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TPS542A52: Question about PFM

Austin Do
Intellectual 2175 points
Part Number: TPS542A52

Hello team,

I have two questions about PFM mode.

1. In datasheet 7.4.1, for the application of 5V input, PFM enabling is not recommended. Can you explain more detailed about it? What happens in case of the low input voltage? Does it affect detecting zero crossing of valley current which results in unexpected waveform..? Or no problem to enable it?

2. My customer notices that Rss value had been changed in revision. What happens if the customer use Rss as 10k or 16.2k? SS CLK and Hiccup duration can be expected as linear interpolation?

Best Regards,

Austin

  • 0
    TI__Intellectual 2670 points

    Hi Austin

    1. The zero cross is powered internally, with low Vin and internal drop the zero cross may loose it accuracy which may result in device not entering into the PFM mode

    2. I think you are referring to SS clk frequency reduced by factor of 2, for the corresponding setting hiccup time is increased by factor of  2, but pls follow the latest datasheet values

    Thank you

    Savith