A light emitting diode (LED) lighting system includes a controller to control current in one or
more LEDs in response to a dimming level input. The LED lighting system implements a …

(57) ABSTRACT A light emitting diode (LED) lighting system includes a PFC and output
Voltage controller and a LED lighting power sys tem. The controller advantageously …

A light emitting diode (LED) lighting system and method are disclosed. The LED lighting
system and method include an LED controller to accurately control a current in an LED …

A lighting system includes time division light output sensing and adjustment for ambient
light. In at least one embodiment, time division light output sensing involves modulating …

In at least one embodiment, a controller allows triac-based dimmer to properly function and
dim a load whose voltage is regulated by a switching power converter. In at least one …

4,334,250 4.409, 476 4.414, 493 4476, 706 4,523,128 4,677,366 4,683,529 4,700,188
4,737,658 4,797,633 4,937,728 4,940,929 4,973,919 4,979,087 4,980,898 4,992.919 …

Adrive With a high impedance input, loW impedance output is created. When a switching or
driving action requiring the sourcing and sinking of current from a common node in a Wide …

In at least one embodiment, brightness multiple LEDs is adjusted by modifying power to
subgroups of the multiple LEDs during different times and detecting the brightness of the …

438 436 voltage indicates a particular dimming level. The drive cur rent varies for different
dimming levels. However, the light source ballast controls drive current so that the drive …

US PATENT DOCUMENTS 6,781,351 B2 8, 2004 Mednik et al. 6,788,011 B2 9, 2004
Mueller et al. 4,075,701 A 2f1978 Hofmann 6,806,659 B1 10/2004 Mueller et al. 4,334,250 A …