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I would like to make a DC-DC buck converter which has 24 V input and three 5 V outputs, but a typical buck converter circuits have only one output. How to change it to three outputs without an extra chip? Is it even possible?

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ocrdu
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hfsrg
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    Do you really need three independent outputs? The output of a normal single-output DC-DC converter can be split to feed any number of loads (with due consideration of load current requirements). – Peter Bennett Mar 24 '23 at 06:23
  • I am making 3 cell lipo battery balanced charger. for supply each cell I need 5v output, each output controlled by arduino so i can control which cell must be charge first. so is it possible to single output to feed 3 cells. – hfsrg Mar 24 '23 at 06:53
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    `3 cell lipo battery balanced charger…` `course work…can't just buy` Do not comment comments asking for clarification or complementary information: update your post (including title). If you want to charge a 3S battery and have access to 24 V power, state it that way - more parameters on battery, power source, environment, skill level, budget welcome. (Quote the problem literally as a block quote: asking for 5 V to charge a Li-po cell is a bit off.) – greybeard Mar 24 '23 at 08:22
  • Unless the cells are no longer connected in series, a which point you don't have a balance charger, just a bunch of chargers, you need isolation between each output. A buck converter does not provide any isolation. – winny Mar 24 '23 at 08:48
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    Perhaps this [document](https://www.renesas.com/us/en/document/whp/how-reconfigure-buck-converter-multiple-outputs) discussion multiple outputs will be helpful for you to think about the overall architecture. – jonathanjo Mar 24 '23 at 09:22

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Hmmmh you are up for a ride here!

(1) In general it is possible to build a 'Single-Input, Triple-Output' DC/DC.

But without any IC - if you see at least FETs and their driving circuits as ICs - it will only be possible with 'extreme engineering'.

(2) Judging from your question - be aware: mis-interpretation can happen - i would say: You are best off with using of-the-shelf parts.

I had a quick look at my favourite suppliers Digikey DC/DCs and Mouser DC/DCs. I guess you could use e.g. three of these Single 24V/5V 5W DC/DC in parallel - so one for each of your 5V Rails.

ElectronicsStudent
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  • thank you for your quick response. This is my course work so I can not just buy it. I need schematic so i can simulate it pls help me to find real schematic and also sorry for bad english – hfsrg Mar 24 '23 at 06:39
  • (Can't use your product hyperlink: 403 forbidden.) – greybeard Mar 24 '23 at 08:49
  • @greybeard all three links open okay from my location, perhaps your browser/network has a different problem? – jonathanjo Mar 24 '23 at 09:15
  • (Works *if* I open digikey.de before - some cookie woodoo?!) Three terminal converters aren't isolated output, which would be required here (well, at least for but one of them). – greybeard Mar 24 '23 at 09:33
  • @greybeard I noticed a few things with digikey myself in the past... The parametric search is in my opinion unbeaten, but there are problems to say at least. – ElectronicsStudent Mar 24 '23 at 09:50