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    USB charger from wall adapter- connect USB shell to ground or leave floating?

    USB charger from 2 wire DC wall adapter- connect USB shell to ground or leave floating?



    If using a 5Vdc wall adapter as a USB charger for a phone would it be better from an EMI perspective to leave the USB shell floating at the connection to the wall adapter or connect it to the -ve side of the wall adapter output?

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  2. #2
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    Re: USB charger from wall adapter- connect USB shell to ground or leave floating?

    connect shell and use large high mu torroid around wires for CM RF isolation..
    A best design is easily achieved with good test specs™
    A better question deserves a better answer. ™
    ... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.

    ... Tony Stewart EE since 1975
    - slightly north of Toronto


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  3. #3
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    Re: USB charger from wall adapter- connect USB shell to ground or leave floating?

    Quote Originally Posted by SunnySkyguy View Post
    connect shell and use large high mu toroid around wires for CM RF isolation..
    Can you please give an example of what would likely be a suitable high mu toroid (part #), keeping in mind I have very little space so the smaller the better.

    Much appreciated.



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  4. #4
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    Re: USB charger from wall adapter- connect USB shell to ground or leave floating?

    A best design is easily achieved with good test specs™
    A better question deserves a better answer. ™
    ... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.

    ... Tony Stewart EE since 1975
    - slightly north of Toronto


    1 members found this post helpful.

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