TPS25750: PD re-negotiation

Ck Lam

Part Number: TPS25750

Hi,

IF a charger has connected to the EVM, how to instruct the EVM to re-kick starts the PD negotiation process?

Example would be in the MCU-based nonintegrated USB PD battery-charger implementation, if MCU has not completed the patch bundle while the charger is connected, how would PD starts the negotiation after the patch bundle is transferred successfully to PD?

Thanks.

over 2 years ago

+1 Conner Gillette over 2 years ago

TI__Genius 13880 points

There are 4CC commands that can be sent to the PD controller to request source or sink capabilities. These can be found in the '4CC Task Detailed Descriptions' section of the TPS25750 Technical Reference Manual here: https://www.ti.com/lit/ug/slvuc05a/slvuc05a.pdf

Additionally, the EVM has switches (S1 on the board) to allow you to choose your dead battery configuration, which determines the devices behavior upon boot up. The details of each dead battery configuration are located in table 9-5 of the TPS25750 data sheet here: https://www.ti.com/lit/ds/symlink/tps25750.pdf

Information on how to configure the switches for the TPS25750EVM can be located in the EVM user guide, section 3.1, here: https://www.ti.com/lit/ug/slvuby2a/slvuby2a.pdf

Kind regards,

Conner Gillette

0 Ck Lam over 2 years ago in reply to Conner Gillette

Prodigy 60 points

So in the MCU-based nonintegrated USB PD battery-charger implementation, the potential configuration would be as below:

The PD configuration could be set to "SafeMode", hence the PD does not enable sink path.
IF a charger is connected, there will be no negotiation process for the PDO.
MCU will then load the configuration onto the PD.
Upon successful loading, PD will start the negotiation process and the charging process could be started.

Is my understanding above correct?

Another option would be using the "AlwaysEnableSink" which can serve the same purpose?

+1 Conner Gillette over 2 years ago in reply to Ck Lam

TI__Genius 13880 points

That is correct. You would want to use SafeMode, and not AlwaysEnableSink, if you're loading from EEPROM.

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TPS25750: PD re-negotiation