1.原理图:
1.issue:
7.4Vout空载/满载时噪声高达408mV-见下图(示波器全带宽,接地弹簧),当示波器切换到20Mhz带宽时,噪声消失,纹波PP值正常
2.噪声和VSW(测试点为L1输入端)的上升沿同步,而且VSW方波有上冲,如图
3.尝试增加100Mhz磁珠、增加滤波电容、增大L1路径(想减小等效感性),没有效果
感觉像是MOS导通瞬间,由于等效电感和电容的关系,形成boost效应造成。
请问各位有没有遇到过类似情况,整改思路如何?
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Hi
看起来噪声来自SW, 建议你将snubber电路加上去,即你电路上为R75, C116.