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I am looking for a way to construct a 1 A, ±15 V split-supply. So far, I've seen a number of designs for split-supplies (http://tangentsoft.net/elec/vgrounds.html), but they are all low current (i.e. 100-300 mA).

My application involves several Mass Flow Controllers that each require a +15 V, 0V, and -15V connection. The data sheet says they draw 300+ mA when in operation (they contain a small heating element).

I attempted two separate solutions using an LM7815 and a LM7915 (one with and without the voltage divider), but they did not work.

enter image description here

Can someone point me in the right direction of an appropriate circuit?

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While I am yet to find a satisfactory answer to my question--I'm still digging--I found the attached circuit on Reddit, and plan on trying it out.

http://www.reddit.com/r/AskElectronics/comments/16owyj/heres_a_rail_splitter_circuit_30v_in_15v_out_aka/

enter image description here

I'm cautious about using a buck converter, because (1) I haven't worked with them before, and (2) having a plus/minus buck converter set up is a very complex place to start.

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If the load draws 300mA you would be wasting 19.5-15*0.3=1.35Watt on each power supply.

I would suggest using buck or buck boost converters instead. Have a look at this app note on how to configure a buck converter for negative voltages.

I think the LM2576 datasheets also have some information on negative configurations.

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  • \$\begingroup\$ Crap, my link looks bad. I'm on a bad phone in the outback, sorry. \$\endgroup\$
    – Dejvid_no1
    Jul 23 '15 at 18:49
  • \$\begingroup\$ According to my understanding of the circuit, the LM7815 only sees 19.5 V between its 'in' and 'gnd' pins (i.e. 39 V / 2)? \$\endgroup\$ Jul 23 '15 at 19:03
  • \$\begingroup\$ Well it looks like read your question too fast! I will edit accordingly. I would still opt for a switched regulator. \$\endgroup\$
    – Dejvid_no1
    Jul 23 '15 at 19:55

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