AVR-Chat

> -----Original Message-----
> From: Mike Bronosky [mailto:Mike@Bronosky.com] 
> Sent: Friday, 19 March 2004 11:11 PM
> To: AVR-Chat@yahoogroups.com
> Subject: Re: [AVR-Chat] Re: back-up power supply circuit
> 
> 
> I havent been following this back-up power supply circuit 
> very closely so I may be way off track here but...
> All you need, besides the BATTERY, POWER SUPPLY and LOAD is 2 diodes.

Been here lol, this was the first idea, but it was pointed out a diode
failiure on the battery line could blow the batteries up (and after some
of the crap NiMh I have found over the last couple of months that
explode even in normal use.....)

The relay Idea was floated as unless the contacts weld (not likely with
only a couple of 100 mA) it is relatively safe.

For Commercial designs I use 2 diodes on the battery line (this has UL
approval on one of my marine designs (and also VME and others)

It has also been suggested to use a power management chip or reg with
battery input etc. 

Regards,

Kat.

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.618 / Virus Database: 397 - Release Date: 9/03/2004