[ARC5] DC-DC Buck/Boost Converter Regulation

[Dennis Monticelli]

Dave,

I do know something about these ebay Chinese DC/DC converters because they
either use switching regulator chips I developed 20 years ago at National
Semiconductor or they use Chinese copies of the same chips  (which became
industry standards long ago and with patents now expired).  Most likely the
circuits and layout techniques were taken from the NSC datasheets and app
notes.  Although I have no direct experience with the Chinese equivalents,
I believe these little modules probably perform OK.  The big question is
whether you really want to use a switcher in your application or could
avoid it.  The reasons have been cited by others.  If you need to boost (or
buck-boost), you really have no choice.  If you are bucking then you may
consider using a linear reg or a switching reg followed by a linear reg (to
clean up the output and improve the dynamic response).  In the latter case
you would, for example, step down from say 35V to 15V via switching and
then linear regulate down to 12V.

Dennis AE6C


On Thu, Oct 31, 2013 at 9:05 AM, David Stinson <arc5 at ix.netcom.com> wrote:

> I've been told that DC-DC Buck or Boost converters like these:
> http://www.ebay.com/itm/**261316095061<http://www.ebay.com/itm/261316095061>
> http://www.ebay.com/itm/**261318532314<http://www.ebay.com/itm/261318532314>
> will regulate their outputs through wide input excersions
> at least as well as something like an LM-317
> (assuming one stays within the devices design limitations).
>
> Can anyone here vouch for that?
> 73 D.S.
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