Analysis and design of a highly efficient and versatile DC-DC converter

The thrive of battery-operated devices and connected devices with the vision of Internet-of-Things (IOT) calls for efficient and versatile Direct Current to Direct Current (DC-DC) converters to fulfil the ever-growing power demand. Adaptive on-time (AOT) control of DC-DC converters has the advanta...

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Main Author: Yu, Guolei
Other Authors: Siek Liter
Format: Theses and Dissertations
Language:English
Published: 2015
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Online Access:https://hdl.handle.net/10356/65841
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-658412023-07-04T16:34:52Z Analysis and design of a highly efficient and versatile DC-DC converter Yu, Guolei Siek Liter School of Electrical and Electronic Engineering Centre for Integrated Circuits and Systems DRNTU::Engineering::Electrical and electronic engineering::Integrated circuits The thrive of battery-operated devices and connected devices with the vision of Internet-of-Things (IOT) calls for efficient and versatile Direct Current to Direct Current (DC-DC) converters to fulfil the ever-growing power demand. Adaptive on-time (AOT) control of DC-DC converters has the advantages of simple structure, good light load efficiency and fast response to load step. The purpose of this research is to develop AOT control in two areas: digital control for its process scalability and flexibility, and ultra-low-power operation. Novel circuit blocks and techniques have been developed to improve the performance of AOT control, which are listed as follows. For data conversion required by digital control, a flash analog-to-digital converter (ADC) using NOR gates as comparators has been proposed and verified by simulation and a prototype chip using 0.35 µm CMOS process. The advantages of the proposed ADC include low power, high speed and small silicon area. Two methods have been proposed to achieve near optimum load transient response: level-based multi-loop control and body-brake. Level-based multi-loop control is able to achieve near minimum output voltage deviation during load transient using a simple algorithm. A new detection method is proposed for body-brake technique to further improve the unloading response. A counter-based dead-time optimization method has been proposed to improve conversion efficiency under heavy load. Under specific simulation conditions, 2.3% efficiency improvement has been observed. In the study of ultra-low-power operation, we further develop the existing method of duty-cycled operation that dynamically changes the system operation frequency with a low-power relaxation oscillator. The duty-cycled operation is referring to the scheme that all active circuit blocks except the system clock are turned off when all the outputs are in regulation, hence the system quiescent current reduces to the system clock block current only. It has also demonstrated that making on-time adaptive to input voltage improves the peak efficiency by about 1% over the input range of 2.65 V to 3.3 V, by a prototype chip using CMOS 0.18 µm process. DOCTOR OF PHILOSOPHY (EEE) 2015-12-23T06:07:10Z 2015-12-23T06:07:10Z 2015 2015 Thesis Yu, G. (2015). Analysis and design of a highly efficient and versatile DC-DC converter. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/65841 10.32657/10356/65841 en 211 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering::Electrical and electronic engineering::Integrated circuits
spellingShingle DRNTU::Engineering::Electrical and electronic engineering::Integrated circuits
Yu, Guolei
Analysis and design of a highly efficient and versatile DC-DC converter
description The thrive of battery-operated devices and connected devices with the vision of Internet-of-Things (IOT) calls for efficient and versatile Direct Current to Direct Current (DC-DC) converters to fulfil the ever-growing power demand. Adaptive on-time (AOT) control of DC-DC converters has the advantages of simple structure, good light load efficiency and fast response to load step. The purpose of this research is to develop AOT control in two areas: digital control for its process scalability and flexibility, and ultra-low-power operation. Novel circuit blocks and techniques have been developed to improve the performance of AOT control, which are listed as follows. For data conversion required by digital control, a flash analog-to-digital converter (ADC) using NOR gates as comparators has been proposed and verified by simulation and a prototype chip using 0.35 µm CMOS process. The advantages of the proposed ADC include low power, high speed and small silicon area. Two methods have been proposed to achieve near optimum load transient response: level-based multi-loop control and body-brake. Level-based multi-loop control is able to achieve near minimum output voltage deviation during load transient using a simple algorithm. A new detection method is proposed for body-brake technique to further improve the unloading response. A counter-based dead-time optimization method has been proposed to improve conversion efficiency under heavy load. Under specific simulation conditions, 2.3% efficiency improvement has been observed. In the study of ultra-low-power operation, we further develop the existing method of duty-cycled operation that dynamically changes the system operation frequency with a low-power relaxation oscillator. The duty-cycled operation is referring to the scheme that all active circuit blocks except the system clock are turned off when all the outputs are in regulation, hence the system quiescent current reduces to the system clock block current only. It has also demonstrated that making on-time adaptive to input voltage improves the peak efficiency by about 1% over the input range of 2.65 V to 3.3 V, by a prototype chip using CMOS 0.18 µm process.
author2 Siek Liter
author_facet Siek Liter
Yu, Guolei
format Theses and Dissertations
author Yu, Guolei
author_sort Yu, Guolei
title Analysis and design of a highly efficient and versatile DC-DC converter
title_short Analysis and design of a highly efficient and versatile DC-DC converter
title_full Analysis and design of a highly efficient and versatile DC-DC converter
title_fullStr Analysis and design of a highly efficient and versatile DC-DC converter
title_full_unstemmed Analysis and design of a highly efficient and versatile DC-DC converter
title_sort analysis and design of a highly efficient and versatile dc-dc converter
publishDate 2015
url https://hdl.handle.net/10356/65841
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