MOSFET drive circuit

[JasminB]

Hello everyone,

I have made a schematic (circuit) (attached as jpg) following layout on the PCB board that I found in battery charger device.
Don't know if I have done a good job and is this circuit made correctly.
It looks like a MOSFET drive circuit, but can not understand the function.
I would like to learn and understand function of this circuit.
It would be really great when someone can explain me how does this circuit works and diodes (D1, D2, D3), which type of diodes are they, MELF package, marked with a blue band, Vf = cca. 0,20V.

Thanks in advance.

 

[Bluejets]

Tr1 doesn't look right being connected directly across the AC.
Didn't look any further.