Patent ID: 11805585

Abstract:
A Light Emitting Diode, LED, based lighting device arranged for emitting a particular color of light, wherein said LED based lighting device comprises a power supply unit arranged for providing a Direct Current, DC, bus voltage for powering LEDs, a plurality of parallel cascaded LED channels, wherein each of said LED channels is connected to said bus voltage and comprises at least one colored LED and a switch for activating said corresponding LED channel, a controller arranged for providing control signals to each of said switches in said LED channels for periodically activating said LED channels, wherein each of said control signals has a duty cycle, and wherein said controller is arranged for determining said duty cycles of said control signals based on a received color set point, wherein said controller is further arranged for determining an amount of deficiency in light output of each of said LED channels caused by parasitic effects in said LED based lighting device, by determining instantaneous currents of each channel and comparing said instantaneous currents with expected currents resulting from the determined duty cycles, and for increasing said duty cycles based on said determined amount of deficiency.