Return to the archive index

Re: Lithium-Ion Battery Packs - Quick Question

"Tung-Yep, Philip" wrote:
> 
> Marcus,
> 
> You may also want to try the Maxim MAX787 (5v) and MAX788 (3.3v) 5A PWM
> step-down switchers.  They need two external caps, a resistor, a Schottky
> diode and a (small) inductor.  I managed to fit the whole circuit for a 5V
> regulator in 3cm x 4cm without much effort.  Not sure what the efficiency is
> - they're simply listed as "high-efficiency" - but mine barely runs warm
> even when supplying 3A.
> 
> Maxim offer free samples
> (http://dbserv.maxim-ic.com/quick_view2.cfm?qv_pk=1271) which solves the
> supply problem and are quick to send them.

I never thought non-comercials were eligible for that. But I tried and
said company=our University. let's see what happens.
(I ordered a sample of 788 and 787, I need a second 5V-supply anyway.)

> 
> Philip
> 
> > -----Original Message-----
> > From: Marcus Wolschon [SMTP:]
> > Sent: Monday, April 29, 2002 12:45 AM
> > To:   
> > Subject:      Re: Lithium-Ion Battery Packs - Quick Question
> >
> > David Pilon wrote:
> >
> > >Marcus,
> > >     I have been using the simple switcher series from national semi
> > (cheap,
> > >but need a coil, cap, and diode).  the elcheapo one (about $2.50) gets
> > >80-90% eff from 10-15V has a imput range of 7-35v.
> > >
> >
> > Wich ones exactly are you refering to?
> > Up to now I found the *
> > *http://www.national.com/pf/LM/LM2640.html *LM2640*
> > 5V/3A+3.3V/4A+12V/0.3A (totally overdimensioned, lot's of external parts
> > needed but very efficient). But as ever, no place to get one nearby.
> > (local electronics-shop does
> > not do orders, they sell just what they have in store.)
> >
> >
> > >  the dearer
> > >ones(about $5 + 1 more cap) get 93%+ eff.  You would need 2 of these to
> > >supply 5+3.3V.  My sbc only wants 5V, so 1 is ok for me.   (btw, use the
> > >#a output rated ones, and to improve eff, use a higherpower diode than
> > >speced - I'm using some 16A schottkey's I had laying arround worth 2-5%
> > >more eff).
> > >
> > >have fun..
> > >
> > >Marcus Wolschon wrote:
> > >
> >
> > Marcus
> >
> > --
> > Subscription/unsubscription/info requests: send e-mail with subject of
> > "subscribe", "unsubscribe", or "info" to 
> > Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
> > Please, *PLEASE* don't subscribe through a forward/expander/false domain
> 
> --
> Subscription/unsubscription/info requests: send e-mail with subject of
> "subscribe", "unsubscribe", or "info" to 
> Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
> Please, *PLEASE* don't subscribe through a forward/expander/false domain

--
Subscription/unsubscription/info requests: send e-mail with subject of
"subscribe", "unsubscribe", or "info" to 
Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
Please, *PLEASE* don't subscribe through a forward/expander/false domain

From Wear-Hard Mailing list Archive (WH)
Maintained by R. Paul McCarty

Archive created with babymail