A switch state is defined as three of six IGBT switches 250, 252, 254, 256, 258, and 260 closed at any given time with the conditions that three switches may never be connected to the same rail (V+ and PGNDS in FIG. 9) and switches diametrically opposed to each other, e.g. 250 and 252; 254 and 256; and 258 and 260, can not be closed at the same time.