按我的原理图布线,发现完全不起振,或者说开关频率极度不正常,不知道哪里出的问题,所有器件全换了一个遍,FB信号线与电感是太近了,但也不至于SW信号成这样,完全懵了。电感也从4.7uH,换过6.8uH,也换了22uH,启动电容也换过,RT电阻更是换了好了多个,从10K,12K,20K,22K,47K,68K,
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Hi
轻载和重载下输出或者SW都不正常吗?
芯片哪里买的?
电路应该没有问题,你可以再用芯片网站的webench确认一下。layout可以参考datasheet, 注意反馈走线不要往电感下走线即可,以及功率回路尽量小。