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TPS7H5001-SP: Duration of OUTA or SRB On Pulses during SET

Alex Driskell
Prodigy 60 points
Part Number: TPS7H5001-SP

Hello,

In the SEE report (SLVK099A), there are SETs that were found when monitoring the OUTA and SRB outputs under a few conditions.

Some of the figures in the report show waveforms of the effect on OUTA and SRB from these SETs, it looks like the OUTA and SRA can be held on for an extended amount of time compared to the typical pulse width, but it's not as clear how long these pulses can be on during an event in the report. Is there a maximum on-time during an event that can be shared? It's not clear from the histograms of the "Duration of Triggers" how much of this time OUTA or SRB are on, worst case.

Thanks

  • 0
    TI__Mastermind 28475 points

    Hey Alex,

    The SETs shown were only negative deviations of the typical pulse widths from the controller.
    Its actually the opposite of what you mentioned where the controller saw shorter pulses than typical here.

    The normalized pulse width event meaning the duration of the on pulse of the controller was 30% less than expected.
    From this information, one could calculate the time periods the device was on and know how that effects the system as a whole

    Thanks,
    Daniel

  • 0 in reply to Daniel Hartung
    Prodigy 60 points

    Hi Daniel,

    I'm a bit confused by what you mean, as I see larger pulse widths than the typical shown before/after the SET in the waveforms shown in Figure 8-16 for OUTA and Figures 8-19 and 8-25 for SRB. This is also reflected in the positive percentages shown in the normalized pulse width histograms in Figures 8-20, 8-23, and 8-26.

    It looks like I can take the max on time to be the max normalized pulse width at the clock frequency of interest, right?

    I'm also a bit confused by what the duration of trigger histograms actually represent. Do the durations presented show the length of time from the trigger until the pulses widths return to the typical width (so the overall duration of the effect)?

    Thanks,

    Alex

  • 0 in reply to Alex Driskell
    TI__Mastermind 28475 points

    Hey Alex,

    Apologies you are correct, I was focused on external clock triggers.

    To find the maximum duty cycle we observed all you would have to do is take the normalized pulse width at the frequency in question and add the normalized pulse width deviation.
    It is not obvious, but page 17 talks about the duty cycle set point as 30%, this number was actually used for all tests, not just the test it talks about.

    The duration of the triggers represent the length of time before the controller returned to normal duty cycle range.
    Of note is that our Worst Case graphics show the worst case the duty cycle deviated from the nominal duty cycle.

    Thanks,
    Daniel