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LM25141-Q1: Standby mode

Wenyi Zhao1
Prodigy 255 points
Part Number: LM25141-Q1

Dear,

I have some questions about the application information in the LM25141-Q1 datasheet.

1. why does it enter standby mode when missing 16 switching cycles In page 21(7.3.14),not 15 or 17? 16 is chosen by what?

2.Can i judge when the controller enter  standby mode not by watching the switching cycle but by Vin, Iin or Pin? Because i don't know when 16 missing switching cycles will occur.

Thanks .

Wenyi

  • 0
    TI__Guru 73072 points

    Hi Wenyi,

    1. 16 cycles is set by an internal counter.

    2. you can look at the SW node voltage to review the number of cycles. Looking at Vin, Iin or Pin will not show it.

    Regards,

    Tim

  • 0 in reply to Timothy Hegarty
    TI__Prodigy 255 points

    Hi Tim,

    1. Yes, i guess 16  may be set by an internal counter, but i mean does 16 follow a certain principle or just because the counter can realize 16? Or why not use 8 or 32 or more?                    

    2. Thanks for your suggestion which i will try latter. And, when i increase the input voltage(e.g light load), can i calculate the voltage or power when it enters standby mode by some expression or other principles?

    Regards,

    Wenyi

  • 0 in reply to Wenyi Zhao1
    TI__Guru 73072 points

    Wenyi,

    1. 16 cycles was designated as an appropriate and convenient wait interval by our design team.

    2. The conditions upon which standby mode is entered are a function of power stage and IC parameters. I haven't got an expression for that, but maybe you can see it in the log scale of efficiency vs. load.

    Regards,

    Tim