Power Supply - pos-neg from single 48V Supply?

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andia

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Jul 11, 2005
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68
Hi all,

is it possible to use a circuit like silentarts FPNPSU ( http://www.silentarts.de/Techtalk-Laden/FPNPSU_rev03-Doku.pdf) to generate a positive and negative rail from a single 48V powersupply. The idea is to connect +48V to the LM317 side and 0V to the LM337 side of the circuit. Would this create +/-24V rails (or lower) or am I on a dead end here?
what would be the best way to create dual from a single supply.
The idea is to use desktop powersupplies with a single output to power mainly opamps circuits (+/-18V to +/-16V) with it.

Thanks, andi
 

Bo Deadly

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Dec 22, 2015
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New Jersey, USA
Sure. Just create a virtual ground with an op amp. Lots of gear have done that. Aside from guitar pedals there are electrovoice and shure circuits that use virtual ground "rail splitter" circuits to make a dual supply from a single.

However there is one major caveat. You cannot push / pull a lot of current to / from the virtual ground without risking ground noise / shifting / stability. So generally you only see it when only high impedance stuff is connected to the virtual ground. Meaning biasing resistors. If everything connected to the virtual ground is 1K or higher with no DC, it will work every bit as well as a proper dual supply. Even for high performance stuff.
 

gyraf

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Jun 4, 2004
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Aarhus, Denmark
Maybe something like this could be the simple solution - https://www.aliexpress.com/item/32570033795.html - if currents and other specs are suitable..

/Jakob E.
 

Rob Flinn

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Jun 3, 2004
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Sussex, UK
You wouldn't be able to split a 48v supply to + & - 24v with a 317/337 combination, because both regulators need to srop at least 3v each to work so at best  you would be getting + & - 21ish volts.
 

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