How do medical power supplies achieve such low leakage current??

[Jon Gerow]

Honestly, I've never had a chance to tear one apart, but in your typical desktop PSU, I've not seen lower than 3.5mV. Medical PSUs can be as low as .2mV.

To reduce EMI, we tend to put a Y capacitor to ground, and that's where you get most of your leakage. But it's not like medical PSUs don't use a Y cap and say "EMI be damned!"

What's the secret sauce?

[ashiekh]

https://378m1o49xyfcl4may47q66uc-wpe...%20Current.pdf

" ...important to substantially reduce the capacitances that cause leakage currents. This poses a special design problem for the power supply and especially EMI filters."

[Jon Gerow]

That document does not answer my questions at all.

I know what leakage current is and how we reduce it today.

I want to know how they reduce it as much as they do in medical PSUs and still pass EMI.

[ashiekh]

Same document

"Condor's medical designs and patented EMI filtering techniques have overcome these problems."

[Jon Gerow]

Same document

"Condor's medical designs and patented EMI filtering techniques have overcome these problems."

No offense, but I don't know what your deal is. LOL!

Let's forget this document and move on because clearly it's not going to answer my question.

I mean, if they had a diagram and component list of what "Condor's medical designs and patented EMI filtering techniques" comprise of... Otherwise, you're answering my questions with ambiguous statements that merely taunt my original question.

Seriously. It's like if I asked how the Prius regenerative braking system works and you replied with "when you slow down the car, it generates electricity."

It's not what I'm asking for.

[ashiekh]

I just don't have the time to track down their patent but thought you might if you knew of its existence, given your question. It didn't give you the answer but rather a clue as to where to find it; thought that might be of interest.

Now do you know what my deal is?

[Stefan Payne]

Buy a Medical PSU, tear it down and post pics of it here?

Maybe they don't use Y Caps.
Maybe they do use Y-Caps but "special ones"...

[Jon Gerow]

Buy a Medical PSU, tear it down and post pics of it here?

Maybe they don't use Y Caps.
Maybe they do use Y-Caps but "special ones"...

I plan to eventually, but they're so expensive.

[ashiekh]

An isolation transformer is one solution, although probably not the one being used.

[Jon Gerow]

An isolation transformer is one solution, although probably not the one being used.

Yeah. That's a solution, but you wouldn't have 80 PLUS Titanium medical PSUs with an isolation transformer on the primary side.