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I am working on a project to power some audio equipment that requires +/- 15V DC. Output current load is about 250mA, maximum. I am wondering if there’s any reason I couldn’t create this using two switching boost converters and a DC wall wart, as shown:enter image description here

Edit: Would this circuit work better? enter image description here

seagull48
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    Theoritically yes, but it would nit be perfectly simetrical (adjustment needed), and also it could be very noisy. – fifi_22 Nov 12 '20 at 20:44
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    That is going to give you a more noisy ground rail then generating a negative voltage using an inverting converter. – user1850479 Nov 12 '20 at 20:44
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    If the +15V boost convertor has no means to pull down, the load between it and +30 can pull it up to +30V. –  Nov 12 '20 at 20:45
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    Why not use a boost and an inverting buck/boost? As @BrianDrummond said a boost converter can't necessarily sink current without special care, so your scheme may not work. – John D Nov 12 '20 at 20:45
  • Thanks for replies! Would the new circuit above solve these issues? – seagull48 Nov 12 '20 at 21:06
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    I would try my dearest to have your input ground. = output ground and use a boost to get to +15 V and an inverting boost to get to -15 V. – winny Nov 12 '20 at 21:08

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Thanks to the helpful replies, I’ve learned about inverting buck boost converters. In case anyone reading this wants to know more about them, here’s some papers by TI:

https://www.ti.com/lit/an/snva856a/snva856a.pdf?ts=1605152504969

https://www.ti.com/lit/an/slyt286/slyt286.pdf

https://www.ti.com/lit/an/slva721a/slva721a.pdf

I’m still not sure why the noisy ground and symmetry would be any less of an issue with this setup, in case someone can explain that further.

seagull48
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    You can also just use isolated converters and hook them up together however you want. – Hearth Nov 13 '20 at 03:44
  • In your first circuit, transients on the negative rail move the positive rail's ground. Since the output ground is the same for both the positive and the inverted signals, transients on the negative rail don't move the positive's ground, and vice versa. – Dave X Apr 22 '22 at 14:07