摘要
基于移动设备应用,在D类放大器设计中提出爆裂和咔嚓(pop-click)噪声抑制及饱和失真补偿技术。通过检测电源电压,顺序控制前置放大器、功率级驱动电路,并在放大器输出与地之间提供放电通道,有效减小爆裂和咔嚓噪声幅度;在反馈环路结构D类功率放大器中,音频输入信号幅度过大,导致放大器输出饱和失真,通过对脉冲宽度调制器输出进行补偿,可有效降低放大器的饱和失真,亦可消除因功率晶体管导通时间过长,而导致功率管发生热损坏的风险。采用上述技术的D类功率放大器在0.35μm CMOS工艺技术上实现,在电源电压为3.6 V时,放大器pop-click噪声幅度为2.0 mV,THD+N为0.025%。
The circuit techniques that suppress pop-click noise and reduce saturation distortion are presented for class D amplifier in mobile application. Pop-click noise level is effectively suppressed by detecting power voltage, controlling preamplifier and driver circuits of power stage in sequence, and providing discharge path between amplifier output and ground. Meanwhile, in class D pow-er amplifier with feedback loop structure, the integrator is easy to saturate when a large amplitude signal is fed into the input ter-minal of the amplifier. Consequently, the saturation distortion is generated in amplifier output when the pulse width modulator fails to modulate input signal due to integrator saturation. The compensation technique in the pulse width modulator output can effectively reduce the saturation distortion, and also eliminate the risk of the transistor switch thermal damage due to power MOSFET still on state. The proposed class D amplifier with the above features was fabricated with 0. 35 μm CMOS process. Pop-click noise level of1. 5 m V, THD ＋ N of 0. 025 % can be achieved in 3. 6 V power supply.
作者
郑浩
刘延飞
王秋妍
杨晶晶
杨东东
Zheng Hao, Liu Yanfei, Wang Qiuyan, Yang Jingjing, Yang Dongdong(Rocket Forces University of Engineering,Xi＇an 710025, Chin)
出处
《电子技术应用》
2018年第5期25-28,共4页
Application of Electronic Technique
