traditional dcdc converter is to use a inductor to make a higher voltage . now i wonder how to design a booster with multioutput.For example ,the input is 1.5v, the output is 1.8v and 3.3v,but there is only a single inductor. it is a DCDC converter, not a AC/AC signal converter.. Sigmatel and phillips have some patents of the technique. i hope some experienced one can help me. u can refer to ST4141 spec for details.
Another idea is to attach a capacitive doubler circuit to the switching node of a boost converter -- this can get you one or two additional output voltages (but only at +/- 2x, +/- 4x, etc... of the main regulated output voltage. See these Maxim App notes for schematics and a better explanation:
they use a synchronous boost converter - ie, the schottky diode is replaced by a pmos switch. on the first cycle, you boost to the first rail, on the second cycle you boost to the second rail.
it's just interleaved boosting. but for your low voltage rails I think charge pump might be the right idea - 200-300mA is not so much for a charge pump actually.