DRIVE DEVICE OF COLOR LED BACKLIGHT

Abstract

Disclosed herein is a drive device of a color light emitting diode (LED) backlight, which is capable of precisely adjusting the forward voltages of color LED arrays for each channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram showing the configuration of a conventional drive device of a white LED backlight;

FIG. 2 is a block diagram showing the configuration of a drive device of a color LED backlight according to the present invention;

FIG. 3 is a circuit diagram showing the configuration of a voltage regulator shown in FIG. 2.

FIG. 4 is a block diagram showing the configuration of a first embodiment of a multi-channel driving unit shown in FIG. 2;

FIG. 5 is a block diagram showing the configuration of a second embodiment of the multi-channel driving unit shown in FIG. 2;

FIG. 6 is a circuit diagram showing a current source shown in FIG. 2;

FIG. 7 is a block diagram showing the configuration of a preferred embodiment of the drive device of the color LED backlight according to the present invention; and

FIG. 8 is a waveform diagram showing voltages of the drive device of the color LED backlight shown in FIG. 7.

Claims

1. A drive device for driving a color light emitting diode (LED) backlight which includes a plurality of color LED arrays, comprising: an I/O interface for inputting/outputting a signal;a control unit for controlling a driving voltage and driving current according to a brightness control signal output from the I/O interface;a DC/DC converter for converting an operation voltage into the driving voltage according to the driving voltage control of the control unit;a voltage regulator for regulating the driving voltage output from the DC/DC converter to a reference voltage without ripple;a multi-channel driving unit for converting the reference voltage output from the voltage regulator into forward voltages of the plurality of color LED arrays according to a plurality of control signals; anda current source for adjusting the amount of the driving current flowing in the color LED backlight according to the driving current control of the control unit.

2. The device according to claim 1, wherein the voltage regulator comprises: an operational amplifier for non-inversion-amplifying a color voltage; anda transistor for converting the driving voltage output from the DC/DC converter into the reference voltage according to the level of an output voltage of the operational amplifier.

3. The device according to claim 1, wherein: the plurality of control signals includes first, second and third control signals,the plurality of color LED arrays includes first, second and third color LED arrays, andthe multi-channel driving unit comprises:a first channel driving portion for converting the reference voltage output from the voltage regulator into a first forward voltage of the first color LED array according to the first control signal;a second channel driving portion for converting the reference voltage output from the voltage regulator into a second forward voltage of the second color LED array according to the second control signal; anda third channel driving portion for converting the reference voltage output from the voltage regulator into a third forward voltage of the third color LED array according to the third control signal.

4. The device according to claim 3, wherein: the first channel driving portion is implemented by a red channel driving portion,the second channel driving portion is implemented by a green channel driving portion, andthe third channel driving portion is implemented by a blue channel driving portion.

5. The device according to claim 4, wherein each of the first, second and third channel driving portions comprises: a filter for filtering a corresponding one of the first, second and third control signals within a predetermined band;an amplifier for amplifying the control signal output from the filter with a predetermined gain; anda driver for converting the reference voltage output from the voltage regulator into the forward voltage according to the control signal output from the amplifier.

6. The device according to claim 4, wherein: the first, second and third control signals are digital signals, andeach of the first, second and third channel driving units comprises:a digital/analog converter (DAC) for converting a corresponding one of the digital signals into an analog control signal; anda driver for converting the reference voltage output from the voltage regulator into the forward voltage according to the control signal output from the DAC.

7. The device according to claim 6, wherein each of the first, second and third channel driving portions 150-1, 150-2 and 150-3 further comprises: a filter for filtering the control signal output from the DAC within a predetermined band; andan amplifier for amplifying the control signal output from the filter with a predetermined gain and supplying the amplified control signal to the driver.

8. A drive device for driving a color LED backlight which includes first, second and third color LED arrays, comprising: an I/O interface for inputting/outputting a signal;a control unit for controlling a driving voltage and driving current according to a brightness control signal output from the I/O interface;a DC/DC converter for converting an operation voltage into the driving voltage according to the driving voltage control of the control unit;a voltage regulator for regulating the driving voltage output from the DC/DC converter to a reference voltage without ripple;a multi-channel driving unit which includes first, second and third channel driving portions for converting the reference voltage output from the voltage regulator into forward voltages of the first, second and third color LED arrays, according to first, second and third control signals; anda current source for adjusting the amount of the driving current flowing in the color LED backlight according to the driving current control of the control unit.

9. The device according to claim 8, wherein: the first channel driving portion is implemented by a red channel driving portion,the second channel driving portion is implemented by a green channel driving portion, andthe third channel driving portion is implemented by a blue channel driving portion.