Cell balancing circuit

[Rokas]

Hello all,

I would like to ask about cell balancing circuit.

This is the very simple balancing circuit for a first cell:



I can't test this circuit till I make a PCB.

Li-ion battery cells' voltage is 4.2. I'm using a microcontroller (3.3V) to drive this FET. FET is logic level.

So, while balancing only one cell it will be capable to charge the gate and VGS will be 3.3V, but how about if I will have more than one cell to balance. So please make it clear: lets say for the second cell VGS will be 3.3 - 4.2 = -0.9V and it won't open? Am I right?

(If I am right I will use NPN to drive it)

 

[amu_cpln]

Your explanation and circuit are not very clear
What do you mean by Balancing single cell
Cell Balancing itself is Balancing multiple cells in a Battery
Did you mean managing multiple batteries ?
And what did the subtraction in voltages mean ???
what is NPN for ?

You need to post complete circuit with more details ( ofcourse, if you know what you want to achieve)