摘要
文中设计了一种应用于ClassD音频放大器中高性能PWM控制。该控制能够在较宽的电源电压范围内,使调制锯齿波的输入电平及音频输入信号经过前置放大后的共模电平跟随电源电压的变化而变化。共模电平经过PWM比较器得到占空比随输入信号变化的控制信号,从而提高系统的输出功率。仿真结果显示,当电源电压在2.4～5V范围变化时,音频信号和调制锯齿波的共模电平偏差在2mV以内,同时锯齿波的幅度也随着电源电压的升高而升高,显示了良好的线性跟随性。
A novel high performance PWM control mode was presented for Class D audio amplifier. Made the input level of modulating saw-tooth wave change with variation of the supply voltage, and shifted the common voltage of input audio signal to the common voltage of the modulating saw-tooth wave in a wide supply voltage, then compared the saw-tooth wave and the audio signal through PWM comparator and got the control signal which duty cycle followed the input audio signal. The PWM controlling mode would increase the system output power in a wide supply input voltage. According to simulation reports, the error between the audio signal shifted and saw-tooth wave was less than 2mV when the input supply voltage varied from 2.4V to 5V, and shown a good linear following characteristic with the supply voltage.
出处
《电子元器件应用》
2012年第7期17-21,共5页
Electronic Component & Device Applications
