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    SMPS inrush current limiter to protect the secondary diodes

    Hello friends

    please guide me. What is the charge current of the capacitors in the circuit below?

    And how is inrush current limited?
    Are Rectifier Diodes Damaged?

    Click image for larger version. 

Name:	20190104_210620.png 
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    Thanks

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    Re: SMPS Inrush Limiter to protect the secondary diodes

    Hi,

    Not sure if this will help at all:

    Design Guide for Rectifier Use Hammond 5c007.pdf

    I am not familiar with series chokes in power supplies, I've seen a low value series resistor before the capacitors to limit the inrush current.

    If you get the datasheet for the MUR1560 and check the diode's ratings, then you can compare it with the power drawn by the expected/maximum load and check the peak impulse rating is much higher than you are expecting.


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    Re: SMPS Inrush Limiter to protect the secondary diodes

    Hi,

    The picture shows the secondary part of a switch mode power supply.
    The shown circuit does not work without (primary side) SMPS controller.

    Inrush current limiting is done by the SMPS controller.

    Klaus
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    Re: SMPS Inrush Limiter to protect the secondary diodes

    Hi,
    Complete schematics
    Click image for larger version. 

Name:	50khz-4n25-sg3525-smps-ir2110-smps-900w-70v-power-supply.png 
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    Re: SMPS Inrush Limiter to protect the secondary diodes

    The NTC thermistor in the AC input limits the inrush current. There is no need to limit the current to the output rectifiers as well.

    Brian.
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    Re: SMPS Inrush Limiter to protect the secondary diodes

    More specifically, the SG3525 soft start circuit limits the transistor and rectifier current during start. With 33 uF it's dimensioned extremely slow.



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