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  1. Problem with IR2153 SMPS

    Quote Originally Posted by dinithm View Post
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    first time turn on - it work fine voltage ok 14.7v, load 4.7ohms
    after 30sec - turned it off ,no heat no problem

    second time turn on - (load 4.7ohms)
    PCB burned AND fused,
    2 fet (irf840) burned

    three times rebuilt it same result,one time fets exploded

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  2. Current transformer calculation

    To determine how to calculate the number of turns according to the current handling for a SMPS.

    1) Determine the voltage needed for sensing and add 1 diode forward voltage in a centre tapped configuration, or 2 diode
    forward voltage drop for a single secondary winding with a bridge rectifier.

    2) Calculate the peak current for the SMPS in the primary winding.
    3) Determine the turns ratio for the current transformer. Please note that the ...