A Novel Color Control Method for Multi-Color LED Systems to Achieve High Color Rendering Indexes

A novel color control method for multi-color LED systems is proposed. The proposed color control method can achieve high color rendering indexes by approximating the spectral power distributions (SPDs) of black bodies. Peaks of the LED channels are read from outputs of color sensors and the peak ratios are controlled to map with that of lights emitted by black bodies. Compared with previous control methods, the proposed method has the merits of 1) not requiring an accurate electrical-optical system model, 2) requiring only a few spectra data for offline calibration, 3) requiring only RGB color sensors for online operations of tetra-color and penta-color LED systems, 4) providing consistent color with high color rendering index, and 5) being applicable to all multi-color LED systems. The proposed control method is evaluated by applying it to a red-green-blue-amber (RGBA) LED system driven by a buck-type single-inductor-multiple-output (SIMO) LED driver with the LED channels connected in series. Experimental results have verified the effectiveness of the proposed color control method.