Wojciech Zabolotny wrote:
> Hi All,
> 
> I need to build a PIC18F4550 based circuit powered from the 4 NiMH
> batteries.
> The problem is that the power supply voltage for fully charged batteries is
> equal to 5.6V which is above acceptable limit for PIC18F4550.
> On the othe hand The fully discharged batteries provide only 4.4V (while PIC
> needs at least 4.2V).

> Or maybe I should use just a Schottky diode with forward voltage of c.a.
> 0.4V?

Seems like any Schottky diode with Vf >= 0.1V would do the trick, if all 
those numbers are valid (and that's pretty much all of them).  Actual Vf 
will depend on how much current you're pulling, so if that varies widely 
it might be problematic.  But it's a small and cheap solution.
-- 
Timothy J. Weber
http://timothyweber.org
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