[Animats]

Nothing there is going faster than about 300KHz, so the signal paths are not a big issue. If things had to go faster, there would be a proper ground plane. The tiny area around the switching IC did require careful layout (it just follows the Linear Technology data sheet) but the rest doesn't matter much.

There is no one ground. The 120VDC side has an HV ground, and the 5VDC side has a ground. The important point is to have separation between the two.

[SV_BubbleTime]

> nothing faster than 300k

That is exactly one of the misunderstandings I’m trying to warn that you are missing.

I’m certain that your switching transition times are massively faster than the 300k period (each rise and fall time).

You can have split grounds, but you don’t have traces under your grounds so in many cases you aren’t even effectively using them. You are grounding a portion of every signal inside every other signal trace.

“The rest doesn’t matter much”… my man, I can’t explain in this form just how wrong you are.

It’s one thing to be wrong on a design from years ago. My old designs were worse. But it’s another thing to willfully ignore all the ways in which someone who knows better is trying to help you with.

Everything you think about that circuit is wrong in ways you aren’t getting - yet.

Try Phil’s lab videos for EMI.

[xeonmc]

off topic, but what do you think of this video by Asianometry talking about the intricacies of analog design for a laymen audience? https://www.youtube.com/watch?v=lNypq1XuZRo

[SV_BubbleTime]

I disliked that video very much. It was FAR too long, talked about things like parasitic capacitance long before even getting near the topic of the video.

Then out of no where it's talking about tantalum nitride...

No, I'm pretty sure that video was made by an AI.