应用于开关电源芯片的频率抖动技术  

The Research of Frequency Jitter Using in Monolithic Switching Power IC

作　　者：孙大成[1] 

机构地区：[1]中国电子科技集团公司第47研究所,沈阳110032

出　　处：《电子与封装》2016年第3期37-40,共4页Electronics & Packaging

摘　　要：为了减小开关电源中的电磁干扰(EMI),研究了单片开关电源中的频率抖动技术,并简要介绍了频率抖动技术及其原理。设计一个具有频率抖动功能的弛张振荡器,分析了以弛张振荡器原理为基础具有频率抖动功能的振荡器结构设计和原理。通过HSPICE仿真分析电路频谱,结果表明频率抖动技术能有效削减方波的各次谐波幅值,从而达到抑制电磁干扰的效果。重点从抖动范围、抖动周期两方面讨论频率抖动模型,频谱对比分析结果表明抖动范围±7%、抖动周期为128T的抖动模型,其谐波至少下降6 d B以上,高次谐波的峰值下降更为明显,满足6 d B工程裕量的要求,能有效抑制电磁干扰。In order to reduce the electromagnetic interference （EMI） of switching power, the main content of this paper is the frequency jitter technology using in monolithic switching power supply, and briefly introduces the frequency jitter technology and its theory. The paper designs a relaxation oscillator which has the function of frequency jitter. Then we focused on the structure design and theory, of oscillator based on the theory of relaxation oscillator which has the function of frequency jitter. The result shows that the frequency jitter technology could effectively decrease the magnitude of all kinds of harmonic waves and we could achieve of goal of eliminating electromagnetic interference. What＇s more, we mainly discuss the frequency jitter model from jitter range and jitter period, and the result of spectrum analysis indicates that the harmonic waves of the jitter model which the jitter range is _＋7% and the jitter period is 128T can decrease 6 dB at least and the peak value of higher harmonic decrease more obviously. It meets 6 dB engineering margin requirement, so that can eliminate the electromagnetic interference more effectively.

关 键 词：开关电源 脉冲宽度调制 频率抖动 电磁干扰 振荡器 频谱分析 

分 类 号：TN432[电子电信—微电子学与固体电子学]