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  1. #1
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    Is it some kind of start delay or transient filter circuit?

    Hello,
    I need to some help to find more information about circuit connected to ADJ pin (D2, R23, D1, R22, C54).

    Has this circuit a name (so I could google that)?

    What function it has?
    Is it some kind of start delay or transient filter circuit?

    Click image for larger version. 

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    Thanks,
    Greg

    •   Alt13th December 2016, 09:56

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  2. #2
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    Re: Is it some kind of start delay or transient filter circuit?

    Hi,

    Has this circuit a name (so I could google that)?
    --> you can google anything!

    And yes, the IC is named in the picture:
    --> MIC69502

    --> datasheet: http://ww1.microchip.com/downloads/e...c/mic69502.pdf

    ....And it takes LESS time for you to google for it than to let us google for it.


    Klaus



    •   Alt13th December 2016, 10:20

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    Re: Is it some kind of start delay or transient filter circuit?

    Out of context I can't be sure but it looks like a circuit to delay the rise of the regulator output as the 3.3V line rises.

    C54 charging through R22 will cause a slight increase in voltage at the ADJ pin which in turn will trick it into thinking it has to reduce it's output voltage to maintain regulation. D1 will be to discharge C54 again when the power is removed. Once C54 is charged, the regulated voltage will be set only by R24 and R25. I would guess D2 is to limit the 'ADJ' voltage rise and also prevent back-flow into the delay components.

    Brian.
    PLEASE - no friends requests or private emails, I simply don't have time to reply to them all.
    It's better to share your questions and answers on Edaboard so we can all benefit from each others experiences.



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