TPS54231: Inquiry about TPS54231

Hello Yokota,

Could you please share your schematic and application conditions (Vin/Vout/Iout)? I want to review your application.

And what's the damage phenomenon of failed board? (e.g. device internal MOSFETs short?)

It should be OK to use it for inverting buck-boost. If you float EN-pin, the device should be enabled.

Hello Miranda,

Thank you for your reply.

Here is the schematic.

Vin is 12V, Vout is -12V, Iout is 0.2A.

The damaged part of the board is the resistor R1.

The resistance value has increased from 1Ω to over 20Ω.

(R1: RK73H2ETTD1R00F)

Hello Yokota,

As the R1 damaged, have you checked R1 voltage during normal operation? Then we can calculate the power poss P=U*U/1ohm, please check whether beyond 0.5W rating?

Hello Miranda,

During normal operation, R1 voltage was 0.02V.

P = 0.02V*0.02V/1Ω = 0.4mW

This is well below the rated 0.5W.

Hello Yokota,

Maybe you didn't capture the worst case? Sorry I couldn't know other reasons of a resistor damage except for overheated.

Besides, have you checked the Vout/SW/IL waveforms? Whether stable during normal operation?