Battery Backup Circuit

[mogwai]

backup battery circuit

Hi all!

This might sound silly :lol:...

I need to provide backup battery supply to a small device.
The device has already a DC power supply. I want to design a circuit between the DC power supply and the device, in order to provide backup battery in case of DC power failure...

The switching circuitry between the two portions can be implemented with a switching diode? Any other ideas or resources on the web?

Thanks in advance!
mogwai.

 

[jdhar]

battery backup circuit

Connect a diode in series with your DC supply and the circuit, and then connect your battery in series with a diode to the cathode of the other diode. Depending on the voltage of your DC supply, the other diode will conduct and provide backup power.

 

[SphinX]

backup power circuit

Salam,

Use the Lead Acid Battery type, It's cheap and have a large capacity.

Look for LM317 datasheet, there is typical application for fixed voltage charging.

What is the your DC power supply value ?

SphinX

 

[otakung]

diode scotchy

I can't use 2 diodes serie with power supply and battery. Because the voltage will drop about 0.7V and some microcontrollers can't run at voltage lower than 4.5V. How should I do?

 

[Elavionic]

battery backup circuit diode

You should be a litle more specifique in your request. For low power aplications see Maxim site, they have lots of supervisor ic capable of
switching from main power supply thru a backup one even using a small coin baterry. Take a look.
For medium power aplications use a lead battery, vey simple and eficient (this subject was already discussed here, search elektroda).

 

[snake]

backup power switching circuit

you can try scotchy diodes or pin diodes but depends on your current

 

[mergus]

scotchy diode

Hi,

If Your need 12-13.7 VDC supply I suggest
PB137 (SGS Thomson) and seal lead batt.

Datasheet:
h**p://www.st.com/stonline/books/pdf/docs/6278.pdf

ciao