D类音频功放中扩频振荡器的设计  

The Design of Spread Spectrum Oscillator for Class D Audio Amplifier

作　　者：张雨河[1] 蔡小祥[1] 王会影[1] 周泽坤[1] 张波[1] 

机构地区：[1]电子科技大学微电子与固体电子学院,四川成都610054

出　　处：《中国集成电路》2011年第9期48-52,共5页China lntegrated Circuit

摘　　要：设计了一种用于D类音频功放的新型扩频振荡器。采用电流控制模式,利用伪随机数字频率调制,使谐波能量更加分散,频谱幅度更小,从而减小D类音频功放的EMI辐射。基于UMC0.6μm30V BCD工艺,对提出的扩频振荡器电路进行仿真验证。结果显示,扩频频率点具有良好的均匀性和随机性,并且D类音频功放的EMI主峰值幅度下降了4dB,其余EMI的峰值幅度下降了大约10dB,扩频降低电磁干扰(EMI)辐射的效果显著。A new type of spread spectrum oscillator for the Class D audio amplifier was proposed. By adopting Current-control mode, and using pseudo-random digital frequency modulation, the harmonic energy was more dispersed, the spectrum magnitude was smaller, which reduced EMI emissions of class D audio amplifier. Based on UMC 0.6 um 30V BCD process, the proposed spread spectrum oscillator circuit was simulated. Simulation results showed that spread spectrum frequency points of the circuit had good uniformity and randomness, and the peak amplitude of the measured out-of-band noise was 4 dB lower than that in fixed frequency Class D audio amplifier, the peak rate of the rest of EMI declined by about 10 dB, and the effect of spreading to reduce electromagnetic interference （ EMI ） emission is remarkable.

关 键 词：D类音频功放 扩频振荡器 伪随机调制 电磁干扰 

分 类 号：TN752[电子电信—电路与系统]