TPS54521: Reverse current

PAN-M

Part Number: TPS54521

Dear all,

In our customer's design, a reverse current flows for input from the output.
I attach this design's circuit and a waveform.

Does this phenomenon not damage a device?
How much can you permit the reverse current when there is not a problem?

Regards,
PAN-M

TPS54521_QA_20200513.pdf

over 3 years ago

0 Ryan Hu (BSR-MV) over 3 years ago

TI__Expert 4035 points

Hi PAN-M,

You need check the inductor current to see if reverse current was formed from VOUT to VIN. You current measured Iin current might not go through the DCDC, might only come from the input cap.

0 PAN-M over 3 years ago in reply to Ryan Hu (BSR-MV)

Mastermind 8375 points

Sorry, measurement point was not clear.
This waveform is inductor current.

Regards,
PAN-M

0 Ryan Hu (BSR-MV) over 3 years ago in reply to PAN-M

TI__Expert 4035 points

PAN-M,

You mean the Iout in the waveform is inductor current, right? If so, the reverse current is only 0.8A, much lower than the 5A rate output current, i see no concern for this. No need worry about it.