TPS23525: OV/UV protection

Wayne Chiu

Part Number: TPS23525

Tool/software:

Hi Team,

Can the OV/UV protection function of TPS23525 OV/UV be turn off? When we do hot swap testing, OV/UV turn on to interrupt the testing.

Test flow: When the system supply by 48V power card originally and then add another 72V power card, we will see TPS23525 turn on the protection as yellow line below. This cannot be resolve by connect OV to ground.

Yellow line: OV

over 1 year ago

0 Kunal Goel over 1 year ago

TI__Guru* 79071 points

Hi Wayne,

I think it is due to current. Due to change in VIN, load cap will take current and cause hotswap to trip due to overcurrent protection.

Regards

Kunal Goel

0 ?? ? over 1 year ago

Prodigy 110 points

Hi Kunal Goel:

This result is remove all cap and put RSNS 0.001 ohm, it meaning current limit 25A.

Does OV/UV pin can floating to turn off OV/UV protection function?

Do you have any idea about why there has a pulse in ground?

0 Kunal Goel over 1 year ago in reply to ?? ?

TI__Guru* 79071 points

Hi Wayne,

Please share schematic for review.

Also test case is VIN is increasing from 48V to 72V?

Please help share more details.

Regards

Kunal Goel

0 ?? ? over 1 year ago

Prodigy 110 points

Hi Kunal Goel:

I remove attached file R4753, C5316,C5315 & modify R4753 to 0R

Move C5317 pin 2 to F2 pin 2

Test case:

One dc power card plug in with 48V

Another one power card with 72V at first, then plug in. system will reboot.

If another one power card plug in at first, then turn on 72V. System is ok, won't reboot.

Does OV pin can floating?

Tim Huang

TPS23525.pdf

0 Kunal Goel over 1 year ago in reply to ?? ?

TI__Guru* 79071 points

Hi Tim,

No OV can not be floating. To disable OV it can be connected directly to -48VDC rail.

Regards

Kunal Goel

0 ?? ? over 1 year ago in reply to Kunal Goel

Prodigy 110 points

Hi Kunal Goel:

I connected directly to -48VDC rail to disable OV.

but there still has pulse like yellow line waveform.

Do you have any idea about why there has a pulse in ground?

Or how to improve?

0 Kunal Goel over 1 year ago in reply to ?? ?

TI__Guru* 79071 points

That might be due to hot plug. Customer can increase caps on GND rail to decrease those pulses.

0 ?? ? over 1 year ago in reply to Kunal Goel

Prodigy 110 points

Hi Kunal Goel:

I have try add 47uf at RTN to -48V， but OV still have 3V pulse. OV to -48V add 10uf.

Tim

0 Kunal Goel over 1 year ago in reply to ?? ?

TI__Guru* 79071 points

Hi Tim,

Looks like you will need to modify layout. It looks GND bounce is happening. You will need to isolate system GND from device GND.

Regards

Kunal Goel

0 ?? ? over 1 year ago in reply to Kunal Goel

Prodigy 110 points

Hi Kunal Goel:

Can Oring MOS switch more slower by change TPS23525 schematic or which resister/capacitance?

Tim

0 Kunal Goel over 1 year ago in reply to ?? ?

TI__Guru* 79071 points

Hi Tim,

Sorry. I did not understand.

Regards

Kunal Goel

Power management

Power management forum

TPS23525: OV/UV protection