| Compared with the traditional audio power amplifiers, the class D amplifier possesses large development foreground. The reason is the later has several characters, such as small volume, high efficiency, low distortion and high power make it apply to mobile devices more and more widely.The familiar linear and non-linear power amplifiers are introduced firstly, and then the analysis of advantages and disadvantages of these amplifier is given in this thesi. Comparison between the traditional class D power amplifier and the amplifier that is based on an improved pulse-width modulated (PWM) modulation for filter-less class-D is done in detail. Filter-less class D amplifier consists of an operational amplifier, a comparator, a tri-angular generator, a power output stage and the protection circuits. The class-D amplifier has been verified in Silicon and can meet all requirements.EDA tool CADENCE is used for the circuit simulation and layout design. The process of CSMC0.5um DPTM CMOS Mixed signal standard CMOS is selected for manufacturing. Testing results show that the output power is3W, the maximum efficiency is higher than90%and THD is smaller than10%. |
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