Abstract: A single-stage modular modulator for pulsed illumination sources uses a full-range converter which converts unregulated DC to a 40-50 kHz carrier modulated at a frequency of a few hundred to a few thousand hertz. The modulated carrier is applied to the illumination source through a step-down transformer followed by a low-pass filter circuit which removes the carrier. The converter is controlled by a modulation control which uses an instantaneous load current signal feedback to follow a modulation commend signal, and a current mode signal representing the primary current of the transformer to compensate for converter output variations caused by input voltage variations.