Patent ID: 8436549

Claim:
An apparatus for driving a color temperature tunable light source, the apparatus comprising: a first group of LED chips mounted on a substrate, the first group comprising at least one LED chip configured to emit blue light encapsulated by a first phosphor; a second group of LED chips mounted on the substrate, the second group comprising LED chips, at least one of the LED chips being configured to emit blue light encapsulated by a second phosphor; wherein the first group of LED chips is mounted in a region that is located within the second group of LED chips; a current driver configured to output a first drive current to drive the first group of LED chips of the light source to emit first color temperature light and to output a second drive current to drive the second group of LED chips of the light source to emit second color temperature light; and a controller coupled to the current driver and configured to control the first and second drive currents so that the first color temperature light and the second color temperature light combine to produce a resulting light having a selected color temperature and a selected intensity value.