TPS65988: TPS65988 Laod test

kerr chang

Genius 4075 points

Part Number: TPS65988

Hi Team

We use TPS65988 on my system. We use E-load and setting 3A.

We start Load 3A on device side fisrt and plug-in Type C on TPS65988. The Vbus will be keep 0V.

if We plug-in Type C cable on TPS65988 first and start load, The Vbus is 20V.

Is it normal status? what is the reason?

over 7 years ago

0 Eric Beljaars over 7 years ago

TI__Mastermind 36756 points

Hi Kerr,

Yes, this is normal. The sink is not allowed to pull current when the VBUS voltage is transitioning. This is aligned with the PD spec.

If this answers your question, PLEASE select This resolved my issue

Thank you,
Eric

0 kerr chang over 7 years ago in reply to Eric Beljaars

Genius 4075 points

Thank you for your great support .

0 kerr chang over 7 years ago

Genius 4075 points

Hi Eric
Sorry , Could you help check which section in PD SPEC?

0 Eric Beljaars over 7 years ago in reply to kerr chang

TI__Mastermind 36756 points

Hi Kerr,

"The Sink Shall transition to Sink Standby before a positive or negative voltage transition of VBUS. During Sink Standby
the Sink Shall reduce its power draw to pSnkStdby."
pSnkSrdby is equal to 2.5W

Thanks,
Eric

0 kerr chang over 7 years ago in reply to Eric Beljaars

Genius 4075 points

Hi Eric

Thank you , We have test system again.

We start Load 3A on device side fisrt and plug-in Type C on TPS65988. The Vbus will be keep 0V.

BTW

We start Load 2A on device side fisrt and plug-in Type C on TPS65988. The Vbus will be 20V

Why Load setting 2A , Vbus will be turn on ?.

0 Eric Beljaars over 7 years ago in reply to kerr chang

TI__Mastermind 36756 points

Hi Kerr,

With a decreased load, we would be able to soft start our interl path without violating the pSnkStdby spec. When the load is too high, the energy is too much to soft start.

Thanks,
Eric

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TPS65988: TPS65988 Laod test