Patent ID: 8531136
Filing Date: 2013-09-10
Classification: H01L,H05B

Abstract:
1. A method of electrically exciting a light engine, the method comprising: processing a periodic waveform of alternating polarity to form an input excitation signal with a voltage amplitude reduced to substantially zero for a first portion of a periodic cycle of the periodic waveform; providing a network of light emitting diodes (LEDs) comprising a first group of LEDs arranged in series connection with a second group of LEDs; applying the input excitation signal to the network of LEDs; diverting current away from the second group of LEDs in response to the input excitation signal voltage being less than an effective forward voltage of the network of LEDs; and delaying conduction of current through the first or second groups of LEDs for a second portion of the periodic cycle of the periodic waveform longer than the first portion to produce a corresponding decrease in an average luminance of the first group of LEDs while maintaining a substantially constant luminance of the second group of LEDs.