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TLE4275-Q1: output current overshoot issue when power on

Kevin-Cheng
Expert 3135 points
Part Number: TLE4275-Q1
Other Parts Discussed in Thread: TLV62065,

Dear team,

our customer test the Iout before the  Cout , when power on, the Iout have 600mA  overshoot with 22uf Cout and 800mA  overshoot with 220uf Cout.

First, we want to know is this overshoot normal for our IC? how to reduce the overshoot. 

Second, We can see the typical output current limit is 700mA, Will the 800mA overshoot cause damage to the chip?

Third， does the current limit refer to the current limiting value of inside MOS ? if not, could you please provide the current limiting value of inside MOS.

  • 0
    TI__Expert 5425 points
    It looks like your question is not related to TLV62065. I have modified the part number according to what I have read in your schematic to get your question directed to the people in charge of this product.
  • 0 in reply to Juergen
    TI__Guru 55940 points
    Thanks

    Hi Kevin,

    The initial peak current that you are seeing is the inrush current to charge the output capacitor. This current is normal.

    When you increased the output capacitor size, it takes longer for the capacitor to charge. As such, the current limit circuitry is engaging to limit the current through the TLE4275-Q1. This is why you see the current reduced to within the current limit range. The maximum current limit is 950 mA; therefore, you are still well within the normal operation of the regulator.

    The current limit is for a linear regulator refers to the current flowing out the OUT pin of the regulator. This is the same as the current flowing through the pass transistor.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Expert 3135 points

    Dear Ryan,

    if the Cout is is very large，will the current overshoot exceed the maximum current limit of IC when power on?

  • 0 in reply to Kevin-Cheng
    TI__Guru 55940 points
    Hi Kevin,

    Current limit will not engage instantaneously as it must first detect the high current; therefore, there can be a brief period of time that the current flowing through the regulator exceeds the maximum current limit. This is normal and true for all of our linear regulators. During startup this extra current is referred to as inrush current and is the current that is charging the output capacitor; therefore, this high current will not be seen by your load.

    Very Respectfully,
    Ryan