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LM25116: current limit

nnn sato
Prodigy 230 points
Part Number: LM25116

What is the error range for the current limit from "Average Load Current at Current Limit (A)" in Step 2 of the "Quick Start Component Calculator"?
For example, maybe ±1%? Also, where can I look in the data sheet to determine this?
Is it possible to set it to 0.1A or something like that?

  • 0
    TI__Guru 58171 points

    Hello nnn 

    'Average Load Current at Current Limit' is just a simple calculation based on your inputs. 

    A=(1+C)xB = (1+0.25)*15 = 18.75A 

    -EL

  • 0 in reply to EricLee
    Prodigy 230 points

    I would like to know how accurate "Average Load Current at Current Limit(A)" is.
    I would like to know what the range of error (± what percentage) is and how to determine it from the data sheet.

    Or, if "Average Load Current at Current Limit (A)" is different, could you please tell me where to look for the current value when current limit is applied and the error range at that time?

  • 0 in reply to nnn sato
    TI__Guru 58171 points

    Hello nnn 

    As I mentioned, "Average Load Current at Current Limit(A)" is just the multiplication of 'Maximum Ave Load Current(A)' and 'Target(%)'. The 'Maximum Ave Load Current(A)' and The 'Target(%)' are both user inputs. Therefore, there shouldn't be any error. 

     Peak current limit level is calculated by EQ (5) . The tolerance of CRAMP, RS is decided by users. tON is a function of VIN ,VOUT and FSW

    And the tolerance of 1.1V / A  is mentioned in the EC table 

    -EL

  • 0 in reply to EricLee
    Prodigy 230 points

    When calculated using formula 5 (peak current) (the formula on the right) of the data sheet,
    It is "Short Circuit Current" in Step 2 of "Quick Start Component Calculator". Is it correct that the current is limited to this value?
    In that case, is "Average Load Current at Current Limit(A)" displayed as a reference value that can flow this value?

    Also, how should I calculate "ton" in equation 5?

  • 0 in reply to nnn sato
    TI__Guru 58171 points

    Hello nnn

    In buck converters, ton = VOUT/VIN/Fsw  if no loss. 

    When the VOUT is grounded, the output current will be limited to 'Short Circuit Current'

    -EL