Provided are a high voltage generating apparatus controlled by a digital control code and a method thereof. The high voltage generating apparatus includes a switching unit for controlling a voltage induced at the secondary coil of a power transformer by an interrupt operation, wherein the interrupt operation interrupts the current flowing through the primary coil of the connected power transformer. A digital controller for controlling the interrupt operation of the switching unit according to the control data. A digital interface for providing the control data to the digital controller is provided. The control data is extracted from the control code transferred using one of a plurality of predetermined communication protocols. The switching unit, digital interface, and digital controller can be implemented in one ASIC (application-specific integrated circuit) chip.