TPS54260 for nEGATIVE CONVERTER

No the maximum voltage difference must be less than 60 V.   There may be another solution, you should try webench to see if it can find one.

Hi,

Soi it can be used only up to -45V.correct?

Can not find any othrt recomended solution by the webench.

Hi Eli,

Do you have a schematic for the circuit you were considering for this application?

For the negative to negative conversion you may need to look into a boost controller based design and not a buck. I can show you an example of this later today.

Regards,
Anthony

Eli,

Please see the attached schematic in the link below for an example schematic I have seen used for a similar application. The additional circuitry to the FB pin is needed because the IC is now referenced to -VIN. If you regulate with a basic voltage divider, the output voltage regulation point would change with VIN. This instead uses the TLV431 shunt reference and regulates the current through Q4 with the voltage at the FB pin.

Let me know if you have any questions. I won't be able to help personally until next week but others will likely be able to provide some input. I also do not directly support the LM5022 so the engineer supporting it may have some additional comments

Anthony

Hi,

But its from -50 to -15,so its onlydifference of  35Visnt it?

I did not see that origianlly.  I thought +50 to -15.

so it can be use4d.correct?

I will defer to Anthony on that...

Hi Eli,

A solution using a buck based topology for negative to negative conversion does not immediately come to mind so I'm not sure if the TPS54260 will work here. Did you have an example schematic of what you're thinking?

I'll look into it some more tomorrow and let you know. Any thoughts on the boost based topology I posted previously?

Regards,
Anthony

Hi Antony,

Please look at page 39 figure 63 in the data sheet who to create negative output

B.regards

Eli

The design you refer to is an inverting buck-boost.  It is used to create a negative rail from a positive input voltage (which I originally thought you wanted).  It will not work to create a negative voltage from another negative voltage.