Patent ID: 8461764

Claim:
A light emitting diode (LED) driver arrangement comprising: a control circuit; a power source; a plurality of LED strings, a first end of each of the plurality of LED strings coupled to a common output of said power source; a plurality of controllable current sources, each responsive to said control circuit; a plurality of electronically controlled switches, a control terminal of each of said plurality of electronically controlled switches coupled to a respective output of said control circuit; and a plurality of isolating unidirectional electronic valves, each of said plurality of controllable current sources, said plurality of electronically controlled switches and said plurality of isolating unidirectional electronic valves mutually associated with a respective one of said plurality of LED strings, a first terminal of each of said plurality of electronically controlled switches coupled to a second end of the respective associated LED string, a first end of each of said plurality of isolating unidirectional electronic valves coupled to the respective associated controllable current source and a second end of each of said plurality of isolating unidirectional electronic valves coupled to said first terminal of said respective associated electronically controlled switch, each of said plurality of isolating unidirectional electronic valves arranged to conduct only when the electric potential at said second end is lower than the electric potential at said first end, said control circuit arranged to alternately open and close each of said plurality of electronically controlled switches, each of said respective associated LED strings thereby producing illumination when the associated electronically controlled switch is at least partially closed, and said control circuit further arranged to operate the respective controllable current source only when said respective associated electronically controlled switch is at least partially closed.