Patent ID: 8587205

Claim:
Lighting device, comprising: an LED driver capable of generating dimmed LED current; a two-terminal LED module, having two input terminals for receiving an input current (Iin) from the LED driver and comprising: a first LED group comprising at least one first type LED for producing light having a first color temperature; a second LED group comprising at least one second type LED for producing light having a second color temperature different from the first color temperature; wherein the LED module is capable of supplying LED currents to the LED groups, these LED currents being derived from the input current (Iin); wherein the LED module produces a light output having at least a light output contributions from the first LED group and from the second LED group; wherein the module is designed to vary the individual LED currents in the individual LED groups in dependency of the average magnitude of the received input current (Iin), such that the color point of the light output of the module varies as a function of the input current magnitude; each of the LED modules including an electronic division circuit capable of controlling a ratio of the LED currents in the first and second LED groups as a function of the input current level retrieved at the input of the LED module; wherein the electronic division circuit comprises a controllable switch for temporally dividing the received input current (Iin) between the two groups of LEDs; a control device for controlling the switch at a switching period T such that the input current is passed on to the first group of LEDs for a first time duration t1 and the input current is passed on to the second group of LEDs for a second time duration t2, with t1+t2=T; a current sensing element arranged for sensing the input current received at the input terminals of the module; the control device being coupled to receive a sense output signal from the sensing element and being designed to vary the ratio t1/t2 of the switching of the switch on the basis of said sense output signal, such that there is at least a range of input current magnitudes where dt1(Iin) is always positive and dt2(Iin) is always negative.