Comment by kragen
3 hours ago
Op-amps are absolutely, 100% analog in every sense; there's no need to limit this assertion with the nonstandard adverb "technically". The term "analog" was invented in the first place specifically to describe circuits made out of op-amps rather than "digital" circuits. And, yes, you can totally balance the charge on your cells using op-amps and similar analog circuits. You will probably want some sharp PWM waveforms in the circuit, but PWM isn't all the way to digital.
I would question whether a PWM "technically" counts as digital... It is on and off, sure, but so is a mechanical power switch, which few would describe as digital. "Digital" is more when we get higher level values represented by multiple signals that are on or off (aka bits).