| In this paper, I design a Class D amplifier based on a project that was been participated when I worked as an intern. This project is to design a high-efficiency and low-distortion Class D amplifier. After read some the domestic and foreign related literatures, I did the following works in detail:⑴Explain some important parameters of Class D audio power amplifier ,and draw a distinction between the advantages and disadvantages of various types of audio amplifier to highlight the advantages of D-type power amplifier;⑵Analyze Class D power amplifier system composition and the basic principle, including pre-amplifier, PWM (triangular wave generated circuit and voltage comparator) and the H bridge output and so on;⑶Design and research the circuit of one Class D audio power amplifier chip which mainly focus on the pre-amplifier module and output module, and simulate the entire chip.The key technologies in the design of Class D power amplifier are the following: PWM (Pulse Width Modulation) technology which modulate a series of pulse width to obtain the required form; negative-feedback technology which reduce distortion of the chip; Filter-free modulation scheme which could minimize switching current and cause us to be possible to use the big loss inductor even speaker to replace the LC filter but still ensure amplifier's high efficiency. Above the key technologies are also the focuses of this thesis.This Class D audio power amplifier chip features as:⑴high efficiency, up 88%;⑵high PSRR, wide supply voltage range, fully differential input, improve the common mode rejection ratio, the output to input negative feedback;⑶output filter-free which save the chip area. |
PDF Full Text Request