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Original question:

TPS65983: How to change the TPS65983 positive voltage transitions slew rate

TPS65981: For negotiated voltage change (9-15V) what is the GPIO7,8 to PP_5V0 to PP_HV switch turn on time ?

M Haglund
Genius 9155 points
Part Number: TPS65981

Hi!

For negotiated voltage change (9-15V) what is the  TPS65981 timimg from switching GPIO7,8  to  PP_5V0 to PP_HV switch turn on?

uS, msec or?

  • 0
    TI__Mastermind 30000 points

    Hello,

    This spec is defined within the datasheet as TON_HV which is 8ms from enable to VBUS = 95% of PP_HV voltage

  • 0 in reply to Adam Mc Gaffin
    TI__Genius 9155 points

    Hi Adam and thanks,

    Can you elaborate why we recommend to slew rate control the DC/DC that is mentioned in the below thread?

    https://e2e.ti.com/support/interface/f/138/t/688876 

    The 9-15V slewing will be done long before the PP_HV switch turn on hence you will have a really high not allowed +30mV/us at the Vbus?

    Or did i miss something?

  • 0 in reply to M Haglund
    TI__Mastermind 30000 points

    Hello,

    The fastest slew rate for a compliant Type-C PD device is defined within the PD spec. That is why the referenced E2E post states that you cannot have a slew rate faster than 30mV/us.

    The 9-15V slewing will be done long before the PP_HV switch turn on hence you will have a really high not allowed +30mV/us at the Vbus?

    • This is not correct. If you are sourcing a 9V contract, you will be using the PP_HV power path, so the PP_HV power path will already be closed. Thus, the slew rate from 9V to 15V will be 100% dependent on the DCDC. So if the slew rate of the DCDC is faster than 30mV/us, your device will no longer be compliant.