Thinking of building a 4 to 6 channel USB LiPoHV charger, need some tips.

[John_Edward]

TL;DR:

I need tips on how to build simple&inexpensive USB powered and MCU controller CC/CV source(s), and how to best measure current (high side, low side, opamp, dedicated chip ?) for a LiIo/LiPo/LiHV charger project.


I fly micro quads and have slowly amassed a bunch of different 1S lipos between 100mAh to 800mAh, and I've used a very simple "Four TP4056 modules bolted together" charger for my on the field charges. It's worked okay but the charge rate has always been a compromise (as it's preset), and now I have LiHV cells as well (3.8V / 4.35V), so I need a new charger.
As far as I know, there are no TP4056 type chips that could easily charge LiPo, LiIon and LiHV (3.6v, 3.7v & 3-8v) cells, and also need an electronics project for school, so I'm thinking of combining these two if possible.
(research, custom pcb, tests and measurements, 20 page report, all the good school project stuff)

My goals would be small footprint, USB powered, 4 to 6 channels of 1S LiPo/LiIo/LiHV charging, and around 1A max charge rate per channel (total limited by input power ofc).
I'm thinking of using an Atmega328 / Arduino as the MCU and using an ADS1115 (15-bit ADC) to guarantee the 50mV voltage accuracy often cited with Lithium charging.
Voltage measurement is easy, and for current reading, using a current shunt and amplifying the voltage with an opamp seems to be the solution, though I'm not sure what would be the best way.

I'm completely lost on the CC part though, and my CV solution is elementary at best;
I've previously used simple transistor CC circuits to drive LEDs, and I can create a Constant Voltage with selectable 4.1/42./4.35 volt output by using an LM317 toggling resistors with transistors, but I don't feel they are the solution in this.

As this is a school project with research being one of the parts and learning being the end goal, I'd prefer to get resources and hints instead of straight answers or circuits, although anything to get me started would be a great help.

So, how would I best do the CC/CV part, seeing as I would need to basically build 4 or 6 copies per charger, one for each cell, and what would be the best way to keep track of the charge current ?