How doeas this DC-DC converter circuit works?

[velnsvinjzin]

dc dc converter circuit

Hello everyone.

I've recently started studying electronics, and now I'm trying to build this DC-DC converter circuit.
Everything seems to be working fine, but I am very keen on knowing, how really does this converter works. If the 12 to 5V is more or less understandable, then the 12V to 170V is kind of a black picture for me, so, that is why I would like to ask, could someone explain me how really it works - what function all of the elements are doing there.

Giant thanks in advance and sorry for my Borat-like English

 

[banjo]

dc-dc converter circuit

This portion of the circuit is a boost converter. It uses the principle of inductive kick to step up the voltage. The current through an inductor cannot change instaneously. If you attempt to make an quick change to the inductor current, the collapsing magnetic field will generate a high voltage that attempts to keep the current going.
Take a look at:

https://en.wikipedia.org/wiki/Boost_converter

For more info on this specific circuit, read the datasheet for the IC. It uses pulse width modulation to achieve the regulation of the output voltage. Don't study this circuit too hard. That controller chip is an old one. In addition, there are hundreds of other chips with similar features.