Design Negative Power Supply with Positive Voltage Input

[Wicketer]

Hey guys,
Are you guys aware of any designs (other than buckboost or charge pump) for negative power supplies using just a positive voltage (and ground of course) as inputs? Creative designs are totally welcome.

Thanks in advance!

 

[milesyoung]

There are other topologies that can provide you with a negative rail, but you haven't really specified what you're looking for in a power supply, other than that.

Should it be a "simple" design? Should it provide isolation? Should it be cheap to build? How much power do you need? etc.

 

[mfb]

Transformers? Ćuk converter?

 

[Windadct]

My favorite SMPS reference...http://www.ti.com/lit/sg/sluw001e/sluw001e.pdf

 

[Wicketer]

Thanks for your replies guys!
milesyoung, the design can be simple as it will be powered with only +5V, and doesn't require isolation...but the design will be weighed against things like how large (or small) of a load it's capable of driving, ripple etc. I'm just juggling ideas to come up with an optimal design for the spec. Any relevant design suggestions rather than general topology will be appreciated too :)

Thanks again!

 

[milesyoung]

It's really hard to come up with a sensible suggestion if not given more to go on - there are so many options. There's a lot of industry resources on the subject, though, that treat the advantages/disadvantages of the various SMPS topologies, e.g.:
http://ww1.microchip.com/downloads/en/appnotes/01114a.pdf

 

[jim hardy]

The spec would help. We don't know if you're powering just a couple opamps or a kiloamp electric motor.

http://datasheets.maximintegrated.com/en/ds/ICL7660-MAX1044.pdf


http://www.ti.com/lit/an/snva006b/snva006b.pdf