| In order to meet the requirements of users for sound effects, more and more devices support 3D sound play. National Semiconductor’s LM4888 is an audio power amplifier chip with 3D sound enhancement. This chip directly processes 3D effects to the analog audio signal input. Due to the simple application and the clear effect, it has been widely used.This thesis introduces the sound field positioning of the human brain work, 3D sound acoustic principles and an implementation of 3D sound --- stereo enhancement technology. This thesis also introduces principles and differences of traditional audio power amplifier and 3D audio power amplifier in portable devices. This thesis will take the LM4888 as an example, introduce 3D sound acoustics, and introduce application and circuit design for 3D enhanced stereo audio power amplifier. This thesis will use the circuit theory analysis, Pspice circuit simulation analysis, and the measured waveforms of the circuit analysis to provide systematic analysis of the LM4888, point out the core elements that impact the 3D effect of 3D sound audio amplifier and its variation.This thesis will give an improved circuit design for current 3D sound audio amplifier application, which will effectively solve the problems encountered in 3D audio amplifier application. This design has been actually used in a mobile phone with 3D audio effects. This thesis will introduce 3D sound audio amplifier applications base on the mobile phone project, such as circuit design, key component selection and PCB design guide.This method of argument and analysis of this thesis is equally applicable to other 3D audio amplifier. So this thesis tries to provide solutions for 3D audio power amplifier in engineering design and application. |
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