TPS51120: TPS51120 NOT WORKING

Hi,

That sounds strange. Before you added the MLCC on 24V Vin bus, did the converter work normally?

I'll check the schematic tomorrow since I'm busy on many other urgent support cases today.

Thanks,

Andrew

Yes, Before add MLCC On +24V, Controller working properly

Thanks

Thanks. I'll look into it and give you feedback tomorrow.

Andrew

Hi MK,

I checked the schematic. I would think it doesn't seem like caused by schematic error by your description.

Does the controller work properly again if you solder down the MLCC?

If not, I think you could firstly check the diode of power Mos and see if the power Mos are already damged.

Thanks,

Andrew

Hi MK,

Another thing that I want to check with you: what's the saturation current of the chosen inductor for those two rails? My concern is that if the load current could be higher than the saturation current, the inductor could be saturated and caused the damage.

Is there any other difference except for adding a MLCC for those two tests?

Thanks,

Andrew

HI Andrew

FET Seems to have been damaged.

After Replacing The FET, It Operates normally.

Thanks for your reply

MK