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LM25141: switching frequency in diode emulation

Yuto Sakai
Mastermind 6100 points
Part Number: LM25141

Hi,

Our customer want to estimate the switching frequency at light load.
I would like to know the threshold at which the high-side FET turns on after switching stops in diode emulation mode.
Does this device turn on the high side FET by monitoring the FB pin voltage drop?
If yes, could you tell me the threshold?

Best regards,
Yuto Sakai

  • 0
    TI__Expert 8245 points

    Hi,

    Normally it's determined by comp voltage in peak current control, when the device enters into light load and has a pulse to charge output capacitor, the internal compensation will wait comp voltage trigger its threshold for the next pulse.

  • 0 in reply to Iven Su
    Mastermind 6100 points

    Hi,

    I understand that if the voltage of the "SLOPE COMPENSATION RAMP" inside the device is higher than the COMP voltage, the pulse will be skipped.
    Is it correct?
    Is there a way to estimate "SLOPE COMPENSATION RAMP"?

    Best regards,
    Yuto Sakai

  • 0 in reply to Yuto Sakai
    TI__Mastermind 35210 points

    Hello Yuto Sakai,

    We can not share over public forum additional information that is not already given in IC datatasheet.

    Iven already specified general idea of how devices regulates in low current operation.

    Webench power designer allows for the simulation of steady state waveforms.

    In addition, orderable EVM is available for this product to measure steady state waveforms.

    Many variables can effect light load mode operation including power conditions and componet selection. For most accurate prediction, please order EVM and measure. This will allow for you to understand device operation and if this device is feasible for your project.

    Thank you.