On Thu, Nov 27, 2008 at 4:54 AM, Andre Abelian wrote: > Michael, > > Then open the page 15 and start thinking about it! Just kidding. > I just wanted to say think you all for help on buck boost circuit. > Voltage set was for OVP over voltage protection purpose and most > Important was current set resistor. I got every thing working fine > And the board functions started @5v. Learning some new every day. If you want to go a bit deep and really understand how the circuit works, then you need to know what is a buck-boost converter. A simple introduction is here. You just need to read the first 6 chapter. The slides are excellent. The book is also very good. Chapter 1-6 + 12-14 are undergraduate level. The other chapters are graduate level. http://ece-www.colorado.edu/~pwrelect/book/slides/slidedir.html Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist