I'm designing a battery charger, and I need to discharge every cell of a LiPo battery on its own at some point using a discharge resistor ( cell balancing ) by controlling switches from a uC, one way would be using a relay or an optocoupler that would be completely isolated from the signal side, but optocouplers usually dont handle much current and i would need to add another transistor stage to handle that, same applies to a relay but in the other way, a uC cant source/sink enough current to switch the relay which again means an extra transistor stage is needed ( plus the diode )
But what about a transistor on its own ? would it work like that ?
There has to be a current path for the signal to go through which is normally done by connecting both grounds, but doing that here would short the cells since every cell would have a transistor on it controlled by the same uC ( every neg cell lead would be connected to the same uC control gnd thus shorting everything )
Can the control signal find a return path through the cells assuming the transistor can handle the volatge of the cells combined ?
not sure if this is the right title for the question.