Patent ID: 7852312

Claim:
A system for controlling a driving lamp of a backlight unit comprising: a liquid crystal display panel; a lamp for emitting light to the liquid crystal display panel; a timing controller for generating a lamp control signal to control a light-on time of the lamp; and an inverter for controlling a light-on and a light-off of the lamp according to the lamp control signal while limiting current and maintaining a constant wattage of the power supplied to the lamp regardless of the light-on time for the lamp, wherein the inverter is provided with a comparing unit for supplying a signal to a lamp controller when the current of the lamp exceeds an established value, and wherein the inverter includes: an oscillator for generating an alternating current, wherein the oscillator includes: a plurality of first switching devices that conduct or block in accordance with a first control signal; a plurality of second switching devices that conduct or block in accordance with a second control signal; and a sensing resistance for detecting power of the oscillator, wherein the first and second pluralities of switching devices are alternately conducting or blocking in accordance with the first and second control signals; a lamp controller for controlling the generation of the alternating current in the oscillator during an established time in accordance with the lamp control signal of the timing controller, and adjusting power applied to the oscillator in accordance with a reference power level, wherein the lamp controller alternately outputs a first control signal and a second control signal to control the generation of current in the oscillator, and wherein the lamp controller compares the detected power with a reference power, and establish a reference voltage according to a difference therebetween so that the lamp controller increases the reference voltage when the power of the oscillator is lower than the reference power, and wherein the lamp is turned on while the first and second control signals are supplied from the lamp controller to the oscillator in each frame, and wherein the lamp controller adjusts a conducting time of the first and second switching devices of the oscillator by the first and second control signals, to adjust an amplitude of the current generated by the oscillator from the reference voltage; and a transformer for converting the alternating current generated from the oscillator to a high voltage that is supplied to the lamp.