How to calculate the capacitor and inductor values?

Discussion in 'General Electronics Chat' started by nepdeep, Dec 24, 2012.

  1. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
    In SMPS the output is dtermned by the dutycycle which is normally decided by the programming resistors generally through the FB pin of the switching regulator....but what are the key factors determining the value of the inductor and capacitor...please some links and details...

    and yes...merry christmas everyone
     
  2. JDT

    Well-Known Member

    Feb 12, 2009
    658
    85
    The simple answer is to look at the data sheet for the switching regulator IC you are using. It will normally have a "applications information" section.

    Actually, value of the inductor can often be quite wide as the device will often terminate the cycle when a certain value of inductor current is reached. So, in effect, the switching frequency is dependent on the inductor value to a degree.

    The capacitor value is normally selected by the maximum amount of ripple allowed on the output. The ESR (equivalent series resistance) of the capacitor is normally more important. Best to have a number of smaller capacitors in parallel.

    Happy Christmas!
     
  3. nepdeep

    Thread Starter Member

    Sep 14, 2011
    139
    0
    thanks a lot sir.....
     
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