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TPS25750: Vin_3V3 pin dips below minimum supply power

Part Number: TPS25750

Hi Team,

Good day!

In regards to this device, Our customer is power cycling the system witth the usb charge cable connected, the power cycle also cycles power to the load switch that powers the Vin_3V3 pin. We have the pd in AlwaysEnableSink mode. We notice that for 100 ms, the Vin_3V3  power rail dips down to about 2.6V. After this event gpio events no longer toggle properly on plug events. We're wondering if the chip does not work properly when Vin dips for 100ms under it's minimum threshold. 

Thank you in advance for the support. 

Best regards,

Jonathan

  • Hi Jonathan,

    Just checking to make sure, but were the gpio events working before the 2.6v dip. Also, does the voltage go back to 3.3 while you are testing the events?

    Thanks and Regards,

    Chris

  • Hi Chris, 

    Yes, GPIOs were working before. Yes, voltage rises back to 3.3V. Also, we manually toggled our load switch enable pin low for 10 seconds so it can drop to 0V before I turn the rail back on. Although rail dropped to 0V for 10 seconds and back up to 3.3V, it still disabled the GPIOs.

    This was while usb power cable is plugged in. It currently only works when usb power cable is not connected during this VIN_3v3 power cycle event.

    We will need this to work in both cases. 

    Please advise

    Thank you!

    Victor

  • Hi Victor,

    Let me talk speak with the team internally and I will get back to you by the end of the week.

    Thanks and Regards,

    Chris Lim

  • Hi Victor,

    We had a couple questions about your setup.

    1. Who is the customer and what is the use case?
    2. Are you using a configuration GUI to program the PD controller? If yes, which Gui and Gui version are you using?
    3. Is this a Customer Design or an EVM?
    4. Where is the patch being loaded from during boot? (EC or EEPROM)
    5. Can you provide scope capture for the Vin3V3 and LDO1V5 during the voltage drop?

    Thanks and Regards,

    Chris

  • Hi Chris,

    1. Customer classified. Use case: charge system, read storage devices

    2. I am using GUI 7.04

    3. Customer Design

    4. EEPROM

    I realized that my issue disappears when I keep my TPS always on. I actually don't need to cycle power. I have bypassed the switch and have it working. 

    Thanks,

    Victor

  • Hi Victor,

    I'm glad you were able to get it working!

    The main concern we had for your issue was that the PD controller would restart without properly checking the RAM and would not re-flash the RAM from the EEPROM after the Voltage on Vin3V3 dropped to 2.6. We are not sure that this was your issue but was our best guess from the current information.

    Closing this thread now.

    Thanks and Regards,

    Chris