TPSM365R3: Use a positive voltage non-isolated dc-dc converter to generate a negative voltage

David Naviaux

Part Number: TPSM365R3
Other Parts Discussed in Thread: TPSM33615

Tool/software:

Is it possible to swap the output and GND pins of this part to generate a negative voltage instead?

You can do this with the non-isolated Mornsun K7812 to switch it from a +12V converter to a -12V converter (at a lower current).

Does TI have any converters that can be used this way?

over 1 year ago

0 Richard Fu22 over 1 year ago

TI__Mastermind 30975 points

Hi David,

It should be doable. I've attached an app note showcasing how to generate an inverting buck-boost from a buck converter. You can do this with any of our buck converters.

Thanks,

Richard

0 David Naviaux over 1 year ago in reply to Richard Fu22

Intellectual 590 points

Richard,

I was not able to find the attachment. Could you send a link to that application note?

Thank you, David

0 David Naviaux over 1 year ago in reply to Richard Fu22

Intellectual 590 points

I know that this can be done with a synchronous buck converter. What I need is a small and inexpensive -5V 300mA - 500mA power supply. I had been using a Mornsun converter for this but it is no longer available. I would like to use a dc-dc converter that is self-contained (minus filtering capacitors) but I cannot find one that mentions generating a negative voltage from the positive dc-dc converter.

I often use an inverting buck-boost converter topology for generating negative voltages up to several amps but I have always used an external inductor taking up quite a bit of PCB space.

Can I use the TPSM33615? It is a synchronous buck converter with the appropriate ratings for what I need.