I need to develop a circuit to charge a single cell 3.7 lithium 2600mAh battery.
Due to EMI needings, I'd like to not use buck or something else so, I've thought to a circuit like te one attached.
Diode D could be (for example) LM431.
R1 and R2 could be calculated in order to have 4.2V (4.2V=battery's charging voltage)...
Box at the center of circuit it's obviously a uP: maybe a tiny or atmega88 if I choose to implement some other features...
uP's tasks are:
- activate/deactivate OA (charge ON/OFF)
- read current (while charge ON)
- read battery's voltage (while charge ON)
- read battery's temperature (charge ON)
- Could someone suggest me a cheap high current opamp with 'enable' command (farnell, rs-components, distrelec...) ?
- What do you think about this solution?
- Do you have cheap alternatives or suggestions?
I could also evaluate to not use a uP!
Best regards, thanks for your help!