Commercial large-area solar simulators are principally in the form of Xenon flashers, which intrinsically have a short flash duration time, typically 100 ms at low spectrum quality and 10 ms at high spectrum quality. This implies measurement time constraints not adapted to the characterization of new generations of photovoltaic modules such as high-efficiency crystalline silicon modules, which can exhibit transient effects leading to measurement artifacts [1]. Moreover, thin film technologies require a high spectral match and possibly a variable spectrum of the illumination source for the accurate power-rating of multi-junctions based solar modules. An alternative large-area solar simulator solution is proposed for the power rating and the diagnostic of such generations of solar modules. The developed simulator makes use of a combination of different power LEDs and halogen lamps in a particular matrix configuration, integrated into a 1 m × 1 m table with mirrors. The constructed prototype demonstrates an AAA classification according to the IEC norms [2], allows for long illumination (200 ms to continuous) and permits controlled variation of the spectrum and of the intensity of the illumination.