AVR-Chat

The MC34063A was what I was remembering. Thanks, Roy.

Jim
\
On Mar 21, 2008, at 12:11 PM, Roy E. Burrage wrote:

> Try an MC34063A, UA3843A, or an LM3425A will all do what you want  
> and do
> it very economically. The first two come in an 8 pin DIP and the last
> one is a 16 pin DIP. All are easy to use, which to use depends upon  
> the
> application.
>
> REB
>
> James Wagner wrote:
> > Shervin -
> >
> > Yes, you probably could, but the 555 only represents a small part of
> > what would go into a switch-mode power supply. Further, the 555 is
> > really designed to vary its duty cycle or pulse width based on
> > external resistors and not voltages. This makes it harder to use for
> > this kind of application than one would really like. IF you REALLY
> > want to experiment and learn what the challenges are for making a
> > SMPS, then charge on. However, since you are posting on an AVR  
> list, I
> > would assume that your goal is to power an AVR or peripheral  
> circuits.
> > If that is the case, then you will be spending a LOT of time on
> > something that really is secondary to your end goal.
> >
> > I can understand, if you are in a part of the world where electronic
> > components are hard to get and you may only have access to 555s and
> > 741 op amps and such. There are some switcher "cores" that have been
> > around for a LONG time and are very low cost and widely available.
> > Unfortunately, I can't find any references to what I remember, but I
> > do know that they are out there. Unfortunately, if your problem is
> > finding modern components, you will also have problems getting
> > Schottky diodes and power inductors you really need for such a  
> supply.
> >
> > Jim Wagner
> >
> > On Mar 21, 2008, at 9:03 AM, Dennis Clark wrote:
> >
> >
> >> Maybe I've lost the spirit of discovery, but I see no reason to
> >> design a
> >> new power supply when there are dedicated switching controllers out
> >> there for a song (low cost).
> >>
> >> Is there a reason you want to do this the hard way?
> >>
> >> DLC
> >>
> >>
> >>> hi friends
> >>> have u ever worked at any switching circuits? i want
> >>> to design a DC power supply.may i use 555 Ic's??
> >>> is there any sites to help me.your ideas could help
> >>> me.
> >>> let me know if u have designed a switching power
> >>> supply
> >>>
> >>> thank u
> >>> have a nice spring holidays
> >>>
> >>> Shervin
> >>>
> >>>
> >>> __________________________________________________________
> >>> Never miss a thing. Make Yahoo your home page.
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> >>>
> >>> ------------------------------------
> >>>
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> >>>
> >>>
> >>>
> >>>
> >> --
> >> Dennis Clark
> >> TTT Enterprises
> >>
> >>
> >>
> >>
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
>
> [Non-text portions of this message have been removed]
>
>
> 



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