Systems and methods presented herein generally provide for the controlled voltage of bipolar electrical energy through the selected operation of power stages. In one embodiment, a system that provides electrical energy includes a power supply and at least two power stages coupled to the power supply. The power stages are operable to selectively output electrical energy. By selecting the number of power stages which are turned on at a given time the total voltage of the electrical energy is controlled at that time. The system may further include one or more controllers coupled to the power stages to control selection of the power stages and thereby vary the output voltage.