A power supply for X-ray generators which includes at least one inverter (11, 12, 13), at least one transformer (111, 121, 131) and at least one voltage cascade (112, 122, 132) for generating a supply voltage for an X-ray tube (15). In order to increase the output power that can be achieved with a comparatively small weight and a low ripple or output capacitance, the voltage cascade is conceived in respect of its capacitances and the stray inductance of the transformers (111, 121, 131) in such a manner that it can be made to operate in the resonance mode by appropriate control of the inverter. In respect of the properties mentioned it is notably advantageous to integrate a two-phase embodiment or three-phase embodiment with an X-ray system so as to form a compact tank generator.