Tiny Li-Ion Charger with no Chip. Schematic & how does it work.

I'm testing a tiny 18650 Li-Ion / Li-Pol cell charger and then taking it to bits, including an autopsy of the transformer. It contains a 2-transistor switching power supply with no optocoupler and a Li-Ion charging circuitry with no dedicated charging chip. There are just two transistors and a TL431 voltage reference. I reverse engineer the schematic and explain how does the switching power supply and the charging circuitry work. You can support me on Patreon: https://www.patreon.com/DiodeGoneWild

• #science_technology
• #li_ion
• #charger
• #schematic
• #teardown