TPS2490: Latch off issue

Ruixin Feng

Intellectual 2375 points

Part Number: TPS2490
Other Parts Discussed in Thread: TPS2491

Tool/software:

Hi team,

I met a TPS2490 issue and hope you could help to give some comments here.

After power up, PG, Gate and PROG pin all keep low. from datasheet, TPS2490 seems latch off.

Design schematics is shown here:

Gate waveform when power up is shown here, left one is bad board and right one is good board.

PROG waveform when power up is shown here. left one is bad board and right one is good board.

VCC is 12V and EN is 3.3V. Do you think TPS2490 is latched off here. Could you pls help to check if any other test we can do to figure out the reason why TPS2490 is latched off? Thanks!

Rayna

10 months ago

0 Amrit Jit 10 months ago

TI__Mastermind 30681 points

Hello Rayna,

What's the VREF voltage of bad board when VCC and EN is supplied?

Thanks

Amrit

0 Ruixin Feng 10 months ago in reply to Amrit Jit

TI__Intellectual 2375 points

Hi Amrit,

The VREF waveform is shown here when VCC and EN is supplied. VREF is 4.05V finally.

Rayna

+1 Amrit Jit 10 months ago in reply to Ruixin Feng

TI__Mastermind 30681 points

Hello Rayna,

Thank you for verifying the VPROG.

We need to check the inrush current during start-up.

Can you please probe input current?

Is there any start-up load while turning ON TPS2491?

Thanks

Amrit

0 Ruixin Feng 9 months ago in reply to Amrit Jit

TI__Intellectual 2375 points

Hi Armit,

do you see any information from VREF?
The load is only R254 when start up.
For input current, do you mean current through Rsense? it’s difficult for customer to probe.
do you think it’s a latch off issue? Could you pls help to check with team about the possible root cause here? Customer is keep pushing for it. thanks a lot!

Rayna

Power management

Power management forum

TPS2490: Latch off issue