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    Choosing between CCM or DCM modes in a buck converter

    Hello friends.

    I would like to know what are the criteria that we consider to choose whether we want to operate a buck dc-dc converter in continuous inductor current mode or discontinuous mode. I have designed a buck dc-dc converter for battery charging.It a bank og lead acid batteries that I intend to connect in parallel. my source is a set of PV arrays. should I go for CCM or DCM ?

    •   Alt13th December 2010, 12:26

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    Re: Choosing between CCM or DCM modes in a buck converter

    You only enter discontinuous mode when the load current is too low for the chosen inductor. This produces more ripple, noise, emissions etc but in your case I'm not sure if that matters at all. You could get away with running in discontinous mode but it's pretty much against regular design practices for bucks where one would design to keep in continuous mode for the lowest currents one can imagine for their application...



    •   Alt14th December 2010, 07:25

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    Re: Choosing between CCM or DCM modes in a buck converter

    Yes I have design my buck converter with a lowest Io(min) of 0.2A. but when using batteries as a load for the converter, does we ALWAYS need CCM or does the battery load also support DCM??



    •   Alt14th December 2010, 09:32

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    Re: Choosing between CCM or DCM modes in a buck converter

    Quote Originally Posted by Ice-Tea View Post
    You only enter discontinuous mode when the load current is too low for the chosen inductor. This produces more ripple, noise, emissions etc but in your case I'm not sure if that matters at all. You could get away with running in discontinous mode but it's pretty much against regular design practices for bucks where one would design to keep in continuous mode for the lowest currents one can imagine for their application...
    Nice information.
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    Re: Choosing between CCM or DCM modes in a buck converter

    Quote Originally Posted by dammadmin View Post
    Hello friends.

    I would like to know what are the criteria that we consider to choose whether we want to operate a buck dc-dc converter in continuous inductor current mode or discontinuous mode. I have designed a buck dc-dc converter for battery charging.It a bank og lead acid batteries that I intend to connect in parallel. my source is a set of PV arrays. should I go for CCM or DCM ?
    If your power is lower (in the range of 250W) you can design CCM mode of operation to take advantage of zero voltage & zero current switching, you will be able to use fast recovery diode for free wheeling



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