Searching \ for '[EE]: [PIC]: Any ideas on backup battery switchove' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/power/batterys.htm?key=battery
Search entire site for: '[PIC]: Any ideas on backup battery switchove'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: [PIC]: Any ideas on backup battery switchove'
2001\03\13@155707 by Rick Mann

flavicon
face
on 3/13/01 6:14 AM, Byron A Jeff at spam_OUTbyronTakeThisOuTspamCC.GATECH.EDU wrote:

> I'm open to any other ideas.

I'm facing a related problem: how to keep my PIC powered long enough in the
absence of line power. I bought a couple of super caps (5V, 1.5 F)
originally to power a clock chip that was designed for this. But I've moved
the clock functionality into the PIC (a 16F877), so now I need to keep power
to the PIC.

I think what I'll do is find a way for the PIC to monitor main power, and
then just go into sleep if that falls below some level. The super cap can
probably be wired straight to Vdd with steering diodes to keep it from
powering the rest of the circuit. Then I'll wire RB0/INT to the supply
outside the diode, and if that level falls from high, it can generate an
interrupt to execute code to handle sleep.

I, too, would appreciate any comments.


------------------------------------------------------------
Roderick Mann                 .....rmannKILLspamspam@spam@latencyzero.com.sansspam

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\13@164143 by Byron A Jeff

face picon face
>
> on 3/13/01 6:14 AM, Byron A Jeff at byronspamKILLspamCC.GATECH.EDU wrote:
>
> > I'm open to any other ideas.
>
> I'm facing a related problem: how to keep my PIC powered long enough in the
> absence of line power. I bought a couple of super caps (5V, 1.5 F)
> originally to power a clock chip that was designed for this. But I've moved
> the clock functionality into the PIC (a 16F877), so now I need to keep power
> to the PIC.
>
> I think what I'll do is find a way for the PIC to monitor main power, and
> then just go into sleep if that falls below some level. The super cap can
> probably be wired straight to Vdd with steering diodes to keep it from
> powering the rest of the circuit. Then I'll wire RB0/INT to the supply
> outside the diode, and if that level falls from high, it can generate an
> interrupt to execute code to handle sleep.
>
> I, too, would appreciate any comments.

Well first off I'd run a couple of tests and see how long the supercap
drives the 16F877. Honestly the difference between sleep and not sleep isn't
much.

BAJ

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2001\03\14@150111 by Ron Wilder

flavicon
face
From my recollection, those super caps have pretty high internal resistance and
my not be able to give you the current you need to run a PIC.  Make sure to
check it out.
Ron

Rick Mann wrote:

{Quote hidden}

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...