Patent ID: 8847519

Claim:
Illumination system comprising a plurality of LEDs with associated driver, each driver comprising: a power input for receiving AC mains voltage; an AC to DC converter for receiving the AC mains voltage and outputting a DC mains voltage; a chopper for receiving the DC mains voltage and for outputting a regularly interrupted output current having a current interruption frequency and a variable duty cycle, and having an input to receive to a control signal; a lamp output, receiving the regularly interrupted output current, for connecting to a light source; a clock generator for generating a clock signal; a controller having a user input for receiving a user input signal indicating a desired dimming level, having a clock input coupled for receiving the clock signal from the clock generator, having a mains input coupled for receiving a mains signal representing the actual phase of the mains voltage at the power input, and having a control output for generating a control signal for the current source means; wherein the controller is designed to synchronize its control signal with the mains signal received at its mains input, wherein each controller and is configured to set an arbitrary value for the phase difference of its output control signal with respect to the input mains signal, wherein the chopper sets the current interruption frequency and the variable duty cycle according to the control signal received at the control signal input.