The UV power, emitted by a XeCl Dielectric Barrier Discharge exciplex lamp, is shown, on the basis of causality analysis, to be controllable by the current supplied to the lamp. Experimentally, the UV radiation is demonstrated to be proportional to the current injected into the gas. A current-mode converter operating in discontinuous current mode controls in a direct form the amplitude and duration of the pulsed UV power radiated by the lamp.