The Research And Design Of CMOS Audio Power Amplifier With High Gain And Low Harmonic Distortion

Audio power amplifier is the basic unit of integrated circuits. It has been widely used in mobile phones, headsets, MP3/MP4, CD Player, audio player and other consumer electronic devices. The performance of the audio power amplifier directly determines the market share of this kind of audio consumer electronics equipment. Therefore, how to design low-power consumption, low noise, low harmonic distortion audio power amplifier has been one of research hot.This paper discusses some of common audio power amplifier design structure, compare of the advantage and disadvantage of these types of design structure, and we finally design an audio amplifier chip with low-power shutdown feature, temperature control feature and low harmonic distortion of class AB power amplifier.Low-power consumption mode, the most blocks of audio amplifier chip are in shutdown status, only some logic in normal status to reduce the overall power consumption of chip. Temperature control block used to monitor the temperature of the chip, when the temperature is higher than a preset value, the power amplifier of chip would be turned off in order to achieve over-temperature protection. Audio amplifier chip typically require high linearity to achieve the best sound effects. This paper discusses and compares three commonly used in lower power amplifier nonlinear distortion (THD) of the technology and summarizes the advantages and disadvantages of these techniques. This paper designs a power amplifier including class AB output stage. This design reduces the total harmonic distortion of audio power amplifier and improves the sound effects of the chip without increasing the additional circuitry.In this design, audio amplifier chip divided into four main parts: the POP-CLICK block is used to generate the stable bypass voltage and reduce the POP-CLICK noise for the chip. The band gap block is used to generate the bias voltage for other blocks of chip. The temperature control block is used to monitor the environmental temperature of power amplifier working, achieving the over temperature protection feature. The power amplifier is used to amplify the input audio signal and generate the differential signal.This design is simulated with CSMS 2P6M technology, and the result of the simulation show that this design can reach the design performance expectations.