Backlight unit and method for driving the same
AssigneeLG Display Co., Ltd.
InventorHoon Jang
Life of this patent
Estimating the term…
Abstract
A backlight unit according to one embodiment includes an LED array having a plurality of LEDs; a voltage generating unit for generating a driving voltage to drive the plurality of LEDs in response to a switching signal; an amplifying unit for feeding the driving voltage back and amplifying the fed driving voltage, to output an amplification signal; a stabilizer for stabilizing the amplification signal; a comparator for comparing the amplification signal with a reference waveform to apply the switching signal to the voltage generating unit; a first switching unit for switching a current of the LED array in response to a PWM dimming signal from a timing controller; and a second switching unit for switching the switching signal from the comparator in response to the PWM dimming signal.
Claims20
A backlight unit, comprising:
- an LED array having a plurality of LEDs;
- a voltage generating unit for generating a driving voltage to drive the plurality of LEDs in response to a switching signal;
- an amplifying unit for feeding the driving voltage back and amplifying the fed back driving voltage, to output an amplification signal;
- a stabilizer for stabilizing the amplification signal;
- a comparator for comparing the amplification signal with a reference waveform to apply the switching signal to the voltage generating unit;
- a first switching unit for switching a current of the LED array in response to a PWM dimming signal from a timing controller;
- and
- a second switching unit for switching the switching signal from the comparator in response to the PWM dimming signal,
- wherein the amplifying unit distributes the driving voltage according to a resistance ratio of a first resistor and a second resistor of the amplifying unit to amplify the fed back driving voltage supplied to a differential amplifier of the amplifying unit.
An apparatus comprising:
- a voltage generator that outputs a driving voltage for a backlight assembly;
- a comparator that outputs a switching signal to the voltage generator based on a comparison between an amplification signal and a reference signal;
- and
- a switch that controls the comparator and operates according to a pulse width modulation (PWM) dimming signal used for switching a current of the backlight assembly, such that the switching signal output from the comparator is synchronized with the PWM dimming signal by controlling an output start of the switching signal to match a rising edge of the PWM dimming signal.
A method for driving a backlight unit, the method comprising:
- generating a driving voltage to drive an LED array in response to a switching signal;
- distributing and feeding the driving voltage back, and amplifying the fed back driving voltage to generate an amplification signal;
- stabilizing the amplification signal;
- controlling a current of the LED array in response to a PWM dimming signal;
- comparing the amplification signal with a reference waveform to generate the switching signal;
- and
- switching the switching signal in response to the PWM dimming signal,
- wherein the distributing the driving voltage corresponds to a resistance ratio of a first resistor and a second resistor of the amplifying unit to amplify the fed back driving voltage supplied to a differential amplifier of the amplifying unit.
Dependencies are inferred from the claim text.