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TPS53689T: TPS53689T VOUT Shutdown During Soft-Start

Part Number: TPS53689T

Tool/software:

Hello,

(1) I wanna ask which parameter and what value in TPS53689T's GUI as below we could fine-tune for VOUT shutdown during soft-start?

Or what are the other parameters you recommend for the issue?

(2) We were sured about controller or power stage were all ready, there was no relevant fault(such as OCP,UVP etc) shown in Status window.

I wanna know if controller's 3.3VDD was always high,

whether the controller could clear "Status Registers" and "Power Stage Status" faults automatically when the fault condition disappeared?

But NVM_FAULT_LOG would always keep record the fault right?

Sincerely

Ringo

  • Hi Ringo, 

    Thanks for posting on the E2E forums, I'll address your questions in the order they came in.

    1. Just to clarify your question, you are looking to fine-tune VOUT during soft-start and soft-stop (sometimes referred to as soft-off), correct? If so, the only values that affect it are going to be TON_RISE, TOFF_FALL, and the separate slew rates for both soft on and soft stop. 

    Output voltage settings will also affect the VOUT during these transitions as well. Notably, VOUT_TRANSITION_RATE and VOUT_SCALE_LOOP will affect VOUT as well, however please note these two fields affect all voltage output, not just only during soft-start and soft-stop.

    2. For the NVM fault logging features, please note that only faults that stop power conversion output are registered into the NVM. The NVM fault memory is retained after the controller loses power, and has to be cleared via command in PMBus. If the NVM already has a fault logged in memory, it will not re-arm to capture a second fault unless the data has been commanded to be cleared. Please see section 7.3.5.3 Automatic Fault Logging in the TPS53689T datasheet.

     The controller will clear some faults when the enable pin is cycled, but not all. For more information on which faults are cleared by which mechanisms, please see the table of faults and behavior in 7.3.5.4 Fault Behavior Summary in the TPS53689T datasheet.

    Kind regards,
    Nick Z