The 5V power supply uses the LM2995 converter circuit

It is often necessary to supply low voltage 220V for power consumption. You could use an external adapter - but it's bad and reduces the size of the device and requires a power source located within the device.
This 5V power supply uses the LM2995 converter circuit and can be directly connected to 220V. To do this, AC is converted into DC voltage through diode bridge VD1 and then reduced to 40V. Above 40 V, we should not use it, since the maximum input voltage of LM2995 cannot exceed 45V.
Transistors T1 and T2 form a pulsating pressure amplitude dependent on Zener diode D1 of up to 40V. This pulsating voltage is smoothed by capacitor C1, which is slightly smoothed. The second is the on-chip downconverter output voltage stability, define the application chip: LM 2575-5 5V, which will be equal. Standard chip bundle of Schottky diodes D2, L1, C2 and C3.