AVR-Chat

Hi Reza,

Try looking at e.g. Seiko Instruments homepage
(http://www.sii-ic.com/en/param_chrt.jsp?subcatID=5). 
There are a lot of semiconductor makers on the marked, which makes
Li-Ion protection chips.

Once lower discharge voltage is surpassed, the chip shuts the battery
down (via external FET). The battery is turned back online again, when
put into a charger. 

This way you also protect the battery from being shorted for a longer
amount of time.

Just some generic Li-Ion information for you :o)

Cheers,
Jesper Holst



--- In AVR-Chat@yahoogroups.com, Reza Naima <reza@...> wrote:
>
> So I'm looking at deploying a device with a Li-Poly battery on board.  
> The voltage of a fully charged battery should be 4.2V, and will drop 
> over time.  My application calls for a 3.3V source, and I was
looking at 
> using a LDO voltage regulator which has a *fault line to indicate when 
> the voltage out is not correct (i.e. below 3.3v).  At this point, I 
> would like to shut down the device, but I'm not sure how to do it.  If 
> the device shuts down, I expect the voltage to rise above 3.3v, the 
> device will power on again, the voltage will drop, it will shut down 
> again.... et cetera... and just oscillate using up more battery and 
> possibly permanently damaging it. 
> 
> This would seem like a common problem.  Has anyone else run into it -- 
> and if so -- what solutions are available?  I can shut down a lot of
the 
> peripherals on the board, but there will be a number of components that 
> I can't shut off and I don't want to run into the situation where the 
> battery is bled dry.
> 
> Thanks in advance!
> Reza
>