At 05:17 AM 1/24/2015, Isaac Marino Bavaresco wrote:

>Dwayne,
>
>I studied your suggestion and improved the design. The circuit is
>attached as a PDF.
>Now it uses a TL431 to detect low input voltage condition and
>disconnects it to avoid brown-out. The circuit will be powered either
>from the external power input or from the battery, not both.

Can I make another suggestion?  Instead of using a TL431 and all the=20
rest of the stuff that you have there, why not use a PNP transistor=20
and base resistor to monitor the voltage across your Li-Ion charger=20
chip. The collector of the PNP transistor is HI when there is=20
sufficient voltage across IC1 and low when not.

dwayne

--=20
Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
www.trinity-electronics.com
Custom Electronics Design and Manufacturing

--=20
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