Class D Audio Amplifiers Offer Theoretical Efficiency of 100% Which Presents Advantages Such as Power Saving and Smaller Heat Generation.DUBLIN, Ireland -- Research and Markets (http://www.researchandmarkets.com/reports/c34632 ) has announced the addition of Class D Audio Amplifier IC Study, 2005-2006 to their offering. Class D audio amplifier, also named switch amplifier, is used to transform the input analog audio signal or PCM (1) See phase change memory. (2) (Plug Compatible Manufacturer) An organization that makes a computer or electronic device that is compatible with an existing machine. digital information into pulse signal of PWM (Pulse Width Modulation) A modulation technique that generates variable-width pulses to represent the amplitude of an analog input signal. Like its fixed-width pulse density modulation (PDM) cousin, the output switching transistor is on more of the time for a or PDM (1) (Product Data Management) An information system used to manage the data for a product as it passes from engineering to manufacturing. The data includes plans, geometric models, CAD drawings, images, NC programs as well as all related project data, notes and , and to control large power switch device to put through/cut off audio power amplifier Power amplifier The final stage in multistage amplifiers, such as audio amplifiers and radio transmitters, designed to deliver appreciable power to the load. . The theoretical efficiency of class A audio amplifier is 25%, and its real efficiency is about 15-20%; the theoretical efficiency of class B is about 75%; the theoretical efficiency of class AB is about 75% as well with a real efficiency between 50%-70%; the theoretical efficiency of class D is about 100% with a real efficiency of more than 85%. The high efficiency of class D offers lots of advantages, such as power saving, which is quite important for MP3 and music mobile phones. Power saving means longer paying time, and can attract more clients. Another advantage is a smaller heat generation, which can reduce heat management costs. For instance, large power class AB amplifiers See amplifier classes. usually need radiator, but the as powerful class D amplifiers An audio amplifier that works in the digital domain. It generates the equivalent analog output for the speakers by using pulse width modulation (PWM) or pulse density modulation (PDM) rather than the traditional digital-to-analog conversion. See PWM and PDM. do not need it. The class D audio amplifier circuit is has a comparably smaller size. Besides, under most conditions, it does not need any heat sinks A material that absorbs heat. Typically made of aluminum, heat sinks are widely used in amplifiers and other electronic devices that build up heat. Small heat sinks are the most economical method for cooling microprocessors and other chips. ; therefore, the entire size can be reduced greatly. It is quite important for car audio and mobile phone due to the strict size requirements. Currently, there are 108 varieties of class D audio IC. The audio amplifier IC markets, which are sensitive to volume, efficiency etc, such as mobile phones, portable audio/video players, flat screen televisions, projection televisions, car audios, notebook computers etc, are all the potential markets of class D audio amplifier IC. Class D audio amplifier IC also has many disadvantages such as EMI (ElectroMagnetic Interference) An electrical disturbance in a system due to natural phenomena, low-frequency waves from electromechanical devices or high-frequency waves (RFI) from chips and other electronic devices. Allowable limits are governed by the FCC. (Electro Magnetic Interference), distortion, narrow frequency response rage, narrow dynamic range, high power requirements and costs, etc. Considering the mobile phone market, the major problems are EMI and cost. However, this market adopts platform strategy; and it is impossible to enter the market solely relying on class D audio amplifier IC. Therefore, the professional manufacturers of class D audio IC should aim at the markets of flat screen television, car audio and multi-channel audio. Considering those markets, the major problems are cost and timbre timbre Quality of sound that distinguishes one instrument, voice, or other sound source from another. Timbre largely results from a characteristic combination of overtones produced by different instruments. , especially the timbre. Topics Covered 1. Brief Introduction of Class D Audio Amplifier 1.1 Basic principle of class D amplifier 1.2 Comparison between class D amplifier and other amplifiers 1.3 Advantages of class D audio amplifier 1.4 Disadvantages and resolutions of class D audio amplifier 2. Class D Audio IC Industry 2.1 Development of class D audio IC 2.2 Example of class D audio amplifier IC for mobile phone application 2.3 Application status of class D audio amplifier IC 3. Class D Audio Amplifier IC Market 3.1 Music mobile phone market 3.3 Portable audio/video player 3.4 Car audio 3.5 Flat screen television 3.6 Home audio system 3.7 PC Multi-media audio 4. Audio IC Manufacturers 4.1 YAMAHA 4.2 TI 4.3 National Semiconductor 4.4 Maxim 4.5 On Semiconductor 4.6 Philip 4.7 Microsemi 4.8 ST 4.9 CIRRUS 4.10 ADI 4.11 WOLFSON 4.12 New Japan Radio 4.13 ZETEX 4.14 AT CHIP 4.15 Monolithic Power 4.16 SIGMATEL 4.18 Power Analog Microelectronics 4.19 Tripath Selected figures and tables Companies Mentioned - YAMAHA - TI - National Semiconductor - Maxim - On Semiconductor - Philip - Microsemi - ST - CIRRUS cirrus coarse hairs, longer than those in the normal coat and less coarse than tactile hairs. cirrus capitis hairs of the forelock. cirrus caudae hairs of the tail. - ADI - WOLFSON - New Japan Radio - ZETEX - AT CHIP - Monolithic Power - SIGMATEL - Power Analog Microelectronics - Tripath For more information visit http://www.researchandmarkets.com/reports/c34632 |
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