>> It looks like I need Boost wide input range IC. Any Idea 
>> will
>> appreciate.

Jinx app note here.
Change inductor somewhat.
For LED drive feedback is from a resistor in LED cathode 
instead of a voltage divider. If you do ant to use this IC 
advise and I'll show you a circuit to halve the Vref drop in 
the LED series resistor.

    http://others.servebeer.com/misc/mc34063/jinxmc34063boostconverter.pdf

Efficiency can be quite good through using external FET.

Other MC34063 material on same page

    http://others.servebeer.com/misc/mc34063/

IC is old, slow, cheap, flexible, available, DIP8 & SOIC8, 
excellent for many uses.



        Russell McMahon


> You could try these two for the MC34063. Cheap and 
> flexible
>
> http://www.onsemi.com/pub_link/Collateral/AN920-D.PDF
>
> http://www.onsemi.com/pub_link/Collateral/MC34063A-D.PDF

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist