I want to build my own 18650 charger without using any specialised IC at start I'm looking fo solutions to two problems:
How to build PWM regulated currency source with regulation at least from 250mA to 3A
How to build 4.20 - 4.25 voltage limiter
The first one is for CC (constant current) charging phase and the second is for CV (constant voltage) charging phase
Can any one help me with this two problems?