> There is a very good application note about this switcher IC on > httt://onsemi.com. Look for AN920-D.PDF. I think that that's the one the basic circuit that Jinx started with came out of. It's a fairly obvious application of the IC of course - although they never seem to have conceived of it being used to drive a FET. In some ways the FET is better to drive as the horrible Darlington drive output which suffers from saturation problems or very high voltage drop when on when driving bipolars, is much happier with FETs due to their higher threshold voltage. (Silicon bipolars have a 0.6v threshold :-) ). RM _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist