一种无需振荡器的数字频率抖动电路及其应用

A Frequency Jitter Circuit with No Oscillator and It's Application

为了解决滞环控制模式开关电源中无振荡器电路,从而无法使用现有频率抖动方式降低EMI和现有频率抖动电路调制方式单一、移植性差的问题,本文提出了一种新型的数字频率抖动电路,该电路结构简单,调制方式多样,可移植性好。本设计采用1μm 40V CMOS工艺进行仿真验证,Hspice仿真结果表明该数字频率抖动电路有效地降低了系统的EMI。

For the need of frequency jitter circuit for hysteretic control mode switch mode power supply （ SMPS ）, a novel digital frequency jitter circuit with no oscillator is proposed. This digital frequency jitter circuit with simple structure has flexible modulation types and good portability. This work was designed using 1μ m 40V CMOS process. The Hspice simulation results showed the proposed digital frequency jitter circuit functioned well in reducing electro-magnetic interference （ EMI ） of SMPS system.