Patent ID: 7891853
Filing Date: 2011-02-22
Classification: H05B,Y02B

Abstract:
1. An apparatus for controlling an operation of an LED in a light unit, comprising: a micro computer configured to sequentially output signals through each channel of a plurality of channels, the plurality of channels including a plurality of red channels, a plurality of green channels and a plurality of blue channels; a plurality of light emitting diode (LED) drivers configured to output pulse width modulation (PWM) dimming pulses for each channel of the plurality of channels; a plurality of switching elements configured to sequentially output, for each channel of the plurality of channels, driving currents according to the PWM dimming pulses; a plurality of light subunits configured to be sequentially driven by the driving currents, each light subunit corresponding to one of the plurality of channels, wherein the plurality of light subunits are arranged in parallel, wherein each light subunit comprises a red series of serially connected red LED chips, a green series of serially connected green LED chips and a blue series of serially connected blue LED chips, and wherein, based on the sequentially output signals, turn-on times of each red series are sequentially delayed by a first predetermined interval, turn-on times of each green series are sequentially delayed by a second predetermined interval, and turn-on times of each blue series are sequentially delayed by a third predetermined interval, thereby reducing the generation of wave noise during an operation of the red LED chips, the green LED chips and the blue LED chips.