A high voltage semiconductor device, particularly a device including a number of high breakdown voltage transistors having a common drain, first well, and insulating structure between the gate and the drain as well as method for using the same is provided in this disclosure. The high breakdown voltage transistors in the device together are in an elliptical shape. A second well region, gate structure, and a source region are partially overlapping discontinuous elliptical rings having at least two discontinuities or openings in a top view. The respective discontinuities or openings define each of the high breakdown voltage transistors.