The system described herein relates to a high-voltage supply unit for providing an output voltage for a particle beam apparatus, wherein the particle beam apparatus is embodied as, for example, an electron beam apparatus and/or an ion beam apparatus. The system described herein is based on the fact that it was recognized that a bipolar voltage supply unit can be formed by means of a unipolar first current source and a unipolar second current source, said bipolar voltage supply unit enabling a load current in two directions. The high-voltage supply unit according to the system described herein can be operated in the 4-quadrant operation. In the 4-quadrant operation, a first voltage source for supplying the first current source and a second voltage source for supplying the second current source are embodied as different voltage sources.