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TPS66021: Supply source for VIN

Dave Lech
Prodigy 10 points
Part Number: TPS66021

Our product can be powered from a barrel jack connector OR USB-C cable but NOT both. The datasheet leads me to believe that the VLDO is powered either from VIN or VBUS.. Our current design has VIN tied to PPHV and has the enable pins set to sink path. the problem we are seeing is that there is very little output on the VLDO output (.3V) and the device is not transferring power to the PPHV pins. When I short the VBUS power to the VLDO pin the dive seems to work and transfers power to PPHV. While this seems to work, I'm not sure this is the correct way to approach this. Why does the VLDO output only show .3V when VBUS is present...I would expect, per the datasheet, to see 5V. Does putting VBUS (5V) on the VLDO output cause any problems?

Thanks for any help.

Dave

  • 0
    TI__Expert 5695 points

    Hi Dave,

    VIN needs to be connected to PP5V, not to PPHV as shown in Figure 29 of the data sheet.

    If the Power multiplexer TPS66021 is configured in Source Mode (barrel Jack),  PP5V will be sourcing voltage to VBUS.In this scenario VLDO pin will just track PP5V.

    If the Power multiplexer TPS66021 is configured in Sink Mode (VBUS voltage is present and PP5V is 0) VBUS will provide power to PPHV and VLDO will regulate down VBUS voltage to 5V to provide power to the internal logic.

    Hope this clarifies the topic.