1、 1 设计高效率音频功率放大器设计高效率音频功率放大器 摘要摘要：传统的音频功率放大器有 A（甲）类，B（乙）类，AB（甲乙）类，D 类等，这类 音频功放曾广泛应用于 MP3、手机等便携消费电子产品的扬声器驱动中。 伴随着科学技术的 迅速发展，生活水平的不断提高，人们对音频功率放大器的要求越来越高。采用高转换效率 的 D 类功率放大器取代传统的线性功放已成为一种必然趋势。D 类功率放大器是一种脉宽调 制(PWM)的开关功放，首先将音频信号通过高增益前置放大器放大,放大后的音频信号进而与 内部三角波相比较进行采样,从而将音频信号的幅度信息转化成 PWM 信号脉冲宽度的变化,然 后将变换得到的 P
2、WM 波整形放大,输出的电流信号通过 LC 低通滤波器被还原成放大的音频信 号。由于功率管工作在开关状态,且导通电阻很小,因此,D 类功放具有很高的转换效率。 关键词关键词：音频功率放大器；高效率；PWM Abstract: The traditional audio amplifier is A, B, AB and D,etc, this kind of audio amplifier was widely used in MP3, mobile phones and portable consumer electronic products in the speaker drivers.
3、 With the rapid development of science and technology, and the continuous improvement of living standards, the people of audio amplifier are increasingly demanding. Adopting high conversion efficiency of D power amplifier instead of traditional linear amplifier has become an inevitable trend. D powe
4、r amplifier is a pulse width modulation (PWM) switch power amplifier, will first audio signals through the preamplifier amplifier, enlarge high-gain ones.the after the audio signal and then compared with the internal triangular sampling, thus the audio signal amplitude information into a PWM signal pulse width, and then the changes of PWM waves will transform the current amplification, plastic output signal by LC lowpass filters and reduction of the
