TPS65988: TPS65988 OVP questions

John Liu59

Part Number: TPS65988

Dear,

For TPS65988, we can set its OVP threshold in the FW, but when the voltage then down to normal value, will the TPS65988 start turn on the FET automatically?

Thanks.

over 6 years ago

0 Eric Beljaars over 6 years ago

TI__Mastermind 36756 points

Hi John,

Once the OVP condition has passed, the TPS65988 should return to normal operation.

Thank you,
Eric

0 John Liu59 over 6 years ago in reply to Eric Beljaars

TI__Intellectual 2735 points

Hi Eric,

How about the accuracy for the OVP protection, and what is its detection time for the OVP ?
In my setting, if the PD contact voltage is 20V, ,and I set 5% ovp trip point, it should be 21V, but we tested when the voltage rise to 22.3V, it tirggered the OVP for the external switch, PP_EXT1 is pulled down.
Also what the hysteresis of the protection, when it will return to normal operation?

Thanks.

0 Eric Beljaars over 6 years ago in reply to John Liu59

TI__Mastermind 36756 points

Hi John,

Section 5 of the following power path app note will answer your questions related to OVP: www.ti.com/.../slva994.pdf

Thank you,
Eric

0 John Liu59 over 6 years ago in reply to Eric Beljaars

TI__Intellectual 2735 points

Hi Eric,

I have read the notes, but can find the information about the accuracy, hysteresis information, it seems in our customer test, the accuracy is not so good, but I will check with them together again.
Also in the note, it said after protection, the CC will be in Hi-z and after 25ms, it will detect again, if there is still OVP, will it protect and set the CC Hi-Z again until the voltage return to normal level?

Thanks.

0 Eric Beljaars over 6 years ago in reply to John Liu59

TI__Mastermind 36756 points

Hi John,

Keep in mind that the percentage you select for OVP will take effect on the Max expected VBUS voltage. This would be negotiated voltage +5% according to the USB PD Spec. So if you select 5% OVP for a 20V Source contract, the OVP trip point would be 20V + 5% = 21V + 5% = ~22.05V.
Your understanding for the OVP protection recovery is correct.

Thank you,
Eric

0 John Liu59 over 6 years ago in reply to Eric Beljaars

TI__Intellectual 2735 points

Thanks for your explanation, Eric.

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TPS65988: TPS65988 OVP questions