In one general aspect, a power semiconductor device can include a semiconductor substrate of a first conductivity type, and a semiconductor layer of a second conductivity type disposed on the semiconductor substrate. The semiconductor layer can include a high voltage unit, a low voltage unit disposed around the high voltage unit, and a level shift unit disposed between the high voltage unit and the low voltage unit. The power semiconductor device can include a first isolation region of the first conductivity type disposed between the high voltage unit and the level shift unit, and a second isolation region of the first conductivity type disposed between the low voltage unit and the level shift unit where the first isolation region and the second isolation region each are vertically aligned in the semiconductor layer and each extends to at least the semiconductor substrate.