A method of generating an output DC voltage of a gas discharge process
voltage supply unit, in which in a first voltage transformation stage a
first DC voltage is transformed into a second DC voltage of a
predetermined voltage range, and the output DC voltage is generated from
the second DC voltage in a second voltage transformation stage. A
switching element of at least one boost converter is switched with a
controlled pulse-duty factor for generating the output DC voltage in the
second voltage transformation stage. This method permits striking and
maintenance of a plasma process.