Li-ion over charge and discharge protection circuit - cut off at 2.9v - would this work?

Thread Starter

voxcon

Joined Jul 13, 2019
2
Hey guys, i couldn't find a lipo battery protection circuit which disconnects the load once the voltage drops below 2.9 volts, thus i tried to build a schematic for such a circuit myself, but i'm not sure if i made any mistakes or not.
Therefore i would be greatful if you could have a quick look at my design and point out any mistakes i have eventually made (i'm sure i've made some, i have no experience in building circuits from scratch).

Parts list:
1x FS312F-G (Battery Protection IC)
1x TC0325F1000T5E (Low TCR SMD Resistors 100Ohms)
1x 0603WAJ0102T5E (Surface Mount 1KOhms)
1x GRM033R60J104KE19D (Multilayer Ceramic Capacitor 0,1nF)
1x FS8205 (MOSFET 2 N-Channel, 20V 6A 1.2V @ 250uA 28 mΩ @ 4A,4.5V)

Ok, so the main component of the circuit is a FS312F-G battery protection IC which monitors the voltage and connects to a two channel FS8205 MOSFET. The IC is able to disconnect ground when the battery i charged above 4.25 volts, or when it is discharged below 2.9v.
The resistors protect the IC from overcurrent and allow voltage monitoring by creating a voltage drop. The capacitor provides a stable current flow to the IC.

Preliminary schematic:

I'm not quite sure if the -BAT line would work or if i would have to connect it differently.

Any help is much appreciated :)
 

Thread Starter

voxcon

Joined Jul 13, 2019
2
Okay, thanks for the help.
I've updated the schematic and the PCB, would it now work properly?

Schematic:


PCB desing:


Thanks for your help guys!
 
Top