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TPS25730: How to disable the integrated switch?

Roy van Lierop
Prodigy 80 points
Part Number: TPS25730
Other Parts Discussed in Thread: TPS3701, SM74611,

Hi,

I want to add USB PD to an existing 24V device. Users can either select a barrel jack or USB type-C. A 20V/3A profile is chosen by resistor values.

What happens when a user is connected via USB type-C (Power path conducting, enabled) and the 24V barrel jack is inserted and applied to PPHV?

  1. Will the overvoltage protection kick?
  2. Will the reverse current protection kick in?

If they don't, then I need to close/disable the conducting path by asserting FAULT_IN low with the help of a lot of external components (TPS3701, TIDUAZ2).
Or use a diode or ideal diode (SM74611) to prevent back feed onto Vbus.
The datasheet only mentions Vbus overvoltage situations and not Vpphv overvoltage situations.

  • 0
    TI__Mastermind 34826 points

    Hi Roy,

    TPS25730 (both D and S version) supports OVP and RCP protection on PPHV. If 24V is present on PPHV then OVP will kick on TPS25730, disabling the sink path (PPHV or PP_EXT). 

    OVP timing for TPS25730D:

    OVP timing for TPS25730S:

    OVP should be enabled regardless of which port (Type-C or Barrel Jack) is first plugged in. If the Type-C port is plugged in (say it negotiated 20V) and then a 24V barrel jack was plugged in afterwards, this will kick in the OVP/RCP protection and disable the sink power path of TPS25730. I do recommend adding in some RCP circuit for the barrel jack in case the power input from the Type-C port (TPS25730 PPHV) is greater than the barrel jack input.

    Thanks and Regards,

    Raymond Lin

  • 0 in reply to Raymond Lin
    Prodigy 80 points

    Thank you for the reply Raymond!

    I was worried that only Vbus was monitored for OVP and would cause ON-OFF-ON-OFF behaviour. 

  • +1 in reply to Roy van Lierop
    TI__Mastermind 34826 points

    Hi Roy, 

    VBUS and PPHV/PP_EXT both have OVP monitoring. Do note when the power path switch is disabled, VBUS will still be at the previously negotiated voltage but this will not feed into the system.

    I'll go ahead and close this thread, for further support please open a new thread so we have better tracking! 

    Thanks and Regards,

    Raymond Lin