摘要
提出了一种用于D类放大器的新型频率抖动电路。采用流控模式和容控模式相结合,利用周期数字频率调制,使能量原本集中的频谱分散到离散频率点上,从而使频谱幅度降低,减小D类放大器EMI的辐射。基于0.5μm CMOS工艺,对提出的频率抖动电路进行仿真验证。结果表明,频率抖动点具有很好的均匀性和线性度,并且D类放大器的EMI峰值幅度下降约13 dB;高频频谱连续,扩频效果显著,频率抖动电路面积约840μm2,消耗的最大电流仅为1.2μA。
A new frequency jitter circuit for Class D amplifiers was proposed.By combining current control mode with capacity control mode,and using periodic digital frequency modulation,the energy concentrated spectrum was spread to discrete frequency points,which decreased the spectrum amplitude and reduced EMI emissions of Class D amplifiers.Based on 0.5 μm CMOS process,the proposed circuit was simulated.Simulation results showed that the circuit had frequency jitter points with excellent uniformity and linearity,and the peak-level of the measured out-of-band noise was about 13 dB lower than that in fixed frequency Class D amplifier.The high frequency spectrum was more continuous,and the effect of spread spectrum was significant.The active area of the proposed frequency jitter circuit is about 840 μm2 and the maximum current consumption is only 1.2 μA.
出处
《微电子学》
CAS
CSCD
北大核心
2010年第5期671-674,679,共5页
Microelectronics
关键词
频率抖动电路
周期调制
EMI
D类放大器
Frequency jitter circuit
Periodic modulation
EMI
Class D amplifier
