With the aim of providing a power supply for the study of dielectric barrier discharge (DBD) excimer lamps (excilamps), a current-mode converter that allows for an accurate adjustment of the electrical power injected into one of those lamps is designed and implemented. Starting from the electrical model of the DBD lamps, the convenience of using a current-mode supply to control the lamp power is demonstrated. With the proposed converter, the current supplied to the lamp has a trapezoidal almost-square shape controlled by means of three parameters, namely, amplitude, duty cycle, and frequency, which provides full control of the lamp electrical power. Implementation is made considering a step-up transformer interfacing the high-voltage lamp with the converter. Experiments demonstrate the operating principle of this converter, including ultraviolet power measurements for a DBD XeCl excilamp. The capabilities of the converter are used to analyze the lamp behavior under different combinations of these three parameters, illustrating its capabilities for finding the optimal operating point of a DBD reactor.