[chbot] Help I don't know enough about SMPS! (And can you help me design one pls)

[Jasper Mackenzie]

Yarrr!
> I have heard good things about LT (Linear Technology). Their reference
> designs (those in the data sheets and appnotes) are reported to work
> reliably. They're big in switch mode designs too. Check their range, but
> I suspect you are pushing the limits (mainly input voltage) with your
> solar panel. They have a good spice simulator too (LTspice), and are the
> only company who bothers to mention Linux and say that LTspice works
> under wine. (There was an article in a recent Elektor about that too).
> The LT semiconductors should all have spice models for their simulator.
> I would make extensive use of that in your position.
  LT Have an amazing array of good stuff, found one that is perfect etc...
BUT I really want to get to know one topology to do it all, and this is  
not working in an easy way,
  so does anyone know of a chip/topology etc. that is both easyish (i.e I  
can make it... ) and efficient over these ranges:

So for ~60V -> 27V (~12A) no problem, buck is easy and rel. efficient it  
seems. no kooky magnetics either.
  BUT 40-60V -> 57V (~6A) is a problem, being buck/boost needing complex  
magnetics etc.... This is the range I am finding difficult, esp as I would  
like minimal (pref. only ref change from micro) modification to change  
Vout.
    I should qualify this somewhat. COmplex isnt a problem if its going to  
work, its that I am not sure if I could get the magnetics, or make them  
right.

Anyone tried Cuk? Not much out there on it in terms of LT etc.

Hopefully I will be able to make it tonight, and have a chinwag with some  
of you expert types.

TIA

Jasper