To see the other types of publications on this topic, follow the link: Class-D audio amplifier.
Dissertations / Theses on the topic 'Class-D audio amplifier'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Class-D audio amplifier.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Caballero, Angel A. 1981. "A class-D-tracking-rail class-A audio power amplifier." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28384.
Full textAbstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 63-64).
A tracking-rail power audio amplifier was designed and partially implemented to deliver up to 100W into an 8Q load with very low signal distortion and high power efficiency. The design uses a class-A amplifier, known for its low signal distortion but low power efficiency (less than 50%), to amplify the audio signal. Class-D amplifiers, known for their high power efficiency (greater than 85%) but high signal distortion, provide a signal output that will serve as the supply voltages of the output stage of the class-A amplifier. Thus, the rails will track the audio signal, highly increasing the power efficiency of the Class-A amplifier. This amplifier can achieve a theoretical efficiency of 80%, but, in practice, it is closer to 70%.
by Angel A. Caballero.
M.Eng.
2
Quibell, Jason. "Digital control of a Class-D Audio Amplifier." Thesis, Cape Peninsula University of Technology, 2011. http://hdl.handle.net/20.500.11838/1116.
Full textAbstract:
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2011Modern technologies have led to extensive digital music reproduction and distribution. It is fitting then that digital audio be amplified directly from its source rather than being converted to an analogue waveform before amplification. The benefits of using a digital controller for audio processing include being able to easily reconfigure the system and to add additional functions at a later stage.Digital audio is primarily stored as Pulse Code Modulation (PCM) while Pulse Width Modulation (PWM) is the most popular scheme used to drive a class-D amplifier. The class-D amplifier is selected in many applications due to its very high energy efficiency. Conventional PCM to PWM conversion is inherently nonlinear. Various interpolation schemes are presented in this research project which help to address the nonlinearity.Digitally generated PWM has a limited resolution which is constrained by the system clock. This thesis presents noise shaping techniques which increase the effective resolution of the PWM process without having to use an excessively high system clock. Noise shaping allows a low resolution modulator to be used to reproduce high resolution audio.
3
PONNAMANENI, SANJITH KUMAR. "A NOVEL AUDIO AMPLILFIER COMBINING LINEAR AND SWITCHING TECHNIQUES." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109274094.
Full text
4
Engstrand, Johan, Niklas Kavathatzopoulos, and Jonathan Nordenholm. "Simulation and Construction of a Half-Bridge Class D Audio Amplifier." Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353789.
Full textAbstract:
Usage of class D audio amplifiers has become increasingly widespread in recent years, mainly due to their high efficiency, which can reach almost 100 %. Class D amplifiers can also be compact, making them suitable for mobile applications. In contrast, the most efficient conventional amplifiers such as class B can reach a maximum efficiency of 78.5 %. The high efficiency of class D amplifiers can be attributed to the switching stage, which in the case of a half-bridge design consists of two amplifying MOSFETs. These MOSFETs are never on at the same time, which minimizes the quiescent current and thereby the power losses. The goal of this project was to design, simulate and construct a half-bridge class D audio amplifier. A working amplifier with 80 % efficiency was built, with power losses occuring mainly in the voltage regulators. Simulations of the amplifier corresponded well with the constructed amplifier apart from issues originating from the aforementioned voltage regulation as well as the triangle wave generator. The goal of the project was achieved and the finished amplifier possessed good sound quality and little unwanted noise. To further improve on the design, better voltage regulation, a full-bridge configuration and a feedback loop could be utilized.
5
Kemp, Pieter Stephanus. "The design of an analogue class-D audio amplifier using Z-domain methods." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20084.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2012ENGLISH ABSTRACT: The class-D audio power amplifier has found widespread use in both the consumer and professional audio industry for one reason: efficiency. A higher efficiency leads to a smaller and cheaper design, and in the case of mobile devices, a longer battery life. Unfortunately, the basic class-D amplifier has some serious drawbacks. These include high distortion levels, a load dependent frequency response and the potential to radiate EMI. Except for EMI, the aforementioned issues can be mitigated by the proper implementation of global negative feedback. Negative feedback also has the potential to indirectly reduce EMI, since the timing requirements of the output devices can be relaxed. This thesis discusses the design of a clocked analogue controlled pulse-width modulated class-D audio amplifier with global negative feedback. The analogue control loop is converted to the z-domain by modelling the PWM comparator as a sampling operation. A method is implemented that improves clip recovery and ensures stability during over-modulation. Loop gain is shaped to provide a high gain across the audio band, and ripple compensation is implemented to minimize the negative effect of ripple feedback. Experimental results are presented.
AFRIKAANSE OPSOMMING: Die klas-D klankversterker geniet wydverspreide gebruik in beide die verbruiker en professionele oudio industrie vir een rede: benuttingsgraad. ’n Hoër benuttingsgraad lei tot ’n kleiner en goedkoper ontwerp, en in die geval van draagbare toestelle, tot langer batterylewe. Ongelukkig het die basiese klas-D klankversterker ernstige tekortkominge, naamlik hoë distorsievlakke, ’n lasafhanklike frekwensierespons en die vermoë om EMI te genereer. Behalwe vir EMI kan hierdie kwessies deur die korrekte toepassing van globale negatiewe terugvoer aangespreek word. Negatiewe terugvoer het ook die potensiaal om EMI indirek te verminder, aangesien die tydvereistes van die skakel stadium verlaag kan word. Hierdie tesis bespreek die ontwerp van ’n geklokte analoog-beheerde pulswydte-modulerende klas-D klankversterker met globale negatiewe terugvoer. Die analoogbeheerlus word omgeskakel na die z-vlak deur die PWM vlakvergelyker as ’n monster operasie te modelleer. ’n Metode word geïmplementeer wat die stabiliteit van die lus verseker tydens oormodulasie. Die lusaanwins word gevorm om ’n hoë aanwins in die oudioband te verseker en riffelkompensasie word geïmplementeer om die negatiewe effek van terugvoerriffel teen te werk. Eksperimentele resultate word voorgelê.
6
Kelati, Amleset. "Theory and Implementation of CMOS Class-D Digital Audio Amplifier for Portable Application." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143518.
Full text
7
Pereira, Nuno Ruben Ferreira. "Implementation of a sigma delta modulator for a class D audio power amplifier." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10046.
Full text
8
Svadbík, Vít. "Návrh a konstrukce spínaného audio koncového zesilovače." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218603.
Full textAbstract:
This work describes the design of audio amplifiers operating in switching mode. The first part describes basic principles of the power stage switching concept. There is described differences between classes of amplifiers according to technology. The second larger part includes design and construction of the switching amplifiers. Design is implemented, including the preamplifier and power supply. Power supply works in switching mode. The measured parameters of the proposed facility are given in the last part.
9
Konečný, Jiří. "Návrh stereo audio koncového zesilovače spínané třídy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220270.
Full textAbstract:
This text analyzes characteristics of audio power amplifiers in class D. The emphasis is placed on more detailed analysis of modulators, drivers, connection topology of power transistors. In the next section of text are analyzed available integrated circuits of power amplifiers in class D which are manufactured by world producers. The last part describes design of all parts of amplifier in class D with discrete components and also of power supplies. According to the plans, the individual parts are made. All parts are tested by measurements and results are evaluated.
10
Melo, João Luís Alvernaz de. "Design of a Continuous-Time (CT) Sigma-Delta modulator for class D audio power amplifiers." Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/13154.
Full text
11
Leitão, Pedro Miguel Vicente. "Design of a power output stage for a class D audio power amplifier based on an 1.5-bit ∑ ∆ M." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10229.
Full text
12
Melša, Vojtěch. "Výkonový audio zesilovač využívající AC/DC měnič." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219827.
Full textAbstract:
The aim of this work was to design and construct a simple audio amplifier, which would be based of involvement and components used in switching power sources on the maximum degree (for example from usual ATX sources for computer). The main motivation for development is the existence of many old sources that do not use and big interest of users for the construction of home audio amplifiers for small and medium power. Amplifiers based on switching power sources with greater efficiency and less weight than comparable classic amplifiers (working in classes A, B or AB). Their disadvantage is the complicated design and introduction of distortion and spurious signals to the amplified signal. This work will be described a design of simple amplifier, which will minimize these negative effects. For shortcomings and wrong parameters this proposed involvement will be eventually described and implemented design of amplifier in class D.
13
Koeslag, Francois. "A detailed analysis of the imperfections of pulsewidth modulated waveforms on the output stage of a class D audio amplifier." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/3972.
Full textAbstract:
Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.Although the Class D topology offers several advantages, its use in audio amplification has previously been limited by the lack of competitiveness in fidelity compared to its linear counterparts. During the past decade, technological advances in semiconductor technology have awakened new interest since competitive levels of distortion could now be achieved. The output stage of such an amplifier is the primary limiting factor in its performance. In this dissertation, four non-ideal effects existing in this stage are identified and mathematically analysed. The analytical analysis makes use of a well-established mathematical model, based on the double Fourier series method, to model the imperfections introduced into a naturally sampled pulsewidth modulated waveform. The analysis is complemented by simulation using a strategy based on Newton’s numerical method. The theory is verified by a comparison between the analytical-, simulated- and experimental results.
14
Nedbal, Jan. "Audio výkonový zesilovač ve třídě D s mikroprocesorovým řízením." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219824.
Full textAbstract:
The thesis deals with the design and practical realization of class D audio power amplifier with microprocessor controlling. The first part describes the integrated circuits used in a preamplifier and his complete design with a description of the control program for ATmega128 microcontroller. The following part describes an integrated power amplifier TAS5613 and his circuits. The next section describes a switching power supply design using integrated circuit TOP261EN. The last section describes measurements of parameters of individual parts of the amplifier.
15
Petrgál, Filip. "Digitálně řízený audio zesilovač ve třídě D s dálkovým ovládáním." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220355.
Full textAbstract:
The contents of this thesis is design of audio power amplifier in Class D with fully digital control and remote control and is divided into two parts . The first part is devoted to the basic principles and theory of key elements of the entire amplifier. The second part consists of a complete description of the design and construction of a power amplifier, digital control with remote control, a spectrum analyzer, equalizer, preamp VU meters and complete power supply. Each proposal contains a detailed analysis of the solutions supported by simulations and software. For individual parts have been completely measured p arameters.
16
Mioni, Daniel Pasti. "Amplificador de audio classe D baseado em modulação sigma-delta destinado a aparelhos auditivos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259311.
Full textAbstract:
Orientadores: Jose Antenor Pomilio, Saulo FincoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-09T03:34:05Z (GMT). No. of bitstreams: 1 Mioni_DanielPasti_M.pdf: 1903299 bytes, checksum: 7343c6fb1cd22aa8df8654d5b9b51852 (MD5) Previous issue date: 2007
Resumo: Desenvolvemos um amplificador de áudio classe D baseado em moduladores S-?, destinado a aparelhos auditivos, a maioria dos quais utiliza baterias de 1,1V e necessita ter baixo consumo de corrente. Neste trabalho os amplificadores e comparadores foram construídos com inversores CMOS, pois um destes inversores, alimentado com uma tensão de 1,1V, pode consumir uma corrente CC tão baixa quanto 400nA, dependendo das dimensões, e proporcionar alto ganho de tensão quando polarizado em sua região linear de operação. Por estes motivos, podem substituir com vantagem amplificadores operacionais e comparadores em algumas aplicações. Um protótipo deste circuito foi implementado com tecnologia CMOS 0,35µm e alcançou um rendimento de 90%
Abstract: This thesis presents the design of a firstorder S-? audioband power amplifier optimized for hearing aid (HA) amplification. The majority of HAs use a 1.1V battery and require very low current consumption to improve battery life. This work made use of amplifiers and comparators based on CMOS inverters because such an inverter, with a 1.1V battery, can operate on a current as low as 400nA, depending on its dimensions, and provide high voltage gain when biased in their linear region. For these reasons, they can substitute with advantage operational amplifiers in some applications. A prototype of this circuit was implemented in a monolithic chip using 0.35µm CMOS technology and achieved 90% of power efficiency
Mestrado
Eletrônica, Microeletrônica e Optoeletrônica
Mestre em Engenharia Elétrica
17
Hardy, Emmanuel. "Etude et développement d'un amplificateur audio de classe D intégré haute performance et basse consommation." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4722/document.
Full textAbstract:
De nombreux dispositifs embarqués récents comme les téléphones portables, les GPS ou encore les consoles de jeu, possèdent un ou des haut-parleurs, chacun étant piloté par un amplificateur audio sur circuit intégré. De tels amplificateurs audio doivent répondre le mieux possible à quatre contraintes : une qualité audio satisfaisante, une immunité aux perturbations induites par le système, une faible consommation et une surface de silicium minimale. Ce travail de thèse sous contrat CIFRE a pour origine la création de l’entreprise Primachip en mai 2009 par Christian Dufaza et Hassan Ihs. Cette startup a été bâtie sur une architecture innovante d’amplificateur audio de classe D intégré. Son originalité repose sur le principe de rétroaction partielle qui s’applique à une boucle contenant un modulateur numérique Delta Sigma (ΔΣ) qui pilote l’étage de puissance et un convertisseur analogique-numérique (ADC) effectuant la rétroaction. Cela permet d’obtenir la stabilité de cette boucle tout en offrant une excellente réjection des bruits de l’étage de puissance. Un prototype sur silicium de l’architecture d’amplificateur de classe D numérique a été conçu et fabriqué. Un nouvel ADC ΔΣ temps continu a été développé pour ce prototype, afin d’obtenir des performances supérieures ou égales à l’état de l’art. Les résultats obtenus sur le circuit se sont révélés encourageants, bien que toutes les spécifications n’aient pas été atteintes. L’analyse des erreurs de ce premier circuit doit permettre la réalisation d’un amplificateur intégré exploitant au mieux cette architecture de classe D numériqueMost current embedded devices, such as smartphones, GPS or portable consoles, feature one speaker or more, those speakers being driven by an integrated audio amplifier. This type of amplifier must meet four specifications: an adequate audio quality, to be immune to system disturbances, low power consumption and the smallest silicon area. This work takes its origin from the creation of Primachip in May 2009 by Christian Dufaza and Hassan Ihs. The aim of this startup was to develop and sell an innovative audio class-D amplifier for mobile market: the digital class-D concept. A partnership with the IM2NP laboratory was decided to propose a PhD topic under CIFRE contract (PhD in an industrial environment), in order to study and improve the amplifier architecture. Its originality is in the partial feedback concept which applies to a loop made of a digital ΔΣ modulator driving the power stage, with an analogue-to-digital converter (ADC) in the feedback path. It makes it possible to achieve stability while offering an outstanding power supply rejection. An integrated prototype of the class-D amplifier was designed, fabricated and evaluated. A new continuous-time ΔΣ ADC has been added to enable the digital class-D loop to achieve performances superior or equal to state of the art. The circuit measurement results were encouraging, although not ideal. The analysis of the prototype errors was performed. The conclusions should allow the design of an integrated audio amplifier making the best of the digital class-D architecture
18
Svadbík, Pavel. "Digitální nízkofrekvenční zesilovač s univerzálními vstupy." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219816.
Full textAbstract:
This diploma thesis deals with digital audio amplifier with universal inputs and its design. The first part describes modulation and audio formats for audio electronics. The thesis contain design of a block diagram of the digital audio amplifier and describes the requirements for functional blocks. As a basic device for audio signal processing was choosen integrated circuit STA326. The thesis continue with circuits design for each blocks with a description of their principles. The next section describes the construction and firmware for microcontroller. The last part of this diploma thesis is targeted on the presentation of the measured parameters of the amplifier. The conclusion summarizes the results that have been achieved and advantages and disadvantages of the digital audio amplifier prototype.
19
Cupák, Jan. "Nízkofrekvenční zesilovač ve třídě D pro aktivní reproduktory." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219135.
Full textAbstract:
This master's thesis deals with design of D class audio final amplifier, which was output power 400 W for 4 ? load impedance. Designed audio amplifier is specifical for active speaker, which consists of satelite speakers and subwoofer. Further more it deals also with other functional blocks, e.g. balanced input preamplifier, active crossover and protection for safety running. Outcome of this work are schemes of each functional blocks of D class audio amplifier, whose functionality was verified by simulation. Thesis also contains full reference material including mechanical arrangement of functional blocks on printed connection board. The conclusion contains the measured parameters of function blocks of produced prototype and complete photographic documentation.
20
BURRA, RAVIKANTH. "DESIGN METHODOLOGIES OF CLASS D AUDIO SWITCHING AMPLIFIERS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123767048.
Full text
21
Jacobs, Deon. "Digital pulse width modulation for Class-D audio amplifiers." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1574.
Full textAbstract:
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.Digital audio data storage mediums have long been used within the consumer market. Today, because of the advancement of processor clock speeds and increased MOSFET switching capabilities, digital audio data formats can be directly amplified using power electronic inverters. These amplifiers known as Class-D have an advantage over there analogue counterparts because of their high efficiency. This thesis deals with the signal processing algorithms necessary to convert the digital audio data obtained from the source to a digital pulse width modulated signal which controls a full bridge inverter for audio amplification. These algorithms address difficulties experienced in the past which prevented high fidelity digital pulse width modulators to be implemented. The signal processing algorithms are divided into modular blocks, each of which are defined in theory, designed and simulated in Matlab® and then implemented within VHDL firmware. These firmware blocks are then used to realize a Class-D audio amplifier.
22
Cartwright, Justin Adam. "A novel technique for harmonic cancellation in class D amplifiers a thesis presented to the faculty of the Graduate School, Tennessee Technological University /." Click to access online, 2009. http://proquest.umi.com/pqdweb?index=2&did=1759989201&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1250263495&clientId=28564.
Full text
23
Thakkar, Darshan Suresh, and darshanst@gmail com. "FPGA Implementation of Short Word-Length Algorithms." RMIT University. Electrical and Computer Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080806.140908.
Full textAbstract:
Short Word-Length refers to single-bit, two-bit or ternary processing systems. SWL systems use Sigma-Delta Modulation (SDM) technique to express an analogue or multi-bit input signal in terms of a high frequency single-bit stream. In Sigma-Delta Modulation, the input signal is coarsely quantized into a single-bit representation by sampling it at a much higher rate than twice the maximum input frequency viz. the Nyquist rate. This single-bit representation is almost exclusively filtered to remove conversion quantization noise and sample decimated to the Nyquist frequency in preparation for traditional signal processing. SWL algorithms have a huge potential in a variety of applications as they offer many advantages as compared to multi-bit approaches. Features of SWL include efficient hardware implementation, increased flexibility and massive cost savings. Field Programmable Gate Arrays (FPGAs) are SRAM/FLASH based integrated circuits that can be programmed and re-programmed by the end user. FPGAs are made up of arrays of logic gates, routing channels and I/O blocks. State-of-the-art FPGAs include features such as Advanced Clock Management, Dedicated Multipliers, DSP Slices, High Speed I/O and Embedded Microprocessors. A System-on-Programmable-Chip (SoPC) design approach uses some or all the aforementioned resources to create a complete processing system on the device itself, ensuring maximum silicon area utilization and higher speed by eliminating inter-chip communication overheads. This dissertation focuses on the application of SWL processing systems in audio Class-D Amplifiers and aims to prove the claims of efficient hardware implementation and higher speeds of operation. The analog Class-D Amplifier is analyzed and an SWL equivalent of the system is derived by replacing the analogue components with DSP functions wherever possible. The SWL Class-D Amplifier is implemented on an FPGA, the standard emulation platform, using VHSIC Hardware Description Languages (VHDL). The approach is taken a step forward by adding re-configurability and media selectivity and proposing SDM adaptivity to improve performance.
24
Liao, Tze Ru. "Delta Sigma Modulated Class D Audio Amplifier." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1907200611045200.
Full text
25
Ming-Jhe, Du. "CMOS Highly-Efficient Class-D Audio Amplifier." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2507200601495000.
Full text
26
HWA-YUAN, LIU, and 劉華元. "Digital Input Class-D Audio Amplifier Design." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/04894591351221180693.
Full textAbstract:
碩士中華技術學院
電子工程研究所碩士班
96
Abstract Due to power saving is current trend for portable electronic product and it is very import to design a system. Although audio amplifier design and application focus quality before,but people are leading concern for efficiency to use consumer product now. First, this master thesis introduce traditional audio amplifier structure and characteristic of Class A,B,AB, moreover, we compare with digital input audio amplifier Class D.we also detail various characteristics and advantage of Class D in the preceding chapter. The major content is discussed how to design a digital input modulator of Class D. We design this digital structure include gain control、3 stage filter、5 order 6 bits sigma-delta modulator and PWM. Per our analysis form actual measurement we have to observe if we achieve original opinion, or not? Maybe we can obtain a way to improve the defects further.
27
Tsai, Chun-Hao, and 蔡俊豪. "Design of Filterless Class D Audio Amplifier." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/22201137769579819716.
Full textAbstract:
碩士國立臺灣大學
電機工程學研究所
95
Over the years, the commercial audio amplifiers are dominated by Class AB amplifier. However, most of Class AB amplifier power efficiency is below 70%, which reduces the overall system battery lifetime and increases the heat dissipation. Therefore, the Class D amplifier with the advantages of high efficiency has been widely investigated recently comparing to the Class AB amplifier. A Class-D amplifier with conventional PWM modulation requires an output filter which needs large area and increasing cost. Therefore, we use unipolar switching pulse width modulation scheme to realize a filterless Class-D power amplifier. In this thesis, we focus on the implementation of Class D amplifier on a monolithic integrated circuit. We observed that the total harmonic distortion (THD) increases due to non-linearity in the triangular wave. To overcome this problem, negative feedback is applied to reduce the harmonic distortion. The circuit is designed using TSMC (2P4M) 0.35um 3.3V CMOS process. The entire circuit contains an error amplifier, two hysteresis comparators, a triangular wave generator, gate-driver circuits, and the H-bridge. The details of the entire circuit will be described thoroughly in this thesis. When a 0.4V, 1KHz input sine wave is applied, the maximum THD is 0.13% and the efficiency is 88.5%.
28
Ru, Liao Tze, and 廖澤儒. "Delta Sigma Modulated Class D Audio Amplifier." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/15258309802344855509.
Full textAbstract:
碩士國立臺灣大學
電子工程學研究所
94
In the portable devices such as PDA, MP3 player or mobile phone and mobile amusement system, the battery life is a very important issue. In order to strengthen the battery lifetime, the high power efficiency will be better. The efficiency of power amplifier is very important. The traditional class A or class AB have lower efficiency than class D. The efficiency of class D will achieve 100% theoretically. The class D audio amplifier is usually with PWM modulator or delta sigma modulator to transform the input signal to a series of pulse signal to control the class D circuit. The traditional PWM modulator or delta sigma modulator are all with clock circuit inside. In order to reduce the clock circuit, a delta sigma modulator with hysteresis comparator is presented in this thesis. In this topology, we can save the chip area and also can achieve a good performance in THD and efficiency. The THD is 0.9% and the efficiency is 87% with 10K Hz input signal in this thesis.
29
Du, Ming-Jhe, and 杜明哲. "CMOS Highly-Efficient Class-D Audio Amplifier." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/06790414067614930660.
Full textAbstract:
碩士國立臺灣大學
電子工程學研究所
94
A one-chip integrated circuit of a 2-W class-D audio power amplifier with very high efficiency using a CMOS technology is presented. Compared with traditional class-AB amplifiers that are very poor at efficiency, most below 50%, the proposed class-D amplifier has the efficiency of 90% at the smaller distortion level. The class-D amplifiers generate pulse-width-modulated (PWM) signals by comparing a triangle-wave with input-signals. An output stage with zero dead time and high efficiency is applied to improve the linearity and reduce wasted battery energy. An approach to reducing distortion is applied by using feedback calibration.
30
Wen, Tsai-sheng, and 溫在勝. "A FILTERLESS DIGITAL CLASS-D AUDIO AMPLIFIER." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/77717355543363797232.
Full textAbstract:
碩士大同大學
電機工程學系(所)
105
Class-D amplifiers become more and more important on the personal mobile system, because of their high efficiency. A conventional class-D amplifier needs a low-pass filter between the output stage and the speaker, but these filters which need to endure high output power usually quite bulky. This design uses filterless technology to eliminate the problem and reduce the circuit area. These days, many companies use USB interface to replace the traditional audio jack. Filterless class-D amplifiers output the digital signal directly, and thus have the potential on these kinds of applications. This thesis will review analog UPWM, digital PWM, digital PDM, and mixed-signal architectures, and make comparison. A chip using digital PDM architecture has been implemented with TSMC 0.18μm CMOS process and the standard cell library provided by TSMC. There is a 16-bit input data bus on this chip. The simulated THD of this chip could achieve 0.000059%. The chip area of the circuit is about 1.27 .
31
SHIH-HSIANG, LIN, and 林世祥. "High Efficiency Class-D Audio Amplifier Design." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/17599257173454224387.
Full textAbstract:
碩士聖約翰科技大學
電子工程系碩士班
97
For the fast growing of electric products, the consumer electronic products are designed toward the direction of tiny and portable. Audio amplifiers are mass needed in these products. The major demands of the consumer products, for example, are: power dissipation, product volume, and heat radiation. The most important design parameter of these is power efficiency. Increasing the power efficiency, it not only lasts the Class-D amplifier battery lives, but also operates in an extra low operating temperature. This paper designs Class-D amplifies based on self-tuning master-slave architecture and sliding mode control architecture. They are implemented with TSMC 0.35um 2P4M CMOS process. By using double triangle-wave generators and double feedback circuits in self-tuning mater-slave architecture, the efficiency of Class-D amplifier is increased and the total harmonic distortion (THD) is decreased. The chip size is 1.575mm x 1.575mm. The measure results show that when the input voltage is 0.6V, the power dissipation is 204mW, and the power efficiency is 89%. Second, the sliding mode control Class-D amplifier is using the sliding mode control modulation and bridge-configured architecture. The chip size is 1.575mm x 1.575mm. The simulation results show that when the input voltage is 0.6V, the power dissipation is 2.13W, and the power efficiency is 90.2%.
32
KuhWun-Rung and 柯文仁. "Design and Implementation of Class D Audio Amplifier." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/45953404292422340546.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
95
This thesis is a study on Class D audio amplifier. By using unipolar pulse width modulation(PWM), current tracking, and PID compensator, the output current can follow the input acoustic signal. This design is quite different from those of traditional amplifiers. The output filter is not required here as the output current is such close to the input signal. First the Matlab and Simulink is used to find the constants of the PID controller by trial and error. Secondly, the Pspice is used to simulate the entire circuit. High speed elements have been chosen for the circuit application to make the design results satisfactory. The simulation results and the implementation ones are quite matched.
33
SU, PO-KAI, and 蘇柏愷. "Electromagnetic interference analysis for Class-D Audio Amplifier." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/6r76wx.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
105
Electromagnetic Interference may be generated by operating of Electrical equipment and electronic product, so as to interfere in operation of other equipment, and even affecting human health. Switching frequency of each transistor must work rapidly in order to obtain better performance of Class D audio amplifier. This is the main source of Electromagnetic Interference. This thesis proposes that used frequency-hopping triangular wave as a carrier of Class D audio amplifier. It causes high power of harmonic no longer concentrated on switching frequency, and spreading the power into a narrow frequency range. This method can obviously reduce Electromagnetic Interference of output signal. Frequency Hopping triangular wave consists of Linear Feedback Shift Register、 Window Comparator, and the setting current circuit in this thesis. Linear Feedback Shift Register consisted of D flip flops and XOR gate. It generates numbers of pseudo random codes when triggered, and these codes separately control the transistors that cause different current to charge or discharge the capacitor of the setting circuit, so we can obtain a triangular wave with difference frequency; Window Comparator fixes the voltage on the range of and of capacitor. This circuit is fabricated by TSMC 3.3V-0.18μm process, load of the buzzer is 8ohm. According to experiment results, the total-harmonic distortion (THD) is about 53dB、 the signal-to-noise ratio (SNR) is about 74dB and the reduction of EMI is about 13dB of the thesis.
34
Wu, Chi-Shuo, and 吳啟碩. "Design and Implementation of Class-D Audio Amplifier." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/45775832435825156603.
Full textAbstract:
碩士國立中央大學
電機工程研究所碩士在職專班
98
The purpose of this paper is to explore the design and implementation of class-D audio amplifier. It is known that class-D amplifier is a nonlinear system. Somehow, in conventional method, class-D amplifier is usually designed through linear model. This indirect method in class-D amplifier design could not analyze the stability of the system directly. In this study, several significant class-D amplifiers in the literatures have been reviewed, and DSMs (Delta-Sigma Modulators) was chosen to be the A/D (Analog to Digital) converter for the class-D audio amplifier due to the low cost, simple circuit and accuracy in A/D converting. The sliding mode control design methodology is developed for designing the continuous time integrator DSMs. It effectively solves the problem for not analyzing the system on the stability in conventional way of designing DSMs. Meanwhile it also improves the drawbacks of DSMs which could only reach up to 50% modulation in stable operation and output data rates are more than 1MHz. In this paper, the design of second and third order DSMs are presented. The proposed DSMs enables the modulation rate up to 75% in stable operation and output data rate are decreased to 100kHz〜250kHz. Furthermore, some parts of the D/A(Digital to Analog) in the system, which includes the shift of DSMs output levels, power MOSFET gate driver, switching output stage, and lossless low-pass filter for filtering high frequency switching noise, are analyzed and implemented as the practical needs. A completed design method of class-D audio amplifier is presented in this study. The proposed amplifier exhibits the features in fast response, strong robustness, easy to implement, and can be produced directly by the commercial electronic elements. Experimental result confirms that the proposed design approach is surely feasible. In the 3.5 ohm load with the RMS output power of 100 watts, the measured maximum power efficiency is 80%, and THD+N that is less than 0.73%, and SNR of 75dB.The proposed class-D audio amplifier can be applied to general audio needs, and is more suitable for the application of the public broadcasting systems that require high efficiency, high power output, such as the air defense alarm system, disaster warning system, outdoor public address system, etc.
35
CHEN, WEI-MING, and 陳威銘. "Multilevel Class D Audio Amplifier Using Active Inductor Technique." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ftwxxp.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
106
With the advancement and trend of technology, it is nothing more than portable electronic products that are small in size, low in cost, high in efficiency, and so on. In the field of audio systems, Class D Audio Amplifier has been widely used in it, especially 4C products. Because of its high efficiency and small size, it is not available in other types of audio amplifiers. In this study, we propose a multilevel converter based on active inductor architecture to design a class D audio amplifier with multilevel output signals to convert the original two-level signal into a multi-level signal. The multilevel technique is composed of a time-division-adder (TDA) and a multilevel converter with an active-inductor (AI) followed by modulator. Each active inductor is segmented into a small set of multiple equal-sized, small drive current active inductors, and the modulated two-level signal is quickly quantized into a decimal number by using a time-division-adder. The number of small sets that are required to be activated by the active inductor is controlled according to the drive current required by its load, and the same output power is achieved with a minimum of working circuits, which greatly reduces unnecessary power consumption on the circuit. Active inductors are composed of several operational transconductance amplifiers (OTAs) and a fixed capacitor. The circuit characteristics are similar to those of general inductors. According to its use of the differential loop of the operational transconductance amplifier, and control the input bias current source of the operational transconductance amplifier, the equivalent inductance of the elastically adjustable transconductance value g_m can be formed. However, the active inductor is applied to the multilevel converter, and the voltage division characteristic between the inductors is utilized to generate a multi-level output signal of equal voltage difference.
36
Liao, Yu-Cheng, and 廖育晟. "Filterless Class-D Audio Amplifier with Multi-Level Converter." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/64940196094663101083.
Full textAbstract:
碩士國立暨南國際大學
電機工程學系
101
In this thesis, we implement two different audio amplifiers architecture, research target is purpose to improve better SNR and THD. This thesis can be divided two part： The first part, we use 0.18μm CMOS technology provided by TSMC, design a clock free class-D audio amplifier. In circuit architecture, we use a simple two-stage operation amplifier as a comparator, generating pulse width modulation. Make analog signal convert to digital signal, and reduce distortion situation, and through the power amplification circuit to increase the current, purpose to increase power of pulse width modulation. The last part is a low pass filter composition of inductance, capacitance and speaker. It can revert pulse width modulation to original analog signal, and drive to latter stage speaker load. The second part, this circuit is also use 0.18μm CMOS technology provided by TSMC, design a filterless class-D audio amplifier with multi-level converter. The basic architecture is multi-level signal. Multi-level architecture can roughly divided to five parts：1. Comparator 2.Shift registers 3.Combined full adder 4.Decoder 5.Multi-level converter. In this method, pulse width modulation signal is arrange too many time divisions and integrate into a binary form. Binary form is decoded to control signal for multi-level converter. Multi-level converter will convert multi-level signal to speaker, replace traditional two-stage signal. So improve THD and SNR without sacrificing power efficiency. Since, this work can be used in any class-D audio amplifier, designing by insert shift registers and adder behind modulator and replace output stage with multi-level converter.
37
Chang, Bo-Chun, and 張博鈞. "EMF of Class-D Audio Amplifier on Biological Effect." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18274522921760725698.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
97
The research in this literature is intended to explore the Class-D audio power amplifier; a digitized traditional analog audio power amplifier which could generate ELF & RF electromagnetic effect on humankind body. A particular setup environment of experiment in this research results the ELF & RF powers generated from Class-D audio power amplifier are larger than the traditional analog audio power amplifier, the ELF power is significant and its electromagnetic effect must be considerable on humankind body is in according with the ICNIRP regulation. Two live examples of ELF protective methods of the experimental device have been demonstrated as well at the chapter 6 of this literature.
38
Sun, Shao-Ming, and 孫紹茗. "Circuit Implementation of A PWM Class-D Audio Amplifier." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/44144231676284639499.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
94
The Class-D amplifier, for its high efficiency, has drawn much attentions recently. However, due to its switching operation, the linearity is needed to be improved by comparing with conventional linear amplifiers. Therefore, the negative feedback is applied in this thesis to reduce the harmonic distortion for better linearity. In addition, to avoid the shoot through current due to both power transistors are switched on at the same time, the dead time control is adopted. The over-current protection circuit is also added to prevent the short circuit by poor wire connection. The large current induced by the short circuit would destroy the overall system potentially. A single-ended input, differential output Class-D audio amplifier with pulse-width modulation (PWM) is implemented with TSMC 0.35um 2P4M 3.3V/5V Mixed Signal CMOS process. The active area of the amplifier is around 0.99 x 0.93 mm2, and the total area is 1.3 x 1.3 mm2. The simulation results show 90dB of SNR and 82% of efficiency can be achieved. THD is around 0.045% while Class-D amplifier deliver 240mW.
39
LIN, YOU-DA, and 林佑達. "An Audio-Hole-Free Over-Temperature Protection Technique for Class-D Audio Amplifier." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/r824g8.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
104
Class-D audio amplifiers have been widely used in a variety of audio equipment. It is characterized by high efficiency and small size that is not able to achieve on other types of amplifiers；However, overheating problems will occur when a circuit has been processed signal at high speed and provided high power in a long time. The focus on this thesis was applying varactor to a triangular wave generator in a class D audio amplifier. Due to the effects of temperature, the current temperature sensor must adjust the value of varactor, and then control the signal’s sampling frequency. Finally, the cooling effect of protection is achieved by reducing power consumption. Furthermore, The author can obtain a current-frequency linear curve relationship by using a window comparactor which locks the varactor’s operating voltage in the range. The varactor, which was operated in Inversion-mode(I-MOS), made individual varactor’s operating region shifting by increasing the varactor’s voltage between the gate and the source. And then the varactor was connected in parallel to increase the overall voltage’s adjustable range. The required varactor’s value of the circuit was combined by the difference between the each varactor’s voltages.Finally, we can reach temperature protection effect because operating frequency is greatly reduced to make power consumption be reduced effectively.
40
Yang, Wen-Tung, and 楊文棟. "Design of Delta Sigma Modulator and Class D Audio Amplifier." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/59863781996633984523.
Full textAbstract:
碩士國立臺灣大學
電機工程學研究所
99
Applications of the delta-sigma modulator in digital and analog circuits are discussed in this thesis. Delta sigma modulator can be used in digital circuits such as digital-to-analog converters and fraction-N frequency synthesizers; or in analog circuits such as analog-to-digital converters, DC-DC converters and switched-mode power amplifiers. According to these applications, a digital modulator for fractional divider and an analog modulator for nonlinear switched-mode power amplifier are proposed in the thesis. We can decrease locking time and reduce channel bandwidth by applying fractional divider in fractional-N frequency synthesizers. Therefore, a digital MASH 1-1-1 modulator based on the carry-look-ahead adder which can integrate with multi-modulus divider to realize the fractional division function is designed and presented in this thesis. Class-D power amplifiers have been widely used as the audio amplifiers in portable devices. The greatest advantage is the high power efficiency of this kind of amplifier, which can improve the operating time and lower the heat dissipation. Nevertheless, the total harmonic distortion in nonlinear amplifiers is much higher than the linear ones. Therefore, the applications of the nonlinear amplifiers are limited to lower-quality audio systems. A class-D audio amplifier system based on a third-ordered analog delta-sigma is proposed and designed in this thesis.
41
Lee, Yueh-Lin, and 李岳霖. "Design and Implementation of a Digital Class-D Audio Amplifier." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/74674784978260375911.
Full textAbstract:
碩士長庚大學
電機工程研究所
93
Recent advances in semiconductor technology have renewed interest in class-D audio amplifiers, especially for portable devices and consumer electronics. In addition to its higher efficiency, class-D amplifiers are smaller, lighter, streamlined, cool and quiet with extended battery life compared to the conventional linear amplifiers. A typical class-D amplifier increases the efficiency of amplifiers in consumer and professional applications from the industrial norm of approximately 50 percent to 90 percent or better. In this thesis, an FPGA (Field Programmable Gate Array)-based Class-D audio amplifier is designed, implemented and tested. The design makes use of digital signal processing and a hard- or soft-based switching power stage to provide both high fidelity and high efficiency. According to the experimental results, the proposed prototype is able to deliver more than 15 W into an 8 load with an efficiency of 80% and total harmonic distortion less than 40 %.
42
Yang, Cheng-Chung, and 楊健忠. "Design and Circuit Implementation of Digital Class-D Audio Amplifier." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/66416396664236345389.
Full textAbstract:
博士國立成功大學
電機工程學系碩博士班
96
The system design and circuit implementation of digital-input class-D audio amplifiers (digital amplifiers) are presented in this dissertation. Due to the high power efficiency of class-D amplifiers, conventional class-A and class-AB amplifiers are gradually being replaced. Digital amplifiers that can achieve high power efficiency and can directly amplify digital audio signals will eventually become the design trend of audio amplifiers. In this dissertation, the design of delta-sigma modulators (DSMs), power MOSFET drivers, and the over-current protection for a 5.1-channel single-chip digital amplifier with 100W root-mean-square (RMS) total output power is presented. To the best of our knowledge, it is the first highly integrated 5.1-channel single-chip digital amplifier. In addition, this dissertation proposes a novel DSM design method to increase the linear output power for future digital amplifier designs. In the 5.1-channel digital amplifier, DSMs with a low over-sampling ratio (OSR) are used in circuits that convert pulse-code-modulation signals into pulse-width-modulation signals. A modified DSM structure is adopted to avoid the degradation of signal-to-noise ratio (SNR) and the maximum stable input magnitude. The improvement is especially obvious under low OSR conditions. For large power MOSFET drivers, driver circuits with unequal slopes of rising and falling edges are proposed to reduce the imperfection of power stage outputs. To protect this amplifier from short circuits and improper loads, a new over-current protection circuit with high supply-noise rejection and low sensitivity to parameter variation of devices is proposed. This single-chip amplifier is fabricated with a 0.35 um 1P3M 3.3/18-V C/D-MOS process. The total chip area is about 50 mm2. Both peak SNR and dynamic range are 84 dB with an A-weighted function compared to the output noise at full scale input. Both peak SNR and dynamic range are 92 dB compared to the output noise at zero input. The RMS output power of five normal channels on five 8 ohm loads and a subwoofer channel on a 3 ohm load are 13WX5 and 35W, respectively. The total RMS output power is 100W @ a 0.3 % total-harmonic-distortion-plus-noise (THD + N) ratio. The measured minimum THD + N ratio is 0.045 %. The measured maximum power efficiency is 88 %. A 128-pin QFP package with an exposed thermal pad is used. With high power efficiency and the exposed thermal pad, no extra heatsinks are necessary. A low cost 5.1-channel high power amplifier system with a small volume is possible. This is a big design breakthrough in high power 5.1-channel Hi-Fi audio amplifier systems. In addition to the aforementioned circuit implementations, this dissertation proposes a novel method for increasing linear output power under the same VDD and loads. This method can save power module costs and can be used in future designs. In digital amplifiers, the linear output power range is usually dominated by DSMs. In a conventional single-stage high-order DSM, part of its root locus is outside the unit circle so the stable input range is limited. A new method is proposed for designing a DSM with its root locus inside the unit circle (RLiUC DSM). The RLiUC DSM can maintain a high signal-to-noise plus distortion ratio (SNDR) at the full scale input magnitude. An RLiUC DSM designed using the proposed method with full scale stable input magnitude and a conventional DSM designed with high peak SNDR are combined to extend the linear output power range of digital amplifiers. Methods to implement this combination are also presented. Compared to the digital amplifiers with conventional DSMs, the maximum linear output power is increased by 20 %. Compared to the state-of-the-art design, the output power region which has very low THD + N ratio is extended 160 % by the proposed method.
43
HSIEH, CHUNG-JUI, and 謝忠叡. "Over Temperature Protection Design of Multilevel Class D Audio Amplifier." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5777bd.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
106
In recent years, class D audio amplifiers are widely used in various audio systems. In general, class D audio amplifiers have filters to reduce noise and harmonic distortion, but many applications are limited by system size, must sacrifice performance, adopt a filterless design, reducing signal using a filter formed by the inductance and capacitance of the wire and the speaker itself. In addition, reliability issues are also very important for class D audio amplifiers, when a circuit or system is operating for a long time or is not operating properly, problems that may cause temporary or sustained temperature rises. I was in this study, combining previously developed multilevel class D audio amplifier technology, achieve its over temperature protection design. Class D audio amplifier implemented in this study, its multilevel technology allows amplifiers to exhibit performance that is not inferior to the use of filters in filterless designs. Over-temperature protection design is based on dynamic adjustment of output power, when the overtemperature protection program is operating, the circuit continues to operate, realize the over temperature protection of the audio hole free. The multilevel class D audio amplifier in this study contains three parts, Pulse width modulation, Multilevel signal converter, and Multilevel output converter, the audio signal is turned into a digital signal with different pulse widths via the pulse width modulation, then, multilevel signal converter calculates the moving average of pulse width, quantified as control signal, control multilevel output stage circuit output corresponding to multilevel output voltage signal. The order of the multilevel output signal is controlled by a multilevel signal converter, the correlation between the operating clock and the pulse width modulation of the carrier clock, over-temperature protection design by adjusting the operation and frequency of multilevel signal converters, control the order of multilevel output signals, limit output signal power. Over-temperature protection design includes a phase-locked loop, current-type temperature sensor and clock control circuit, phase locked loop locks pulse width modulated carrier clock, and provide frequency multilevel pulse signal in multilevel signal converter, a current-type temperature sensor senses a temperature state and gives a quantized value to the clock control circuit, according to the state of temperature rise, the clock control circuit sends the reduced-order control signal to the multilevel signal converter and the frequency divider in the phase-locked loop, dynamically adjust the audio amplifier output order, by reducing the output power, suppression of temperature increase. I was in this study, a circuit that achieves a decrease in output power when the temperature rises, when the temperature rises from 60℃ per degree 10℃, output power decreased by 8.4%. When the user is in normal use, over-temperature protection mechanism suppresses both output power and temperature rise, the entire process of multilevel class D audio amplifiers does not need to cut off the power and audio hole free problem.
44
"Class D Audio Amplifier Design with Power Supply Noise Cancellation." Master's thesis, 2015. http://hdl.handle.net/2286/R.I.36035.
Full textAbstract:
abstract: In this thesis, a digital input class D audio amplifier system which has the ability
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.Dissertation/Thesis
Masters Thesis Electrical Engineering 2015
45
Hsu, Chih-jung, and 許志榮. "Sliding Power Supply Circuit for Multilevel Class-D Audio Amplifier." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/36263073303688556469.
Full textAbstract:
碩士國立雲林科技大學
電子與資訊工程研究所
99
This paper presents a robust power supply circuit for multilevel converter of class-D audio amplifier. Based on pulse-width-modulation buck converter, we develop a sliding-switching technique comprises a loading monitor and a voltage level controller. The loading monitor continuously checks the internal control signal of multilevel class-D amplifier to identify whether the loading is light or heavy. The voltage level controller then feedbacks corresponding voltage level to modulate pulse width of control signal in buck converter and adjust supplying current and power delivery. The proposed sliding-switching technique stabilizes the voltage variation of power supply under the situation of alternating light and heavy loading and consequently enhances the performance of total-harmonic-distortion. To demonstrate the practicability, an integrated multilevel class-D amplifier with proposed power supply circuit is implemented under TSMC 0.35μm process. The simulation results show that the total-harmonic-distortion is improved more than 11dB without increasing power consumption of circuit.
46
Chung, Chih-Wei, and 鐘志偉. "Adaptive Overcurrent Protection Scheme for Multilevel Class D Audio Amplifier." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/40130457076684379136.
Full textAbstract:
碩士國立雲林科技大學
電子與資訊工程研究所
97
In this thesis, we propose an adaptive protecting scheme against the overcurrent of multilevel output class-D audio amplifier, which enable audio amplifier to prevent from causing the problem of audio holes. The core concept is to change the output signal density of pulse-width modulation (PWM) by detecting the current amount of the output stage and then feedbacking the controlling signal with adjustable duty cycle. Due to the decrease of the pulse density of the pulse-width mudulation, it makes that both the resulting value of the time-division-adder (TDA) and the output voltage level of the dual H-bridge multilevel converter decrease according to the duty ratio. In this way, we reach to that decreasing the additional current caused by overcurrent by adjusting the output voltage so as to keep the maximum power in the limited range all the time. By analyzing and simulating, it proofs that the proposed methodology not only effectively solves the overcurrent problem of audio amplifier, but also is different from the conventional ones protecting circuit by means of switching off power transistors directly. So there is not any problem of audio holes.
47
WANG, LI-JIN, and 王梨瑾. "An Audio-Hole-Free Over-Temperature Protection Technique of Multilevel Class D Audio Amplifier." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8b39uk.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
105
The Class-D audio amplifier is widely used in a variety of sound systems. It is compared with other types of audio amplifier, high efficiency, and small size；When a circuit has been the processed signal at high-speed in a long time will cause overheating problems. The common practice is to circuit the voltage, current, and frequency to do the temperature improvement. This paper to change the output power of multilevel Class D audio amplifier for research. In this paper, the continuous dynamic regulates circuit in the D class audio amplifier output power. When the current temperature sensor (current temperature sensor) detects a multilevel class D audio amplifier over-temperature, it will regulate the dynamic regulate circuit to control the output power, and finally, reduce the power consumption to achieve continuous over-temperature protection effect. And then use the signal before the frequency to regulate the multilevel class D audio amplifier output power, and effectively reduce its power consumption, to achieve Uninterruptible Power and audio-hole-free problem over-temperature protection effect. Keywords: Multilevel Class D Audio Amplifier; Temperature Sensor.
48
Liu, Rui-feng, and 劉瑞峰. "A Study on Over-Temperature Protection for Class-D Audio Amplifier." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/12348400519925358725.
Full textAbstract:
碩士國立雲林科技大學
電子與光電工程研究所碩士班
101
Class D audio amplifiers have been widely used in modern equipment and contained highly efficiency on power delivery. However the excessive power-loss will convert into heat after operating for a long time and the circuits have over-temperature problem. In this paper, I will combine the several circuits to change the triangular wave generator output amplitude. And the circuit includes current comparator、shift register and triangular wave generator combined with switch capacitors. The current comparator is used in comparing with a fixed reference current and the other current produced by a linear temperature sensor. The comparator result is control signal that sends to the shift register which delivers to the switch capacitor to sequentially switch and produced capacitor value, and the triangular wave generator generates different amplitude. Furthermore, the output power of the power transistor of the class D amplifier will be reduced. The simulation results showed that the shift signal to switch in different capacitance; change triangular wave generator output amplitude and let power transistor would have different maximum output power. And also the level of Class D amplifier reduced by the combining circuit.
49
Lin, Yu-Hsiu, and 林裕修. "Novel Three-Level Modulation Technique for A Class-D Audio Amplifier." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/89841129522886394608.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
93
This thesis presents a novel three-level modulation technique for a Class-D audio amplifier, attempting to improve the poor performance of the conventional two-level modulation scheme at low input levels. The main drawback of the conventional two-level PWM (pulse-width modulation) and SDM (sigma-delta modulation) Class-D amplifier is that, with a zero input or small input, the excessively fast switching action at the output causes unwanted switching loss and switching noise, resulting in unnecessary energy waste and SNDR degradation. The presented three-level modulation circuit mainly consists of a linear feedback compensator, two comparators, and a switching logic circuit. The simulation and experimental results shows that the proposed three-level modulation s cheme outperforms the two-level sigma-delta modulation scheme in both efficiency and performance.
50
Shen, Jian-Hong, and 沈劍虹. "Design of Integrated Boost Converter and Class-D Audio Power Amplifier." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/w556s2.
Full textAbstract:
博士國立臺北科技大學
電腦與通訊研究所
102
In the first part of this thesis, a high-efficiency fast-transient-response V2-controlled boost converter with small equivalent series resistor (ESR) capacitor is presented. The proposed boost converter can achieve fast and stable load transient response without relying on equivalent series resistance of the output capacitor. The switching frequency of the proposed boost converter is 500 kHz for nominal 2.5~4.2V input and 3.3~5V output application. Experimental results show the transient recovery time inheriting the advantage of V2 control is shorter than 6.7μs with the load step from 250 to 20 mA and the highest efficiency can be up to 95.4%. The proposed boost converter has been fabricated with a 0.35μm 2P4M 3.3V/5V CMOS process, the total chip area is about 2.25 mm2, including PADs. In the second part of this thesis, we presented two class-D amplifiers, compared their differences and explained why distortion performance can be modified. The traditional H-bridge class-D audio amplifier has a disadvantage of low power efficiency which is worse than realized. However, the proposed circuit improves the drawback and provides high power efficiency at the same time. When a 0.7VPP and 1 kHz sine wave is used as an input signal, the minimum THD is 0.029% and the maximum power efficiency is 83%. The fully differential class-D audio amplifier is implemented with a TSMC 0.35μm 2P4M 3.3V CMOS process, and the chip area is 6.6 mm2, including PADs. In the third part of this thesis, a class-D audio amplifier that employs sigma-delta (ΣΔ) modulation techniques with compensators is presented. The compensator increases the audio-frequency loop gain, and leads to better rejection of audio-frequency disturbances. At a sample rate of 10MHz, the proposed class-D amplifier achieves 0.04% THD and a signal to noise ratio of 87dB with efficiency above 92%. The proposed audio amplifier was implemented in a TSMC 0.35μm 2P4M 3.3V CMOS process and the chip area is 1.95 mm2, including PADs. In the fourth part of this thesis, this part presents an integrated low-voltage THD reduction high efficiency class-D audio amplifier using inverter-based operational transconductance amplifiers (OTAs). We propose a negative feedback loop which can compensate for external perturbations and improving output precision. The use of inverter-based OTA and comparator provides low-voltage operation and low-power dissipation. The audio amplifier operates with a 1.5V supply voltage with maximum power efficiency of 90%. The proposed class-D amplifier was implemented using a TSMC 0.18μm 1P6M CMOS process, and the active chip area is 1.87 mm2, including PADs.