This is a reverse engineering of the DD4012SA 5v buck regulator for replacing LM7805 TO-220 regulators.
ME3116 is the IC, https://datasheet.lcsc.com/szlcsc/Nanjing-Micro-One-Elec-ME3116_C97643.pdf
R2 = 2K for all Voltages
3.3V R1 = 6.34k
5V R1 = 10.7K
12V R1 = 28.7k
To Calculate other output voltages: Vout = Vfb(1+(R1/R2))
Vfb = 0.8v
R2 = 2000
!! for learning and the fun of it, maybe next time an op-amp?!!
(all recycled parts, LED's are new)
Part of 9 and 5 volt power supply recycling project.
Power from right after rectifier, this circuit and sensing circuit need common ground.
Sense -> Low: Red LED ON = Power ON, Status LED Blue = Standby, No power to terminals.
Sense -> High: Red LED ON = Power ON, Status LED Green = runnin...