Looking for battery powered solution for my project

[FFly]

Battery Powered Solution

Hi,
I am working in a project that needs battery backup for the power supply subsystem. Since my battery knowledge is almost NULL, I appreciate any feedback.
I am assuming the battery related part will include a rechargable battery, charger and a low voltage detector.

 

[DrShoe]

Re: Battery Powered Solution

Use the MAX712 switching mode for charging and the MAX710 for 5V buck/boost

 

[IanP]

Re: Battery Powered Solution

Before you start building Battery Charger + Power Supply, have a look at small computer UPS which has all you need.
Economically speaking, this is probably cheaper option..

 

[FFly]

Re: Battery Powered Solution

I am looking for a power supply with a small footprint. A small UPS won't work.

My system has one external DC (7-12V) voltage supply. I want to have an internal battery backup to be able to run even if the external power supply is removed. I wantthe external power supply to charge the battery when it is connected to my small system.

I appreciate any input.

 

[IanP]

Re: Battery Powered Solution

To select components and the size of a battery could you tell us what is the current requirement of your circuit?
The 7-12V voltage: how is it converted and is there on-board regulator?

 

[FFly]

Re: Battery Powered Solution

To select components and the size of a battery could you tell us what is the current requirement of your circuit?
The 7-12V voltage: how is it converted and is there on-board regulator?

The system has 2 linear LDO regulators (5v and 3.3v). The overal current rating of the system when battery powered should be 500mA.

I appreciate your help.

 

[penasita]

Re: Battery Powered Solution

I think the MAX712 is a good option for the battery charging circuit. It lets you supply the load while you charge the battery. I am using it in a design after a long search about battery chargers.
With respect to the LDO, it depends on the load you have. if you have low power analog board, I would use a charge pump to be able to power from the 2 batteries NiMH up to 2V.