Patent ID: 8072163

Claim:
A driver apparatus for powering a solid-state light source, the driver apparatus comprising: a constant current power source with an input to receive input electrical power and an output coupleable to a solid-state light source, the output operative to provide electrical output current to drive the at least one solid-state light source; a memory storing a lumens per amp performance characterization of the solid-state light source over time as well as a volts per amp performance characterization of the solid-state light source over time; and a controller operatively coupled with the memory and with the power source to receive at least one feedback value from the power source and to provide a current setpoint signal or value to the power source; the controller being operative in a normal mode to provide an operating current setpoint value or signal to cause the power source to drive the solid-state light source at a corresponding output current level; and the controller being operative in a test mode: to provide a test mode current setpoint value or signal to cause the power source to drive the solid-state light source at a corresponding predetermined test current level, to receive a voltage feedback value from the power source while the power source is driving the solid-state light source at the test current level, to determine an estimated degradation of the light source based at least partially on the voltage feedback value using the volts per amp performance characterization, and to update the current setpoint value or signal based on the estimated degradation using the lumens per amp performance characterization.