TPS2379: Oscilloscope measure

Daniel Campano

Part Number: TPS2379

Hi All,

I have tried to measure the voltage on the C bulk capacitor with an oscilloscope to see the voltage raising. When the oscilloscope prove is connected to the C bulk it doesn't do the handshake and I don't know why it is happen. The prove can disturb the handshake?, if that is the case how I could get the measurements?. The schematic is identical to TPS2379EVM-106 development board.

Thanks,

Winsu

over 6 years ago

0 Thomas Amlee over 6 years ago

TI__Genius 9230 points

Hi Winsu,

Are you taking the measurement with any other probes connected? Additionally, what jumpers do you have populated?

Regards,
Tom Amlee
PoE PD Apps Engineer

0 Daniel Campano over 6 years ago in reply to Thomas Amlee

Intellectual 470 points

Hi Tom,

No, It is the single probe connected. J7 is not pupulated ( CLS is 63.4ohm), XDEN is not popullated ( 24.9k DEN) and J5 is not populated ( I'm making use of Q3) , no jumper has been populated.

Thanks,

Winsu

0 Thomas Amlee over 6 years ago in reply to Daniel Campano

TI__Genius 9230 points

Hi Winsu,

Have you verified that you are able to get handshake to occur without a probe attached?

Could you take a waveform of VDD-VSS when plugging into a complaint PSE to check the handshake?

Are you using a PSE that is complaint with the type 1 or 2?

Thanks,
Tom Amlee
PoE PD Apps Engineer

0 Thomas Amlee over 6 years ago in reply to Thomas Amlee

TI__Genius 9230 points

Hi Winsu,

Any updates on this issue?

- Tom

0 Daniel Campano over 6 years ago in reply to Thomas Amlee

Intellectual 470 points

Hi Tom,

I'm sorry, I haven't been able to do anything further. I will click resolve and if I need help again I will ask again.Thanks for your help.

Regards,

Winsu

Power management

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TPS2379: Oscilloscope measure