Lithium-Ion Low Voltage Cut-Off (retool of Minty Boost)

[J_Dowty]

Hello guys, I'm new around here.. and frankly.. it's been a day or two since I've designed anything.
I'm sure this is already designed into a single IC already, however, I'm looking into furthering my understanding more than simplifying.
I've got fairly decent knowledge on components theory, and applications.. but as far as actual integration and design.. I need to learn.

Currently, I've come into possession of a number of 18650 Li-Ion batteries.
Working on some simple projects, and first on the list, is retooling the Minty Boost. Mostly for higher current output (~1.5A@5v) for newer phones/devices.
I have the charge/discharge parts worked out, but that doesn't include a low voltage cut-off.

Using parts on hand from scrapped PCB's, I've found a wonderful IC in the PVN012.
Rated clear up to 4.5A DC and a low control current of 3mA, it seems perfect.

What are some good ways to wire this up as a 3V cut-off?
I would appreciate explanations and anything I could learn from this.


I look forward to the responses, and hopefully, becoming a fairly active member of this community.
Thanks again for any help.

-John

 

[MrAl]

Hi,

It depends what accuracy you are looking for in that "3v" spec. If you can get away with approximately 3v then you can use a couple diodes and resistor in series with the internal LED to get the thing to turn on somewhere around 3v. If you need something like 1 percent accuracy then you need a reference diode and comparator IC to measure the voltage and compare, then turn the LED on or off as required. This will get you to an accuracy of about 3mv after adjustment, and maybe 0.5 percent over temperature.

BTW welcome to the forum.

 

[KeepItSimpleStupid]

Welcome.

Well, getting 5V at 1.5 Amps probably won't get you anywhere because you have to provide the proper signature to be able to use it.