a combined charge / recharge xerographic power supply is provided that utilizes one power supply to drive the charge pin scorotron and recharge discorotron grids of a electrophotographic or xerographic system . the power supply uses recycled power from the pin scorotron grid to drive the discorotron grid . in particular , the power supply uses power that is dissipated in the traditional shunt regulator attached to the pin scorotron grid terminal to drive and provide active current to the discorotron grid through a series - pass regulation circuit . thereby providing reduced electromagnetic emissions and reduced unit manufacturing costs .