Fly back converter

[Behzadd]

Hi
Im working on an brima 160 welding inverter.it has a flyback converter for supplying 24 v and 12v for control and mosfet drive boards.
What that i cant undrestand is the method of controlling the switch of this odd type of flyback control circuitary as shown bellow.
Do this analog method has a name?
Thank you for paying attention

 

[(*steve*)]

This is a switch mode power supply. The mosfet turns on and off rapidly, controlled by the optocoupler and the transistor to maintain the output voltage (24V) between fairly tight limits.

An additional three terminal regulator provides an auxillary 12V output that is probably only capable of fairly low current.

 

[Behzadd]

Dear steve
This is you kind
But let me to ask some more questions:
I know the other ones which work with an pwm controller ics.
I hasent encountered before with this one using fully analog constituents for mosfet switching.
Please tell me, if this kind of controlling circuitary of the power mosfet has defined topology name.