Efficient integrated DC-DC converters for ultra-low voltage energy harvesters

Download
2017-8
Jayaweera, Herath
The self-starting on-chip fully integrated ultra-low voltage DC-DC converters for energy harvesting applications presented in literature generally have low efficiency and output power capacity. Any improvement in DC-DC converter circuits in terms of energy efficiency, output power, self-starting modes, and voltage gain will contribute significantly to the widespread application of energy harvesters. Two novel fully integrated, self-starting, ultra-low voltage DC-DC converter topologies and model based optimization methodologies for these converters are studied in this thesis for efficient micro-power energy harvesting applications. According to the pre-layout simulations in standard UMC 180nm CMOS technology, the proposed 3-, 4-, and 5-stage DC-DC converter with voltage doubling LC oscillator can achieve 47.9%, 51.5%, 51.7% efficiency, and deliver 343 µW at 1.02 V output, 385 µW at 1.39 V output, and 454 µW at 1.65 V output respectively for 0.2 V input. The voltage quadrupling LC tank coupled DC-DC converter with 4 and 3 stages can achieve 33% and 31% efficiency while delivering 1193 µW at 2.18 V output, and 778 µW at 1.77 V output respectively for 0.2 V input. The measurements from the fabricated test chip for the first topology indicate major deviations from the simulations, i.e. the measured simulation peak efficiency is < 7% at 0.2 V input. Comprehensive design validation and analysis is presented for the discrepancy, which results in post-layout simulations of a new model that can be correlated to silicon observations. The fixes to the design and layout have been taped out as part of a second revision of the test chip to overcome the problems. The post-layout simulations for the new design achieve a peak efficiency of 41.5% at 1.54 V output, and 41% at 1.27 V output with 5 and 4 stages respectively for 0.2 V input. The theoretical analysis and optimization methods presented in this thesis are verified through simulations in Cadence environment.

Suggestions

Active clamped ZVS forward converter with soft-switched synchronous rectifier for maximum efficiency operation
Acik, A; Cadirci, I (1998-05-22)
An active-clamped, zero-voltage switched forward converter equipped with a soft-switched synchronous rectifier is designed and implemented for some low output voltage applications where maximized efficiency is of utmost importance. The converter efficiency is maximized due to soft-switching of the main, active clamp and the synchronous rectifier MOSFET switches. Experimental results are presented for a converter with a de input voltage of 48V, an output voltage of 5V and a de electronic load up to 10A. The ...
Modeling and Control of Interleaved Multiple-Input Power Converter for Fuel Cell Hybrid Electric Vehicles
Hegazy, Omar; Van Mierlo, Joeri; Lataire, Philippe (2011-09-10)
Interleaving techniques are widely used to reduce input/output ripples, to increase the efficiency and to increase the power capacity of the DC/DC converters. This paper proposes an interleaved multiple-input power converter (IMIPC) that interfaces the fuel cell and energy storage systems (e.g. Batteries or/and Supercapacitors) to the powertrain of the hybrid electric vehicles. The IMIPC is responsible for the power-flow management on-board vehicle for each operating mode. In this research, the IMIPC is pro...
Energy Conversion Efficiency of Single-Phase Transformerless PV Inverters
Özkan, Ziya; Hava, Ahmet Masum (2013-11-30)
In grid-connected photovoltaic (PV) applications, power semiconductor energy conversion efficiency of PV inverters is one of the major figures of merits to evaluate and compare these systems as the payback ratio of the overall system is tightly related to the energy conversion efficiency and as semiconductor losses comprise the majority of energy losses. In order to wisely choose the PV inverter topology and associated semiconductors, analytic evaluation of semiconductor losses of topologies is required. Fu...
Low input voltage and high step-up integrated regulator for thermoelectric energy harvesting
Pathirana, W. P. M. R.; Jayaweera, H. M. P. C.; Muhtaroglu, Ali (2015-03-26)
This paper presents a low input voltage and high step-up fully integrated DC-DC regulator in 0.18 mu m standard CMOS technology for thermoelectric micro-power generation. The circuit avoids off-chip components, non-standard processes, and is thus suitable for ultra-low voltage low profile system-on-chip applications. The proposed system can deliver a regulated output voltage of 1.5 V at 31 mu W output power with an input voltage as low as 0.2 V. The maximum simulated efficiency is 22% at the given step-up r...
Operating principles and practical design aspects of all SiC DC/AC/DC converter for MPPT in grid-connected PV supplies
ÖZTÜRK, SERKAN; Popos, Polat; Utalay, Volkan; Koc, Atila; Ermiş, Muammer; ÇADIRCI, IŞIK (2018-12-01)
A 20 kW, 20 kHz high frequency (HF) link maximum power point tracking (MPPT) converter for a grid-connected PV supply, based on all silicon carbide (SiC) power semiconductors, is presented. In the developed converter, SiC power MOSFETs are used in the low-voltage PV panel side and SiC Schottky diodes on the high-voltage DC output, in order to maximize the power conversion efficiency and the power density. Operating principles of the resulting dual H-bridge MPPT converter and the practical aspects of the con...
Citation Formats
H. Jayaweera, “Efficient integrated DC-DC converters for ultra-low voltage energy harvesters,” M.S. - Master of Science, Middle East Technical University, 2017.