In this paper, the performance of a self-powered unipolar gate driver supply circuit for power devices is studied, with the aim of analyzing the viability of using such circuits in high voltage applications with discrete components. A simplified model of the circuit, capturing the essential features, is proposed, from which practical design guidelines are provided to optimize the overall circuit performance. These design guidelines allow a proper component selection that can result in significant improvements in the circuit performance. Experimental results of typical parameters characterizing the turn-on and turn-off transients, including the turn-on and turnoff energy loss, are provided for a wide range of current values and different gate resistances. The results are compared to those obtained using a conventional gate driver power supply.