A ground power unit having a power supply unit capable of accepting a wide range of AC input voltages and producing one or more DC power signals for powering components of the GPU is disclosed. In one embodiment, the power supply unit includes a rectifier that converts an AC input power to a DC link power. The power supply unit includes a gate driving circuit that has a power MOSFET transistor which, under the control of a PWM controller, produces a switched DC signal. The DC link power and the output of the gate drive circuitry are provided to a transformer, which modulates the signals and produces a first DC output power signal that is load independent and a second DC output power signal that is load dependent.