Patent ID: 8415894

Claim:
A drive arrangement for light sources including a power supply, said power supply comprising: a two-wire connection line configured to feed at least one of an at least one first and second light source, wherein the first wire of said two-wire connection line is configured to be connected to a fixed, constant voltage level, and wherein the second wire of said two-wire connection line is configured to be coupled to at least one switch element adapted to selectively connect said second of said two-wire connection line to ground to apply on/off signals to said two-wire connection line, and a controller configured to control operation of said switch element, said controller being sensitive to a dimming signal representative of a desired dimming level for at least one of said at least one first and second light sources and an information-carrying digital signal, wherein said power supply further comprises: a return line connected to ground, and wherein said power supply is configured to power: said at least one first light source having associated a current regulator and being connected to said power supply via said two-wire connection line, and said at least one second light source having associated a serial bus receiver configured to act as a controlled current regulator powered with a constant powering signal applied between said one of said two-wire connection line and said additional return line connected to ground, wherein said serial bus receiver is sensitive to the signal on said two-wire connection line and arranged to understand said on/off signals as a digital signal transmitted over said two-wire connection line, and wherein said controller is configured to control operation of said switch to: PWM modulate an on/off signal applied to said connection line as a function of said dimming signal by selectively varying the duty cycle of the PWM modulated signal sent as a high current flow over said two-wire connection line towards said at least one first and second light source, whereby the average current conveyed towards said at least one first and second light source and determined by said PWM modulated on/off signal controls the brightness of said at least one first and second light source having associated a current regulator and being connected to said power supply via said two-wire connection line, transmit said information-carrying digital signal as an on/off information signal applied to said connection line, whereby the information carried by said informationcarrying digital signal is transmitted over said two-wire connection line, whereby said digital signal conveys to said serial bus receiver the dimming information identifying the level of dimming to be applied to said at least one first and second light source associated with the respective serial bus driver.