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LM5025: Delay time of internal current source at UVLO

Hidekazu Someno
Expert 5130 points
Part Number: LM5025

Hi Application team;

 

LM5025 has the hysteresis by turning internal current source on or off for UVLO function.

 

Can you tell us the delay time of turning off/on of the internal current source?

- From UVLO voltage increases >2.5V_threshold to changing 20uA current source to ON

- From UVLO voltage decreases <2.5V_threshold to changing 20uA current source to OFF

 

Regards,

H.Someno

  • 0
    TI__Genius 9140 points

    Hi H.Someno,

    The delay time is a internal time that can not be share with customer, but the time is so small that  will not influence the UVLO function.

    Usually if you place a resistor divider to do the UVLO, it is better to in parallel with a filter cap(for example 0.01uF) to help avoiding noise. Here is a application circuit in the below link:

    The RC that form in the circuit is at least 80uS, and the delay time is ns ratio. I hope this helps you.

  • 0 in reply to David Huang33
    TI__Expert 5130 points

    Thanks for your answers.

    My customer has an additional question related to this UVLO.
    When UVLO is detected(UVLO voltage decreases <2.5v), Does this IC behave like the following sequencing?
    If not, please tell the correct sequencing operation for them.

    1. UVLO detection --> 2.switching operation stop --> 3.Then, UVLO hysteresis current(20uA) off

    Regards,
    H.Someno

  • 0 in reply to Hidekazu Someno
    TI__Genius 9140 points

    Hi H.someno,

    Yes, the operation you list is correct.