Efficiency Improvement of LDO Output Based Linear Regulator With Supercapacitor Energy Recovery – A versatile new technique with an example of a 5V to 1.5V version

Supercapacitors are used in various industrial applications and the supercapacitors technology is gradually progressing into a mature state. Common applications of supercapacitors are in electric vehicles, hybrid electric vehicles, uninterruptible power supply (UPS) and in portable devices such as cellular phones and laptops. The capacitance values range from fractional Farads to few thousand Farads and their continuos DC voltage ratings are from 2V to 6V. At University of Waikato, a team works on using supercapacitors for improving the efficiency of linear voltage regulators. In particular, this patented technique aims at combining off the shelfs LDO ICs and a supercapacitor array for improving end to end efficiency of linear regulator. My work is aimed at developing the theoretical background and designing prototype circuitry for a voltage regulator for the case of unregulated input supply is more than 3 times of the minimum input voltage requirement of the LDO which is applicable for a 5V to 1.5V regulator. Experimental results are indicated with future suggestions for improvement

Modularizing the LDO to optimize performance based on application design constraints

This thesis aims to construct a modular low-dropout regulator that gives designers more freedom in building a highly efficient regulator that meets application demands. This modular design is able to separate DC regulation and high-frequency supply rejection while not compromising on either of the two. Flexibility is a key requirement during both design and post-design. The proposed regulator is able to achieve all the required goals with full spectrum power supply rejection. By splitting the pass device, this design is able to achieve the best of both internal pole dominant and external pole dominant linear regulators

Electrical performance characteristics of high power converters for space power applications

The first goal of this project was to investigate various converters that would be suitable for processing electric power derived from a nuclear reactor. The implementation is indicated of a 20 kHz system that includes a source converter, a ballast converter, and a fixed frequency converter for generating the 20 kHz output. This system can be converted to dc simply by removing the fixed frequency converter. This present study emphasized the design and testing of the source and ballast converters. A push-pull current-fed (PPCF) design was selected for the source converter, and a 2.7 kW version of this was implemented using three 900 watt modules in parallel. The characteristic equation for two converters in parallel was derived, but this analysis did not yield any experimental methods for measuring relative stability. The three source modules were first tested individually and then in parallel as a 2.7 kW system. All tests proved to be satisfactory; the system was stable; efficiency and regulation were acceptable; and the system was fault tolerant. The design of a ballast-load converter, which was operated as a shunt regulator, was investigated. The proposed power circuit is suitable for use with BJTs because proportional base drive is easily implemented. A control circuit which minimizes switching frequency ripple and automatically bypasses a faulty shunt section was developed. A nonlinear state-space-averaged model of the shunt regulator was developed and shown to produce an accurate incremental (small-signal) dynamic model, even though the usual state-space-averaging assumptions were not met. The nonlinear model was also shown to be useful for large-signal dynamic simulation using PSpice

Efficiency improvement of LDO ouput based linear regulator with supercapacitor energy recovery - a versatile new technique with an example of a 5v to 1.5 v version

Supercapacitors are used in various industrial applications and the supercapacitors technology is gradually progressing into a mature state. Common applications of supercapacitors are in electric vehicles, hybrid electric vehicles, uninterruptible power supply (UPS) and in portable devices such as cellular phones and laptops. The capacitance values range from fractional Farads to few thousand Farads and their continuos DC voltage ratings are from 2V to 6V. At University of Waikato, a team works on using supercapacitors for improving the efficiency of linear voltage regulators. In particular, this patented technique aims at combining off the shelfs LDO ICs and a supercapacitor array for improving end to end efficiency of linear regulator. My work is aimed at developing the theoretical background and designing prototype circuitry for a voltage regulator for the case of unregulated input supply is more than 3 times of the minimum input voltage requirement of the LDO which is applicable for a 5V to 1.5V regulator. Experimental results are indicated with future suggestions for improvement

Hand gesture recognition through capacitive sensing : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Electronics & Computer Engineering at Massey University, School of Food and Advanced Technology (SF&AT), Auckland, New Zealand

Figures 1.1, 1.2, 1.3, 2.1, 2.3 & 2.4 are re-used with permission. Figure 2.2 (=Smith, 1996 Fig 1) ©1996 by International Business Machines Corporation was removed.This thesis investigated capacitive sensing-based hand gesture recognition by developing and validating through custom built hardware. We attempted to discover if massed arrays of capacitance sensors can produce a robust system capable of simple hand gesture detection and recognition. The first stage of this research was to build the hardware that performed capacitance sensing. This hardware needs to be sensitive enough to capture minor variations in capacitance values, while also reducing stray capacitance to their minimum. The hardware designed in this stage formed the basis of all the data captured and utilised for subsequent training and testing of machine learning based classifiers. The second stage of this system used mass arrays of capacitance sensor pads to capture frames of hand gestures in the form of low-resolution 2D images. The raw data was then processed to account for random variations and noise present naturally in the surrounding environment. Five different gestures were captured from several test participants and used to train, validate and test the classifiers. Different methods were explored in the recognition and classification stage: initially, simple probabilistic classifiers were used; afterwards, neural networks were used. Two types of neural networks are explored, namely Multilayer Perceptron (MLP) and Convolutional Neural Network (CNN), which are capable of achieving upwards of 92.34 % classification accuracy

Analysis on Supercapacitor Assisted Low Dropout (SCALDO) Regulators

State-of-the-art electronic systems employ three fundamental techniques for DC-DC converters: (a) switch-mode power supplies (SMPS); (b) linear power supplies; (c) switched capacitor (charge pump) converters. In practical systems, these three techniques are mixed to provide a complex, but elegant, overall solution, with energy efficiency, effective PCB footprint, noise and transient performance to suit different electronic circuit blocks. Switching regulators have relatively high end-to-end efficiency, in the range of 70 to 93%, but can have issues with output noise and EMI/RFI emissions. Switched capacitor converters use a set of capacitors for energy storage and conversion. In general, linear regulators have low efficiencies in the range 30 to 60%. However, they have outstanding output characteristics such as low noise, excellent transient response to load current fluctuations, design simplicity and low cost design which are far superior to SMPS. Given the complex situation in switch-mode converters, low dropout (LDO) regulators were introduced to address the equirements of noise-sensitive and fast transient loads in portable devices. A typical commercial off-the-shelf LDO has its input voltage slightly higher than the desired regulated output for optimal efficiency. The approximate efficiency of a linear regulator, if the power consumed by the control circuits is negligible, can be expressed by the ratio of Vo/Vin. A very low frequency supercapacitor circulation technique can be combined with commercial low dropout regulator ICs to significantly increase the end-to-end efficiency by a multiplication factor in the range of 1.33 to 3, compared to the efficiency of a linear regulator circuit with the same input-output voltages. In this patented supercapacitor-assisted low dropout (SCALDO) regulator technique developed by a research team at the University of Waikato, supercapacitors are used as lossless voltage droppers, and the energy reuse occurs at very low frequencies in the range of less than ten hertz, eliminating RFI/EMI concerns. This SCALDO technique opens up a new approach to design step-down, DC-DC converters suitable for processor power supplies with very high end-to-end efficiency which is closer to the efficiencies of practical switching regulators, while maintaining the superior output specifications of a linear design. Furthermore, it is important to emphasize that the SCALDO technique is not a variation of well-known switched capacitor DC-DC converters. In this thesis, the basic SCALDO concept is further developed to achieve generalised topologies, with the relevant theory that can be applied to a converter with any input-output step-down voltage combination. For these generalised topologies, some important design parameters, such as the number of supercapacitors, switching matrix details and efficiency improvement factors, are derived to form the basis of designing SCALDO regulators. With the availability of commercial LDO ICs with output current ratings up to 10 A, and thin-prole supercapacitors with DC voltage ratings from 2.3 to 5.5 V, several practically useful, medium-current SCALDO prototypes: 12V-to-5V, 5V-to-2V, 5.5V-to-3.3V have been developed. Experimental studies were carried out on these SCALDO prototypes to quantify performance in terms of line regulation, load regulation, efficiency and transient response. In order to accurately predict the performance and associated waveforms of the individual phases (charge, discharge and transition) of the SCALDO regulator, Laplace transform-based theory for supercapacitor circulation is developed, and analytical predictions are compared with experimental measurements for a 12V-to-5V prototype. The analytical results tallied well with the practical waveforms observed in a 12V-to-5V converter, indicating that the SCALDO technique can be generalized to other versatile configurations, and confirming that the simplified assumptions used to describe the circuit elements are reasonable and justifiable. After analysing the performance of several SCALDO prototypes, some practical issues in designing SCALDO regulators have been identified. These relate to power losses and implications for future development of the SCALDO design

Parasitic extraction of a power management integrated circuit PCB

Abstract. In this master’s thesis parasitic extraction of a power management integrated circuit was established and evaluated using Ansys Q3D. From PCB the S21 parameter was extracted between two nodes from output and input to efficiently show the parasitic properties of the PCB. Extraction was done over frequencies from 100 kHz to 100 MHz. This was done using multiple different settings for the extraction to find out the optimal settings in terms of accuracy and time to solution. An evaluation module PCB was designed for the power management integrated circuit using Altium. In this design the best practices for PCB layout design were utilized to get the performance as good as possible. Some of the PCB design choices were evaluated with Ansys Q3D to make an informed decision of the better design choice. A measurement setup was established and validated by using a known component to ensure the setup is working as expected. The PCB was measured without components except the ones needed for the experiment. Measurements were taken with S21 shunt-through method with spectrum analyser with built-in network option, external vector signal generator and external pre-amplifier to get more dynamic range. The output and input were evaluated with and without a capacitor to get a broader understanding of the modelling accuracy. A case with two capacitors was tested. These models were compared with a measurement result to evaluate the accuracy of the tools and methods. It was noticed that with simple geometries the different extraction options do not significantly affect the extraction accuracy. At the same time, the time to solution varies greatly which leads to the use of the simpler extraction settings to save time. When comparing the simulation with measurement the best average error was 3.3 % and the worst 34.3 %. The simulations matched the measurements best when a capacitor was placed and worst with open termination with no components. The model accuracies obtained in this thesis reflect what has been seen in previous studies in terms of frequency range and deviation from measured results.Parasiittisten ominaisuuksien ekstraktointi tehonhallinta piirilevyltä. Tiivistelmä. Tässä diplomityössä parasiittisten ominaisuuksien ekstraktointityövaihe luotiin, sekä sen suorituskyky arvioitiin käyttäen Ansys Q3D ohjelmaa. Piirilevyltä ekstraktoitiin S21 parametri kahden solmun väliltä tulo- ja lähtöpuolelta käyttäen 100 kHz–100 MHz taajuusaluetta. Tällä tavoin saatiin tehokkaasti esitettyä piirilevyn parasiittisten ominaisuuksien muodostama impedanssi. Tämä tehtiin käyttäen useita eri asetuksia, joita on saatavilla ohjelmistossa. Nämä asetukset vaikuttavat eri tavoilla ekstraktoinnin tarkkuuteen. Näitä tuloksia vertailemalla löydettiin tarkkuuden ja simulointiajan suhteen optimaaliset asetukset, joilla tehdä ekstraktointi. Työtä varten suunniteltiin piirilevy tehonhallinta integroidulle piirille käyttäen Altium ohjelmaa. Tässä suunnittelussa käytettiin hyviä käytänteitä, jotta piirilevyn suorituskyvystä saataisiin mahdollisimman hyvä. Jotkin suunnitteluvalinnoista perustuvat Q3D:llä saatuihin tuloksiin, jotta voitiin valita useista vaihtoehdoista paras. Mittauksia varten suunniteltiin ja toteutettiin mittausjärjestelmä, jonka toiminta varmennettiin mittaamalla tunnetun komponentin impedanssi ja vertaamalla sitä valmistajan antamaan dataan. Valmistetulta piirilevyltä mitattiin käyttäen vain niitä komponentteja, jotka olivat merkittäviä tutkimukselle. Mittaukset tehtiin käyttäen S21 shunt-through menetelmää käyttämällä spektrianalysaattoria, jossa on sisäänrakennettu verkkoanalysointioptio. Tämän kanssa käytettiin ulkoista vektorisignaaligeneraattoria ja ulkoista esivahvistinta, jotta saataisiin enemmän dynaamista aluetta. Vertailuun valittiin piirin ulos- ja sisääntuloverkot kondensaattorilla ja ilman, jotta saataisiin laajempi käsitys mallinnuksen tarkkuudesta. Myös kahden kondensaattorin tapaus käsiteltiin. Näitä mallinnuksella saatuja tuloksia verrattiin mittaamalla saatuihin tuloksiin. Työssä huomattiin, että tässä sovelluksessa, jossa on yksinkertaisia geometrioita, eri ekstraktointi vaihtoehdot eivät vaikuttaneet tarkkuuteen huomattavasti. Ekstraktointiin kulunut aika vaihteli huomattavasti joidenkin vaihtoehtojen välillä, jonka takia valittiin yksinkertaisempi mallinnustapa, jotta säästettäisiin aikaa. Verrattaessa simuloituja ja mitattuja tuloksia, huomattiin että paras keskiarvoinen virhe oli 3,3 % ja huonoin 34,3 %. Simuloinnit vastasivat mittauksia parhaiten, kun tarkasteltiin tapauksia, joissa oli käytössä yksi kondensaattori ja huonoin, kun käytettiin avointa terminointia. Tässä työssä saadut tulokset vastaavat hyvin aikaisemmissa tutkimuksissa saatuja tuloksia sekä taajuusalueen puolesta, että eron mittauksen ja simuloinnin välillä

Modeling and Analysis of Power Processing Systems

The feasibility of formulating a methodology for the modeling and analysis of aerospace electrical power processing systems is investigated. It is shown that a digital computer may be used in an interactive mode for the design, modeling, analysis, and comparison of power processing systems