The Test And Simulation Of Single-Channel Audio System Based On TAS2560

The design concept of Class D power amplifier is completely different from that of the former analog power amplifier.The direct work saturation and cut-off state of power transistor in Class D power amplifier effectively avoids the power consumption problems caused by the transistor linear working area in analog power amplifier.The power consumption of transistor saturation voltage drop is the main power consumption of Class D power amplifier.In ideal condition,the transistor breakover internal resistance can be deemed as zero;in cut-off state,there will be no power consumption due to the infinite internal resistance.Therefore,its theoretical efficiency ranks top among all the power amplifiers.Higher efficiency means lower power consumption.Besides,the problems in heat emitting and dissipation have been solved.As a result,under the same nominal power,Class D power amplifier can obtain smaller encapsulation size and application circuit scale.Currently,Class D power amplifier is widely used in the terminal products.The thesis focuses on building the complete link simulation in audio system and realizing the co-simulation of circuit model and the physical model of acoustical generators.An integrated design of Class D audio system contains the audio circuit hardware design and loudspeaker design.Based on the Class D power amplifier chip TAS2560 of SMART PA series by Texas Instruments,sets up the single channel circuit of Class D audio power amplifier as the actual model machine,conducts the tests and analysis,and establishes the TAS2560 input and output audio data collection system with STM32F429 as the master control core.The thesis states the working mechanisms of Class D power amplifier,obtains the mathematical expression of PWM output signal based on the bivariate Fourier Transform,and mathematically verifies the feasibility of Class D digital power amplifier and the reasons for its nonlinear distortion.Gets the TAS2560 amplitude frequency and phase frequency characteristics from monophonic test experiment and builds TAS2560 monophonic simulation behavioral model.Besides,establishes TAS2560 discrete time-domain behavioral model by applying the three-order discrete Volterra series referring to the TAS2560 actual audio input and output data.In the Volterra model identification process,the thesis illuminates the kernel function parameter of TAS2560 Volterra model as well as the ill-posed problems in solving procedure in advantage of the inverse problem theory.After obtaining the linear ill-conditioned equations set generated in Volterra model identification process by use of the Tiknonov regularization method,receives the stable solution of Volterra series kernel function.Then writes the TAS2560 monophonic and Volterra series behavioral model by MATLAB and builds TAS2560 circuit simulation model.At last,based on the COMSOL Multiphysics multi-physical simulation platform,establishes the taper moving-coil loudspeaker virtual model and realizes the co-simulation of MATLAB and COMSOL through LiveLink for MATLAB interface.By setting the TAS2560 output voltage as the excitation source for the loudspeaker voice coil,the thesis finally obtains the output current of audio system and sound pressure distribution of the loudspeaker under different excitation conditions for output voltage,lay a foundation for the design of the loudspeaker.