I will not argue semantics with you Roman. But I would like to see a converter built according to your logic work. The part about 'changing input current until maximum output current is reached' might work, assuming that this cannot lead to control loop latchup. I think that what you are doing is in the right direction, especially with Spehro's comments. I was simply proposing to chop the input and output. You propose modulating the input so a synchronous detection of the output modulation allows feedback in the correct direction. That is 'less brutal' chopping I think. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.