paper, a very high switching frequency Point of Load (POL) buck converter is proposed. The main feature of the proposed converter is small footprint, high efficiency, very low output ripple and excellent transient response. These superior features enable the replacement process of the inefficient LDO in many battery powered applications. The improved transient response has been achieved th...Show More

A novel integrated 50 MHz POL solution utilizing internal OTA compensation

Yasser Nour;Shimaa Nagar;Mohamed Orabi;Ashraf Lotfi

Year: 2010 | Conference Paper |

Coss capacitance contribution to synchronous buck converter losses

Mohamed Orabi;Ahmed Abou-Alfotouh;Ashraf Lotfi

2008 IEEE Power Electronics Specialists Conference
Year: 2008 | Conference Paper |
Cited by: Papers (4)
Understanding the contribution of MOSFET parasitic elements on converter efficiency is a vital topic for MOSFET designers. Used simple excel sheets for efficiency calculation is not accurate and often give a mismatch that can not be explained. On the other hand, doing simulation analysis is good for explanation but not for design as it consumes a huge time that designers haven't. Therefore, this p...Show More

Coss capacitance contribution to synchronous buck converter losses

Mohamed Orabi;Ahmed Abou-Alfotouh;Ashraf Lotfi

Year: 2008 | Conference Paper |

Analysis of the Buck Converter for Scaling the Supply Voltage of Digital Circuits

Andres Soto;Angel de Castro;Pedro Alou;Jose A. Cobos;Javier Uceda;Ashraf Lotfi

IEEE Transactions on Power Electronics
Year: 2007 | Volume: 22, Issue: 6 | Journal Article |
Cited by: Papers (48)
The energy consumption in mobile systems has become a big challenge that limits high performance and autonomy in mobile systems. The dynamic voltage scaling (DVS) is a recent technique that reduces energy consumption varying dynamically the supply voltage of the system accordingly to the clock frequency. The Buck topology is a good candidate to supply step variations of the output voltage meeting ...Show More

Analysis of the Buck Converter for Scaling the Supply Voltage of Digital Circuits

Andres Soto;Angel de Castro;Pedro Alou;Jose A. Cobos;Javier Uceda;Ashraf Lotfi

Year: 2007 | Volume: 22, Issue: 6 | Journal Article |

Operating Limitation of Buck Power Supplies Feeding DDR Memories -Source-Sink-Mode

Mohamed Orabi;Ali Ghahary;Ashraf Lotfi

2007 IEEE Power Electronics Specialists Conference
Year: 2007 | Conference Paper |
Cited by: Papers (1)
This paper highlights an important design feature for power supply used in DDR memories applications. As, the power has to alternate in source and sink current mode, the converter operating conditions change. The input parasitic inductance plays in an aggressive way to the lower FET voltage (switch-node voltage). The analysis, limitation of load current that converter can sink is made clear in thi...Show More

Operating Limitation of Buck Power Supplies Feeding DDR Memories -Source-Sink-Mode

Mohamed Orabi;Ali Ghahary;Ashraf Lotfi

Year: 2007 | Conference Paper |

Compensation Circuit Design Considerations for high Frequency DC/DC Buck Converters with Ceramic Output Capacitors

A. Abou-Alfotouh;A. Lotfi;M. Orabi

APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition
Year: 2007 | Conference Paper |
Cited by: Papers (6) | Patents (1)
Modern power applications are driving the demand for power supply systems with fast transient response. This requires high bandwidth in addition to a robust system. The latest technology allows designing very high switching frequency (in the MHz range) DC-DC converters using ceramic capacitors as an output filter. Using traditional linear control will limit the maximum achievable bandwidth, and us...Show More

Compensation Circuit Design Considerations for high Frequency DC/DC Buck Converters with Ceramic Output Capacitors

A. Abou-Alfotouh;A. Lotfi;M. Orabi

Year: 2007 | Conference Paper |

Analysis of the buck converter for scaling the supply voltage of digital circuits

A. Soto;A. de Castro;P. Alou;J.A. Cobos;J. Uceda;A. Lotfi

Eighteenth Annual IEEE Applied Power Electronics Conference and Exposition, 2003. APEC '03.
Year: 2003 | Conference Paper |
The energy consumption in mobile systems has become a big challenge that limits high performance and autonomy in mobile systems. The dynamic voltage scaling (DVS) is a recent technique that reduces energy consumption varying dynamically the supply voltage of the system accordingly to the clock frequency. The buck topology is a good candidate to supply step variations of the output voltage meeting ...Show More

Analysis of the buck converter for scaling the supply voltage of digital circuits

A. Soto;A. de Castro;P. Alou;J.A. Cobos;J. Uceda;A. Lotfi

Year: 2003 | Volume: 2 | Conference Paper |

Issues and advances in high-frequency magnetics for switching power supplies

A.W. Lotfi;M.A. Wilkowski

Proceedings of the IEEE
Year: 2001 | Volume: 89, Issue: 6 | Journal Article |
Magnetic components have been and will continue to be an essential element in power conversion and management circuits. Due to this pivotal role, magnetic components have seen continuous efforts to develop materials, winding structures, and manufacturing and assembly techniques toward the never ending goals of high efficiency, smaller size, and automated manufacturing. The authors present an up-to...Show More

Issues and advances in high-frequency magnetics for switching power supplies

A.W. Lotfi;M.A. Wilkowski

Year: 2001 | Volume: 89, Issue: 6 | Journal Article |

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