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TPD2S300: TPD2S300 VCONN Without Low Resistance Mode

Eric K.
Prodigy 70 points
Part Number: TPD2S300
Other Parts Discussed in Thread: TPS65982, , TPD6S300, BQ25895, TPD6S300A

We are using the TPS65982 as our PD-controller and discovered that our TVS diodes are not enough to protect its CC1 & CC2 pins in short-to-VBUS events. This has lead us to find your TPD2S300 and TPD6S300(A) CC protection ICs. We prefer to use the TPD2S300 over TPD6S300(A) since it is simpler for our application and is more cost-effective, but we are not sure if our requirement to supply VCONN is met by TPD2S300.

We are using the BQ25895 in our application, and its PMID pin is supplying PP_CABLE and PP_5V0 of the TPS65982.

We do not have a 8.7V to 22V supply in order to allow the TPD2S300 to enter its low resistance mode, although we would still like to be able to supply VCONN when necessary.

Since our device is a DRP that can sink or source VBUS, we are not targetting to be able to supply devices over VCONN (VPDs), but rather supply VBUS if the other device negotiates as a PD sink.

However, we intend to support DisplayPort alt mode and would likely need to be able to supply VCONN in passive cables with an e-Marker inside them. We would like to be able to support USB-C to DP captive cables.

Given our application, with the requirement to be able to support USB-C to DP captive cables, would we still be able use the TPD2S300 with VM=LDO_3V3=3.3V when supplying VCONN for such condition or would we have to go with TPD6S300(A) instead? Would TPD2S300's R_ON be too high for us to be able to properly supply VCONN in this situation?

Given that we don't need to supply VPDs and don't necessarily have to support active cables, do we still need to be able to supply 1 Watt over VCONN if need to be able to use USB-C to DP captive cables for example?

Best regards,

Eric

  • 0
    TI__Mastermind 28260 points

    Hello Eric,

    The expert covering this device is currently out of the office this week. They will be back in office next week so please expect a slight delay in the response. Thanks in advance for your patience.

  • 0 in reply to Adam Mc Gaffin
    TI__Genius 9630 points

    Hello Eric,

    If you want to provide VCONN, then you will need to supply a higher voltage to the VM pin, 8.7 V–22 V. The device cannot guarantee 1W of power unless it is in the low resistance mode. This way with 200 mA flowing through the TPD2S300, the voltage drop is much lower across the TPD2S300 and it is easier to achieve the VCONN voltage requirements given in the USB Type-C Specification.

    The TPD6S300A has a charge pump so its input voltage fits your range of supply. 

    Thanks,

    Emma

  • 0 in reply to Emma Hoying
    Prodigy 70 points

    Hi Emma,

    We'll go with TPD6S300A to avoid any uncertainty when it comes to supplying VCONN.

    Thanks for the help.

    Best regards,

    Eric