Making -5V from a 5V supply (2A output min)

Fabrice Debart

Other Parts Discussed in Thread: LM675, TPS54560, TPS7A33, TIDA-00270

Hi,

I'm looking for a solution to generate a -5V from a +5V supply. It needs to provide at least 2A of output current. Ideally low noise as it's for an audio application (so I'd rather not use a buck convertor).

I thought about using a LM675 into an inverting configuration, but its supply voltage needs to be much higher than the input voltage (and I can't use +/-15V in my system).

Is there anything you could recommend?

Thanks,

over 9 years ago

0 JohnTucker over 9 years ago

TI__Guru**** 191445 points

I think you will need an inverting buck boost. Since the current is derated by a factor of 1-D, you will need a 4A device to sorce 2 A load current. you might look at TPS54560 to start with. here is an app note on creating an inverting buck boost supply:

www.ti.com/.../slva317b.pdf

0 Anthony F over 9 years ago

TI__Mastermind 35165 points

Since you mentioned low-noise I also suggest looking at adding the TPS7A33 for post-regulation after the inverting buck-boost. However I realize this will not supply the full 2 A load you need. For this reason I am moving this to the Linear Regulator forum to see if they have any more suggestions to get more current.

0 Ryan Eslinger over 9 years ago in reply to Anthony F

TI__Guru 55940 points

I agree with John that starting with an inverting buck boost to start. You can clean up the rail with a negative LDO; however, we do not have a 2A negative LDO at this time. You could use two LDOs in parallel such as in TIDA-00270 in order to hit your current requirements.

Very Respectfully,
Ryan

0 Fabrice Debart over 9 years ago

Prodigy 20 points

Thank you all for your answers. Very useful. I'll look into it.

Power management

Power management forum

Making -5V from a 5V supply (2A output min)