Patent ID: 8896227
Filing Date: 2014-11-25
Classification: H05B,Y02B

Abstract:
1. A system to drive light emitting diodes (LEDs) comprising: a string of LEDs coupled across a voltage source configured to provide an input voltage, the string of LEDs comprising a plurality of separate groups of LEDs; a plurality of switch circuits, each of the switch circuits comprising a switch coupled in parallel with an associated one of the groups of LEDs to control current flow through the associated group of LEDs in response to a control signal from a controller circuit; a switch protection circuit associated with at least one of the switches, the switch protection circuit configured to place the at least one of the switches into a conducting state in the event of failure of an LED in the associated group of LEDs, wherein the failure places the LED into an open state; and a controller protection circuit associated with the at least one of the switches, the controller protection circuit configured to isolate the controller circuit from a voltage applied across the at least one of the switches and comprises a diode.