Low battery shut-off - best way?

[lee321987]

Hello, I'm building a DC-DC boost converter, it's called the Mintyboost - here is the link:
Minty Boost! - USB charger for your gadgets

It takes 2 AA batteries and boosts them to 5V so you can charge USB devices.

I'm going to use NIMH rechargeable batteries, so in order to avoid over-discharging my batteries, I need to make the device shut off when the batteries are below a certain level. I was thinking ~2.2V.

What would be the least power-consuming way to do this? Or the best way, or any thoughts you have on this...?

 

[saikat36]

Use Transistor as a switch to on -off.

 

[lee321987]

How would I make the transistor turn off when the supply is 2.2V?

 

[firry]

you can make a low queicent current Undervoltage Lockout block to turn off the transistor. typically, the Iq of the UVLO is about 5uA.

 

[lee321987]

Is there an IC that is a UVLO? I can't find one. Is there another name for them?

 

[firry]

Is there an IC that is a UVLO? I can't find one. Is there another name for them?

You can find any RESET IC to shut down your system.