Low Battery protection

[tazntex]

Just curious, is there a simple efficient way to add on a 9V battery powered project ,feeding a LP2950ACZ-5.0 regulator (5V) with a 16F628A, processor some kind of protection that when the battery goes down to about 6.2V it will not provide power to the regulator?

Thanks for any suggestions.

[languer]

why 6.2V? will the regulator be unpowered? If you want to "feed" two power supplies into the regulator, and want the highest one to always power it, a blocking diode is the solution (it can be more complicated than this, but the idea is the same).

[tazntex]

Thanks for the reply, what I am trying to do is to prevent any damage to any components because of a low battery. What I mean is if I am using a 9V battery to feed the lp2950 5v regulator and forget to turn if off over a period of time the battery will be discharged and and I would like to "disconnect" the battery from the circuit that way I could prevent damaging any components like voltage regulator and anything things else connected that requires 5v. I having been experimenting with a 6.2v zener but something around that voltage would allow me to get the maximum use of my 9v battery but would like it to have a very low current. Anyhow I am just looking for a suggestion, I've been searching the forum but haven't found anything of interest on a low battery condition but after few batteries I figured I needed to do something.


Thanks

[rsocor01]

What I mean is if I am using a 9V battery to feed the lp2950 5v regulator and forget to turn if off over a period of time the battery will be discharged and and I would like to "disconnect" the battery from the circuit that way I could prevent damaging any components like voltage regulator and anything things else connected that requires 5v

I have never seen any component getting damaged because of a low voltage. I usually test my circuits by let them run until the battery completely drains to get a battery lifetime plot, and never had any problems. Let's see what other people in the forum has to say about it.

Robert

[Acetronics2]

Hi,

The 16F628 has built in Comparators ... so, it's easy to get an interrupt if an input voltage goes under a choosen reference ...

till the regulator has sufficient supply, you can get some 5v absolute reference ...

Why not do it simple ???

Note a MC33064P5 can also do it ...

Alain

[Tywais]

A LTC1440 can do it and is what I use for one of my systems with 9V battery operation. It can operate with supply voltage from 2-11 volts. 2 resistors to set the trigger point and a on/off output that can be used to drive an LED or disconnect your power source from the circuit using either a relay or MOSFET.