Patent ID: 8493004

Claim:
A light generating device, comprising: an input for connecting to an AC voltage source; a rectifier for rectifying the AC input voltage and providing a rectified AC output voltage (Vin); a controllable current source; a switch matrix comprising a plurality of controllable switches (S 1 -SN), the matrix having a voltage input terminal coupled to an output of the rectifier for receiving the rectified AC output voltage (Vin) and having a current input terminal coupled to the current source; a plurality of n LED groups (D 1 , D 2 , . . . Dn), each group comprising a plurality of LEDs connected in series and/or in parallel, each LED group being connected to output terminals (A 1 , K 1 ; A 2 , K 2 ; A 3 , K 3 ; . . . An, Kn) of the switch matrix; a controller having an input coupled to the rectifier for receiving a signal indicating the momentary value of the rectified AC output voltage (Vin), having a first control output coupled to the switches (S 1 -SN) of the switch matrix for controlling the switch state of these switches (S 1 -SN), and having a second control output coupled to the controllable current source for controlling the current generated by the current source; wherein the controller is configured to control the switch state of the switches (S 1 -SN) and the current generated by the current source dependent on the momentary value of the rectified AC output voltage (Vin); wherein the controller is capable of operating in at least three different control states, wherein in a first one of said control states the switches (S 1 -SN) are put is a state so that all LED groups (D 1 , D 2 , . . . Dn) are mutually connected in parallel, wherein in a second one of said control states the switches (S 1 -SN) are put is a state so that all LED groups (D 1 , D 2 , . . . Dn) are mutually connected in series, and wherein in a third one of said control states the switches (S 1 -SN) are put is a state so that at least two of said LED groups (D 1 , D 2 , . . . Dn) are mutually connected in parallel while also at least two of said LED groups (D 1 , D 2 , . . . Dn) are mutually connected in series.