XL6009/LM DC converters in series with pseudo-isolation

[Stephen37]

Hello everyone,
I need a 90-100V DC power supply and I was thinking whether I can isolate the inputs of XL6009 and put two of them in series (the outputs).

The implementation would be one DC converter connected to its own 5V usb battery power bank and the outputs will be set to 45V each to provide 90V in series.

Would this work or the smoke will come out ? If not why ?

[Rick Law]

From the way you frame the question, I take it you are new with little experience...  I am rather inexperience too.

One thing I learned is that the datasheet tells you a lot.  The answer to the question you asked is right in there.  I googled the part and found the datasheet:
https://www.nikom.biz/pdf/XL6009.pdf

Look at the "XL6009  Electrical  Characteristics" in the datasheet, it tells you the operational limits.  Output voltage is there.  Reading the datasheet over is a great way to learn, so, rather than just throwing the answer back at you, I will let you explorer it and find it yourself - it is there.

[Stephen37]

I never tested a dc converter in series, I don't know whether only the inputs need to be isolated or the entire switch.

The data sheet says the operational limits for one device in normal non-isolated mode, it doesn't say anything about output in series.

[ledtester]

How much power do you need?

There are a bunch of "nixie tube power supply" circuits which step up a low DC voltage to a much higher voltage.

[Zero999]

It should work in theory, but the XL6009 is only really designed to work up to 36V and stepping up 5V to 45V, using a simple boost converter is a fairly big voltage jump. You could use the XL6009 to drive a suitable transformer, with a snubber circuit. If it's wound/connected like an autotransformer, it will be more efficient.