Patent ID: 9554435
Date: 2017-01-24
CPC Classifications: G02B,H02J,H05B

Claim:
1. An apparatus for controlling a level of luminance produced by a color light-emitting diode (LED) array, comprising: a parallel array of LEDs consisting of at least one LED corresponding to each of three primary colors; a light flux sensor flux-coupled to the LED array to sense a magnitude of light flux output from a selected LED; a pulse width modulation (PWM) selector communicatively coupled to the LED array to select a predetermined light flux magnitude set-point signal associated with a predetermined primary color for a predetermined flux bit-slice period; a flux comparator coupled to the PWM selector and to the light flux sensor to compare the sensed magnitude of light flux output to the light flux magnitude set-point signal; and a current drive circuit communicatively coupled to the flux comparator to selectively charge an energy storage device used to supply current to the LED array when the sensed magnitude of light flux output is less than the light flux magnitude set-point, the energy storage device coupled between the current drive circuit and a common anode terminal of the LED array.