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LM25141-Q1: LM25141-Q1

Part Number: LM25141-Q1

Hello,

i have a generic question:

Do you have any guide for selecting the soft start time( or capacitor value) during the initial design of the power supply?

i have generally selected this value with thumb rule. Do we have a guidance precisely showing the soft start duration needed in any design. Keen to understand this concept in detail!

regards

Shreeharsha K

Robert Bosch India

  • Hi Shreeharsha,

    The soft-start time is typically in the range of 2-4ms and set by the soft-start capacitor (basically a current source charging a cap to a certain reference voltage).

    The main concern is the current into the output caps for a given dv/dt at startup. This current = Cout*dv/dt should not cause current limit to engage (especially if there is also a resistive load present at startup). In general, a higher output cap value requires a longer soft-start time.

    Regards,

    Tim